Coupling of FRAPCON for fuel performance analysis in the Monte Carlo code MCS

Abstract

The steady-state fuel behavior prediction code FRAPCON has been coupled with the Monte Carlo code MCS to accomplish fuel performance analysis capability. The Monte Carlo based multi-physics coupling analysis for large-scale light water reactors (LWRs) with high fidelity has mostly focused on the inner coupling of the Monte Carlo neutronics analysis code and the thermal–hydraulics code. However, there are still some issues that cannot be considered precisely when predicting fuel thermal conductivity, and the gap thermal conductance between fuel pellets and cladding with the increase of burnup. Therefore, the FRAPCON has been chosen in this paper to be coupled with the MCS code to increase the accuracy of fuel temperature calculations and the corresponding fuel temperature feedback. A fixed-point iteration scheme is adopted for the coupling interface, which has been verified by a single rod case. In addition, the paper also depicts the application of the MCS/FRAPCON coupling system to the BEAVRS quarter core benchmark, by comparison with MCS internal one-dimension T/H solver — TH1D. The results clearly explain the necessity for considering the fuel performance in multi-physics coupling analysis and demonstrate the capability of the MCS/FRAPCON coupling system.