Nuclear waste generated by nuclear power reactors is extremely dangerous to health and the environment for thousands of years.
Ratepayers and taxpayers fund billions of dollars to store this highly radioactive nuclear waste.
The NRC evaluated storing spent fuel over three timeframes: 120 years (short-term), 220 years (long-term) and indefinitely.
“Because the timing of repository availability is uncertain, the GEIS analyzes potential environmental impacts over three possible timeframes: a short-term timeframe, which includes 60 years of continued storage after the end of a reactor’s licensed life [of 60 years] for operation; an additional 100-year timeframe (60 years plus 100 years) to address the potential for delay in repository availability; and a third, indefinite timeframe to address the possibility that a repository never becomes available. All potential impacts in each resource area are analyzed for each continued storage timeframe.” Generic Environmental Impact Statement for Continued Storage of Spent Nuclear Fuel Final Report, NUREG-2157, Volume 1, September 2014, page iii and xxx (ML14196A105). Also, significant public comments were received that challenges many of the NRC regarding ability to safely store the waste even short-term. Generic Environmental Impact Statement for Continued Storage of Spent Nuclear Fuel Final Report, NUREG-2157, Volume 2, September 2014 (ML14196A107.pdf)
San Onofre storage canisters may start leaking radiation into the environment as early as 2020, possibly sooner.
The NRC reported a similar container at the Koeberg nuclear plant in South Africa failed after 17 years from chloride induced stress corrosion cracking (CISCC), triggered by corrosive salt in the marine environment.
Koeberg is located in a similar corrosive marine environment as San Onofre: on-shore winds, surf and frequent fog. The Koeberg container crack depth was 0.61″. The San Onofre canisters are 0.625″ thick. The canisters at other California locations are even thinner (0.50″). There are over 2000 loaded canisters in the U.S. Most are 1/2″ (0.50″).
San Onofre started loading canisters with spent fuel in 2003. If San Onofre canisters have experience similar to Koeberg, that means a canister at San Onofre would start releasing radiation into the environment as early as 2020.
NRC documents provide data that indicate thin storage containers can fail 16 years after a crack initiates
The NRC claims fuel must be reloaded into new canisters every 100 years, unless there is a permanent repository. However, they have no technical basis to state these canisters will last 100 years, but they do have data that indicates a much sooner potential failure rate.
None of the current U.S. thin steel storage canisters are adequately designed for over 20 year storage and may start failing in as little as 17 to 20 years with through-wall cracks. Vendor claims of longer storage times are not supported by data. There is no aging management designed into these thin canisters. They cannot even be inspected for cracks or repaired. The NRC lowers safety standards so the utilities can continue using them rather than requiring more robust designs.
Numerous factors can trigger stress corrosion cracks in these thin canisters. Salt moist air is one that the NRC has studied more extensively than the others.
Documents supporting the above facts and more details are provided on this webpage.
Challenges to implementing a permanent repository, such as Yucca Mountain are significant and the NRC recognizes this.
- Press Release: August 26, 2014, NRC Approves Final Rule on Spent Fuel Storage and Ends Suspension of Final Licensing Actions for Nuclear Plants and Renewals
- NRC decision for indefinite on-site continued storage of nuclear waste website
- The only current geological repository for some types of nuclear waste, the Waste Isolation Pilot Plant (WIPP) near Carlsbad, New Mexico, is shut down indefinitely due an exploding waste storage canister that contaminated the facility. Residents were promised it would be safe for at least 10,000 years, but it leaked radiation into the environment in less than 15 years due to a failed steel storage container.
- The cause of the New Mexico nuclear waste accident remains a mystery. However, blaming it on “kitty litter” organic material is questionable. Claims they required only inorganic material be used conflicts with this 1988 study that states sawdust (organic) material was typically used at Los Alamos National Laboratories. See SAND87-7170 Rates of CO2 Production From the Microbial Degradation of Transuranic Wastes Under Simulated Geologic Isolation Conditions, January 1988, page 4: Three types of organic-matrix wastes were investigated for this study: organic composite, sawdust (representative of plywood boxes), and asphalt (also referred to as bitumen, a potential waste encapsulant, widely used for low-level wastes, particularly in Europe). The composition of the organic composite waste material is given in Table 1. This material is typical of transuranic-contaminated (primarily plutonium-contaminated) organic wastes generated at the Los Alamos National Laboratories.
- WIPP waste is stored in thin-wall steel drums that cannot adequately be inspected or maintained and is not designed for long term integrity. See WIPP-016, Rev. 0, Nuclear Criticality Safety Evaluation for Contact-Handled Transuranic Waste at the Waste Isolation Pilot Plant, May 2008, Page 11: Modeled 55-gallon drum wall thickness 0.0478” (0.12141 cm).
- The Hanford nuclear waste storage site in Washington has continuous problems with leaking steel containers and the waste has infiltrated groundwater near the Columbia River. Numerous attempts to improve the situation have failed.
- GAO-15-354 report, Hanford Waste Treatment, DOE Needs to Evaluate Alternatives to Recently Proposed Projects and Address Technical and Management Challenges, May 2015
- Washington Examiner article, $19 billion later, 56 million gallons of nuclear waste still untreated, May 6, 2015.
- GAO-15-40 report HANFORD CLEANUP Condition of Tanks May Further Limit DOE’s Ability to Respond to Leaks and Intrusions, November 2014
- 6 more workers sickened by radioactive fumes at Hanford nuclear site, RT, May 4, 2016
Attempts to implement permanent or consolidated interim storage sites for U. S. spent nuclear fuel have failed.
- Civilian Nuclear Waste Disposal, RL33461, Mark Holt, Congressional Research Service, April 24, 2015:
Page 30: Given the delays resulting from the ongoing shutdown of the nuclear waste program, longer on-site storage is almost a certainty under any option. Any of the options would also face intense controversy, especially among states and regions that might be potential hosts for future waste facilities. As a result, substantial debate would be expected over any proposals to change the Nuclear Waste Policy Act, including those of the Blue Ribbon Commission.
Summary: In January 2013, NE [DOE’s Office of Nuclear Energy] issued a nuclear waste strategy based on the Blue Ribbon Commission recommendations. The strategy calls for a pilot interim storage facility for spent fuel from closed nuclear reactors to open by 2021 and a larger storage facility, possibly at the same site, to open by 2025. A site for a permanent underground waste repository would be selected by 2026, and the repository would open by 2048. DOE requested $30 million for FY2016 to develop an integrated waste management system as outlined by the new waste strategy—up from $22.5 million provided for FY2015. The House Appropriations Committee on April 22, 2015, approved $175 million for DOE and NRC to continue the Yucca Mountain licensing process and provided no funding for DOE’s integrated waste strategy (H.R. 2028, H.Rept. 114-91).
- U.S. Court of Appeals for the Federal Circuit, Southern California Edison Company, Plaintiff-Appellee, v. United States, Defendant-Appellant, 2010-5147, Appeal from the U.S. Court of Federal Claims, Case No. 04-CV-109, Judge Lawrence M. Baskir. DECIDED: August 23, 2011, award $142,394,294 to Southern California Edison
Page 3-4: DOE has yet to accept spent fuel from SONGS. Despite the 1987 amendment, the question of where and how the Government will dispose of the wastes remains unanswered to this date. The Government’s current estimate is that it will not begin accepting the waste until 2020, if at all. See S. Cal. Edison v. United States, 93 Fed. Cl. 337, 341-42 (2010).
In 2010, the Secretary of Energy, at the direction of the President, established The Blue Ribbon Commission on America’s Nuclear Future. The Commission’s charge was to conduct a comprehensive review of policies for managing the back end of the nuclear fuel cycle. See Presidential Memorandum of Jan. 29, 2010—Blue Ribbon Commission on America’s Nuclear Future, 75 Fed. Reg. 5485 (Feb. 3, 2010). The Commission has just released its report: “[t]he overall record of the U.S. nuclear waste program has been one of broken promises and unmet commitments.” Blue Ribbon Commission on America’s Nuclear Future Draft Report to the Secretary of Energy, Blue Ribbon Commission on America’s Nuclear Future, July 29, 2011, at xiv, … The Commission further concluded that the recent “decision to suspend work on the [Yucca] repository has left . . . [states and communities across the United States] wondering, not for the first time, if the federal government will ever deliver on its promises.” Id. at 25; see also Mark Maremont, Nuclear Waste Piles Up—in Budget Deficit, Wall St. J., Aug. 9, 2011, at A3 (describing the current and projected federal liabilities associated with the Government’s promise to dispose of the SNF).
Against this backdrop, it is hardly surprising that in 2001, SCE began constructing dry storage facilities, known as the Independent Spent Fuel Storage Installation (“ISFSI”), for its SONGS-produced nuclear waste. S. Cal. Edison, 93 Fed. Cl. at 346. SCE created its ISFSI facilities to provide on-site storage for part of its SNF rather than to continue using an outside company. Id. Following the construction of the first ISFSI facility, SCE filed a complaint in the Court of Federal Claims seeking damages from the United States as a result of DOE’s breach of the Standard Contract. SCE requested damages in the following categories: costs of constructing and operating the ISFSI facilities; overhead allocated to the ISFSI project; off-site storage of SNF; and costs associated with SCE’s participation in a limited liabilities corporation with other nuclear utilities known as the Private Fuel Storage project.
- Skull Valley, Utah Private Fuel Storage Project failure
- Edison, along with other utilities attempted to create a private fuel storage facility in Skull Valley, Utah. In it’s February, 19, 2009 federal filing, Edison claimed it spent $2,088,656 for the Private Fuel Storage project in Skull Valley, Utah, which has since been abandoned. The PFS project itself has ceased activity and is currently and effectively “dead,” due to the lack of certain required federal agency approvals and state and local political opposition. See Devia v. Nuclear Regulatory Commission, 492 F.3d 421, 425 (D.C. Cir. 2007). Since the cessation of PFS activities, no member has sold or otherwise disposed of its nominal interest in the venture. The PFS LLC was formed in 1996.
- Mescalero Apache Monitored Retrievable Storage Project failure
- Prior to 1996, SCE made payments in support of this project to predecessor companies, including Northern States Power Co. and Mescelaro Fuel Storage LLC. See Sachs, Noah, The Mescalero Apache and Monitored Retrievable Storage of Spent Nuclear Fuel: A Study in Environmental Ethics. Natural Resources Journal, Vol. 36, p. 641, 1996. Available at SSRN: http://ssrn.com/abstract=917190
- Western Governors Association (WGA) Energy Policies include information on some major hurdles that must be overcome before implementation of consolidated interim storage and transport of spent nuclear fuel and other nuclear waste.
Do we really have the right to demand that the citizens of the future guard our radioactive rubbish?
Letter to my dear: 3000 generations grandchild to visualize nuclear waste.
What can we do to ensure the nuclear waste at all the nuclear plants around the country doesn’t leak radiation into the environment?
The NRC and Department of Energy (DOE) are overly influenced by the nuclear industry, so we cannot count on them to protect us. The nuclear industry has influence over our Congress (both Democrats and Republicans) and the Senate has control over the NRC’s budget.
It is up to citizens to become educated on the facts and educate other and our elected officials. The public and our local, state and federal elected officials have been given misinformation about the safety of nuclear waste and about the ability to safely store it. All waste storage methods have serious risks, but some are safer than others.
We must insist the waste containers are as safe as possible, that they are designed so they can be easily and reliably monitored and fully inspected as they age, and that there is a realistic mitigation plan, in case of potential failure. That is not happening today. Learn the facts here and then take action now. We don’t have time to waste.
Dry storage containers may crack within 20+ years
Link to agenda and all presentation slides from the NRC 2014 Division of Spent Fuel Management Regulatory Conference (DSFM REGCON), held November 19-20, 2014
This presentation by Donna Gilmore to the NRC on dry cask nuclear waste storage issues was delivered, by invitation, as part of the 2014 annual NRC Regulatory Conference held Nov. 19-20, 2014 in Rockville, Maryland. Why are the NRC and Southern California Edison favoring inferior, short-lived, thin-walled, unsafe stainless steel canisters to store San Onofre’s tons of nuclear waste in a corrosive seaside environment instead of the long-lasting, thick-walled, top-of-the-line technology available?
Gilmore presents a strong case for regulators and utilities to take the lead in setting the highest possible standards for America’s growing inventory of radioactive waste that will remain deadly for hundreds of thousands of years longer than human civilization has yet existed. With no safe long-term storage sites having been found despite over half a century of attempts to find them, Gilmore urges officials not to ‘play bureaucratic roulette’ with the future of California and the rest of the nation.
The NRC technical staff stated the stainless steel nuclear waste dry storage canisters used throughout the U.S. may crack within 30 years from stress corrosion cracking in marine environments. And there is no current technology to inspect or repair these canisters for cracks and no current method to replace these canisters. Other stainless steel products can be inspected and repaired, but that technology cannot currently be used for canisters filled with nuclear fuel waste.
The nuclear waste containers used in the U.S. were not designed to last for more than 20 to 40 years.
- The NRC is evaluating some unresolved critical aging management issues.
- For details on current problems with thin storage canisters and how the NRC is ignoring these, see Donna Gilmore’s response to NRC’s Draft SFM-Interim Staff Guidance (ISG)-2 Revision 2, Fuel Retrievability in Spent Fuel Storage Applications, ocket NRC-20150-0241, November 20, 2015
Stress corrosion cracking can cause thin stainless steel dry storage canisters to fail
NRC metallurgist Darrell Dunn said cracks of the thin (1/2 to 5/8 inch) stainless steel spent fuel containers may initiate in 16 years. This is of particular concern near coastal environments. These dry storage containers are the primary radiation barrier to the highly radioactive spent fuel.
In the August 5, 2014 NRC public meeting on stress corrosion cracking, the NRC stated: “…Based on estimated crack growth rates as a function of temperature and assuming the conditions necessary for stress corrosion cracking continue to be present, the shortest time that a crack could propagate and go through-wall was determined to be 16 years after crack initiation…” See page 4 of meeting summary. August 5, 2014 NRC Chloride Induced Stress Corrosion Cracking Regulatory Issue Resolution Protocol (TAC LA0233) meeting documents.
- Chloride-Induced Stress Corrosion Cracking Tests and Example Aging Management Program, Darrell S. Dunn, NRC (ML14258A082), August 5, 2014
- Summary of August 5, 2014, NRC Public Meeting with the Nuclear Energy Institute on Chloride Induced Stress Corrosion Cracking Regulatory Issue Resolution Protocol (ML14258A081), September 9, 2014
- NRC link to documents for August 5, 2014 NRC meeting (ML14258A087)
Power plant operating experience with stress corrosion cracking of stainless steel shows estimated crack growth rate of up to 0.91 mm (0.036 inch)/year for cold metal. Hotter metal, such as spent fuel dry storage canisters, will have increased crack growth rate, although initiation of the crack may take longer. The Koeberg South Africa plant 304L stainless steel refueling water storage tank (RWST) had multiple cracks up to 15.5 mm (0.61 inch) deep within 17 years, which is deeper than the thickness of most U.S. canisters (0.61 inch vs 0.50 to 0.625 inch thick). The Koeberg tank required dye penetrant testing (PT) to reveal cracks. This cannot be done with canisters filled with spent fuel. Note: South Africa uses thick (about 14″ thick) ductile cast iron (DCI) cask storage for Koeberg spent nuclear fuel. DCI casks do not have cracking issues.
More examples and details
- NRC presentation on Chloride-Induced Stress Corrosion Cracking Tests and Example Aging Management Program, Darrell Dunn, August 5, 2014 ML14258A082
- Regulatory Issue Resolution Protocol (RIRP) Pilot: Marine Atmosphere Stress Corrosion Cracking (SCC), NRC Sara DePaula and Greg Oberson, April 12, 2012 ML12128A200
The rate of crack propagation is strongly dependent on temperature but is relatively unaffected by stress intensity. Rates of CLSCC propagation can vary from 0.6mm per year at near ambient temperatures to >30mm per year at temperatures ~100 degrees C. See Chloride stress corrosion cracking in austenitic stainless steel, Assessing susceptibility and structural integrity, UK, prepared by the Health and Safety Laboratory for the Health and Safety Executive, 2011 R Parrott, et. al., SK17 9JN (page vii)
Crack initiation is an unknown variable, since the nuclear industry has not been inspecting installed dry storage canisters and has yet to develop a method to inspect them for cracks.
However, a 2014 inspection for sea salts, found sea salt crystals on a Diablo Canyon canister that had only been loaded for two years. Only two Diablo canisters were inspected, ranging from only 2 to 3.5 years in service with heat load of 15 to 20 kW at time of loading. The canister loaded for only two years had sea salts and a low enough temperature range and sufficient moisture to trigger the corrosive environment needed for stress corrosion cracking initiation — much sooner than the NRC expected.
- Understanding the Environment on the Surface of Spent Nuclear Fuel Interim Storage Containers, Charles R. Bryan and David G. Enos, Sandia National Laboratories, PSAM 12, June 2014
- Results of Stainless Steel Canister Corrosion Studies and Environmental Sample Investigations, Charles Bryan and David Enos, Sandia National Laboratories, FCRD-UFD-2014-000055, SAND2014-20347, September 25, 2014 (abundant sea salt found and frequent daily fog).
- California climate zone data shows both Diablo Canyon (Zone 5) and San Onofre (Zone 7) are located in high moisture zones (with on-shore winds, surf, and frequent fog); enough moisture to dissolve salts on the canisters, starting the pitting and cracking process.
Diablo Canyon canisters measured temperatures ranged from 49°C (120°F) to 118°C (245°F). Calculated temperatures ranged from 60°C (140°F) to 105°C (221°F). Lid – measured temperatures ranged from 87°C (188°F) to 97°C (207°F).
Salt deliquescence can occur on interim storage containers only over a small part of the temperature and relative humidity (RH) range that the storage containers will experience. A reasonable maximum possible absolute humidity is 40-45 g/m3; for sea salts, this corresponds to a maximum temperature of deliquescence of ~85ºC. Reference: Data Report on Corrosion Testing of Stainless Steel SNF Storage Canisters, FCRD-UFD-2013-000324, Sandia Lab, September 30, 2013.
The NRC has no current mitigation plan for stress corrosion cracks, no adequate inspection plan, and no ability to monitor for helium leaks (which would be an early indicator of canister failure). The NRC frequently follows ASME manufacturing standards. However, ASME does not have spent fuel canister standards for “subcritical crack growth from stress corrosion cracking (SCC), and its impact on inspection intervals and acceptance criteria.” Instead, the NRC said canisters with corrosion and/or SCC must be evaluated for continued service in accordance with ASME B&PV Code Section XI IWB-3514.1 and IWB-3640 (which limits cracks to no more than 75% through-wall).
The ability to inspect these canisters for cracks is limited due to inadequate technology. The NRC is allowing 5 years for the nuclear industry to develop an inspection solution. However, the design of U.S. stainless steel sealed canisters (with unsealed concrete overpacks/casks) makes it difficult to inspect even the exterior of the canisters.
- Canisters at higher temperatures will have faster crack growth rate. Sandia Chart below shows higher temperatures can cause canisters to penetrate the wall in less than 5 years. This chart assumes canister wall is 0.625″ (5/8″) thick. The majority of the U.S. canisters are only 0.50″ (1/2″) thick. It is unknown when a crack will start, but these canisters are subject to corrosion and cracking from environment conditions such as ocean salts (chlorides). air pollution (e.g., vehicle exhaust sulfides), pitting, and microscopic scratches. Draft Geologic Disposal Requirements Basis for STAD Specification, A. Ilgen, C. Bryan, and E. Hardin, Sandia National Laboratories, March 25, 2015, FCRD-NFST-2013-000723 SAND2015-2175R, page 46
Once a crack starts it can grow through canister wall in less than 5 years due to hotter canister temperatures, e.g., 60 degrees C (140 degrees F) or above. Sandia National Lab, 3/25/2015 SAND2015-2175$, page 46
Additional stress corrosion cracking information:
- Calvert Cliffs Stainless Steel Dry Storage Canister Inspection Report, 2014
- DOE Data Report on Corrosion Testing of Stainless Steel SNF Storage Canisters, Sandia Labs, September 30, 2013
- EPRI Chloride Induced Stress Corrosion Cracking of Spent Fuel Canisters, December 18, 2012 slide presentation (ML13022A316).
- EPRI Update on In-Service Inspections of Stainless Steel Dry Storage Canisters presentation January 28, 2014
- NRC Fourth Request for Additional Information for Renewal Application to Special Nuclear Materials License No. 2505 for the Calvert Cliffs Site Specific Independent Spent Fuel Storage Installation (TAC NO. L24475), June 23, 2014
- Outside Diameter Initiated Stress Corrosion Cracking Revised Final White Paper, PA-MSC-0474, October 13, 2010, Ryan Hosler (AREVA), John Hall (Westinghouse) (includes San Onofre and others).
- NDE to Manage Atmospheric SCC in Canisters for Dry Storage of Spent Fuel: An Assessment, DOE, PNNL-22495, ML13276A196, September 2013
- EPRI Failure Modes and Effects Analysis (FMEA) of Welded Stainless Steel Canisters for Dry Cask Storage Systems, 3002000815, December 2013, includes dates U.S. casks first loaded (page 2-4 through 2-6)
- Chloride stress corrosion cracking in austentic stainless steel – recommendations for assessing risk, structural integrity and NDE based on practical cases and a review of literature, UK, July 2010
- Flaw Growth and Flaw Tolerance Assessment for Dry Cask Storage Canisters. EPRI, Palo Alto, CA: October 14, 2014. 3002002785
- Critique of EPRI Flaw Growth and Flaw Tolerance Assessment for Dry Cask Storage Canisters, D. Gilmore, May 17, 2015 (EPRI ignored Koeberg and Diablo Canyon data)
- EPRI Literature Review of Environmental Conditions and Chloride-Induced Degradation Relevant to Stainless Steel Canisters in Dry Cask Storage Systems 3002002528, May 27, 2014 The Calvert Cliffs ISFSI is located approximately 3000 feet from brackish water and 65 miles from the open ocean.
