Full-scale neutronic/thermal–hydraulic coupling analysis of plate-type reactor based on RMC and MOOSE

In this paper, a three-dimensional full-scale neutronic/thermal–hydraulic coupled analysis for the plate-type reactor is proposed based on the Multiphysics Object-Oriented Simulation Environment (MOOSE) and Monte Carlo code RMC. For fast thermal–hydraulic calculation, two-dimensional heat transfer model and one-dimensional coolant subchannel model are established, and integrated into the thermal–hydraulic analysis code SPhase. The verification of SPhase is first implemented through analytical solutions and numerical codes. The three-dimensional neutronic model and calculation schemes are verified through RMC to ensure the accuracy of physics calculation. The full-scale JRR-3M critical coupled simulation under steady state is realized through cell-level resolution, and the criticality search is implemented using the dichotomous method. Comparisons between calculation results with and without thermal feedback are herein proposed for safety analysis of JRR-3M. In the critical condition, the thermal feedback introduces a negative activity of about 400 pcm. The insertion of absorbers renders the complexity of core power distribution. The reflection effect results in peak thermal neutrons flux near the reflector, and the maximum assembly temperature reaches 340 K at the edge of the core. This work provides a reference for correlational studies on neutronic/thermal–hydraulic characteristics and safety analysis of plate-type reactors.