PARCS pin-wise simulation with a cross section correction system based on the Super-Homogenisation method

Abstract

A cross-section (XS) correction system was developed at the Karlsruhe Institute of Technology (KIT) for pin-wise simulations in PARCS, utilizing the SuPer-Homogenization (SPH) method in an iterative Python-based framework. The system uses Monte Carlo Serpent2 pin-wise solutions as a reference to correct homogenized pin-wise XS, improving PARCS’ accuracy in predicting neutron reaction rates and pin-wise power distributions. Verification was conducted with four test cases of increasing complexity: (a) a 3x3 mini assembly, (b) KONVOI reactor fuel assemblies, (c) a 3x3 mini-core, and (d) the Karlsruhe Small Modular Reactor (KSMR). Results show that the corrected XS significantly enhances PARCS’ diffusion solver accuracy, closely matching Serpent2 results, in pin-by-pin core simulations. Notably, this approach outperforms traditional assembly-wise Pin Power Reconstruction (PPR), particularly in central core regions. The key outcome of this work is that, for PARCS pin-wise simulations, computational accuracy is enhanced, making the prediction of local safety parameters feasible, especially if coupled with a Thermal-Hydraulic (TH) code, such as a sub-channel code. Furthermore, this work extends PARCS’s capability to perform pin-wise simulations with the standard nodal solver.