- Photos of Stress Corrosion Cracking, Corrosion Morphology
- Non-destructive testing (NDT) educational course material
- Chloride stress corrosion cracking in austenitic stainless steel, Assessing susceptibility and structural integrity, UK, prepared by the Health and Safety Laboratory for the Health and Safety Executive, 2011 R Parrott, et. al., SK17 9JN. The following applies to inspections in vessels and pipes, but indicates the limitations of various inspection options, even in containers without spent nuclear fuel.
…Leak detection is not a reliable indicator of CLSCC [chloride stress corrosion cracking] because cracks are highly branched and may be filled with corrosion products. Nevertheless, it is recommended that where pipework or vessels develop leaks in service, they should always be investigated for possible CLSCC by NDE non-destructive examinations] or by in-situ metallography.
CLSCC can generate very large cracks in structures where, as in the case of reactors, the residual stress from welding dominates and operational stresses are low by comparison. If undetected by NDE, the large cracks might introduce failure modes with consequences that were not anticipated by the original design, e.g. complete separation of attachments, toppling of tall columns under wind loading or collapse of long pipe runs due to self-weight.
The simplest and most effective NDE technique for detecting CLSCC is dye penetrant testing. Eddy Current Testing (ECT) is effective with purpose-designed probes that have been calibrated on known defects. ECT was found to be ineffective on the samples from the reactor due to limited penetration of the current and sensitivity to surface imperfections that could not be distinguished from cracking.
Crack sizing by eddy current testing may be limited and is not possible by penetrant testing.
Ultrasonic flaw detection can be applied as a manual or an automated NDE technique for detecting CLSCC. For structures with complex design features and welds as on the reactors, the trials indicated that ultrasonic testing would require a range of probes, several complimentary scans and be very time consuming. Ultrasonic flaw detection did not cover all design details and possible crack position orientations found on the reactor, and crack sizing was difficult.
- April 21, 2015 NRC and NEI meeting on Chloride Induced Stress Corrosion Cracking and Aging Management
Factors other than chloride-induced stress corrosion cracking (CISCC) can cause corrosion and cracking in these thin canisters. Environmental and other factors still need to be addressed by the NRC and nuclear industry. For example,
Many storage cask designs utilize ventilation that allows decay heat to dissipate by thermal convection to the atmosphere. Cooler air is drawn into the cask ventilation, passing over the canister with warmer air exiting the cask. The flow of air over the canister also allows atmospheric dust to follow the same path, some of which is deposited on the surface of the canister. The geographic location of the storage facility impacts the composition of dust, with coastal sites containing higher amounts of chloride-bearing sea-salts (EPRI, 2005) and ammonium salts (Enos et al., 2013).
Inland sites containing higher levels of silicate, carbonate and aluminate material impacted by local soil and geology. As the temperature and relative humidity fluctuate at a site, components of the deposited dust (particularly chlorides) can dissolve in absorbed moisture (deliquescence). The dissolved ions are then available to participate in corrosion of the canister. Research has shown that with deposited sea salt, a relative humidity at or above 15% can support deliquescence and subsequent corrosion of the canister steels…
Another factor that can affect corrosion (including SCC) is the presence of gamma radiation from the encased fuel leading to the formation of radials and molecules after radiolysis of the water (and brine) on the surface of the waste canister. Some of the species are highly oxidizing and their reactions in pure water are numerous. In brine solutions, the reactions (and shear number of species) is complex, including radials and molecules of chloride species. Farmer et al. (1988) reviews work performed on gamma irradiation of austenitic stainless steels (such as 304) in water and salt solutions, generally finding that the irradiation increased intergranular SCC even at low chloride concentrations.
LLNL Input to SNL Report on the Composition of Available Data for Used Nuclear Fuel Storage and Transportation Analysis, M. Sutton, J. Wen, Lawrence Livermore National Laboratory, LLNL-TR-659020, August 19, 2014. Used Fuel Disposition Campaign Milestone M4FT-14LL0810044
The CSI Designs Stainless Steel Selection Guide identifies various stainless steel alloys and the advantages and disadvantages of each. It shows the nuclear industry uses 304/304L and 316/316L stainless steel even though they know these alloys are susceptible to stress corrosion cracking:
Stress corrosion cracking (SCC) is one of the most common and dangerous forms of corrosion. Usually it is associated with other types of corrosion that create a stress concentrator that leads to cracking failure.
Nickel containing stainless steel is especially susceptible to chloride induced SCC. Figure 7 (page 16) indicates the maximum susceptibility is in the nickel range of about 5-35% and that pure ferritics, such as Types 430, 439, and 409 are immune. The point of maximum susceptibility occurs between 7-20% nickel. This makes types 304/304L, 316/316L, 321, 347, etc., very prone to such failure.
NRC Proposed Aging Management
The NRC recommends that only one canister at each plant needs to be inspected within the first 20 years after fuel loading and then inspect that same canister every 5 years.
Initially, they are recommending inspection within 25 years in order to give the industry 5 years to develop an inspection solution.
The NRC wants the inspection to occur prior to relicensing and wants it as a condition of licensing.
The nuclear industry doesn’t want to inspect even one canister at each plant and wants the NRC to relicense canisters prior to any inspection of any canisters. See July 14-15, 2014 Meeting to Obtain Stakeholder Input on Potential Changes to Guidance for Renewal of Spent Fuel Dry Cask Storage System Licenses and Certificates of Compliance.
NRC staff plans to revise NUREG-1927, “Standard Review Plan for Renewal of Spent Fuel Dry Cask Storage System Licenses and Certificates of Compliance, March 2011, in May of 2015, now that it’s known the dry storage systems have aging issues and must last for 60 to 300+ years.
The NRC Division of Spent Fuel Management is limiting their aging management research to the thin canister designs, due to budget concerns. They are ignoring the fact that the thick cask designs would eliminate many of the problems that the thin canisters have. Instead, they are setting the safety standards lower.
This November 2014 report, Available Methods for Functional Monitoring of Dry Cask Storage Systems, Xihua He, et.al., outlines the many challenges to develop inspection and monitoring technology or to adapt existing technology to the thin canisters and their concrete overpacks/casks.
…Substantial advancement in technology may be necessary for methods that are not presently designed or packaged for field use…
…No suitable method was identified for detecting and monitoring of atmospheric deposition of solid chloride-containing salts that may lead to degradation of safety significant SSCs, such as welded stainless steel canisters used in the majority of DCSSs…
…Stress corrosion cracking sensors are limited. Surrogate sensors, which are an instrumented SCC coupon, have been developed for condition monitoring in field applications. Significant advancement and qualification testing would likely be necessary to use the sensor for DCSS monitoring. Other methods, such as fiber optic sensors or crack propagation sensors, have significant limitations (e.g., unknown temperature and radiation tolerances). Fiber optic sensors appear to be the only direct method of monitoring the actual component of interest. Implementation of this type of system would be challenging, given the temperatures and radiation near the canister surface. Such an application also would need to consider the possible detrimental effects of attaching a sensor to the canister surface…
…Concrete degradation monitoring methods are well developed and have sufficient sensitivity to detect degradation before physical deterioration begins. However, these methods also have limitations, such as being labor intensive and limited to interrogation depths of 10 cm [4 in] or requiring access to the interior surfaces. Embeddable sensors have been developed and are commercially available; however, significant effort would be required to install these sensors in existing DCSSs. In addition, determining an optimized location for sensor placement may require analysis or knowledge of susceptible areas for degradation…
…Monitoring the canister internal environment poses several challenges because of high temperatures, radiation, and accessibility difficulty…
NRC’s Expert Panel Workshop on Degradation of Concrete in Spent Nuclear Fuel Dry Cask Storage Systems, February 24-25, 2015, identified numerous concrete aging management problems, particularly with below ground systems (such as the Holtec UMAX dry storage system) due to limited inspection capability, ground moisture and chemical reactions with concrete. Concrete is not an issue in thick steel or ductile cast iron casks, since they don’t use concrete for gamma and neutron shielding.
- NRC Concrete Expert Panel Workshop, February 24-25, 2015
U.S. utility companies choose the inferior steel/concrete canister designs due to cost. According to the National Research Council of the National Academies (2006), Safety and Security of Commercial Spent Nuclear Fuel Storage, National Academies Press, Washington D.C., page 63.
The vendors informed the committee that cost is the chief consideration for their customers when making purchasing decisions. Cost considerations are driving the cask industry away from all-metal [thick] cask designs and toward [steel/]concrete designs for storage.
The cost and lack of a solution for the disposal of the steel/concrete canister materials has not been fully addressed. The following report identifies the issues. However, it assumes no canisters or fuel assemblies will leak and cause a higher level of contamination that will make it even harder to dispose of this material. Considerations for Disposition of Dry Cask Storage System Materials at End of Storage System Life, presented by Rob Howard, Oak Ridge National Laboratory, at Symposium on Recycling of Metals arising from Operation and Decommissioning of Nuclear Facilities, April 8-10, 2014
The thin canisters also result in more Carbon-14 into the environment. This is a dangerous and challenging radioactive isotope to manage.
Carbon-14 is a radioactive isotope of carbon and is a pure beta emitter with a half-life of 5730 years; it decays to 14N by emitting low energy beta radiation with an average energy of 49.5 keV and a maximum energy of 156 keV. Carbon-14 is easily transferred during biological processes and soil–plant interactions involving carbon compounds. The metabolism and kinetics of 14C in the human body follow those of ordinary carbon. Inhaled 14CO2 rapidly equilibrates with the air in the lungs and enters many components of body tissue. The biological half-life of 14C is approximately 40 days. It has been found that accumulation of 14C in the human body via respiration is insignificant compared with that from ingestion of contaminated food. In addition, 14C can be easily concentrated in the food chain. Studies have shown concentration factors of 5000 for fish and molluscs and 2000 for soil sediments. Management of Waste Containing Tritium and Carbon-14, IAEA, 2004
It’s not practical to repair a damaged canister, says Dr. Kris Singh, CEO, Holtec International.
“…It is not practical to repair a canister if it were damaged… if that canister were to develop a leak, let’s be realistic; you have to find it, that crack, where it might be, and then find the means to repair it. You will have, in the face of millions of curies of radioactivity coming out of canister; we think it’s not a path forward…
…A canister that develops a microscopic crack (all it takes is a microscopic crack to get the release), to precisely locate it… And then if you try to repair it (remotely by welding)…the problem with that is you create a rough surface which becomes a new creation site for corrosion down the road. ASME Sec 3. Class 1 has some very significant requirements for making repairs of Class 1 structures like the canisters, so I, as a pragmatic technical solution, I don’t advocate repairing the canister.”
Instead Dr. Singh states
…you can easily isolate that canister in a cask that keeps it cool and basically you have provided the next confinement boundary, you’re not relying on the canister. So that is the practical way to deal with it and that’s the way we advocate for our clients.
However, there are many problems with Dr. Singh’s solution of putting cracked and leaking canisters inside [transport] casks.
- There are no NRC approved Holtec specifications that address Dr. Singh’s solution of using the “Russian doll” approach of putting a cracked canister inside a [transport] cask.
- NRC requirements for transport casks require the interior canister to be intact for transport. This NRC requirement provides some level of redundancy in case the outer cask fails. Does this mean this leaking canister can never safely be moved? Who will allow this to be transported through their communities? How stable is the fuel inside a cracked canister?
- What is the seismic rating of a cracked canister (even if it has not yet cracked all the way through)? The NRC has no seismic rating for a cracked canister, but plans to allow up to a 75% crack (IWB-3640). There is no existing technology that can currently inspect for corrosion or cracks. The NRC is allowing the nuclear industry 5 years to develop it. It is likely to be inadequate due to the requirement the canisters must be inspected while in the concrete overpacks.
- What is the cost for the transport casks that will be needed for storage? Will they be on-site? Where is this addressed? Transport casks are intended to be reusable because of their higher cost. How and where will they be stored and secured on-site?
- How will the leaking canisters be handled by the Department of Energy at the receiving end of the transport? The DOE currently requires fuel to be retrievable from the canister.
A better solution is to use casks that are not susceptible to cracks, that can be inspected and repaired and that have early warning monitoring systems that alert us before radiation leaks into the environment.
Thick casks used in most other countries and some U.S. sites have superior features to the U.S. thin canisters
- Thicker walls (e.g., 10 to 20 inches thick) vs. 1/2 to 5/8 inch thick.
- Ability to remotely monitor for helium leaks.
- Ability to easily inspect the exterior of the canisters.
- Not subject to stress corrosion cracking.
- Not subject to concrete degradation. Concrete overpacks/casks are not needed.
- Robust radiation protection for both storage and transport.
- Reduced cask drop and handling risks results in fewer opportunities for significant radionuclide releases. SANDIA Human Reliability Analysis Informed
Insights on Cask Drops, NUREG/CR-7016, February 2012 (ML110610673), pp 7-1 and 7-2)
- Adequate aging management and mitigation solutions.
- Steel/concrete storage systems do not have adequate aging management and mitigation solutions. They were designed without these and technology to address these limitations has not been developed.
- There are inspection limitations with forged steel containers with welded seams. This is not the case for ductile cast iron casks.
- Forged steel: The welds can only be checked by UT, VT, RT. There are no conclusions on the properties of the weld metal and the basic material possible. This can be done only by using a separate sample, which does not have to have the same basic properties.
- Ductile cast iron: Samples out of ductile cast iron containers can be taken either directly from the cask body or from an extra cast-on test block from the same melt, and the same cast. The material properties are the same everywhere. Thus, there are unambiguous characteristic for each container available
- Ductile cast iron casks meet ASME standards for storage and transportation. ASME/BPVC – Code Case N-670-1, Use of Ductile Cast Iron Conforming to ASTM A874/A 874M-98 or JIS G5504-2005 for Transport and Storage Containments, Section III, Division 3, January 4, 2008
- The German ductile cast iron casks (e.g., CASTOR) perform in an exemplary manner and do not have embrittlement issues according to this Sandia National Laboratories report, Fracture Mechanics Based Design for Radioactive Material Transport Packagings Historical Review, SAND98-0764 UC-804, April 1998
The numerous studies cited show that DI [ductile iron] is a well characterized material that does have sufficient fracture toughness to produce a containment boundary for RAM [radioactive material transport] packagings that will be safe from brittle fracture. All the drop tests discussed in this report were conducted using DI packagings and the studies indicate that even with drop tests exceeding the severity of those specified in 10CFR71 the DI packagings perform in an exemplary manner. [page 53]
The use of a fracture mechanics based design for the radioactive material transport (RAM) packagings has been the subject of extensive research for more than a decade. Sandia National Laboratories (SNL) has played an important role in the research and development of the application of this technology. Ductile iron has been internationally accepted as an exemplary material for the demonstration of a fracture mechanics based method of RAM packaging design and therefore is the subject of a large portion of the research discussed in this report. SNL’s extensive research and development program, funded primarily by the U. S. Department of Energy’s Office of Transportation, Energy Management & Analytical Services (EM-76) and in an auxiliary capacity, the office of Civilian Radioactive Waste Management, is summarized in this document along with a summary of the research conducted at other institutions throughout the world. In addition to the research and development work, code and standards development and regulatory positions are also discussed. [Abstract]
The proposed use of ferritic materials for packaging containment has not been without controversy and critics. Ferritic materials, unlike austenitics, such as stainless steel, may exhibit a failure mode transition with decreasing temperatures and/or increasing loading rates from a ductile, high-energy failure mode to a brittle, low-energy fracture mode at below-yield stress levels. Regulators have thus been justifiably cautious regarding the use of ferritics for RAM package applications and have indicated that certification of such packages would require extensive confirmatory research and supporting data (although ferritic RAM packages for storage applications have been certified by the NRC). However, the general conclusion of the research reported herein is that appropriate engineering design methodologies exist which, when rigorously applied to RAM transport packaging conditions and environments, warrant the use of suitable ferritic materials for packaging containment. This report summarizes the Sandia work in support of that conclusion. The report also cites and references parallel research and conclusions of other institutions. [page viii]
Dr. Wolfgang Steinwarz, Executive Vice President of the German dry cask manufacturer Siempelkamp – whose highly robust nuclear waste storage containers are in use around the world (with only limited use in the U.S.) – explains how his company’s technology is setting a high international bar for safe, long-term radioactive waste containment. Dr. Steinwarz is an internationally renown expert in ductile cast iron technology. This is his presentation from the November 19-20, 2014 NRC Annual Regulatory Conference, held in Rockville, Maryland.
- References for thick cask technology
- Experience with Ductile Cast Iron Fuel Casks, Siempelkamp, Dr. Wolfgang Steinwarz, November 20, 2014 NRC presentation
- BAM Overview of Preparation of a Safety Case for a Dual Purpose Cask for Storage and Transport of Spent Fuel and Recommendations to WASSC and TRANSSC from WASSC/TRANSSC Working Group, Bernhard Droste, BAM Federal Institute for Materials Research and Testing, Germany, Chairman of International Workshop on the Development and Application of a Safety Case for Dual Purpose Casks for Nuclear Spent Fuel, IAEA International Atomic Energy Agency, Vienna, Austria, May 19-21, 2014
- Long Term Storage of Spent Nuclear Fuel and HLW in Dual Purpose Casks towards Disposal – Challenges and Perspectives – Holger Völzke, Dietmar Wolff, (BAM)(Federal Institute for Materials Research and Testing (BAM), June 2015
- CASTOR A High Bech Product Made of Ductile Cast Iron — Siempelkamp Brochure
- BAM test results for CASTOR transport containers
- Fracture Mechanics Based Design for Radioactive Material Transport Packagings Historical Review, Sandia SAND98-0764 UC-804, April 1998
- Interim storage of spent nuclear fuel (SNF) and vitrified highly active waste (HAW) in Germany, Christoph Gastl, Federal Office for Radiation Protection, IAEA
Vienna, July 2013
- GNS CASTOR Presentation, June 09-11, 2010, Varna, Bulgaria (slide 18: CASTOR V/19, V52)
- Dry Cask Storage Recommendations to Edison’s Community Engagement Panel (CEP), July 17, 2014
- International Symposiums on the Packaging and Transportation of Radioactive Materials – Index
- Siempelkamp: Ductile cast iron (DCI) seismic and aging, October 27, 2014
- Highest score for Siempelkamp: Container development on the international road to success, (BlueBox, BlueBarrel and TUK-141), June 2014
- Summary of Pre-Application Meeting With Siempelkamp Nukleartechnik GMBH (TAC No. L24696) (Docket No. 71-9369), December 5, 2012
- Experience in preparation of spent nuclear fuel including damaged for shipment, V. Smirnov, et. al., Sosny R&D Company, July 8-10, 2014 (use of leak tight ampoules for damaged fuel, stored in DCI TUK-11 casks). U.S. damaged fuel is stored in unsealed containers (damaged/failed fuel cans)
NRC Branch Chief Aladar Csontos said a cask design similar to the CASTOR V/21 would probably be a safer choice in a coastal environment such as San Onofre, although all canister designs have potential problems.
- Germany currently uses a newer version of the ductile cast iron CASTOR cask (CASTOR V/19) and also has some Areva TN-24G thick steel casks made to German specifications. A newer German Areva model TN-24E has a copper exterior layer.
Germany purchased 70 TN-24E casks in 2013 for a value over $276 million. They house them in hardened buildings that provide additional environmental and radiation protection. Remote monitoring is also provided, unlike U.S. dry storage systems.
Japan has nine thick forged steel casks at Fukushima Daiichi, stored in a building with remote monitoring capabilities. The fuel assemblies all have low burnup (< 24,000 MWD/T or <29,000 MWD/T) with fuel cladding temperature of only 90 -140 degrees C. The NRC allows fuel cladding drying temperatures up to 400 degrees C for high burnup fuel (>45,000 MWD/T) and even higher for lower burnup fuel.
The Fukushima casks survived the Fukushima disaster, but are superior to the inferior thin canister U.S dry storage systems and were house in a building.
- Belgium uses TN-24 thick steel casks stored in buildings.
- Areva TN-24 metal casks used for transport and storage in other countries including the U.S. (Areva brochure states more than 150 casks
from the TN®24 family have been delivered to U.S.
- U.S. sites using thick casks include: Prairie Island for storage and transport (TN-40). Others in U.S. using thick casks for storage include: North Anna (TN-32), McGuire (TN-32), Surry (TN-32, Castor V21 and X33, and Peach Bottom (TN-68). The TN-32 is currently licensed for general use (ML010460291).
- To learn how other countries are managing their waste, see IAEA July 8-10, 2014 Conference presentations.
- Housing casks in buildings would have eliminated cask degradation problems caused by moisture at Peach Bottom and Three Mile Island. See more advantages and details on building storage: Safety Aspects of Dry Spent Fuel Storage and Spent Fuel Management, W. Botsch, et.al, February 24, 2013
- Spent fuel pools are needed to unload failed canisters and cask. However, the NRC allows pools to be destroyed after all fuel is loaded into dry storage, claiming nothing will go wrong. This December 1, 2010 Peach Bottom TN-68 cask event report is an example of why the pools are needed in case of cask or canister failure. [NOTE: The Areva thick steel TN-68 cask worked as designed. It has a lid monitoring early warning system, so casks can be unloaded and repaired (e.g., seal replaced) before a radiation leak. If this had been a thin steel canister that leaked, there is no early warning system and the canister cannot be repaired.]
