Fuel performance analysis of BEAVRS benchmark Cycle 1 depletion with MCS/FRAPCON coupled system

Abstract

A fuel performance (FP) analysis of the BEAVRS (Benchmark for Evaluation and Validation of Reactor Simulations) benchmark Cycle 1 depletion is performed using the MCS/FRAPCON coupled code system. MCS/FRAPCON is a cycle-wise Picard-iteration inner-coupling code system. It is based on the Monte Carlo neutron-transport code MCS and employs the steady-state fuel behavior prediction code FRAPCON as a thermal-hydraulic (T/H) and FP solver. MCS is developed by the Computational Reactor Physics and Experiment Lab of Ulsan National Institute of Science and Technology for the high-fidelity full-core analysis of large-scale commercial light water reactors. Results of power, fuel temperature, coolant temperature and coolant density distributions are presented and analyzed for a quarter-core pin-wise depletion simulation of the BEAVRS Cycle 1 benchmark with T/H and FP feedback (10 axial meshes per pin, 180,870 depletion cells in total). For code-code comparison purpose, the depletion simulation is also conducted with the MCS/TH1D (internal one-dimensional T/H solver) and MCS/CTF (external sub-channel 3D T/H solver) coupled code systems. The dependence to the burnup of the power, fuel temperature, coolant temperature, and coolant density distributions is analyzed by comparison between the three coupled systems. Validation is performed against BEAVRS measured data for the calculated boron letdown curve and calculated distributions of axially-integrated assembly-wise detector signal. Finally, unique distributions of parameters that can only be obtained by FP analysis are examined to illustrate the advanced analysis capability of MCS/FRAPCON.