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DOE Issues EPRI Plan for Spent Fuel Storage Demo

Nov. 14, 2013—A full-scale study of the safety of storing high-burnup used nuclear fuel in dry casks is being undertaken to further confirm existing data and support the technical bases for its long-term storage and transportation, a draft plan released for comment by the U.S. Department of Energy said this week.

The draft test plan was developed by the Electric Power Research Institute, lead contractor in the DOE-sponsored study. EPRI’s plan proposes using a specially instrumented dry storage cask to monitor conditions and changes to high-burnup used fuel stored for a test period that could last for 10 years or longer. The test cask would be placed at the independent spent fuel storage installation at Dominion Virginia Power’s North Anna nuclear energy facility.

Apart from Dominion, other team members include cask vendor Transnuclear and fuel suppliers AREVA and Westinghouse.

The study described in the test plan will update the results of a similar study completed at Idaho National Laboratory in 1999 that examined fuel having characteristics that were typical at that time. Since that study, the industry increasingly has been able to extract more energy from nuclear fuel by operating reactors at higher power levels and by using longer cycles between refueling. The resulting higher-burnup used fuel is both more radioactive and hotter. DOE and EPRI note in their draft test plan that as of the end of 2012 about 200 used fuel casks (of a total of more than 1,700) contain at least some high-burnup fuel and that “almost all” used nuclear fuel now being loaded into casks in the United States is high-burnup. The cask involved in this study will be loaded with a representative selection of high-burnup fuel.

Another reason cited for updating the study is the continuing need for a permanent solution for the disposal of used nuclear fuel from reactor sites, which makes it more likely that fuel is stored in dry casks for periods longer than the original 20-year license. Based on the INL study and other information, the NRC in 2011 revised its used fuel storage regulations (10 CFR Part 72) to increase the licensing period for dry casks to 40 years with the option for additional renewals of up to 40 years.

The nuclear energy industry recognizes the need for a greater understanding of the technical bases for the extended storage of used fuel beyond 60 years, the EPRI plan says. EPRI notes that while extensive data and models currently exist on the long-term storage of both low-burnup and high-burnup fuel, some research and data needs have emerged from DOE’s smaller-scale studies. The main goals of the DOE/EPRI full-scale test are “to provide confirmatory data for model improvement, provide input to future dry storage cask design, support license extensions for [used fuel storage facilities] and support transportation licensing for high-burnup spent nuclear fuel.”

Under the plan, Dominion would apply for a storage license amendment from the NRC by 2015 to allow a specially instrumented Transnuclear TN-32 demonstration cask to be loaded in 2017. Measurements of conditions inside the cask and of the state of the stored fuel at the end of a storage period of 10 years or more will be compared with data on about two dozen “sister” fuel assemblies examined at the beginning of the test.

EPRI said the data obtained from the test also could help answer NRC requests for information from applicants for dry storage license extensions on the condition of high-burnup spent fuel after the initial 20-year license period.

The deadline for submitting comments to DOE on the test plan is Dec.12.