Towards high-fidelity high-resolution modeling of a BWR fuel assembly by CASMO-5

This study focuses on analyzing the depletion of a fuel assembly irradiated in the boiling water reactor and reaching deep burnups. CASMO-5 was utilized to calculate the power, exposure, and nuclide concentration behavior throughout the reactor core cycles. The variation in the concentrations was assessed in relation to model parameters and bundle’s operational conditions. Furthermore, the calculated concentrations were validated against post irradiation examination of a fuel rod sample. The key finding of this study is the high sensitivity of nuclides to the number of energy groups and coolant void fraction, which can explain a great deal of the observing discrepancy of actinide concentrations from experimental data. • Analysis of fuel assembly depletion in a boiling water reactor at high burnups. • CASMO-5 calculation of power, exposure, and nuclide number densities. • Sensitivity analysis to model parameters and operational conditions. • Validation of nuclide inventory against post-irradiation examination data. • Observed high sensitivity to number of energy groups and coolant density.