In contrast, NRC’s Darrell Dunn estimates U.S. thin stainless steel canisters may have through-wall cracks within 8 years after the crack appears, due to the higher heat loads allowed in U.S. canisters. He said once a crack appears in a canister, the heat level of the canister determines how fast the crack will spread through the canister.
The NRC is continually approving higher heat loads in dry canisters, increasing the number of spent fuel assemblies allowed in a canister, and increasing allowable fuel burnup and uranium enrichment.
The nuclear plants are shortening cooling times for higher burnup spent fuel, which increases safety risks. The spent fuel pools are overcrowded, so the nuclear plants need to move spent fuel out of the pools in order to make room for more nuclear waste.
Technical Data Gaps: Unsolved critical issues for nuclear waste storage and transportation
- There are critical gaps in knowledge for safely storing nuclear waste, in spite of the nuclear industry and NRC saying it’s safe. This January 14, 2013 INMM Spent Fuel Management Seminar presentation outlines 26 of these major gaps in knowledge. This includes both short term and long term storage problems and problems in addition to high burnup used fuel [see Data Gap Summarization slide]. Also, the DOE Office of Nuclear Energy (DOE-NE), Office of Fuel Cycle Technology states
“…there are a collective total of 94 technical data gaps identified by the various reports to support extended storage and transportation of [Used Nuclear Fuel] UNF”.
…”Because limited information is available on the properties of high burnup fuel (exceeding 45 gigawatt- days per metric ton of uranium [GWd/MTU]), and because much of the fuel currently discharged from today’s reactors exceeds this burnup threshold, a particular emphasis of this [Used Fuel Disposition Campaign (UFDC)] program is on high burnup fuels.”
- Detailed technical gap reports
- DOE Review of Used Nuclear Fuel Storage and Transportation Technical Gap Analyses, July 31, 2012
- DOE Gap Analysis to Support Extended Storage of Used Nuclear Fuel, January 31, 2012
- NRC draft report Identification and Prioritization of the Technical Information Needs Affecting Potential Regulation of Extended Storage and Transportation of Spent Nuclear Fuel, May 2012 (ML120580143)
- Dry Transfer Facility (Hot Cell) limitations
- Dry Transfer Systems for Used Nuclear Fuel, Brett W. Carlsen, Michaele BradyRaap, INL/EXT-12-26218, Idaho National Laboratory, May 2012 (addresses needs and current inadequacies for transferring fuel from one canister to another — wet or dry).
- Viability of Existing INL Facilities for Dry Storage Cask Handling, Randy Bohachek et. al., Revision 1, April 30, 2013, Idaho National Laboratory, FCRD-UFD-2013-000027. INL/EXT-13-29035 [for EPRI high burnup demonstration project]
- The only fuel-handling method currently available to the commercial nuclear generating industry is to bring a cask back into a spent fuel pool for reopening.
- Removal of a welded storage cask lid is problematic, and resealing such a cask has never been done. Continued storage and periodic examination of a deheaded cask would be costly and technically challenging.
- 14-ft fuel rods [are] about the longest that can be shipped within U.S. DOT regulations.
- Fuel from new reactor designs (such as the Westinghouse AP1000) will present challenges, because that fuel is just over 15 ft (4.57 m) in length. No shipping cask today can accommodate such a long fuel rod.
- The NRC Commissioners directed staff to “encourage the adoption of state of the art technology for storage and transportation”. Staff Requirements – COMDEK-09-0001 – Revisiting the Paradigm for Spent Fuel Storage and Transportation Regulatory Programs, February 18, 2010 . Instead, the staff has continued to reduce standards, approving storage containers that cannot be inspected, repaired, maintained or adequately monitored.
The staff should undertake a thorough review of the regulatory programs for spent fuel storage and transportation to evaluate their adequacy for ensuring safe and secure storage and transportation of spent nuclear fuel for extended periods beyond the 120 year timeframe considered up to this point. This review should include the standards, regulations, guidance, review processes, and inspection and enforcement procedures. The staff should also undertake research to bolster the technical basis of the NRC’s regulatory framework to support extended periods. The review should identify risk-informed, performance-based enhancements that will bring increased predictability and efficiency to the regulatory processes, and should investigate ways to incentivize these processes to encourage the adoption of state of the art technology for storage and transportation in a risk-informed, performance-based manner. The review should be conducted in a transparent, participatory, and collaborative manner with our stakeholders.
The review should also benefit from experience gained through the Multi-National Design Evaluation Process (MDEP) for reactors and consider opportunities for comparing and, where appropriate, harmonizing, international standards for transport packages and storage casks.
The staff should develop a project plan for Commission approval, including objectives, plans, potential policy issues, projected schedules, performance measures, and projected resource requirements. Such a plan should leverage, as appropriate, improvement initiatives that the staff already has underway.
High Burnup Fuel: Unsafe in storage & transport
Most nuclear plants now use high burnup fuel, which is over twice as hot and over twice as radioactive as fuel originally approve for use by the NRC.
The NRC has so little confidence in the safety of high burnup spent nuclear fuel, they have taken these actions:
The NRC approved high burnup fuel (greater than 45 GigaWatt days per metric ton of uranium (>45 GWd/MTU)) in the 1990’s based on how it performed in reactors. They did not consider the consequences of storage of the spent fuel. High burnup fuel is low enriched uranium (up to 5% U-235) that is allowed to burn over twice as long in reactors. Experimental data suggests fuel with burnup as low as 30 GWd/MTU shows signs of premature failure. And this November 23, 1976 memo to Prairie Island indicates the NRC was concerned about high burnup (defined then as >20 GWd/tU).
The nuclear industry switched to high burnup fuel because it can burn longer in a reactor, increasing industry profits. However, it reduces our safety.
Nuclear plants’ spent fuel pools are filling to capacity. After densely double racking their spent fuel pools (another safety problem), using high burnup fuel allows them to delay or avoid procuring expensive dry cask storage systems.
This is an example of the NRC and nuclear industry putting profits before safety. See high burnup fuel summary below, followed by government and technical documents that substantiate these facts. Some nuclear experts, even at the NRC, are not aware of all this information.
High Burnup Fuel Summary
- No approved short term storage. High burnup fuel is so dangerous and unstable, the NRC will not approved more than 20 years of dry cask storage, even though this deadly waste needs to be stored for thousands of years. Instead the NRC proposes a “demonstration project” that includes requirements for technology that does not yet exist — the ability to monitor the waste inside the dry cask storage system.
- No approved safe transportation. The NRC has not approved* safe transportation canisters and casks for high burnup fuel due to potential failures of the protective fuel cladding and the unpredictability and instability of high burnup fuel. The protective cladding around the enriched uranium fuel is becoming brittle, making it more fragile and more likely to shatter. This can release radiation into the environment, risking our safety as well as the safety of nuclear workers. See NRC Interim Staff Guidance – 11, Revision 3 (ISG-11)
- Note: The NRC approved the first high burnup transport cask NUHOMS®-MP197HB (Certificate of Compliance No. 9302, Revision No. 7) on April 23, 2014. However, no justification for this is shared with the public. The entire section regarding high burnup fuel and the section on mitigation in case of an accident were marked “proprietary”. Therefore, public and independent review is not possible. For something that has for years been an unsolved problem, this refusal to share the data justifying this major safety change in NRC’s position is unacceptable.
- NRC Draft Regulatory Issue Summary 2015-XX Considerations in Licensing High Burnup Spent Fuel in Dry Storage and Transportation, April 20, 2015
- Over twice as radioactive. High burnup used fuel is over twice as radioactive as lower burnup fuel. Assumptions made that it would react similar to lower burnup fuel are proving false. For example, see Nuclide Importance to Criticality Safety, Decay Heating, and Source Terms Related to Transport and Interim Storage of High-Burnup LWR Fuel, NUREG/CR–6700, January 2001.
- Requires up to 20+ years in spent fuel pools. High burnup fuel waste is over twice as hot as lower burnup fuel, requiring up to 20+ years in spent fuel pools before it is cool enough to transfer to dry canisters and casks. Lower burnup fuel normally requires 5+ years to cool in the spent fuel pools.
- Requires more space for storage. High burnup fuel waste requires more space in a permanent repository than lower burnup fuel because it is over twice as radioactive and over twice as hot. No designs have been developed or approved for this waste.
NRC is approving even higher burnup levels. Instead of solving the high burnup storage problems, or stopping use of this unnecessary fuel, the NRC and nuclear industry are raising the maximum allowable burnup from 60 to 62 GWd/MTU. The higher the burnup the more radioactive and the more dangerous. The industry wants to increase the burnup level even higher in order to increase industry profits. And new generation nuclear reactors use high burnup fuel. Note: San Onofre’s high burnup dry storage cask system is approved for a maximum of 60 GWd/MTU.
- Burnup as low as 30 GWd/MTU increases risks of cladding damage, which can result in an explosion. If moisture or air enters a storage container with breached cladding, an explosion can result from zirconium hydrides at a temperature of 270° C (580° F). Specifications require containers to be dry before loading fuel. However, this is subject to errors or accidents.
- Even 5% oxygen in helium, can cause zirconium powder to ignite. Any mechanical or chemical process that reduces the [zirconium] cladding to turnings, chips, granules, or powders can generate a pyrophoricity or flammability hazard.
Zirconium powder is so highly flammable they are used in fireworks.
- Many metal hydrides are spontaneously combustible in air. Spontaneous combustion of zirconium-hydrides would render moot the issue of “ignition” temperature that is the focus of the [NRC] staff analysis of air interactions with exposed cladding. The staff has neglected the issue of hydrides and suggested that uncertainties in the critical decay heat times and the critical temperatures can be found by sensitivity analyses. Sensitivity analyses with models lacking essential physics and chemistry would be of little use in determining the real uncertainties. Dana A. Powers, ACRS Chairman, ACRS Recommendations for Improvements to the NRC Staff’s “Technical Study of Spent Fuel Pool Accident Risk at Decommissioning Nuclear Power Plants,” April 13, 2000, (ML003704532), p. 3
- Other references on failure with high burnup fuel
Plotting more than 4,400 measurements from commercial fuel-rods taken from reactors around the world, Figure 20 shows the maximum outer-surface oxide-layer thickness data in low-Sn Zircaloy-4 cladding plotted as a function of burnup. Taking these oxide thickness measurements, the maximum wall thickness average (MWTA) hydrogen content can be calculated using a hydrogen evolution model. Figure 21 plots the wall-average hydrogen content in low-Sn Zircaloy-4 cladding as a function of burnup from both measured and model-calculated data. For a discharge burnup in the range of 60-65 GWd/MTU, the maximum oxide thickness is 100 μm and the average hydrogen concentration is 800 ppm, which corresponds to a metal loss of 70 μm using conservative assumptions. Source: Spent Fuel Transportation Applications – Assessment of Cladding Performance: A Synthesis Report, EPRI-TR-1015048, December 2007.
- The Explosive Characteristics of Titanium, Zirconium, Thorium, Uranium, and their Hydrides, Irving Hartman, John Nagy, Murray Jacobson U.S. Bureau of Mines, Report of Investigation 4835, U.S. Dept. of Interior, December 1951
- Review of Zirconium-Zircaloy Pyrophoricity, November 1984 RH0-RE-ST~31P, Thurman D.Cooper, Research and Engineering, Rockwell Int., DOE
- EPRI Report 1013448 Spent Fuel Transportation Applications: Longitudinal Tearing Resulting from Transportation Accidents – A Probabilistic Treatment, December 2006, Chart p. 3-3.
- NWTRB Executive Summary of the Evaluation of the Technical Basis for Extended Dry Storage and Transportation of Used Nuclear Fuel, December 2010.
- Zirconium Hydride Material Safety Data Sheet (MSDS)
- Manhique, AJ 2003, Optimisation of alkali-fusion process for zircon sand: a kinetic study of the process, MSc dissertation, University of Pretoria, Pretoria
- Damaged Spent Nuclear Fuel at U.S. DOE Facilities, Experience and Lessons Learned, by INL, Nov 2005 INL/EXT-05-00760, Page 4& 5:
The uranium metal SNF [Spend Nuclear Fuel] within the DOE inventory contains many elements whose cladding was breached during reactor discharge, subsequent handling, or storage. Initial cladding failures varied from minor cracks to severed fuel elements. The reaction of exposed uranium metal with water produces uranium dioxide and hydrogen. This reaction is not a result of chemical impurity of the basin water. It is a chemical reaction of the water with the uranium metal. Uranium hydride forms from the available hydrogen, particularly where there is a limited amount of oxygen (see Reference 3). The lower densities of the uranium oxide and uranium hydride products relative to the uranium metal cause swelling of the material within the cladding and subsequent additional cladding damage. Additional water reaction then occurs with the newly exposed uranium metal. Each cycle of fuel-water reaction results in fission product releases and contamination of water in the canister or the storage pool. Examples of uranium metal SNF element damage after extended water storage are shown in Figure 3. In extreme cases, the uranium metal has also been known to completely oxidize and form a mud-like mixture with the water.
The generation of high surface area uranium metal SNF fragments and uranium hydride necessitates additional measures during SNF drying, dry storage, and transportation because of the pyrophoric nature of these materials when exposed to air. As a result, degraded uranium metal fuels are stored and transported in inerted canisters after removal from the basin and drying. Radiolysis of water within the SNF-water corrosion products must also be addressed for long-term storage because of the ability of the resultant gases to overpressurize containers, embrittle welds on containers, and reach flammable concentrations.
- NRC’s 1997 NUREG-1536 Standard Review Plan for Dry Cask Storage Systems defines high burnup as >40 GWd/MTU, but in the July 2010 NUREG-1536 revision it redefines it as >45 GWd/MTU. The 1997 NUREG-1356 page 96 states:
High-burnup of fuel (greater than 40,000 MWD/MTU) causes effects, such as wall thinning from increased oxidation and increased internal rod pressure from fission gas buildup, and changes in fuel dimensions that must be evaluated. The SAR should use conservative values for surface oxidation thickness. Oxidation may not be of a uniform thickness along the qxial length of the fuel rods and average values may under predict wall thinning. Temperature limits will be more restrictive with increased fuel cooling time (and/or increased burnup), largely as a result of creep cavitation.
- The NRC has no experience in transferring failed (damaged) fuel from one cask to another and no procedures for doing this. In fact, no spent fuel bundle, damaged or not, has ever been transferred from one dry cask to another. Since high burnup fuel is more likely to fail sooner in storage, this becomes an even bigger and more urgent problem. And the failure could result in a breach of the cask, exposing radiation to the environment.
- The Department of Energy (DOE) states fuel burnup as low as 30 GWd/MTU shows signs of cladding degradation. All current San Onofre dry casks have high burnup fuel assemblies over 30 GWd/MTU. San Onofre also has 95 failed spent fuel bundles stored in 15 dry casks.
- Dr. Einziger [misspelled as Eisinger] stated on 6/20/2007 at the Advisory Committee on Nuclear Waste 180th Meeting (p.70): “There is nothing holy about 45 gigawatt days per metric ton. Maybe it’s 42, maybe it’s 48. But that’s — in that general burnup range is where many of the properties of the fuel start going from a linear low value to an exponential value. There’s a change in the shape of the curve where things get a little dicier.”
Nuclear Waste Handouts
- Dry Cask Storage Recommendations to CEP 7/17/2014
- High Burnup Fuel: Pushing the Safety Envelope, Resnikoff & Gilmore
- Dry Storage Canister Recommendations Letter to CPUC 06-16-2014
- Choose Safety Over Profits 05-22-2014
- Nuclear Waste Recommendations
- High Burnup Fuel – Executive Summary
- Stop the High Burnup Nuclear Experiment
- Summary Comments to the NRC on Waste Con GEIS
This video explains in seven minutes why what is happening with San Onofre’s nuclear fuel waste and other nuclear fuel waste around the country is incredibly dangerous and why it’s important for everyone to know about this. Residents must pressure the NRC, utility owners, local, state and federal regulators and elected officials to do everything they can to make sure nuclear waste storage decisions are based on safety, not profits. Cutting corners on design, materials and personnel puts all of Southern California, major seaports and the nation’s food supply at risk.
Dry Storage Canisters and Casks
The U.S. dry storage canisters at San Onofre and most other U.S. nuclear plants are only 1/2″ to 5/8″ thick stainless steel.
In other countries, such as Germany, 14″ to 20″ thick ductile cast iron canisters/casks are used, such as the CASTOR V/19.
The U.S. nuclear industry could have chosen the thick CASTOR sealed ductile cast iron casks (e.g., the V/21 approved by the NRC).
Instead, they use lower quality canisters, choosing profits over our safety. It’s up to us to change this. Insist on higher quality canisters for waste that will be stored on-site at nuclear plants around the country for decades, if not longer.
The NRC only approves dry storage systems requested by manufacturers for approval. The manufacturers only request approval if they have a utility customer that wants to buy their systems. The NRC prioritize their workload based on customer needs. Therefore, in order to have the NRC approve a better dry storage system, the utility companies must be encouraged to procure safer and more long lasting dry casks sytems.
The dry storage systems used in the U.S. require thick concrete overpacks because the thin stainless steel canisters do not protect from gamma rays and neutrons. The concrete overpacks are not sealed and do not provide protection from Cesium-137 and other types of radiation, so we’re dependent on the welded stainless steel canisters to contain the radiation. Fuel cladding is supposed to provide another layer of protection. However, damaged fuel cladding removes this protection.
Since the thin stainless steel canisters do not protect workers from gamma rays and neutrons, it is dangerous and difficult for them to inspect canisters for corrosion and cracks. Inspection of even the exterior of the thin steel canisters is not done, once the canister is loaded with spent fuel and inserted into the overpack.
Three thin canister manufacturers and designs used in the U.S are Areva Transnuclear NUHOMS, Holtec above ground (HI-STORM) and underground (UMAX and site-specific HI-STAR HB/ISFSI Vault) and NAC MAGNASTOR dry storage systems.
See Details on U.S. approved canisters: Storage and Transport Cask Data For Used Commercial Nuclear Fuel, 2013 U.S. Edition, 13 ATI-TR-13047.
Southern California Edison considered the Holtec UMAX and Areva NUHOMS 32PTH2 systems and selected the Holtec UMAX system. Both these thin canister systems had licenses pending at the NRC. Comments were submitted to the NRC by various groups and individuals recommending licenses not be approved. The NRC stopped approval of both systems based on public comments. This Edison July 14, 2014 slide presentation provides a high level comparison of the two systems, the locations Edison considered, and some of the key impacts of each site location. Only Holtec, Areva-TN and NAC were allowed to bid on the dry storage system project. No thick cask vendors were allowed to bid.
- SCE’s project scope document outlines SCE’s requirements for the dry spent fuel storage system.
- SCE’s Vendor Assessment Matrix does not address inspection and corrosion issues of the thin steel canisters.
- Holtec’s warranty is very limited (10 years on underground system and 25 years on the Holtec MPC thin canister) and contains many exclusions. Holtec is providing only a two-year warranty for the Areva NUHOMS canisters it plans to load at San Onofre.
Update: Holtec obtained a license amendment to use the Holtec HI-STORM UMAX system in high seismic areas effective September 8, 2015. However, it’s not approved for any specific site, including San Onofre; that requires additional approvals, and they are only certified safe for 20 years. Any issues that may occur after 20 years are not considered by the NRC, even though they know they must last for decades and they do not have aging issues resolved. See more details below.
- Holtec International HI-STORM UMAX Canister Storage System, Certificate of Compliance No. 1040, Amendment No. 1 Direct Final Rule, Federal Register Vol. 80, No. 173, pp 53691 – 53694, effective September 8, 2015
- Letter To Coastal Commission regarding Holtec UMAX NRC approval, September 18, 2015, outlines the limitations of the approval, including the following items:
- Not an approval for use at San Onofre. “This rulemaking makes no determination regarding the acceptability of this amended system for use at any specific site.”
- Certified for only the initial 20 years. Any evaluation for conditions that may occur after this [such as cracking, inspection, aging management, fuel cladding failure from high burnup fuel] are outside the scope of this approval. “Long-term” [as referenced in the Holtec Safety Evaluation] is a general descriptive term that is not required to support any regulatory or technical evaluation, and thus is not required to be more formally defined.
- Excludes any plan for storing failed (cracking) canisters. Both San Onofre V.P. Tom Palmisano, and Holtec President, Dr. Kris Singh, state transfer casks can be used to store failed canisters (July 23, 2015 Community Engagement Panel meeting). However the NRC states “The HI-STORM UMAX transfer cask is authorized to transfer intact canisters [e.g., not cracking or otherwise failed canisters].” “Implementing corrective actions in the event of a failed MPC [multi-purpose canister] is the responsibility of the general licensee and those corrective actions are not incorporated into CoC [Certificate of Compliance] No. 1040.”
- Approved only for 0.5” thick canisters – not the 0.625” thickness San Onofre proposes. “The nominal MPC thickness for the canisters certified under CoC No. 1040, Amendment No. 1 is 0.5”. The NRC has no knowledge of a Holtec proposal to increase the thickness of an MPC to 0.625”. If presented with an amendment request to do so, the NRC will evaluate it in accordance with 10 CFR part 72 requirements.”
- The underground system evaluated is different than the system proposed for San Onofre. The approval is for an underground system, not the partially underground system proposed for San Onofre. “Pursuant to the regulatory requirements in 10 CFR 72.212(b), any general licensee that seeks to use this system must determine that the design and construction of the system, structures, and components are bounded by the conditions of the CoC by analyzing the generic parameters provided and analyzed in the FSAR [Final Safety Analysis Report] and SER [Safety Evaluation Report] to ensure that its site specific parameters are enveloped by the cask design bases established in these reports.”
