Watts Bar Unit 1 Multi-Physics Multi-Cycle Depletion Benchmark Evaluation with WIMS/PANTHER

This work presents EDF Energy UK solutions to the TVA Watts Bar Unit 1 Multi-Physics Multi-Cycle Depletion Benchmark using the JEF2.2 library. Hot zero power states were analyzed with both the SERPENT Monte Carlo code and a deterministic two-step WIMS10/PANTHER methodology. Reactivity parameters are compared against plant measurements and VERA results calculated using the ENDF/B-VII.1 library. Depletion calculations for the first three operating cycles were also performed in WIMS10/PANTHER, and predicted power distributions were compared to flux measurements from plant instrumentation. The impact of applying embedded supercell corrections within the PANTHER model was also evaluated. The results demonstrate good agreement with plant data across reactivity and powershape metrics, supporting the suitability of WIMS10/PANTHER for multi-cycle pressurized water reactor analysis. The inclusion of embedded supercell corrections provides a clear improvement in power-shape prediction accuracy relative to both plant measurements and Monte Carlo reference solutions. Overall, the benchmark comparisons show that WIMS/PANTHER yields reliable predictions of reactivity and power shape and that the inclusion of embedded corrections in PANTHER further enhances pin-level accuracy.