Frequently Asked Questions about Accident Tolerant Fuels

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General Questions

How will the NRC know if ATF is safe?

The NRC regulations contained in Title 10 of the Code of Federal Regulations provide reasonable assurance of adequate protection of public health and safety. All vendors and licensees must meet all applicable regulations, and the new technologies being developed as ATF are no exception. When ATF topical reports and other ATF-related licensing actions are received by the NRC, they will be reviewed, and NRC staff will make a safety finding as part of this review process.

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Why does the NRC need to review ATF?

NRC-granted licenses are generally explicit regarding what materials can be used in fuels inserted into power reactors. Additionally, the NRC approves the fuel analysis methods for normal, abnormal, and accident scenarios. ATF would likely alter both materials and analysis methods; therefore, licensees would need to request approval to make those changes, with supporting evidence verifying that they will maintain reactor safety.

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What are the staff’s plans for addressing the environmental impacts from ATF implementation?

As discussed in the Project Plan, staff review of requests to adopt increased enrichment and higher burnup beyond the current licensed limits would include an evaluation of the potential environmental impacts of the license amendment request. The staff is determining what environmental evaluations can be completed prior to the first ATF license amendment requests with respect to Table S-3 under 10 CFR 51.51, Uranium fuel cycle environmental data, Table S-4 under 10 CFR 51.52, Environmental effect of transportation of fuel and waste, and decommissioning impacts.

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Increased Enrichment and Higher Burnup Questions

How will the NRC determine if ATF with increased enrichment is safe?

The NRC regulations provide reasonable assurance of adequate protection of public health and safety. Vendors and licensees must meet the applicable regulations, and fuel with increased enrichment is no exception. When increased enrichment topical reports and other related licensing actions are received by the NRC, they will be reviewed, and the NRC staff will make a safety finding as part of this review process.

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How will the NRC ensure increased enrichment processes prevent proliferation?

The regulations in 10 CFR Part 73, "Physical protection of plants and materials," proscribes requirements for the establishment and maintenance of a physical protection system which will have capabilities for the protection of special nuclear material. Licensees must follow the security requirements of 10 CFR Part 73. For increased enrichment, vendors and licensees must make appropriate changes, if any, to their security plans, equipment, and forces to maintain the same level of physical protection as prior to increased enrichment.

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Source terms for nuclear facilities using ATF or fuels designed for higher burnup and increased enrichment could be impacted. What is being done to consider these possible impacts?

Implementation of ATF or fuels designed for high burnup and increased enrichments, and associated facility modification by nuclear power plant licensees, should be supported by licensee evaluations of significant radiological and nonradiological impacts of the proposed actions. Such evaluations should consider the impact of the proposed changes on the facility’s compliance with the regulations, licensee commitments relevant to accident source terms, and any other facility-specific requirements. The NRC staff does not expect a complete recalculation of all facility radiological analyses but does expect licensees to evaluate impacts of the proposed changes and update affected analyses and the design documents appropriately.

The NRC is currently in the process of updating Regulatory Guide 1.1831, 2, "Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors". This update will account for near-term ATF concepts, fuel burnup levels up to approximately 68 GWd/MTU peak rod-average, and U-235 enrichments up to 8%. Also, the NRC is currently working to determine the generic source term for a burnup level of approximately 75 gigawatt days per metric ton of uranium peak rod average using the MELCOR severe accident code and incorporating insights from the NRC-sponsored severe accident phenomena identification and ranking table exercise.

1 Regulatory Guide 1.183 Revision Public Meeting Slides (11/19/2020)
2 Final Regulatory Guide (RG) 1.183 Revision Public Meeting #2 Slides

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Transportation and Storage

Is irradiated ATF more dangerous than normal irradiated fuel?

The NRC staff is reviewing and evaluating the performance of systems containing irradiated ATF. For the ATF lead test assemblies inserted in power reactors, the staff has not identified any characteristics that suggest the irradiated ATF designs present a greater hazard to the public. The NRC is applying the same performance requirements to irradiated ATF fuel as conventional zirconium alloy cladded uranium dioxide fuel.

Please see Spent Fuel Storage in Pools and Dry Casks Key Points and Questions & Answers for more information about spent fuel transportation and storage.

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