- The NRC approved a 20-year general license for the UMAX system April 6, 2015 for lower seismic risk areas. Federal Register Notice List of Approved Spent Fuel Storage Casks: Holtec International HI-STORM Underground Maximum Capacity Canister Storage System, Certificate of Compliance No. 1040, Docket NRC-2014-0120, March 6, 2015
- Underground systems are more likely to have overheating problems from wind affects than above ground cask systems. Impact of Variation in Environmental Conditions on the Thermal Performance of Dry Storage Casks, NRC NUREG-2174, February 2015 (ML15054A207)
- Holtec submitted an NRC application for their proposed HI-STAR 190 transport cask on August 7, 2015. This requires high burnup fuel canisters to be intact prior to shipping in the transport cask.
Humboldt Bay’s Holtec HI-STAR HB/ISFSI Vault underground dry storage system was loaded with spent fuel in Fall 2008. The system is approved for that site only and contains only low burnup fuel that had already cooled 35 years in the spent fuel pools. It is nothing like the fuel stored at San Onofre and Diablo Canyon and very different from the system proposed for San Onofre. Humboldt Bay has only five casks, loaded with a total of 390 fuel assemblies; 130 of these assemblies had damaged fuel cladding at the time of loading. The latest NRC Humboldt Bay inspection report outlines some of the problems encountered with the underground system (e.g., water intrusion, broken concrete vault lid view port). Note: The word “inspection” is misleading. Not all critical parts of the system are designed to be inspected.
- Humboldt Bay NRC ISFSI Inspection May 31, 2013 ML13151A317 (includes Humboldt Bay Dry Cask inventory on last page)
- Humboldt Bay NRC Inspection Report 050-00133/10-001; 072-00027/10-001, February 9, 2010 ML100400102
- NRC issuance of exemption from certain emergency planning requirements in response to an August 14, 2012, request from the PG&E, Federal Register Volume 79, Number 232 Docket No. 50-133; NRC-2014-0225, December 3, 2014
- Dry Cask Storage, Pacific Gas & Electric, Humboldt Bay Power Plant, WM2010 Conference, March 7-11, 2010, Phoenix, AZ
- The Not-So-Peaceful Atom, The North Coast Journal, Japhet Weeks, March 20, 2008
- Video interview with former Humboldt Bay PG&E Nuclear Plant Technician Bob Rowen regarding PG&E nuclear safety violations, “A True Story of Betrayal of the Public Trust, Nuclear Power at Humboldt Bay“, January 26, 2015 http://youtu.be/-d4TisLh6UM
- Safety Evaluation Report Docket No. 72-27 Humboldt Bay Independent Spent Fuel Storage Installation, November 2005
- Coastal Commission Addendum to Staff Report E-11-018 – Class B and C Waste Storage Facility at Humboldt Bay Power Plant, adjacent to Humboldt Bay south of Eureka, Humboldt County (PG&E), September 7, 2012
- Humboldt Bay Power Plant, Unit 3 – License Amendment Request 13-01 Addition of License Condition 2.C.5, “License Termination Plan” ( ML131300009), released May 13, 2013
Rancho Seco, near Sacramento, California has 22 loaded Transnuclear NUHOMS-24P thin spent fuel storage canisters (21 with spent fuel and one with Greater Than Class C (GTCC) waste.
- First Rancho Seco canister was loaded April 19, 2001. These canisters are subject to corrosion from a marine environment even though they are not close to the ocean.
- There is no money allocated in the decommissioning trust fund to replace these canisters or mitigate an “accident.”
- The spent fuel pool was destroyed, so there is no current method to reload fuel to another canister.
- Rancho Seco Facility and Independent Spent Fuel Storage Installation (ISFSI) Inspection Report 05000312/2013007 and
07200011/2013001, August 22, 2013 (see last two pages for canister inventory)
- Safety Evaluation Report for Rancho Seco
- The marine air over the Pacific Ocean cause winds to diverge approximately at the RSNGS site, with the heavy marine air flowing northward into the San Joaquin Valley and southward into the Sacramento Valley. (page 2-4)
- Storm water runoff at the site is controlled primarily by surface ditches. Hadselville Creek on the north side of the site receives all drainage from the site and empties into Laguna Creek to the west. Laguna Creek is a tributary of the Consummes River, the Consummes River is a tributary of the Mokelumne River, and the Mokelumne River is a tributary of the Sacramento River… (page 2-5)
- Approximately 40 wells were identified within a 2-mile radius of the plant. (page 2-5)
- Groundwater at the RSNGS site occurs as a part of the Sacramento Valley Groundwater Basin. Initial tests at the site indicated the presence of groundwater underlying the site at approximately 150 ft below grade. This water table has been receding over recent years. Exploratory boring at the RSNGS site revealed that in the upper 200 ft of soil at the site, rocks are mainly highly permeable siltstone, sandstone, and silty sandstone. From 200 to 350 ft, the rocks are thick interbedded siltstone, claystone, and sandstone. The permeable sandstones in this interval constitute the major local aquifers. Permeability below 200 ft is estimated at 10,000 ft/yr in the horizontal direction and 2,000 ft/yr in the vertical direction. Groundwater in the local domain will not be affected by operation of the ISFSI because the facility produces no liquid, solid, or gaseous effluents [as long as the spent fuel storage canisters do not have cracks]. Page 2-7
High Burnup Fuel Details
- Since the 1990’s, the NRC has allowed reactor operators to move to high burnup fuel (>45 GWd/MTU) because it can burn longer in the reactor, thereby increasing nuclear industry profits.
- High burnup fuel definition: “Burnup” refers to the amount of power extracted from the fuel, typically stated in gigawatt-days per metric ton of uranium (GWd/MTU). U.S. nuclear plants have been shifting from lower burnup (less than approximately 45 GWd/MTU) to higher burnup fuels (above 45 GWd/MTU) in recent years, and continued research is needed to better understand the impacts, if any, of high burnup fuels on storage, transportation, and disposal. The NRC and DOE define anything above 45 GWd/MTU as high burnup fuel, although fuel as low as 30 GWd/MTU can present performance problems. See more information below.
- Experimental data over the last twenty years suggest that fuel utilizations as low as 30 GWd/MTU can present performance issues including cladding embrittlement under accident conditions as well as normal operations. …These cladding performance issues need to be addressed before extended fuel utilization fuel can be loaded into dry casks and transportation systems. See DOE A Project Concept for Nuclear Storage and Transportation, SRNL, June 15, 2013.
- The NRC has “insufficient data to support a licensing position” on high burnup dry cask storage per Dr. Robert E. Einziger.
- See his presentation (slide 7) on Status of NRC Research on High Burnup Fuel Issues, at the March 13, 2013 Regulatory Information Conference session on W24- Storage and transportation of High Burnup Fuel. Dr. Einziger is a Senior Materials Scientist in the NRC’s Division of Spent Fuel Storage & Transportation.
- Hear audio of the March 13, 2013 Conference session on Storage and transportation of High Burnup Fuel. Dr. Einziger’s presentation starts at 39:50 minutes.
- Recent experiments conducted by Argonne National Laboratory on high burnup fuel cladding material indicate that the current knowledge in cladding material property is insufficient to determine the structural performance of the cladding of high burnup fuel after it has been stored in a dry cask storage system for some time.
…The uncertainties in material property and the elevated ductile to brittle transition temperature impose a challenge to the storage cask and transportation packaging designs because the cask designs may not be able to rely on the structural integrity of the fuel assembly for control of fissile material, radiation source, and decay heat source distributions. The fuel may reconfigure during further storage and/or the subsequent transportation conditions. In addition, the fraction of radioactive materials available for release from spent fuel under normal condition of storage and transport may also change. The …(NRC) is working with the scientists at Oak Ridge National Laboratory (ORNL) to assess the impact of fuel reconfiguration on the safety of the dry storage systems and transportation packages. The NRC Division of Spent Fuel Storage and Transportation has formed a task force to work on the safety and regulatory concerns in relevance to high burnup fuel storage and transportation. Source: Regulatory Perspective on Potential Fuel Reconfiguration and Its Implication to High Burnup Spent Fuel Storage and Transportation – 13042, WM2013 Conference, February 24-28, 2013, Phoenix, Arizona, Zhian Li, Meraj Rahimi, David Tang, Mourad Aissa, Michelle Flaganan, NRC; John C. Wagner, Oak Ridge National Laboratory
- The NRC approved high burnup fuel based on false assumptions. In addition, they did not know how high burnup fuel would react in dry storage.
High Burnup Fuel: New Zirconium fuel claddings Zirlo and M5 have higher failure risk
Newer Zirconium alloy claddings (Zirlo and M5) degrade faster with high burnup fuel than earlier claddings, such as Zircaloy-4. San Onofre and other plants are approved for use of M5 cladding. Diablo Canyon uses Zirlo cladding.
- Ductile-to-Brittle Transition Temperatures for High-Burnup PWR Cladding Alloys Mike Billone and Yung Liu Argonne National Laboratory U.S. NWTRB Winter Meeting November 20, 2013, DOE Slide Presentation
- Slide 6 Cladding Mechanical Properties and Failure Limits
- Available for HBU Zircaloy-4 (Zry-4) with circumferential hydrides
- Available for Zry-2 but data needed at high fast fluence (i.e., HBU)
- Data needs
- Tensile properties of HBU M5® and ZIRLO™ cladding alloys
- Failure limits for all cladding alloys following drying and storage
- Radial hydrides can embrittle cladding in elastic deformation regime
- Slide 12 Summary of Results
- Susceptibility to Radial-Hydride Precipitation
- Low for HBU Zry-4 cladding
- Moderate for HBU ZIRLO™
- High for HBU M5®
- Susceptibility to Radial-Hydride-Induced Embrittlement
- Low for HBU Zry-4
- Moderate for HBU M5®
- High for HBU ZIRLO™
- Susceptibility to Radial-Hydride Precipitation
- Slide 6 Cladding Mechanical Properties and Failure Limits
- Fuel Disposition Campaign: Embrittlement and DBTT of High-Burnup PWR Fuel Cladding Alloys, Prepared for DOE Used Fuel Disposition Campaign, M.C. Billone, T.A. Burtseva, Z. Han and Y.Y. Liu, Argonne National Laboratory September 30, 2013, FCRD-UFD-2013-000401
- San Onofre Nuclear Generating Station, Units 2 and 3 – License Amendment Request RE: Use of Areva Fuel [M5], NRC Request for Additiona Information (RAI), August 1, 2012 (ML12207A261)
High Burnup Fuel Demonstration Project is not a solution
The NRC and DOE propose a “Demonstration Program” (High Burnup Dry Storage Project) for the industry to prove they can safely store high burnup fuel for another 20 years. However, the proposal doesn’t include developing better designs or materials for the dry canisters, and it requires the invention of instrument sensor technology that does not currently exist. Also, Dr. Einziger said it is up to the nuclear industry to solve this problem. However, the industry has known about this problem for decades, yet has no solution. They continue to use high burnup fuel, putting profits before safety.
- See Division of Spent Fuel Storage and Transportation Interim Staff Guidance-24, Revision 0, The Use of a Demonstration Program as Confirmation of Integrity for Continued Storage of High Burnup Fuel Beyond 20 Years
- EPRI has the DOE contract for the High Burn-up Dry Storage Cask Research and Development Project. See Draft Test Plan for Contract No.: DE-NE-0000593 and EPRI High Burnup Dry Storage Cask Research and Development Project Final Test Plan Rev. 9 02-27-2014, Contract No.: DE-NE-0000593.
- North Anna ISFSI High Burnup Dry Storage Research Project, TN-32 Storage Cask, Tom Brookmire presentation, Dominion, October 7, 2014 (ML14276A654)
High Burnup Fuel: U.S. Inventory
- Virtually all U.S. operating reactors are projected to have high burnup fuel. And the majority of the fuel in the spent fuel pools is high burnup.
- See Range of Burnup for Used Nuclear Fuel by Reactor, DOE, March 31, 2011 (Table 7). Table 7 provides the projected range of used fuel burnup for the assemblies discharged by the reactor.
- Table 7 is part of Inventory and Description of Commercial Reactor Fuels within the United States, DOE, March 31, 2011.
- Reactors decommissioned after 1997 are all projected to have produced high burnup fuel.
- The DOE EIA required all nuclear plants to submit spent fuel inventory reports by September 30, 2013. However, some have not yet complied (as of 2/24/2014). See DOE EIA Nuclear Fuel Data Survey Form GC-859. This is mandatory and the data is public, as stated on the form:
Data on this mandatory form are collected under authority of the Federal Energy Administration Act of 1974 (15 USC Schedule 761 et seq.), and the Nuclear Waste Policy Act of 1982, as amended (42 USC 10101 et seq.). Failure to file after receiving Energy Information Administration (EIA) notification may result in criminal fines, civil penalties and other sanctions as provided by the law. Data being collected on this form are not considered to be confidential. Title 18 U.S.C. 1001 makes it a criminal offense for any person knowingly and willingly to make to any Agency or Department of the United States any false, fictitious, or fraudulent statements as to any matter within its jurisdiction.
- Some of the Table 7 DOE inventory data appears to be based on projections rather than actual inventory. It also appears there may be a problem obtaining current inventory data from the nuclear industry. See this quote from the DOE report’s Conclusion (page 14):
This report provides the inventory of used nuclear fuel being stored in the United States based upon publicly available resources. It includes the most current projections of used fuel discharges from operating reactors. It includes a status of negotiations between DOE and industry. These negotiations are ongoing and are expected to result in a framework for cooperation between the Department and industry in which industry will provide and specific information on used fuel inventory and the Department will compensate industry for the material required for R&D and TEF activities.
- Over 200 dry casks contain high burnup fuel. The first high burnup fuel was loaded in 2003 at Maine Yankee. Maine Yankee loaded their high burnup fuel assemblies in “damaged fuel cans” as a safety precaution. However, they may be the only nuclear plant that has done this. See July 25, 2012 Nuclear Energy Institute (NEI) slide below. The NRC will not renew current high burnup 20-year dry cask licenses, due to the instability and unpredictability of high burnup fuel. High burnup storage problems need to be solved as soon as possible. However, they do not appear to be receiving the priority needed from the NRC, DOE or nuclear industry. And industry profits are currently a factor when developing solutions. This puts the public at risk for dangerous radiation releases. With no technology to monitor inside dry casks, we won’t know there is a problem until it’s too late. The response “it hasn’t happened yet”, is not a solution.
- The majority of U.S. plants may have high burnup used fuel exceeding 60 GWd/MTU. The NRC used this January 2001 NRC report Environmental Effects of Extending Fuel Burnup Above 60 GWd/MTU (NUREG/CR-6703) to justify amounts up to 75 GWd/MTU, even though they knew there were problems with even lower burnup levels. Example: Catawba Nuclear Station, Units 1 and 2, Environmental Assessment And Finding of No Significant Impact for increasing to 62 GWd/MTU
San Onofre Nuclear Waste
San Onofre major decommissioning issues
- Spent Fuel Pool Island. Edison plans to convert from once-through-cooling of the spent fuel pools to a spent fuel pool island (SFPI) using air-chillers at an estimated installation cost of $18,270,000. They will still use some once-through-cooling. The SFPI system is proposed to be installed in 2015.
- Edison submitted an NRC License Amendment Request on August 20, 2015 to lower safety standards for spent fuel pool cooling. They need this in order to use this lower grade cooling system. The NRC responded with a request for more information on November 12, 2015 (ML15314A321),
- This system requires four 200-ton heat capacity chillers (similar to technology used to cool large fish aquariums); two shipping containers housing four water pumps and piping necessary to circulate water through the spent fuel pools and chillers; and approximately 100 feed of pre-fabricated stainless steel piping to connect the spent fuel pools to the chillers (50% to be installed within the existing spent fuel buildings).
- Chillers are not nuclear rated and have only been used at a few locations and never in as challenging environment as San Onofre. This is an experimental system that the NRC doesn’t even plan to review until after it’s installed.
- Maine Yankee rejected using chillers for their spent fuel pool island. “ This system involves the use of a chiller (air conditioner) to remove heat. The system was rejected because: A. High initial cost. B. Still requires water or air cooled condenser, and C. Complex equipment and controls to maintain.” See Page 9 of report.
- Rancho Seco only used chillers for three years. They had fewer fuel assemblies and no high burnup fuel and the fuel was much cooler than San Onofre’s, so the demand for cooling was much less than San Onofre’s needs. They are also not located in a corrosive marine environment. Per Einar Ronninger, SMUD Decommissioning Project Manager, from its start in 1975 to the permanent shutdown in 1989 Rancho Seco only had a total equivalent of 6 full power years. Rancho Seco was also down from the mid to late 1980’s and then only operated for two years before permanent shutdown in 1989 (phone conversation with Donna Gilmore 7/14/2015 and Rancho Seco NRC Inspection Report, August 31, 1999, page 11)
The new spent fuel pool cooling system began operation on April 20, 1999. The operational acceptance test required the cooling system to operate for 8 weeks with less than 72 hours downtime. The 8-week test started on May 18, 1999 and ended on July 15, 1999, for a total of 8 weeks and 2 days. The total time the unit was down for maintenance repair was 19.5 hours.
- Coastal Commission denied Edison’s request for a permit waiver and is requiring Edison apply for a new Coastal Development Permit for this chiller cooling system. Santa Barbara Coastal Commission meeting May 14, 2015. Edison has been trying since February 2015 to obtain a Coastal permit waiver.
- San Onofre spent fuel pool cooling system and chiller waivers 9-15-0417-W and 9-15-0162-W memo to Coastal Commission from Donna Gilmore, May 14, 2015
- Notice of Coastal Development Permit DE MINIMUS Waiver, Permit No. 9-15-0162-W, April 3, 2015, scheduled for April 15-17, 2015 Coastal Commission meeting in San Rafael
- Cancelled Notice of Coastal Development Permit DE MINIMUS Waiver, Permit No. 9-15-0162-W, February 26, 2015 and Coastal Commission March 11, 2015 meeting notice and agenda.
- Coastal Commission application to install the new UMAX system is pending, tentatively scheduled for October 2015 Coastal Commission meeting. There are numerous concerns. The proposed installation is too close to the bluff. Doesn’t meet Coastal Act requirements. Needs updated seismic evaluation. Does not have NRC approval for UMAX system installation. Potential issues with water and soil moisture and chemistry.
- Letter to Coastal Commission regarding Holtec UMAX NRC approval, September 18, 2015
- Holtec International HI-STORM UMAX Canister Storage System, Certificate of Compliance No. 1040, Amendment No. 1 Direct Final Rule, Federal Register Vol. 80, No. 173, pp 53691 – 53694, effective September 8, 2015
- 3.19.15 Incomplete Filing Letter SONGS ISFSI
- NRC status of decommissioning. See status of all decommissioning power plants and information on decommissioning process at NRC Backgrounder on Decommissioning Nuclear Power Plants.
- NRC exemption for ISFSI costs. Dry storage of spent nuclear fuel is not part of the legal definition of decommissioning funds, but the NRC is allowing exemptions to fund the Independent Spent Fuel Storage Installation (ISFSI) from ratepayer decommissioning funds, claiming there are sufficient funds to do both decommissioning and spent fuel management. However, the Irradiated Fuel Management Plan (IFMP) makes unrealistic assumptions about the cost to manage the waste. It assumes nothing will go wrong with the storage canisters and that the Department of Energy (DOE) will start accepting the fuel “by 2024” and that “all fuel will be removed from the SONGS site by 2049.” They provide no facts to support these assumptions and ignore all the NRC and other data that indicates otherwise. The NRC, DOE and nuclear utilities have been trying for decades to find a site that will accept this nuclear waste, but all attempts have failed for legal, technical and political reasons.
- San Onofre Nuclear Generating Station, Units 2 and 3- Exemptions from the Requirements of 10 CFR Part 50, Sections 50.82(a)(8)(i)(A) and Section 50.75(h)(2) (TAC NOS. MF3544 and MF3545 (ML14101A132), September 5, 2014
- San Onofre Nuclear Generating Station, Units 2 and 3- Review and Approval of the Irradiated Fuel Management Plan (TAC NOS. MF4894 and MF4895) (ML15182A256), August 19, 2015 (page 5)
- Interim Storage of Spent Fuel in the United States, Allison Macfarlane,
Security Studies Program, Massachusetts Institute of Technology, 2001, Section 2.1. Legislative History (PDF pages 4 through 8)
- Internal Revenue Service may not allow spent fuel management costs to be included as decommissioning costs for tax purposes. See similar IRS ruling dated March 6, 2015.
- Unfunded storage costs. Safety and financial impact of the NRC August 2014 decision to allow nuclear waste storage to continue indefinitely on-site has not been addressed in the decommissioning process or the dry storage licensing process, or any other process.
- Dry cask storage aging issues. The NRC plans to have an aging management plan in NUREG-1927 sometime in 2015. However, Mark Lombard, NRC Director of Spent Fuel Management Division, said he is limited his Division’s evaluations to the existing thin steel canister designs, in order to have the vendors fund the planning and research for continued on-site storage. He is ignoring the leading dry storage technologies used internationally. See Reasons to Buy Thick Nuclear Waste Storage Casks.
- TOTAL: 2776 spent fuel assemblies (SFA) in the pools.
- 1426 SFA (1318 + 108 with zero burnup) in U2 Spent Fuel Pool.
- 1350 SFA in U3 Spent Fuel Pool.
- 31 failed (damaged) fuel assemblies (15 in U2 and 16 U3).
