Technologies: Coated Cladding | Doped Pellets | FeCrAl Cladding | Increased Enrichment | Higher Burnup | Longer Term Technologies

Increased Enrichment

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For implementation of the near-term ATF concepts (chromium-coated cladding, doped pellets, FeCrAl cladding), fuel vendors and power reactor licensees are exploring the possibility of increasing the maximum enrichment of fuel up to 10%. Currently, NRC regulations state that uranium-235 enrichment levels in power reactor fuel may be no more than 5% by weight, unless significant additional restrictions, plant systems, or analyses are implemented. To receive approval for the increased enrichment levels in the manufacture and use of fuel, vendors and licensees may need to request exemptions from the appropriate NRC regulations and license amendments to change their allowed enrichment levels.

The fuel vendors and power reactor licensees consider the potential advantages of increased enrichment to be:

  • Increased operational flexibility
  • Fewer fuel assembles to purchase
  • Ability to achieve higher burnup

An increase of the enrichment levels has wide ranging effects on the entire nuclear fuel cycle. In addition to the potential regulatory issues, many activities are necessary for increased enrichment to be implemented. Some of these activities include:

  • Criticality safety analyses and facility changes for fuel enrichment and fabrication facilities
  • Development of transportation casks for UF6, UO2, and fresh fuel assemblies
  • Changes to source term calculations
  • Modification of reactor fuel analysis codes
  • Criticality safety analysis of spent fuel pools and modifications for higher heat loads
  • Development and analysis of dry storage casks

NRC staff is proactively considering rulemaking now to reduce unnecessary exemption requests and facilitate increased regulatory efficiency and consistency while continuing to ensure safety. The Commission has reviewed SECY-21-0109, “Rulemaking Plan on use of Increased Enrichment of Conventional and Accident Tolerant Fuel Designs for Light Water Reactors,” which would allow for staff to thoroughly review the potential regulatory implications of increased enrichment fuels and identify and assess the potential costs and benefits of changing regulatory requirements that impact their use. SRM-SECY-21-0109 has been issued in response to SECY-21-0109. The Commission has approved the staff’s proposal to initiate rulemaking to amend requirements for the use of light water reactor fuel containing uranium enriched to greater than 5.0 weight percent uranium-235. If licensees submit applications before the final rule, the NRC will evaluate exemptions on a case-by-case basis. Increased enrichment-related licensing actions received by the NRC can be found on the ATF-related licensing actions page.

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Page Last Reviewed/Updated Tuesday, October 25, 2022