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

Higher Burnup

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Background information on burnup.

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 an increase in the burnup limit to 75 or 80 gigawatt-days per metric ton of uranium (GWd/MTU). The current burnup upper limit for a nuclear fuel rod varies slightly among the three fuel vendors, but it corresponds to roughly 62 GWd/MTU when averaged over the rod. This limit is contained within the NRC-approved fuel analysis methods of each individual NRC-issued license. To increase this burnup limit, licensees would need a license amendment and provide a technical justification that the fuel remains safe during operation and after removal from the reactor.

Increasing the burnup limit may provide several potential advantages for licensees, including:

• Longer reactor cycles – reactors can operate longer between refueling outages
• Need to purchase fewer fuel assemblies from fuel vendors

Higher burnup may have significant effects on power operation and the back-end of the nuclear fuel cycle. In addition to license amendments, several of the other specific tasks necessary for higher burnup to be licensed may include:

• Update of fuel analytical models which predict fuel behavior and performance to capture higher burnup effects
• Update of design bases and safety analyses at higher burnup levels
• Changes to source term calculations
• Development of transportation and dry storage casks for higher burnup
• Criticality safety analysis of spent fuel pools and modifications for higher heat loads
• Address technical challenges (e.g., Fuel Fragmentation Relocation and Dispersal)

The NRC staff is currently preparing to review topical reports and license amendments regarding higher burnup. Higher burnup-related licensing actions received by the NRC can be found on the ATF-related licensing actions page.