- Unit 2 Spent Fuel Pool Inventory Report
- Unit 3 Spent Fuel Pool Inventory Report
- The last fuel loaded into the pools from Unit 2 on July 18, 2013 and from Unit 3 on October 5, 2012.
- Total high burnup fuel: Edison reported to the CPUC there are 1115 High Burnup spent fuel assemblies in the pools. However, the total is 1220 if you round up, as required by the cask manufacturer. In addition, the NRC requires a 7% error margin be added to the burnup calculation. This brings the total to 1607 high burnup spent fuel assemblies (834 in Unit 2 and 773 in Unit 3). Note: SFA 40 to . That would bring the total to 1935 high burnup fuel assemblies (985 in Unit 2 and 950 in Unit 3).
- Total 51 loaded dry storage canisters per 2014 NRC San Onofre ISFSI Inspection Report.
- Total 42 loaded dry storage canisters per 2011 NRC San Onofre ISFSI inspection report.
- All the dry stored fuel is 30+ GWd/MTU. The DOE states fuel as low as 30 GWd/MTU shows similar problems to high burnup fuel. One canister is 29.5 GWd/MTU, but burnup is rounded up to the next whole number to allow for margin of error.
- 8 High Burnup fuel assemblies in dry casks, according to Edison. Edison adds 7% to the burnup GWd/MTU in their Loaded Casks 2014 Inventory Report. However, their count of 8 high burnup fuel assemblies doesn’t reflect the 7%, so the actual high burnup count for loading purposes is higher.
- 1 placed in the pool 8/17/1991. Moved to dry storage 2/28/2007. Approximately 15.5 years in pool.
- 2 placed in the pool 7/22/1995. Moved to dry storage 4/7/2008. Approximately 12.75 years in pool.
- 5 placed in the pool 1/2/2001. Moved to dry storage 6/30/12. Approximately 11.5 years in pool.
- 2011 Inventory Information
- 95 FAILED (DAMAGED) fuel assemblies stored in dry casks. This is higher than normal for nuclear reactors and the NRC says they are not sure why. 2011 NRC San Onofre ISFSI inspection report, page 11 (ML111430612).
- Unit 1
- 19 canisters; 9 with 27 failed fuel assemblies; one canister with Greater-than-Class-C (GTCC) waste removed from the internals of reactor Unit 1. GTCC remains hazardous for more than 500 years. It is the most hazardous form of low-level waste (LLW). GTCC consists of activated metals, sealed sources, and contaminated trash. The radionuclides in these wastes are primarily cesium-137 and americium-241.
- Burnup ranges from 34.9 to 43.2 GWd/MTU, with maximum initial fuel enrichment of 4.02%.
- Unit 2
- 11 canisters; 4 with 46 failed fuel assemblies.
- Burnup ranges from 38.3 to 48.3 GWd/MTU, with maximum initial fuel enrichment of 4.49%.
- Unit 3
- 12 canisters; 2 with 22 failed fuel assemblies.
- Burnup ranges from 29.5 to 50.1 GWd/MTU, with maximum initial fuel enrichment of 4.6%.
- Unit 1
- 95 FAILED (DAMAGED) fuel assemblies stored in dry casks. This is higher than normal for nuclear reactors and the NRC says they are not sure why. 2011 NRC San Onofre ISFSI inspection report, page 11 (ML111430612).
- Unit 1 24-assembly Model 24PT1-DSC canister is allowed a maximum 4 failed fuel assemblies per canister and is not licensed for high burnup fuel. It is approved for transportation.
- Unit 2 and 3 24-assembly Model 24PT4-DSC canister is allowed 12 maximum failed fuel assemblies per canister and is licensed for high burnup fuel for a maximum 20 years. There is no approval for over 20 years for high burnup fuel canisters, due to insufficient data about high burnup fuel safety. There is no approval for transport of high burnup fuel.
- The NUHOMS MP197HB Transport Cask is approved for high burnup fuel transport for the 24PT4-DSC. However, according the Safety Evaluation Report, Revision No. 7 (ML14114A132.pdf)
- The 24PT4-DSC still needs to be approved for high burnup fuel transport.
- The NUHOMS 32PTH2 is not approved for use in the MP197HB (page 2)
- Minimum cooling time for the 24PT4-DSC high burnup fuel is 15 years (page 3).
- Loaded transport weight of MP197HB is 152 tons, exceeding current rail transport standards (page 2)
- Maximum heat load for transport of 24PT4 DSC is 24kW, for a 37-fuel assembly canister, 22kW (page 14).
- NUHOMS dry casks system CoC 1029 technical specifications for 24PT1-DSC and 24PT4-DSC, Amendment No. 1
- NUHOMS dry cask systems not used at San Onofre (CoC 1004): NUHOMS-24P, -24PHB, -24PTH, -32PT, -32PTH1, -52B, -61BT, and -61BTH. Systems, Amendment No. 11, (CoC, Technical Specifications, SER) (72-1004). ML120130550. Amendment 11 approved January 7, 2014.
Additional San Onofre Nuclear Waste Information
- The NRC is considering requiring high burnup fuel assemblies be treated like damaged fuel and encased in stainless steel Failed Fuel Cans, providing an extra layer of protection. However, the nuclear industry is resisting this due to cost. For San Onofre, this would mean a maximum 12 of the 24 fuel assemblies in a canister could be high burnup fuel (page 2-10 of technical specifications).
- Nuclear fuel assemblies must cool in the spent fuel pool before they can be moved to dry casks. The maximum heat load for the 24PT4-DSC dry shielded canister(page 2-3 of technical specifications) is 1.26 kW per assembly and 24 kW per canister. Below are two of the Tables that may be used to calculate the amount of cooling time required. Table 2-9 only cools the fuel to 1.26 kW per assembly. Table 2-12 cools the fuel to 0.9 kW per assembly.
- It may be safer to cool the fuel assemblies to a lower temperature before putting them in dry casks, especially for high burnup fuel. However, nuclear plants may want to speed the process, if it is more profitable for them.
- Spent fuel pools are dangerously over crowded, so it may be desirable to move the lower burnup fuel to dry casks, leaving the high burnup in the pools. They are far safer less densely packed. However, nuclear plants may not want to do this for cost reasons.
- Note: San Onofre’s older NUHOMS® 24PT1-DSC is not approved for and was not used for high burnup fuel. Maximums allowed for the 24PT1-DSC are: 45 GWd/MTU for fuel with an initial enriched uranium weight up to 3.96% of U-235 (Table 2.4) and 25 GWd/MTU for MOX Fuel (Table 2.1).
- Note: MOX fuel was used experimentally in San Onofre Unit 1. “A plutonium recycle demonstration program was conducted by Edison Electric Institute and Westinghouse Electric Corporation during 1968 to 1974. Radiochemical analyses were made on six pellet samples from four MOX fuel pins irradiated for either one or two cycles in the San Onofre PWR Unit 1.
- QUESTION FOR THE NRC: Why is the NRC continuing to allow high burnup fuel use when they don’t have a safe solution to store or transport this waste — even short-term?
Q: Does San Onofre have high burn-up nuclear fuel and, if so, how does that affect the way you store this used fuel? A: Like many other nuclear plants, San Onofre has taken advantage of improvements in fuel technologies that allow nuclear plants to extract more energy from the fuel by achieving higher burn-up levels. SCE is licensed to use this fuel and store it in the spent fuel pool, and our dry storage canisters are licensed separately to store high burn-up fuel. Once this fuel is removed from the reactor, it is stored in accordance with NRC regulations and in the same manner as San Onofre’s other used fuel — initially in a steel-lined, concrete spent fuel pool and later in dry cask storage. What Mr. Palmisano doesn’t say:
- NRC’s regulations won’t renew dry cask storage for high burnup after the initial 20 years, because of insufficient data that it is safe.
- NRC’s regulations won’t approve transportation casks for high burnup fuel.
- San Onofre’s decision to switch to high burnup fuel was made to increase profits at the expense of our safety.
- The enriched uranium (U-235) fuel used in high burnup is hotter and more radioactive coming out of a reactor than conventional fuel and at San Onofre their higher burnup level requires it remain in the spent fuel pools for a MINIMUM of 20 years (rather than the normal 5 years) to cool sufficiently before it can be moved to dry cask storage.
- Elias Henna, from Southern California Edison (SCE), said San Onofre high burnup fuel has to cool for “about 15years” in the spent fuel pool.
- “Some fuel assemblies cannot be transferred from the SONGS 2 & 3 spent fuel pools to dry storage until 12 years after they are discharged from the reactor because they require up to 12 years of thermal cooling before they can be placed in dry storage canisters,” according to SCE Supplemental Testimony: SONGS 2 & 3 Early Decommissioning Scenario July, 22, 2013, submitted to the California Public Utilities Commission.
- High burnup fuel is more difficult to store and transport.
- There is no transportation cask approved for high burnup fuel.
- NRC Spent Fuel Transportation Risk Assessment (Draft) NUREG-2125, May 2012, page 139, 6.3 Effect of Transportation of Higher Burnup Spent Nuclear Fuel
At the time the analyses for this report were completed, the maximum burnup for the spent fuel transported in any of the casks was 45 GWD/MTU. Current reactor operations result in spent fuel with burnup levels higher than this. A detailed examination of the effect of the higher burnup levels is outside the scope of this document, but this section provides some general insights on expected changes resulting from transporting these higher burnup spent fuels. …Insufficient data exists to accurately estimate the rod-to-cask release fractions for higher burnup fuel…
Typically, according to NRC officials, spent fuel must remain in a pool for at least 5 years to decay enough to remain within the heat limits of currently licensed dry cask storage systems. Spent fuel cools very rapidly for the first 5 years, after which the rate of cooling slows significantly. Spent fuel can be sufficiently cool to load into dry casks earlier than 5 years, but doing so is generally not practical. Some casks may not accommodate a full load of spent fuel because of the greater heat load. That is, the total decay heat in these casks needs to be limited to prevent the fuel cladding from becoming brittle and failing, which could affect the alternatives available to manage spent fuel in the future, such as retrieval. In recent years, reactor operators have moved to a slightly more enriched fuel, which can burn longer in the reactor. Referred to as high-burn-up fuel, this spent fuel may be hotter and more radioactive coming out of a reactor than conventional fuel and may have to remain in a pool for as long as 7 years to cool sufficiently. [Note: the 7 year information is out of date. Cooling time can range from a 7 to 20 year minimum, depending on the dry cask specifications and the level of fuel burnup and uranium enrichment].
- Nuclear engineers have long known of increased risks from high burn-up fuels. However, they continue to experiment at our expense and continue to increase the burnup rate — for industry profits. The high the burnup, the higher the risk of failure.
- Argonne scientists reported high burn-up fuels may result in fuel rods becoming more brittle over time. The U.S. Nuclear Waste Technical Review Board (NWTRB) December 2010 report, “Evaluation of Technical Basis for Extended Dry Storage and Transportation of Used Nuclear Fuel”, December 2010 states insufficient information is available on high burnup fuels to allow reliable predictions of degradation processes during extended dry storage.
Only limited references were found on the inspection and characterization of fuel in dry storage, and they all were performed on low-burnup fuel after only 15 years or less of dry storage [using the CASTOR V/21 cask, which has very difference specifications than the stainless steel canisters commonly used in the U.S. today (maximum 21 PWR fuel assemblies, maximum initial U-235 enrichment 2.2% – 2.3%, maximum burnup 35 GWd/MTU, maximum fuel assembly heat generation 1kW, side-wall thickness 14.9″, two stainless steel bolted lids (11.4″ and 3.5″ thick) and no damaged fuel assemblies allowed.] Insufficient information is available on high-burnup fuels to allow reliable predictions of degradation processes during extended dry storage, and no information was found on inspections conducted on high-burnup fuels to confirm the predictions that have been made. The introduction of new cladding materials for use with high-burnup fuels has been studied primarily with respect to their reactor performance, and little information is available on the degradation of these materials that will occur during extended dry storage. The NWTRB also states [page 11]: These [degradation] mechanisms and their interactions are not well understood. New research suggests that the effects of hydrogen absorption and migration, hydride precipitation and reorientation, and delayed hydride cracking may degrade the fuel cladding over long periods at low temperatures, affecting its ductility, strength, and fracture toughness. High-burnup fuels tend to swell and close the pellet-cladding gap, which increases the cladding stresses and can lead to creep and stress corrosion cracking of cladding in extended storage. Fuel temperatures will decrease in extended storage, and cladding can become brittle at low temperatures.
- High burnup fuel creates problems in numerous areas of reactor safety. The nuclear industry continues to experiment with different alloys, water chemistry, etc, but have yet to succeed in solving high burnup problems. However, this hasn’t stopped the U.S. nuclear industry from using high burnup fuel and has not stopped the NRC from approving use of this dangerous fuel. IAEA: Current Trends in Nuclear Fuel for Power Reactors, August 2007. The nuclear industry’s response is to downplay the data and claim there is no probability problems will happen. See EPRI In Use: High Burn-Up Fuel Transportation, January 2013.
Concrete aging problems
The types of dry storage systems used in the United States are subject to concrete failure within the needed storage period of the dry storage system. The U.S. dry storage systems use concrete overpacks or casks for protection from certain types of radiation (gamma and neutron).
The NRC gave a presentation on these unresolved concrete aging issues in their July 14, 2014 presentation on Generic Concrete Aging Management. No solutions have been identified at this point. The option of using thick forge steel or thick ductile cast iron cask designs was not considered in this presentation. Thick casks don’t require concrete.
Concrete degradation reports
- NRC Concrete Expert Panel Workshop, February 24-25, 2015
- NRC A Summary of Aging Effects and Their Management in Reactor Spent Fuel Pools, Refueling Cavities, Tori, and Safety-Related Concrete Structures, NUREG/CR-7111, January 2012
- DOE Activities at ORNL in support of continuing the service of nuclear power plant concrete structures, D. J. Naus, Oak Ridge National Laboratory, May 2012: Examples of age-related degradation include: corrosion of steel reinforcement in water intake structures, corrosion of post-tensioning tendon wires, rock anchor/tendon coupling failure, leaching of tendon gallery concrete, larger-than-anticipated loss of prestressing force, concrete spalling at containment buttress, water infiltration, and leakage of corrosion inhibitors from tendon sheaths. Other examples include cracking and spalling of containment dome concrete due to freeze-thaw damage, low strengths of tendon wires, and corrosion of concrete containment liners (interior areas as well as backside areas adjacent to concrete). Recently, concrete cracking due to alkali-silica reactions has been identified at one plant , and internal concrete cracks associated with architectural features of a shield building were observed at another plant during construction of an opening to replace the reactor pressure vessel head . Also, leakage of water from spent fuel pools and refueling cavities has occurred at several plants that may potentially result in erosion of the concrete or corrosion of carbon steel components it contacts, particularly for pressurized-water reactors that utilize borated water . A review of plant operating experience indicates that aging degradation of concrete has primarily been in the form of cracking/spalling/loss of material due to aggressive chemical attack . [See document for references].
- FHWA Alkali-Silica Reactivity Field Identification Handbook [concrete damage], December 2011: Two types of alkali-aggregate reaction (AAR) are currently recognized depending on the nature of the reactive mineral; these are alkali-silica reaction (ASR) and alkali-carbonate reaction (ACR). Both types of reaction can result in expansion and cracking of concrete elements, leading to a reduction in the service life of concrete structures. This handbook serves as an illustrated guide to assist users in detecting and distinguishing ASR in the field from other types of damages.
- Special NRC Oversight at Seabrook Nuclear Power Plant: Concrete Degradation. Seabrook developed concrete degradation due to alkali-silica reaction (ASR). Concrete issues, other than ASR, have also been experienced at other nuclear power plants. Crystal River 3 was shut down due to cracking (e.g., delamination) of the concrete walls in the plant’s containment building. The issue occurred during work on an opening in the containment in preparation for a steam generator replacement project. Duke Energy, the plant’s owner, announced on Feb. 5, 2013 that it planned to permanently cease operations at the Florida facility. In 2011, the Davis-Besse nuclear power plant discovered cracking in the Ohio plant’s Shield Building wall, a concrete enclosure around containment, while contractors were creating an opening for replacement of the reactor vessel head. Information related to this issue can be found in NRC Inspection Report IR 05000346/2012007. …the concrete degradation mechanisms in these plants is different than that identified at Seabrook.
San Onofre’s Elias Henna says high burnup may not be worth the risk and costs
Elias Henna, from Southern California Edison (SCE), said high burnup fuel has to cool for about 15 years in the spent fuel pool. See March/April 2003 Radwaste Solutions Saving a Few Hundred Million Dollars, p.69 (A Session Report from the 2002 American Nuclear Society (ANS.org) Winter Meeting):
Elias Henna, from Southern California Edison (SCE), which is decommissioning San Onofre-1, stated that the unit was shut down prematurely in 1992. The plant needed some $125 million in upgrades, and the expenditure was not deemed prudent at the time. This decision is now regretted in many quarters, Henna said. Henna noted that his company is learning a lot from the San Onofre-1 cleanup, because it has two operating units sharing the plant site. His major suggestion was one that might seem counterintuitive, he said: If you have already decided on a decommissioning date sometime in the future, toward the end of life, switch to shorter refueling cycles and use lower burnup fuel. That way you will have to cool the fuel in the pool only five years, whereas high-burnup fuel has to cool for about 15 years. In this way, he said, you will add a couple more refueling cycles but can shorten your decommissioning project by some four years (assuming no technological breakthroughs in canister design and no change in U.S. Nuclear Regulatory Commission regulations). You will add about $191 million in fuel costs, he noted, but will save up to $261 million in decommissioning costs. This idea is more appropriate for a plant operating in a regulated market not a free market, he conceded. SCE is current replanning the fuel cycles of Units 2 and 3 toward the end of plant life to incorporate this idea. Henna also touched on the issue of safety. One incident can shut down the whole project, and you may not be able to go back to work for a couple of years.
source: Managing Aging Effects on Dry Cask Storage Systems for Extended Long-Term Storage and Transportation of Used Fuel, Argonne National Laboratory, June 30, 2012
Dry Canisters: No ability to monitor inside or outside U.S. dry storage canisters
There is no ability to monitor inside dry canister systems. In the October 7, 2014 NRC meeting regarding the Dominion, DOE and EPRI High Burnup dry cask demonstration project, it was confirmed the lid monitoring for the project only applies to a TN-24 bolted lid cask and there are no plans for this project to develop internal monitoring for welded canisters (the main type used in the U.S.). The above information is an update to the below Forbes article.
There is no ability to monitor inside dry casks. Uncertain as to what is happening inside dry casks, the Department of Energy and the industry’s Electric Power Research Institute (EPRI) are embarking on a four-year, $16 million project to develop instrumented lids that can report on the status of the spent rods inside. At a 2011 conference, Argonne and DOE scientists proposed modifying sensors that are already used to monitor other nuclear materials during packaging and shipping. “The current built-in sensor suite consists of seal, temperature, humidity, shock, and radiation sensors” they said. “Other sensors can be easily added as needed. The system can promptly generate alarms when any of the sensor thresholds are violated.” To monitor the interior of dry casks, the current sensors need several improvements, according to the Argonne scientists:
- The ability to endure temperatures above 200 degrees C
- The ability to endure radiation levels higher than 1000 rads per hour
- A means of “harvesting” the energy inside the container
- Batteries that will power the sensors for more than 10 years, and
- A way to wirelessly transmit the sensor data out of the cask.
See details below regarding cask monitoring and related information.
- Fancy New Lids for Nuclear Waste Casks, As Contents Get Hotter – Forbes – May 2, 2013.
- EPRI Press Release and Schedule, April 22, 2013
- NRC: The Use of a Demonstration Program as Confirmation of Integrity for Continued Storage of High Burnup Fuel Beyond 20 Years (Draft)
- Briefer on the DOE’s High Burn-Up Used Fuel Demonstration Project, Power Engineering, October 11, 2013.
- EPRI Draft Test Plan for Contract No.: DE-NE-0000593
- EPRI Final Demonstration Test Plan 2014-02-27
Bolted-lid thick casks such as the NRC approved Areva series (TN-24, TN-32 and TN-40) and the Castor series (V/21 and X/33) can be inspected inside and out. The thin (1/2″ to 5/8″) canisters systems cannot be inspected on the outside and cannot be inspected on the inside without destroying the canister.
“The current method of monitoring for a leak in bolted dry casks by a change in pressure in the space between inner and outer lids has worked well and needs no improvement.”
- NRC Job Code V6060: Extended In‐Situ and Real Time Monitoring, Task 3: Long‐Term Dry Cask Storage of Spent Nuclear Fuel, Argonne National Laboratory, March 2012, ANL/NE‐12/18, ML13015A321, J.D. Lambert, S. Bakhtiari, I. Bodnar, C. Kot, J. Pence (ML13015A321)
- NUREG- 1571 Information Handbook on Independent Spent Fuel Storage Installations, NRC Office of Nuclear Material Safety and Safeguards, M. G. Raddatz, M. D. Waters, December 1996 (ML010450036)
San Onofre: Plans to procure inferior dry cask system
Southern California Edison plans to upgrade to NUHOMS® 32PTH2 dry cask system in September 2014. This means storing 32 fuel assemblies rather than the current 24 fuel assemblies in each dry canister. The higher number of fuel assemblies brings higher risk of radiation releases, especially for high burnup fuel. The canisters are only 5/8″ thick stainless steel and eliminated the ability to even containerize (“can”) damaged fuel assemblies. NRC Interim Staff Guidance ISG-22, Revision 12, Potential Rod Splitting Due to Exposure to an Oxidizing Atmosphere During Short-term Cask Loading Operations in LWR or Other Uranium Oxide Based Fuel, and NRC SECY-01-0076 states spent fuel must be retrievable. It is unclear how this new container can meet this requirement.
