APR-1400 WHOLE-CORE DEPLETION ANALYSIS WITH MCS

Abstract

This paper presents verification and validation elements of UNIST inhouse Monte Carlo code MCS for the multi-physics analysis of an APR-1400 (Advanced Power Reactor 1400 MW electricity). One remarkable capability of MCS is the capability to simulate large-scale core pin-wise depletion analysis (chain of ~1,373 isotopes) with thermal-hydraulic feedback and critical boron concentration search. This capability, one of the most compelling advances for reactor analysis, has been previously verified and validated against several benchmark problems, including the BEAVRS benchmark released by MIT. In this work, MCS is compared with the deterministic STREAM/RAST-K 2.0 two-step code system and validated against measured plant data. The core parameters analyzed by MCS include critical boron concentration, quantities measured in low power physics tests, power profiles, and temperature profiles. Overall, MCS shows an excellent performance: the MCS solutions for the low power physics tests satisfy predefined acceptance criteria, the root-mean-square (RMS) error of critical boron concentration is within 25 ppm throughout all the burnup steps and the RMS errors of assembly power profiles at 8.0 GWd/MT and 15.0 GWd/MT are correspondingly 2.80% and 1.03% compared to measured data. MCS temperature profiles are verified against STREAM/RAST-K 2.0 solutions because measured temperature data is not available, and a good agreement is observed between both codes. The obtained results reinforce the confidence in MCS’ capability to perform high-fidelity multi-physics calculations for a practical PWR core.