ANALYSIS OF HIGH BURNUP FUEL DURING NORMAL OPERATION, ANTICIPATED OPERATIONAL OCCURRENCES, AND DESIGN BASIS ACCIDENTS

The US Nuclear Regulatory Commission limits fuel enrichment to 5wt%, effectively limiting the discharge average burnup levels to 62 GWd/MTU. There has been interest in extending the burnup limit beyond 62 GWd/MTU and extending fuel cycles from 18 months to 24 months to improve the economics of large-scale PWRs. It has been shown that in order to increase the cycle length and burnup levels, enrichments above 5wt% are required. Increasing enrichment and burnup levels both present operational performance and safety questions. This work seeks to assess the fuel performance of two fuel designs, both with increased enrichment and implemented burnable absorbers. This work leverages a loose coupling of PARCS, RELAP5-3D, and BISON to evaluate fuel performance during steady state operation, select anticipated operational occurrences, and select design basis accidents. It will address if the current Westinghouse fuel design or the proposed MIT annular fuel design are sufficient to meet criteria described in the NRC SRP during steady state operation, control rod withdrawal scenarios, and control rod ejection scenarios.