…Damaged spent fuel assemblies are to be canned, and thus are individually retrievable from the storage canister in which they are placed. An individual can contains any gross fuel particles such that the canned assembly remains retrievable. Several cans may then be placed inside a storage canister, along with intact (uncanned) assemblies.
Staff practice has been to consider damaged fuel assemblies retrievable if they are placed into individual cans. The staff believes this practice is consistent with the retrievability requirements of 10 CFR 72.122(l) and 72.236(m).
- This request has been approved by the NRC and will be effective June 30, 2014, unless significant adverse comments are received. UPDATE: The NRC withdrew their approval based on comments we submitted. However, this is only a partial victory. The NRC plans to modify and reissue it and will not allow further comments. This direct rule approval included both storage and transport of high burnup fuel without providing justification for the regulatory changes on high burnup fuel. It flagrantly violated the requirements of the Atomic Energy Act and the Administrative Procedure Act for prior notice and opportunity for public participation in NRC decisions affecting public safety and the environment.
- Please urge your state elected officials and regulators to:
- Require Southern California Edison to end the current bid process and restart the bidding process. All current bidders use thin stainless steel canisters with concrete overpacks, subject to short-term aging problems. Rebidding may bring in higher quality canister designs, such as the thick ductile cast iron canisters used in Germany and elsewhere.
- Require the CPUC to not approve payment for a canister design until Edison and the NRC can demonstrate this design will last the 100+ years required for on-site storage and that there is an inspection and remediation plan in case of canister failure. CPUC Commissioner Florio said we want these canisters to last — we don’t want to have to buy them again. Edison’s Tom Palmisano said the cost is about $400 million for the dry storage system. It is paid by ratepayers. We don’t need another “steam generator” like boondoggle, but it looks like we’re headed for another one if the CPUC doesn’t act.
- Comment letter to NRC urging withdrawal of final ruling on the NUHOMS 32PTH2 (submitted May 15, 2014 and corrected May 27, 2014)
- Donna Gilmore Comment to NRC Docket No. 2013-0271 NUHOMS32pth2, May 15, 2014 regarding redefining damaged fuel
- 04-15-2014 Federal Register Notice re NUHOMS 32PTH2 dry cask approval
- SCE Request to replace Dry Cask Storage System to NUHOMS® 32PTH2, February 10, 2012 (NRC ML12046A013).
- SCE CPUC 2015 Rate Case Application
- NRC approved the request for the NUHOMS® 32PTH2 dry cask system. See latest specifications and other details (released April 8, 2014) at
- Federal Register link for NUHOMS 32PTH2 approval and withdrawal. Refer to Docket ID NRC-2013-0271 in any correspondence to the NRC about this.
- NRC documents for approved NUHOMS® 24PT1 and 24PT4. The 24PT4 was approved for high burnup fuel storage (up to 60 GWd/MTU) for 20 years, effective May 16, 2005.
- See list of Dry Spent Fuel Storage Designs approved by the NRC for general use.
- See § 72.214 For list of approved spent fuel storage casks and dates approved.
- Transnuclear (NUHOMS) 32-TN Dry Cask System Final Safety Evaluation Report (ML003696918)
- See Part 72—Licensing Requirements for the Independent Storage of Spent Nuclear Fuel, High-Level Radioactive Waste and Reactor-Related greater than Class C Waste.
San Onofre: Eliminates 39 emergency responder positions
The NRC’s March 26, 2014 San Onofre inspection report cited Edison for eliminating 39 emergency response positions without obtaining NRC approval. Edison’s justification was that 18 months of cooling reduced radiation and heat levels enough to reduce dose consequences from an accident. How can such a claim be made when the tons of nuclear waste at San Onofre remains highly radioactive and hot?
The NRC report states that Edison claimed that because they “…had been in cold shutdown/refueling for over 18 months, sufficient time has elapsed to allow reductions in decay heat and radioactive material inventory such that dose consequences from an accident would not exceed the threshold for an Alert emergency declaration.”
The NRC notice of violation states “The failure to obtain prior NRC approval before implementing Emergency Plan changes that required such approval was a performance deficiency. This violation was …determined to be more-than-minor… The violation was determined to be a Severity Level IV violation according to Section 6.6, “Emergency Preparedness.” This finding has been entered into the licensee’s corrective action program as Nuclear Notification 202734313. (Section 1EP4).” (See list of eliminated positions in the report.)
San Onofre: Worst safety complaint record
Edison has the worst safety complaint record and highest rate of retaliation against employees of both active and inactive nuclear power plants, so we should demand more oversight and more public involvement in the decommissioning process.
All current waste storage options have serious drawbacks. It is important for the public to understand the risks and benefits of each storage option and get involved. This issue affects both current and future generations.
High Burnup Spent Fuel: What are the implications? June 2009 slide presentation by Hugh Richards, Nuclear Consultation Group, describes the current problems with storage of high burnup spent fuel.
- High Burnup Radioactive Spent Fuel presentation, Dr. Paul Dorfman, May 8, 2009. Excellent slide presentation summarizing high burnup problems. PDF version of presentation.
- The Hazards of Generation III Reactor Fuel Wastes: Implications for Transportation and Long-Term Management of Canada’s Used Nuclear Fuel, May 2010 by Marvin Resnikoff, Ph.D, Jackie Travers, and Ekaterina Alexandrova, Radioactive Waste Management Associates. Excellent report explaining dangers of higher burnup fuel.
- Table 3 shows the AECL ACR-1000, Westinghouse AP1000, and Areva EPR new generation reactors. They use enriched uranium (higher burnup fuel). Canada currently uses a much lower burnup fuel than the U.S. Canada decided to not build generation III reactors.
- Memo from Marvin Resnikoff to Bob Halstead, 7/18/2013, NUREG-2125 Review: “…NUREG-2125 [NRC Spent Fuel Transportation Risk Assessment] and its supporting references cannot support the conclusion that no radioactive material would be released in a severe transportation accident involving a truck cask.”
- NRC: Interim Staff Guidance – 11, Revision 3 Cladding Considerations for the Transportation and Storage of Spent Fuel. Approved by L. W. Camper on November 17, 2003. Eliminates approval of transportation casks for high burnup fuel. Until further guidance is developed, the transportation of high burnup commercial spent fuel will be handled on a case-by-case basis using the criteria given in 10 CFR 71.55, 10 CFR 71.43(f), and 10 CFR 71.51. Also, maximum fuel cladding temperature is now 400° C (752° F).
- NRC: Retrievability, Cladding Integrity and Safe Handling of Spent Fuel at an Independent Spent Fuel Storage Installation and During Transportation Docket: NRC-2013-0004- Maine Yankee response, March 2013. The NRC asked stakeholders (ML12293A434) critical questions that indicate they may be planning to lower storage safety standards. Here are two of the questions and one significant answer from Maine Yankee.
- Should each high burn-up spent fuel assembly be canned to ensure individual fuel assembly retrievability? Additionally, should spent fuel assemblies classified as damaged prior to loading continue to be individually canned prior to placement in a storage cask?
At Maine Yankee, the high burn-up spent fuel assemblies (greater than 45,000 MWd/MTU average assembly burn-up) were placed in damaged fuel cans. The spent fuel assemblies were transferred to dry cask storage over a decade ago. At that time, there was considerable uncertainty regarding the status of the integrity of high burn-up spent fuel. In Maine Yankee’s case, the 90 canned high burnup spent fuel assemblies were accommodated in the 60 SNF canisters, without requiring the acquisition of additional canisters. The extra cost for performing this activity was approximately $800,000 in 2002 dollars (i.e., essentially the cost of the 90 damaged fuel cans).
- Given the uncertainty with the material properties of high burn-up spent fuel, it is unclear whether some spent fuel may degrade during storage periods longer than 20 years and subsequent transportation. The NRC would like external stakeholders to provide an assessment of: 1. Whether ready-retrieval of individual spent fuel assemblies during storage should be maintained, or 2. Whether retrievability should be canister-based.
This question reveals that the NRC is considering bowing to industry pressure to lower safety standards. The licensees that responded to this question all supported lowering the standard to canister-based, rather than the current requirement that spent fuel assemblies be removable.
- Dry Storage Demonstration for High-Burnup Spent Nuclear Fuel – Feasibility Study, EPRI, Palo Alto, CA, and U.S. Department of Energy, Washington, DC: 2003. 1007872. See Chapter 5 Conclusion (starts on page 5-1) for good summary of high burnup issues.
- HANDBOOK to Support Assessment of Radiological Risk Arising From Management of Spent Nuclear Fuel, Gordon R. Thompson, January 31, 2013
- Although the economic advantage of zircaloy cladding [over stainless steel cladding] during routine operation of an NPP is clear, there is a price to be paid in terms of radiological risk. Zircaloy, like zirconium, is a chemically reactive material that will react vigorously and exothermically with either air or steam if its temperature reaches the ignition point – about 1,000 deg. C.
- The potential for ignition of zircaloy is well known in the field of reactor risk, and has been observed in practice on a number of occasions. For example, during the TMI reactor accident of 1979, steam-zirconium reaction occurred in the reactor vessel, generating a substantial amount of hydrogen. Some of that hydrogen escaped into the reactor containment, mixed with air, and exploded. Fortunately, the resulting pressure pulse did not rupture the containment. Similar explosions during the Fukushima #1 accident of 2011 caused severe damage to the reactor buildings of Units 1, 3, and 4.
- …stainless steel could substitute for zircaloy as a cladding material. The nuclear industry would undoubtedly resist this substitution, which would adversely affect the economics of NPP operation and would disrupt long-established practices in the industry. Also, stainless steel can react exothermically with air or steam, although with a lower heat of reaction than is exhibited by zircaloy.
- If water were lost from a [spent fuel] pool equipped with low-density racks, there would be vigorous, natural convection of air and steam throughout the racks, providing cooling to the SNF. Thus, in most situations, the temperature of the zircaloy cladding of SNF in the racks would not rise to the ignition point. Exceptional circumstances that could lead to ignition include the presence of SNF very recently discharged from a reactor, and deformation of the racks. Even then, propagation of combustion to other fuel assemblies would be comparatively ineffective, and the total release of radioactive material would be limited to the comparatively small inventory in the pool.
- Faced with the problem of growing inventories of SNF, the nuclear industry could have continued using low-density racks in the pools while placing excess fuel in dry casks. That approach would have limited SNF radiological risk. Instead, the industry adopted a cheaper option. Beginning in the 1970s, the industry re-equipped its pools with higher density racks. In the high-density racks that are now routinely used around the world, the center-center spacing of fuel assemblies approaches the spacing in a reactor… To suppress criticality, the assemblies are separated by plates containing neutron-absorbing material such as boral (boron carbide particles in an aluminum matrix).
- Two studies completed in March 1979 independently identified the potential for a pool fire. One study was by members of a scientific panel assembled by the state government of Lower Saxony, Germany, to review a proposal for a nuclear fuel cycle center at Gorleben. After a public hearing where the study was presented, the Lower Saxony government ruled in May 1979, as part of a broader decision, that high-density pool storage of spent fuel would not be acceptable at Gorleben.
- …NRC concedes that a fire could spontaneously break out in a spent-fuel pool following a loss of water, and that radioactive material released to the atmosphere during the fire would have significant, adverse impacts on the environment.
- Gordon Thompson’s January 6, 2014 presentation to the NRC made the case for expedited transfer of spent fuel from pools to dry casks. He qualified his recommendation by pointing out there are problems with high burnup fuel that need solutions.
- Slide 8 compares potential radiation releases, based on the inventory of Cesium (
Cs-137). All of these scenarios are catastrophic, yet the NRC and nuclear industry are not effectively dealing with any of them.
- Peach Bottom Pool: 2,200 PBq (One of two neighboring pools)
- Fukushima #1 Unit 4 Pool: 1,100 PBq
- Fukushima #1 Unit 3 Reactor: 350 PBq
- Dry Cask (32 PWR assemblies): 67 PBq
- Fukushima Fallout on Japan: 6 PBq
- Slide 5 gives the Ignition Delay Time for fuel in a spent fuel pool based on fuel age. This is for a severe reference case for PWR reactor fuel.
- Fuel Age Ignition Delay Time
- 10 days 1.4 hours
- 100 days 3.9 hours
- 1,000 days 21.0 hours
- Ignition delay time (IDT) is the time required for decay heat to raise fuel temperature from 100°C to 1,000°C under adiabatic conditions, for a fuel burnup of 50 GWt-days per Mg U. IDT is 30% higher for BWR fuel (with channel boxes).
- Fuel Age Ignition Delay Time
- The presentation doesn’t address delay time for a high burnup fuel criticality in dry casks, since it was focused on spent fuel issues.
- It is doubtful there would be any delay time to respond to a hydrogen initiated event or fire in dry casks, since there is no monitoring technology to know whether cladding is failing inside the dry cask container. Current high burnup dry cask containers are only licensed for 20 years. There are no solutions for after 20 years and no solutions to mitigate a failed container. In addition, very little spent fuel has ever been transferred from one container to another. San Onofre has never done this. An employee at San Onofre who manufactured the containers explained what the process would be, but said it’s never been done. And locations that have shut down all their fuel and transfer pools are not equipped to even do this. The NRC does not have mitigation procedures or requirements. For example, the NRC initially asked Prairie Island for their mitigation plan in case of dry cask failure, before they would renew their dry cask license for over 20 years. The NRC subsequently removed this request. Prairie Island is the first nuclear facility up for renewal of their 20 year high burnup license. See June 6, 2013 NRC High Burnup RAI #3-2 Clarification memo to Prairie Island (ML1316A291.pdf).
- The Prairie Island Indian Community is concerned about these issues and recommends all high burnup fuel be treated like damaged fuel assemblies and canned. All fuel in Prairie Island spent fuel pools is high burnup.
- The NRC is considering treating high burnup fuel as damaged and in January 2013 asked stakeholders about the cost for this as well as other safety concerns about high burnup fuel storage and retrievability. See NRC ML12293A434.
- Slide 8 compares potential radiation releases, based on the inventory of Cesium (
- A partially or fully drained spent fuel pool fire can result in a self-sustaining zirconium fire. See page 3-1 Technical Study of Spent Fuel Pool Accident Risk at Decommissioning Nuclear Power Plants, NUREG-1738, February 2001, NRC, Division of Systems Safety and Analysis Office, T.E. Collins, G. Hubbard, ML010430066
- The NRC dry cask storage standards do NOT meet the professional American Society of Mechanical Engineers (ASME) Code and standards. The NRC should require the ASME stamp. This is another example of the NRC allowing profits over safety. For a list of improvements that should be made to dry casks standards, see the C-10 Research and Education Foundation Inc. Petition for NRC Rulemaking to Upgrade Interim Dry Cask Storage Code Requirements.
- Principles for Safeguarding Nuclear Waste at Reactors, Hardened On-Site Storage (HOSS) recommendations from various environmental organizations and coalitions.
METAL CORROSION FROM COASTAL ENVIRONMENT: Nuclear waste storage near the coast could fail and release radiation due to the corrosive nature of salt air with metal. Pitting corrosion in a salt fog environment is troubling. If a canister became sufficiently corroded, it would have to be replaced and the fuel assemblies moved. Further, the canister and fuel rods are pressurized, so leakage would be out of the canister. The NRC considers this a major issue, but doesn’t have adequate solutions.
- NRC’s NUREG/CR-7030 states atmospheric corrosion of sea salt can lead to stress corrosion cracking within 32 and 128 weeks in austenitic [corrosion resistant] stainless steel canisters. See Atmospheric Stress Corrosion Cracking Susceptibility of Welded and Unwelded 304, 304L, and 316L Austenitic Stainless Steels Commonly Used for Dry Cask Storage Containers Exposed to Marine Environments, NUREG/CR-7030, October 2010 (ML103120081).
- Premature Degradation of Spent Fuel Storage Cask Structures and Components from Environmental Moisture, NRC Information Notice 2013-07, April 16, 2013 (ML12320A697). Examples from Peach Bottom and Three Mile Island show problems with dry cask integrity (e.g., steel and concrete water degradation issues).
- Potential Chloride-Induced Stress Corrosion Cracking [SCC] of Austenitic Stainless Steel and Maintenance of Dry Cask Storage System Canisters, NRC Information Notice 2012-20: November 14, 2012 (ML12319A440).
Several failures in austenitic stainless steels have been attributed to chloride-induced SCC. The components that have failed because of this failure mechanism at nuclear power plants…are made from the same types of austenitic stainless steels typically used to fabricate dry cask storage system canisters. …empirical data has demonstrated that this failure mechanism is reproducible in Type 304 and 304L stainless steel as well as in Type 316L stainless steel. Accordingly, the NRC expects that all types of austenitic stainless steels typically used to fabricate dry cask storage system canisters (304, 304L, 316, and 316L) are susceptible to this failure mechanism…Several instances of chloride-induced SCC have occurred in austenitic stainless steel components that were exposed to atmospheric conditions near salt-water bodies…. relevant examples:
In the fall of 2009, three examples of chloride-induced SCC which extended through-wall were discovered at the San Onofre Nuclear Generating Station (SONGS) in the weld heat-affected zone (HAZ) of Type 304 stainless steel piping. The piping included 24-inch, Schedule 10 emergency core cooling system (ECCS) suction piping; 6-inch, Schedule 10 alternate boration gravity feed to charging line piping; and an ECCS mini flow return to refueling water storage tank. While the through-wall failures were attributed to chloride-induced SCC, surface pitting was also observed on the surface of the pipes, with a greater concentration in the weld HAZ. All three pipes were exposed to the outside ambient marine atmosphere. Through-wall cracks developed after an estimated 25 years of service….
Usually, most of the surface remains unattacked, but with fine cracks penetrating into the material. In the microstructure, these cracks can have an intergranular or a transgranular morphology. Macroscopically, SCC fractures have a brittle appearance. SCC is classified as a catastrophic form of corrosion, as the detection of such fine cracks can be very difficult and the damage not easily predicted. Experimental SCC data is notorious for a wide range of scatter. A disastrous failure may occur unexpectedly, with minimal overall material loss.
To evaluate the effects of non-chloride and chloride-rich salt mixtures, a final series of tests was performed in which U-bend specimens were deposited with a mixture of ammonium nitrate and sodium chloride with nitrate-to-chloride molar concentration ratios of 3.0 and 6.0. Extensive cracking was observed on these specimens.
- Overview of NUREG/CR-7170, “Assessment of
Stress Corrosion Cracking Susceptibility for
Austenitic Stainless Steels Exposed to
Atmospheric Chloride and Non-Chloride Salts”
Greg Oberson, NRC presentation, Extended Storage Collaboration Program Meeting, December 3-5, 2013
NRC waste confidence decision: indefinite continued storage
In spite of all of the above issues, on August 26, 2014 the NRC approved a final rule and its associated generic environmental impact statement (GEIS) amending 10 CFR Part 51 to that states nuclear waste can remain at existing nuclear power facilities short term (60 years), long term (over 100 years) and indefinitely. They change the name from “waste confidence” to “continued storage.” Below is historical background that lead up to the decision.
- The federal court threw out the NRC ruling that waste can be stored safely at nuclear power plants for 60 years and required them to complete an environment impact of the consequences for extended storage at U.S. nuclear plants.
- The NRC then drafted a Generic Environmental Impact Statement (GEIS) report that concluded waste can be stored indefinitely at the nuclear plants with no significant environmental impact. In this report, the NRC failed to even mention its own documented technical concerns about spent fuel. This seriously compromises the scientific integrity of the draft GEIS. See Arjun Makhijani’s complete comments to the GEIS.
- See NRC Waste Confidence web link for current information and status on “waste confidence” issues.
- See comments below submitted by informed activists and nuclear scientists regarding the NRC’s ludicrous Generic Environmental Impact Statement (GEIS) (Docket NRC-2012-0246) that claims all nuclear waste can be stored indefinitely at all existing nuclear power plants. The NRC’s GEIS is based on unsubstantiated hope. The courts should reject it. Diane Curran’s submitted comments on behalf of numerous groups also includes a petition to the NRC. Please support this petition. Details below.
- Waste Con Comments, SanOnofreSafety.org
- High Burnup Executive Summary, SanOnofreSafety.org
- Waste Con Group Comments, Coalition to Decommission San Onofre, Sierra Club Angeles Chapter
- Waste Con Group Comments, and Petition to Revise and Integrate All Safety and Environmental Regulations Related to Spent Fuel Storage and Disposal, submitted by Diane Curran of Harmon, Curran, Spielberg & Eisenberg, L.L.P; and Mindy Goldstein and Jillian Kysor of Turner Environmental Law Clinic
- 50 Years of Power 500,000 Years of Radioactive Waste, Daniel Hirsch, December 20, 2013
- Waste Con Comments, Citizens’Oversight
- Waste Con Group Comments, Nuclear Information & Resource Service (NIRS)
- Sierra Club Nuclear Free Campaign
- Court orders NRC to take second look at waste storage plants for 60 years – Brattleboro Reformer, June 8, 2012
Concluding the Nuclear Regulatory Commission did not examine the environmental effects of failing to establish a permanent repository for nuclear waste, an appeals court in Washington, D.C., threw out an NRC ruling that governed the storage of spent nuclear fuel at the nation’s power plants.
“The court found the commission failed to evaluate future dangers and consequences in making its waste confidence decision in December 2010,” said Susan Kinsman, spokeswoman for Connecticut Attorney General George Jepsen, one of the plaintiffs in the case.
In that decision, the NRC increased the number of years that spent nuclear fuel can be stored onsite from 30 to 60 years after a nuclear power plant ceases operations.
But late on Friday, the U. S. Court of Appeals for the District of Columbia ruled that the decision rises to the level of a major federal action, which requires either an environmental impact statement or a finding of no significant environmental impact, neither of which the NRC conducted.
… The court also determined that the NRC violated the law when it found “reasonable assurance” that sufficient, licensed, off-site storage capacity will be available to dispose of nuclear power plant waste “when necessary.”
The appeals court wrote that the NRC “apparently has no long-term plan other than hoping for a geologic repository.”
Vermont Attorney General Bill Sorrell characterized the NRC’s 2010 decision as “wishful thinking”...more
California and Arizona Nuclear Waste
- SCE Fact Sheet – Decommissioning San Onofre Nuclear Generating Station, June 25, 2013
- SCE Request to replace Dry Cask Storage System to NUHOMS® 32PTH2, February 10, 2012 (NRC ML12046A013)
- SCE SONGS 2 and 3 Early Decommissioning Scenario – CPUC Supplemental Testimony, 07-22-2013
- SCE Briefing on San Onofre Nuclear Generating Station, Units 2 & 3 Retirement Plans, June 19, 2013
- NUHOMS® 24PT1 and 24PT4 dry casks approved by NRC.
- The 24PT4 was approved for high burnup fuel storage (up to 60 GWd/MTU) for 20 years effective May 16, 2005.
- The 24PT1 is not approved for high burnup fuel storage (Table 2-1).
- High burnup fuel must cool for up to 20 years depending on uranium enrichment and burnup level (Tables 2-9 to 2-16). See Table 2-12 below
- San Onofre NRC License Amendment approved for high burnup: fuel assemblies having a maximum U-235 enrichment of 4.8 weight percent (w/o) to be stored in both the spent fuel racks and the new fuel racks., October 3, 1996
- San Onofre ISFSI Inspection Reports:
- NRC Inspection Report: San Onofre Independent Spent Fuel Storage Installation (ISFSI), May 5, 2016 (ML16127A580) and Errata to report, August 3, 2016 (ML16216A364), link to both (ML16216A349) Includes inspection of Spent Fuel Pool Island cooling system. Claimed to be non-safety related system, which allows lower standards for defense in depth (e.g., commercial grade rather than nuclear grade standards).
- NRC Inspection Report: San Onofre Independent Spent Fuel Storage Installation (ISFSI), February 13, 2014 (ML14045A317)
- NRC Inspection Report: San Onofre Independent Spent Fuel Storage Installation (ISFSI), May 20, 2011. Dry cask inventory is at end of document.
- Plans for Decommissioning of San Onofre Nuclear Generating Station Units 2 and 3 (NRC website)
- SCE 10/07/2013 CPUC Presentation: San Onofre Physical Systems and Assets (I.12-10-013)
- SCE Unit 1 San Onofre Decommissioning Cost Study submitted to the NRC August 31, 2012.
- SCE Unit 1 Federal Pre Trial Brief Case No 04-109C – compensation for nuclear waste storage, February 13, 2009, This SCE Memorandum of Contentions of Fact and Law contains important details about San Onofre waste storage. For example:
- In 1974 and 1976, SCE shipped 48 and 51 spent fuel assemblies, respectively, from Unit 1 to the General Electric (GE) facility at Morris, Illinois, to be reprocessed at that facility. The GE Morris reprocessing facility never became operational. In 1977, President Carter indefinitely deferred the spent fuel reprocessing program in the United States. SCE subsequently shipped 171 additional Unit 1 spent fuel assemblies from the Unit 1 spent fuel pool to the Morris facility in 1980, such that a total of 270 Unit 1 spent fuel assemblies were stored there.
- Those 270 Unit 1 assemblies remain stored at Morris today. From July 1, 1998 through December 31, 2005, SCE had paid GE a total of $26,827,548, for storage of the 270 assemblies of Unit 1 spent nuclear fuel.
- SCE awarded $142,394,294 in federal lawsuit to compensate for Unit 1 nuclear waste storage. Summary:
- In 1983, Congress enacted the Nuclear Waste Policy Act, authorizing contracts with nuclear plant utilities, generators of spent nuclear fuel (SNF) and high-level radioactive waste (HWL) under which the government would accept and dispose of nuclear waste in return for the generators paying into a Nuclear Waste Fund, 42 U.S.C. 10131. In 1983, the Department of Energy entered into the standard contract with plaintiff to accept SNF and HLW. In 1987, Congress amended the NWPA to specify that the repository would be in Yucca Mountain, Nevada. The government has yet to accept spent fuel. The current estimate is that the government will not begin accepting waste until 2020, if at all.
- In 2001, plaintiff began constructing dry storage facilities to provide on-site storage for SNF rather than to continue using an outside company (ISFSI project).
- The Court of Federal Claims awarded $142,394,294 for expenses due to DOE’s breach; $23,657,791 was attributable to indirect overhead costs associated with the ISFSI project. The Federal Circuit affirmed. Breach of the standard contract caused plaintiff to build, staff, and maintain an entirely new facility; the ISFSI facilities had not existed prior to the breach and were necessitated by the breach.
Diablo Canyon Nuclear Power Plant
- NRC Inspection Report: Diablo Canyon Independent Spent Fuel Storage Installation (ISFSI), May 20, 2013. Dry cask inventory is at end of document. Diabo Canyon uses Holtec dry storage casks.
Holtec Quality and Debarment Issues
- In October 2010, TVA debarred Holtec International, Inc., based on the results of a criminal investigation.
- Office of the Inspector General, Tennessee Valley Authority, Semiannual Report, April 1, 2013 – September 30, 2013, Page 12
- Debarments – In 2010, TVA and the OIG worked collaboratively to develop a suspension and debarment process for contractors that defraud TVA. That same year, Holtec International, Inc. (Holtec), a dry cask storage system supplier for TVA nuclear plants, became the first contractor to be debarred in TVA history. Holtec’s debarment lasted sixty days. Also, Holtec agreed to pay a $2 million administrative fee and submit to a year-long monitoring program for its operations.
- Office of the Inspector General, Tennessee Valley Authority, Semiannual Report, October 1, 2010 to March 31, 2011 , page 8
- The OIG initiated a first in TVA history; the debarment of a contractor doing business with TVA. In October 2010, TVA debarred Holtec International, Inc., based on the results of a criminal investigation conducted by the OIG. Because of our recommendation, TVA created a formal suspension and debarment process and proceeded to debar Holtec for 60 days. Holtec agreed to pay a $2 million administrative fee and submit to independent monitoring of its operations for one year. The TVA Board’s Audit, Risk, and Regulation Committee and TVA management fully supported the OIG’s recommendation to create a suspension and debarment process and submit Holtec to that process. TVA’s Supply Chain organization and Office of General Counsel worked collaboratively with the OIG to achieve this milestone in TVA history.
- How does one contractor being debarred make life better for Valley residents? Ultimately, the less vulnerable TVA is to fraud the better chance rates stay low. This debarment signaled TVA’s commitment to do more than simply ask for the money back. This debarment action was literally heard around the world and drew a line in the sand. Yes, much of this was symbolic, but symbols matter when you are the largest public power company in America.
- Contractor Misconduct Leads to First TVA Debarment and the Collection of $2 Million Administrative Fee, Page 35
- The OIG previously reported that a TVA technical contract manager received money from a TVA contractor. Criminal actions were taken against the former TVA technical contract manager in that investigation. In addition, a report of administrative inquiry was issued to TVA management regarding the actions of the contractor, Holtec International, Inc. In response to this report, TVA established and filled the position of a TVA suspension and debarment officer to review the matter, which led to the first debarment action at TVA. Holtec International, Inc., received a sixty-day debarment (October 12 through December 12, 2010); and, by agreement with TVA, will pay a $2 million administrative fee to TVA; appoint a corporate governance officer and an independent monitor (at the contractor’s expense); implement a code of conduct, to include training for all employees, executives, directors, and officers; add three noncompany members to its board of directors and sign an administrative agreement ensuring compliance to the above terms.
- More reports on TVA Holtec disbarment
- Office of the Inspector General, Tennessee Valley Authority, Semiannual Report, April 1, 2013 – September 30, 2013, Page 12
- Reports of Holtec quality control issues brings in to questions how reliable these casks will be over time.
Oscar Shirani alleges that all existing Holtec casks, some of which are already loaded with highly radioactive waste, as well as the casks under construction now , still flagrantly violate engineering codes (such as those of the American Society of Mechanical Engineers [ASME] and American National Standards Institute [ANSI]), as well as NRC regulations. He concludes that the Holtec casks are “nothing but garbage cans” if they are not made in accordance with government specifications.
Although NRC has dismissed Shirani’s concerns, NRC Region III (Chicago office) dry cask inspector Ross Landsman refused to sign and approve the NRC’s resolution of Shirani’s concerns, concluding that this same kind of thinking led to NASA’s Space Shuttle disasters. He stated in September 2003, “Holtec, as far as I’m concerned, has a non-effective QA program, and U.S. Tool & Die has no QA program whatsoever.” Landsman added that NRC’s Nuclear Reactor Regulation division did a poor follow-up on the significant issues identified, and prematurely closed them.
Palo Verde Nuclear Generating Station, Arizona
Parts of California receive electricity from Palo Verde. Southern California Edison is part owner (15.8%), so the California Public Utilities Commission has regulatory authority.
- Palo Verde consists of 3 reactor units totaling 3,379 MW of capacity, located approximately 40 miles west of Phoenix, Arizona. Units 1 and 2 were completed in 1986 and Unit 3 was completed in 1988. The plant is operated by Arizona Public Service (APS), and is jointly owned by APS (29.1%), Salt River Project (SRP – 17.5%), El Paso Electric Company (15.8%), Southern California Edison (SCE – 15.8%), Public Service of New Mexico (“PNM” – 10.2%), Southern California Public Power Authority (SCPPA – 5.9%), and the Los Angeles Department of Water and Power (LADWP – 5.7%). The SCPPA Palo Verde participants include Azusa, Banning, Burbank, Colton, Glendale, Imperial Irrigation District, LADWP, Pasadena, Riverside and Vernon. See cityofpasadena.net/waterandpower/IRPglossary
- Arizona Public Service (APS) is authorized to act as agent for the PVNGS licensees and has exclusive responsibility and control over the physical construction, operation and maintenance of the facility.
Palo Verde has one of the worst safety complaint records from employees, per NRC safety allegation statistics.
- Palo Verde, the largest nuclear plant in the nation, uses reprocessed sewer water to cool the fuel. It is the only plant in the nation that does this. It sits on 4,000 acres.
- Palo Verde Nuclear Generating Station, Units 1, 2, 3 and Independent Spent Fuel Storage Installation (ISFSI) Inspection Report, March 27, 2015,
- Currently has 125 loaded dry storage casks (see attachment 2).
- Cask loading started in March 2003.
- High burnup fuel maximum is about 55 GWd/MTU and maximum Uranium-235 enrichment just under 4.7%.
- NAC International (NAC) Universal Multi-Purpose [thin] Canister System (UMS) is used under NRC Certificate of Compliance No. 1015
- The NAC TSC-24 canister holds 24 pressurized water reactor (PWR) fuel assemblies.
- The ISFSI consisted of 12 large rectangular concrete storage pads, each approximately 285′ x 35′. Each pad can accommodate 28 VCCs [vented concrete casks] arranged in two parallel rows of 14 casks. The design capacity allowed for a total of 336 VCCs. The ISFSI at Palo Verde contains a large earthen berm within the ISFSI protected area. The berm is 120 feet wide at the base, 12 feet wide at the top, and 18 feet tall. The earthen berm extends around the ISFSI pad on three sides, specifically on the east, west, and south. [see photo above]
- The NAC UMS FSAR, Section 9.2.1 required an annual inspection of the concrete
casks that includes visual examination of the concrete, vent screens, and other
attached hardware for damage. If concrete defects are found larger
than 1-inch in diameter and deeper than 1-inch, repair by grouting is required.
The annual visual inspections for 2013 through 2014 were reviewed. The 2013
annual inspection was documented in Component Observation Report (COR) 13-9-001, Revision 0. The 2014 report was documented in COR 14-9-001, Revision 0. Both reports documented that no new indications of concrete pop-outs or voids > 1/2-inch in depth, no indications of spalling or scaling, and no new indications of concrete reinforcing bar corrosion were observed. The deficiencies noted during the inspections included minor efflorescence in portions of concrete surfaces typically in the upper half of the cask, random map cracks ranging from hairline to 0.016 inches, and rust on VCC steel lifting lugs which was removed and touched up [with] a corrosion-inhibiting coating. All other deficiencies noted, were minor superficial surface issues that did not affect the function of the casks.
- Note: the thin steel multi-purpose canisters (MPC) are not inspected, since no current inspection technology can be used to inspect canisters filled with spent nuclear fuel.
- Status of dry cask storage at all U.S. nuclear power plants, StoreFUEL, April 3, 2012
- U.S. Independent Spent Fuel Storage Installations (ISFSI) Map, NRC, March 17, 2015 (ML15078A414)
- Blue Ribbon Commission on America’s Nuclear Future, January 2012 report, Page 78: The government is in default on a contractual obligation to dispose of spent fuel from nuclear utilities;
- The user fees being paid to the government to finance the activities needed to meet that obligation are used to offset the [federal] deficit, while expenditures for those activities are constrained under limits on discretionary appropriations; and all the while, taxpayer liabilities resulting from failure to meet the government’s contractual obligations continue to grow.
- The Financial Report of the U.S.Government for FY 2011 reports that these liabilities totaled $49.1 billion— including both the unpaid damages for non-performance and unspent Nuclear Waste Fund fees and interest.
- Blue Ribbon Commission website with archived links.
- Transporting Nuclear Materials: Design, Logistics, and Shipment, U.S. House Energy and Commerce Committee Hearing, October 1, 2015 identifies the numerous obstacles to transport spent nuclear fuel for interim or permanent storage.
- NRC Fact Sheet website: Decommissioning Nuclear Power Plants
- NRC Nuclear Waste Information Digest 2013-2014
- NRC Information Digest 2013-2014
- NRC Backgrounder on High Burnup Spent Fuel
- NRC Status of Decommissioning Program 2012 Annual Report (includes summary of decommissioning process).
- U.S. Nuclear Waste Policy Act of 1982
- Managing Aging Effects on Dry Cask Storage Systems for Extended Long-Term Storage and Transportation of Used Fuel Rev. 1, Argonne National Laboratory for DOE, September 30, 2013
- Managing Aging Effects on Dry Cask Storage Systems for Extended Long-Term Storage and Transportation of Used Fuel Rev. 0, Argonne National Laboratory for DOE, June 30, 2012
- IAEA: Current Trends in Nuclear Fuel for Power Reactors [high burnup problems], August 2007
- NRC memo to Commissioners on high burnup 7/6/1998 – The NRC has known for decades of high burnup problems, but chose to ignore them.
- Interim Storage Pilot Project Evaluation and related issues
- Research and Development Activities Related to the Direct Disposal of Dual Purpose Canisters, William Boyle, DOE, NWTRB Spring Board Meeting, April 16, 2013
- The DOE Standard Contract each utility must sign, requires individual fuel assemblies to be retrievable from the storage canister. It does not consider spent fuel in canisters to be an acceptable waste form. “To ensure the ability to transfer the spent fuel to the government under the Standard Contract, the individual spent fuel assemblies must be retrievable for packaging into a DOE-supplied transportation cask.” Slide 2
- Thin steel storage canisters are too hot to transport and too hot for final disposal. A canister holding 37 fuel assemblies may require cooling over 45 years before it is cool enough for final disposal. Slide 10.
- DOE Standard Contract: 10 C.F.R Part 961
- Implications of Repackaging Used Nuclear Fuel, Rob Howard, DOE, NWTRB workshop, November 18-19,2013
- Preliminary Evaluation of Removing Used Nuclear Fuel from Shutdown Sites, October 1, 2014, FCRD- NFST-2014-000091 Rev. 1, PNNL-22676 Rev. 4 (updated with more details on decommissioned plants, including San Onofre Unit 2 and 3 and notes four Unit 1 mixed oxide (MOX) fuel assemblies are stored in dry casks (model 24PT1).
- Preliminary Evaluation of Removing Used Nuclear Fuel from Shutdown Sites, Final, September 30, 2013, PNNL-22676 Rev. 1 Prepared for DOE Nuclear Fuels Storage and Transportation Planning Project, Steven J. Maheras, et.al. (PNNL), Interim Storage and Transportation Logistics for nuclear waste at shutdown reactors.
- Logistical and Operational Issues Associated with the Transport of Stranded Fuel from Shutdown Reactor Sites presentation, Jeffrey Williams, DOE, Nuclear Waste Technical Review Board, October 17, 2012
- Research and Development Activities Related to the Direct Disposal of Dual Purpose Canisters, William Boyle, DOE, NWTRB Spring Board Meeting, April 16, 2013
- Interim Storage of Spent Fuel in the United States, Allison Macfarlane,
Security Studies Program, Massachusetts Institute of Technology, 2001
- DOE: Project Concept for Nuclear Fuels Storage and Transportation: Fuel Cycle Research & Development. FCRD-NFST-2013-000132, Rev. 1, June 15, 2013 (full report). Abstract. Interim storage pilot – includes costs, transport issues, and other factors]. Also, see this caution about cladding performance issues that need to be addressed before extended fuel utilization fuel can be loaded into dry casks and transportation systems.
Section 6.1.3 Extended Fuel Utilization (High Burnup Fuel): The current burnup limit on fuel in dry cask storage and transportation systems is 45,000 MWd/t assembly average burnup. In contrast, the maximum one pin burnup limit on in-reactor fuel is 60,000 MWd/t to 62,000 MWd/t. There are test assemblies currently in reactors that are attempting to drive fuel to 70,000 MWd/t. Along with these extended fuel utilization limits are new fuel cladding and assembly skeleton materials. Experimental data over the last twenty years suggest that fuel utilizations as low as 30,000 MWd/t can present performance issues including cladding embrittlement under accident conditions as well as normal operations. The NRC is actively seeking rulemaking to address cladding performance for loss of coolant accidents and reactivity insertion accidents. These cladding performance issues need to be addressed before extended fuel utilization fuel can be loaded into dry casks and transportation systems.
- Nuclear Fuels Storage and Transportation Planning Project Inventory Basis, June 16, 2014
- Oak Ridge National Lab has recognized the need to treat all fuel assemblies as damages by suggesting a new dry storage system “Flexible Integrated Modular Nuclear Fuel Canister System” that would basically treat all fuel assemblies as potentially damaged by canning four fuel assemblies into a sealed container, then storing these sealed containers into a larger canister. Currently, canned damaged fuel assemblies are not sealed containers. This allows for air drying of damaged fuel assemblies along with the rest of the fuel assemblies in the canister. Therefore, currently, the required first line of protection (the Zircoloy cladding) is gone. This new design attempts to solve that problem, particularly due to the cladding failure problems with high burnup fuel.
- NRC requirements to renew dry cask storage for high burnup over 20 years (High Burnup RAI #3-2 Clarification).
- Provide justification for the acceptability of the storage of high burnup (HBU) fuel by providing a strategy that includes an aging management program (AMP) to demonstrate that HBU fuel is protected against possible degradation that may lead to gross ruptures for storage periods beyond 20 years and potential operational safety issues during removal from storage…
- Nuclear power plant responses below say they will use one Demonstration Project that just monitors a high burnup fuel assembly in a bolted dry cask:
- NRC: The Use of a Demonstration Program as Confirmation of Integrity for Continued Storage of High Burnup Fuel Beyond 20 Years – Interim Staff Guidance-24 (Draft)
Ductile-to-Brittle Transition Temperature for High-Burnup Zircaloy-4 and ZIRLO™ Cladding Alloys Exposed to Simulated Drying-Storage Conditions M.C. Billone, T.A. Burtseva, and Y. Yan Argonne National Laboratory September 28, 2012.
“…the trend of the data generated in the current work clearly indicates that failure criteria for high-burnup cladding need to include the embrittling effects of radial-hydrides for drying-storage conditions that are likely to result in significant radial-hydride precipitation...A strong correlation was found between the extent of radial hydride formation across the cladding wall and the extent of wall cracking during RCT [ring-compression test] loading.”
Per Peterson, U.C. Berkeley nuclear engineer and member of President Obama’s Blue Ribbon Commission on Nuclear Waste acknowledged this potential for cladding embrittlement in a May 12, 2014 email exchange with Donna Gilmore, Marvin Resnikoff, and OC Register reporter Teri Sforza. He was not aware of this information prior to being informed by Ms. Gilmore and Marvin Resnikoff. The Blue Ribbon Commission recommendations were made prior to this.
Thank you for sending the Billone reference. I have reviewed it, and you are correct that NRC interim staff guidance permits spent fuel cladding to be heated, when placed into dry cask canisters, to higher temperatures (up to 400°C) than occur during reactor service, during the vacuum drying of the fuel in the canister before it is filled with helium. The experiments performed by Billone et al. show that significant radial hydriding and embrittlement can occur in high-burnup cladding when heated to these temperatures. I will follow up to learn more about this problem. I don’t see a reason why drying cannot be accomplished while limiting peak fuel temperatures to significantly lower values, but it does appear possible that current drying protocols during canister loading may cause fuel to reach temperatures high enough to cause this additional radial hydriding and resulting cladding embrittlement.
- Sandia National Laboratory’s April 2011 presentation on Research Needs for Extended Storage of Used Nuclear Fuel outlines the high priority critical dry storage problems that must be solved in current dry storage technology. They emphasized the serious dry storage problems caused by high burnup fuel.
- Rock Solid? A scientific review of geological disposal of high-level radioactive waste September 2010 by Helen Wallace. This
overview of the status of research and scientific evidence regarding the long-term underground disposal of highly radioactive wastes, shows there is no known safe permanent solution.
This review identifies a number of phenomena that could compromise the containment barriers, potentially leading to significant releases of radioactivity:
- Copper or steel canisters and overpacks containing spent nuclear fuel or high-level radioactive wastes could corrode more quickly than expected.
The effects of intense heat generated by radioactive decay, and of chemical and physical disturbance due to corrosion, gas generation and biomineralisation, could
impair the ability of backfill material to trap some radionuclides.
- Build-up of gas pressure in the repository, as a result of the corrosion of metals and/or
the degradation of organic material, could damage the barriers and force fast routes for radionuclide escape through crystalline rock fractures or clay rock pores.
Poorly understood chemical effects, such as the formation of colloids, could speed up the transport of some of the more radiotoxic elements such as plutonium.
Unidentified fractures and faults, or poor understanding of how water and gas will flow through fractures and faults, could lead to the release of radionuclides in groundwater much faster than expected.
- Excavation of the repository will damage adjacent zones of rock and could there by create fast routes for radionuclide escape.
- Future generations, seeking underground resources or storage facilities, might accidentally dig a shaft into the rock around the repository or a well into contaminated groundwater above it.
Future glaciations could cause faulting of the rock, rupture of containers and penetration of surface waters or permafrost to the repository depth, leading to failure of the barriers and faster dissolution of the waste.
- Earthquakes could damage containers, backfill and the rock.
- An Assessment of Materials for Nuclear Fuel Immobilization Containers, AECL-6440 K. Nuttall and V.F. Urbanic, Atomic Energy of Canada Ltd, Chalk River Nuclear Laboratories, September 1981 (ML040150703)
…Of the remaining alloy systems discussed, the commercial alloys considered as most promising can be ranked according to their crevice corrosion behaviour in aqueous chloride solutions…
… Of the materials reviewed, the [titanium] Ti-0.2% Pd alloy is the most resistant to crevice corrosion in chloride solutions. However, it is at least a factor of two more expensive than C.P. titanium.
…Sandia workers have eliminated the 300-series type stainless steels [e.g. 304, 304L, 316, 316L] from their list of candidate alloys for waste and fuel immobilization containers for the waste Isolation Pilot Plant [WIPP] because of the likelihood of SCC in the salt environment…
- NAS Report on Disposal of Radioactive Waste on Land (1957). Numerous reports and articles use this National Academy of Sciences report as the initial justification that there is a deep geological disposal solution. However, they leave out these important qualifiers, as stated in the Abstract on Page 1:
The research to ascertain feasibility of [deep geological] disposal has for the most part not yet been done… This initial report is presented in advance of research and development having been done to determine many scientific, engineering and economic factors, and, in the absence of essential data, represents considered judgments subject to verification.
- Practical Guidelines for the Fabrication of Duplex Stainless Steels, IMOA, London, 2009 compares various types of stainless steel.
- Duplex Stainless Steels — An Introduction video, University of Pennsylvania, Hira Ahluwalia, October 15, 2015 (brittle at or above 300°C)
- DOE: MOX fuel used in San Onofre Unit 1: Benchmark of SCALE (SAS2H) Isotopic Predictions of Depletion Analyses for San Onofre PWR MOX Fuel, February 2000. Four MOX fuel assemblies were loaded at the start of cycle 2 of the San Onofre Nuclear Generation Station Unit 1 and irradiated during both cycles 2 and 3. Burnup between 8,167 and 20,891 MWd/MTHM (Megawatt days per metric ton heavy metal (U + Pu)).
- Reducing the Hazards from Stored Spent Power-Reactor Fuel in the United States, 2000-2003 [HOSS], Robert Alvarez, Jan Beyea, Klaus Janberg, Jungmin Kang, Ed Lyman, Allison Macfarlane, Gordon Thompson, Frank N. von Hippe
At the time this report was written the authors stated they propose on-site dry-cask storage for about 30 years of older spent fuel that would, according to current plans, remain in pools for that length of time. Spent-fuel casks have already been in use for about 20 years and there is no evidence that they cannot last decades longer without significant deterioration. [However, this website provides evidence that this not now the case with the thin canisters].
- Industry Spent Fuel Storage Handbook, 2010, EPRI
- Dry Spent Fuel Storage Designs approved by the NRC for general use
Transport and Yucca Mountain Issues
- Potential Rail, Barge and Truck Routes to Yucca Mountain, 2002, Interactive – find your state
- A Brief History of Irradiated Nuclear Fuel Shipments: Atomic Waste Transport “Incidents” and Accidents the Nuclear Power Industry Doesn’t Want You to Know About, May 16, 2002 by Kevin Kamps (NIRS)
- Nuclear Waste Transport Accidents in the U.S. Fact Sheet
- Is Yucca Mountain a long-term solution for disposing of US spent nuclear fuel and high-level radioactive waste? Mike Thorne and Associates Limited, 2012 J. Radiol. Prot. 32 175
- Water intrusion and other technical issues
- Political, legal and social issues
- GAO-10-48 NUCLEAR WASTE MANAGEMENT Key Attributes, Challenges, and Costs for the Yucca Mountain Repository and Two Potential Alternatives, November 2009
- DOE EIS-0250: FINAL ENVIRONMENTAL IMPACT STATEMENT, Geologic Repository for the Disposal of Spent Nuclear Fuel and High-Level Radioactive Waste at Yucca Mountain, Nye County, Nevada
California has already had a nuclear reactor meltdown (near Simi Valley) and the waste has yet to be cleaned up.
“The problems there began in 1959, when a nuclear reactor partially melted down, contaminating portions of the hilltop facility and spewing radioactive gases into the atmosphere. That incident wasn’t publicly disclosed until 1979. By then, more mishaps had followed, including reactor accidents in 1964 and 1969. The worst contamination is thought to be in a parcel known as Area IV, where the meltdown occurred…”
More information: LA’S Nuclear Secret, KNBC, Joel Grover and Mathew Glasser
Hanford Nuclear Waste Leaks
The timeline for officials to clean up the biggest, most toxic nuclear waste site in the Western hemisphere is shrinking. The race to clean up 56 million gallons of radioactive liquid waste sitting at the Hanford site, 230 miles east of Portland, becomes more urgent each year. With an estimated price tag of $120 billion, and a theoretical deadline of 2047, cleanup efforts are continually stalled by obstacles including time, money, the danger of the task at hand, and the sheer vastness of the site. Attempts to store liquid and solid radioactive waste from the 586 square-mile site – which supplied the plutonium for the bomb that ended WWII — have been failing for decades.
1. Your Health and the Columbia River
“…[Radiation] gets into the organisms, like fish we that we eat, and so it would essentially degrade the health of the river, and be at some point, a threat to human health,” said Dr. John Howieson, Vice Chair of the Oregon Hanford Cleanup Board. Howieson said the health risks to human health through ingestion are much more of a threat than simple exposure. For example, when isotopes were deposited on plants near the Chernobyl site near Pripyat, Ukraine, cows ate those plants and children drank milk from the cows, causing widespread deformities. Ingestion through vaporization, as happened at the Hanford site in March 2014, is equally dangerous…
2. The Waste Storage Tanks
…In October 2012, the U.S. DOE released images confirming a double-shell tank, known as AY-102, was leaking through its inner shell. “I think most of us felt that those double tanks were probably good for a long, long time. The fact that one of them failed really caught our attention,” said Howieson. “If a catastrophic failure of [AY-102] occurred it would relay so much radioactivity into the soil it would eventually have a deleterious effect on the Columbia river,” said Howieson. Documents show six other tanks may be leaking, and 13 more could be compromised…
3. What’s really in the river water
…By the late 1940s and early 1950s, radioactivity was detected as far as the mouth of the Columbia River, near Astoria, Ore., said Howieson. Matt McCormick, Department of Energy Manager for Richland Operations Center at Hanford, said some uranium and a hydrogen isotope have made it to the river through contaminated groundwater…
…Columbia Riverkeeper spokesperson Dan Serres claims the public should be starting to worry about the level of infiltration in the groundwater and the river. “The department of ecology for the State of Washington acknowledges that there is nuclear waste that reaches the Columbia River from Hanford today,” he said…
4. Political action and inaction
…Oregon Senator Ron Wyden makes a cause out of keeping Hanford’s urgency among the top priorities of America’s chief lawmakers. In April 2013, he challenged U.S. Energy Secretary (then-nominee) Ernest Moniz on whether he was satisfied with federal cleanup efforts. Moniz admitted he was not. “This is the most contaminated piece of federal property,” said Wyden. “It adjoins the lifeblood of our region, the Columbia River, and we’ve got to turn this around.” Wyden called for more action from the DOE, and asked for an investigation by the Government Accountability Office into Hanford’s tank monitoring system after frustration over recurring problems…
5. ‘Solutions:’ the troubled vitrification plant
…The DOE’s plan to dispose of the 56 million gallons of sludge safely is through a process called vitrification. A $13 billion plant is under construction to turn the nuclear sludge into massive glass cylinders. However, the project has been plagued with delays, budget issues and major safety concerns…
6. Safety concerns and ‘whistleblower’ dismissals
…When two former employees of DOE vitrification plant project subcontractor URS raised concerns over the likelihood of a major explosion on site, they claim they were unduly fired. Nuclear engineer Walt Tamosaitis and former safety manager Donna Busche said they warned a catastrophic explosion – not unlike past disasters– was imminent if construction continued. Busche said URS fired her to set a precedent for other employees with safety concerns. Nuclear engineer Dr. Walt Tamosaitis says he was unfairly fired for speaking out about safety concerns at the Hanford nuclear site (CBS). “To summarily remove me from the projects sends a clear and present message to employees — that if you speak up — you will be fired,” said Busche. Construction in one area of the vitrification plant, the pre-treatment facility, has since been halted altogether because of design flaws. “If the explosion were severe enough, it would be released to the public, it would very similar to the explosion you saw at Fukushima,” said Tamosaitis…
- DOE’s Hanford cleanup web page states the waste plan is to send waste to WIPP and to vitrify the waste. It doesn’t mention the problems with both of these “solutions”, thereby giving people unsubstantiated hope that this can be accomplished. It does mention the unsolved problem of the waste plumes moving towards the Columbia River.
The liquid waste that had been poured onto the ground or held in ponds or trenches has long since evaporated or soaked into the soil on the Site. In doing so, the waste did contaminate some of the soil and is thought to have also created underground “plumes” of contaminants. A “plume” is kind of like an underground river where the contaminants join with the water that exists beneath the surface of the Earth. Many of these plumes move in varying speeds and move toward the Columbia River. Hanford employees are actively involved in projects designed to prevent any more of the contamination from reaching the river. Several different strategies are being used in that effort. More…
Learn in this “DC Days” video from experienced activists, such as Arjun Makhijani, the issues and challenges of nuclear waste and nuclear proliferation and how money overrides safety and logic.
Deep Borehole geological nuclear waste storage
The NWTRB makes a strong case why bolehole nuclear waste storage is not a good idea.
- NWTRB Technical Evaluation of the U.S. Department of Energy Deep Borehole Disposal Research and Development Program, January 2016
- DOE has identified the following waste forms as potential candidates for deep borehole disposal:
- Cesium and strontium capsules stored at the Hanford site in Washington State.
- Untreated calcine high-level radioactive waste currently stored at the Idaho National Laboratory.
- Salt wastes from electrometallurgical treatment of sodium-bonded fuels that could be packaged in small canisters as they are produced.
- Some DOE-managed spent nuclear fuel currently stored in water-filled pools at the Idaho National Laboratory and at the Savannah River Site in South Carolina.
- DOE has acknowledged that all of the above waste forms also could be accommodated in a mined, geologic repository. However, DOE believes the deep borehole disposal concept “could offer a pathway for earlier disposal of some wastes than might be possible in a mined repository.” DOE also has indicated that commercial spent nuclear fuel is not being considered for deep borehole disposal, mainly because of its size.
- A deep borehole disposal system could be as complex as a mined, geologic repository and assessing the performance of each of these disposal options may require an equivalent level of data collection and testing. However, deep boreholes lack the easy working access for characterizing the disposal zone that shafts, ramps, and tunnels would provide in the case of a much shallower mined, geologic repository. Thus, the ability to characterize the disposal zone in a borehole is extremely limited as compared with a mined, geologic repository. Also, the Board has not been presented with any compelling evidence that deep borehole disposal can be accomplished more quickly than disposal in a mined, geologic repository. Both approaches will pass through a lengthy, sequential process of developing regulations, site selection, data acquisition and analysis, licensing, and construction.
- DOE has identified the following waste forms as potential candidates for deep borehole disposal:
- NWTRB Deep Borehole Disposal of Spent Nuclear Fuel and High-Level Waste, August 20, 2013 — advantages and challenges [unresolved issues].
- NWTRB Letter to DOE regarding R&D plan for deep borehole disposal 7/30/2013: …Research related to deep borehole disposal should not delay higher priority research on a mined geologic repository… Because deep borehole disposal is in the earliest stages of development, significant technological challenges must be resolved… Because of these technological challenges and the significant scale of a deep borehole disposal program, the Board reiterates its long-standing support of mined geologic disposal and notes that virtually every national nuclear waste disposal program is pursuing development of a mined geologic repository for disposing of spent nuclear fuel and high-level radioactive waste .
- U.S. Nuclear Waste Technical Review Board (NWTRB) website. The NWTRB is an independent agency of the U.S. Government. Its sole purpose is to provide independent scientific and technical oversight of the Department of Energy’s program for managing and disposing of high-level radioactive waste and spent nuclear fuel.
Other Waste Issues
- Civilian plutonium. The United States has no separated civilian plutonium. At the end of 2011, an estimated 546 tonnes of plutonium was contained in spent fuel stored at civilian reactor sites and 12 tonnes of plutonium in spent fuel stored elsewhere. These 12 tonnes include the 7.8 tonnes of government owned plutonium that was declared as excess to national security needs that is accounted for in the weapon plutonium section. Additional information about highly enriched uranium at fissilematerials.org.
- Lawrence Livermore National Laboratory Measurements of Plutonium-bearing Oxide in DOE-STD-3013-2000 Containers Using Calorimetry and Gamma Isotopic Analyses, June 23, 2004Each DOE-STD-3013-2000 container consists of a screw-lid stainless-steel convenience can enclosed in a welded stainless-steel primary within a welded stainless-steel secondary container. The wall thickness of the 3013 convenience can and primary and secondary containers is 1.0 [0.04″], 1.5 [0.06″] and 3.0 mm [0.12″], respectively…
- DOE Standard for Stabilization, Packaging, and Storage of Plutonium-Bearing Materials, DOE-STD-3013-2012, March 2012
A significant portion of the DOE plutonium oxide inventory contains chloride. For example, the oxide material from electrorefining processes can contain percent levels of chloride. The presence of even lower levels of chloride can catalyze stress corrosion cracking in stainless steel, the material specified in this Standard for the containers (Section 18.104.22.168). The Standard does not impose a limit on chloride contamination because the extent of corrosion is limited by the available moisture, rather than the available chloride. The available moisture limitation in this Standard is considered sufficient to avoid significant corrosion.
22.214.171.124 Both the inner and outer containers shall be fabricated of 304L or 316L series stainless steel or equivalent. Closure welding shall be performed using procedures that minimize sensitization of the materials of construction to minimize stress corrosion cracking.
Stress corrosion cracking (SCC) has been identified as being the greatest threat to 3013 container integrity. [Kolman 2001] Room temperature SCC of 304L and 316L stainless steels is reported to occur with the alkaline earth chlorides MgCl2 and CaCl2 commonly present in plutonium processing salts. [Shoji/Ohnaka 1989; Tani et al., 2009] The attack is most aggressive at or slightly above the deliquescent relative humidity of the component salt. The deliquescent relative humidity is the lowest relative humidity at which a solution is formed from the salt and water vapor. The solution formed at the deliquescent relative humidity has the highest chloride concentration possible for the salt. Room temperature SCC of 304L in contact with plutonium oxide with a small amount of CaCl2 and 0.5wt% moisture has been observed in the MIS program. [Zapp/Duffey 2008] The amount of water in these tests is consistent with the formation of deliquesced CaCl2.
- Nuclear power and nuclear weapons — explaining the connection, FOE Australia
- NRC Uranium Enrichment Fact Sheet
- NRC 2014 Poster Licensing High Burnup Fuel
- Nuclear waste management companies and related links
- Alloys – Relative Cost Ratio, 2012
- BeyondNuclear.org Radioactive Waste website.
- Agreement between the government of the United States of America and the government of the Russian Federation concerning the disposition of highly enriched uranium extracted from nuclear weapons, February 18, 1993
- U.S. Nuclear Fuel Cycle – World Nuclear Association
- Additional Russian uranium supplies through 2022 via USEC transitional supply contract with Russia, after their purchases from Russia under the Megatons to Megawatts program.
- NRC approves 10% U-235 enrichment for USEC American Centrifuge Plant in Piketon, Ohio. The licence authorises 7 million SWU/yr enrichment up to 10% U-235, though normal levels today are only up to 5%, which is becoming a serious constraint as reactor fuel burnup increases. In March 2009, USEC said that it had commitments for $3.3 billion of services from ten customers including leading utilities in the USA, Europe and Asia, and amounting to more than half of the initial sales from the plant.
- Store Fuel, December 3, 2013, Spent fuel storage status and statistics
- World Nuclear Association Information Library
- The Engineer’s Professional Role, Nader, February 1967
- Sierra Club Nuclear Policies
- Hearing on “Update on the Current State of Nuclear Waste Management Policy,” Subcommittee on Environment and the Economy (May 15, 2015)
- Testimony of Geoffrey Fettus, Natural Resources Defense Council, Inc, Hearing on “Update on the Current State of Nuclear Waste Management Policy,” Subcommittee on Environment and the Economy (May 15, 2015)
- The only situation where NRDC sees merit in a pilot project(s) is to address the current total stranded spent fuel at the closed reactor sites, accommodated in a hardened building at one or more sites that follows the example of the Ahaus facility in Germany. Potential volunteer sites that have already demonstrated “consent” are operating commercial reactors. Far less of the massive funding that would be necessary in the way of new infrastructure would be required and the capacity for fuel management and transportation is already in place, along with consent necessary for hosting nuclear facilities in the first instance.
- Also ahead is the looming debate over consolidated storage. Just to focus on one of the potential sites, the Waste Control Specialists (WCS) corporation has announced that it will seek to establish “interim” storage site for the nation’s commercial spent nuclear fuel at its existing “low-level” radioactive and hazardous waste site in Andrews County, Texas, just across the border from New Mexico’s defense waste transuranic repository, the Waste Isolation Pilot Plant (WIPP) and even closer to Urenco’s uranium enrichment plant, officially in Eunice, NM. As we understand it, WCS will submit a license application to the NRC sometime in the next two years. In essence, the WCS proposal is to site a dry storage facility containing transport casks (that have also not been licensed yet) containing high-level radioactive waste from reactors across the country. WCS suggests this “interim” site would exist for 60 years, after which the waste could then be moved again to some permanent repository that not only doesn’t yet exist, but there isn’t even a plan to get there.
- There are several problems with this proposal. First, and most obviously from NRDC’s perspective, immediately going forward with a consolidated storage proposal before working out the details of a comprehensive legislative path for nuclear waste storage and disposal (and connecting the licensing of storage to the licensing of a permanent repository) entirely severs the link between storage and disposal, and creates an overwhelming risk that a storage site will function as de facto final resting place for nuclear waste. Or, in the alternative and also just as damning, it sets up yet another attempt to ship the waste to Yucca Mountain or even open up New Mexico’s WIPP facility for spent nuclear fuel disposal– a site designed and intended for nuclear waste with trace levels of plutonium, not spent fuel (that has already blown plutonium throughout the underground and into the environment, contaminating 22 workers, and is functionally inoperable for years). All of this runs precisely counter to the BRC’s admonition that “consent” come first – a potentially ironic turn after decades of promises were delivered to New Mexico that it would never be asked to turn WIPP into a commercial nuclear waste repository.
- And that’s the beginning of the problems of moving forward with consolidated storage before Congress sets out a comprehensive plan. Others are more practical in nature. In contrast to the defunct Private Fuel Storage (PFS) site proposed in Utah, which actually obtained a NRC license even though nearly every single major Republican office-holder in the state objected to it, the WCS proposal isn’t designed as a private site where WCS would negotiate with each nuclear utility to accept its waste. The PFS scheme failed in part because such a private site transfers no liability for the nuclear waste, thus no utility was interested in the retention of the liability–especially as the waste would have to be transported hundreds or thousands of miles. In this instance, as we understand it, WCS will be requesting DOE accept title to the waste and all liability for transportation to Andrews County, Texas. And while WCS states that Andrews County supports the idea, it’s not at all clear over the long term whether consensus will include more than the statement of a local governing body. Indeed, Texas and New Mexico will both need to be involved and already there are high-ranking objections from New Mexico. http://www.tomudall.senate.gov/?p=press_release&id=1947.
- Testimony of Geoffrey Fettus, Natural Resources Defense Council, Inc, Hearing on “Update on the Current State of Nuclear Waste Management Policy,” Subcommittee on Environment and the Economy (May 15, 2015)
NRC REG CON 2015
- Dry Cask Storage Coast to Coast – Problems and Recommendations, November 18, 2015 NRC SFM Regulatory Conference, Erica Gray presentation
- Other presentations.