Development and evaluation of a two-dimensional neutron diffusion model of a small modular heat-only reactor TEPLATOR using COMSOL

Abstract

TEPLATOR, a collaborative innovation between researchers from the University of West Bohemia (UWB) and Czech Technical University (CTU), represents a promising solution for environmentally sustainable energy demands. This small modular heat-only reactor features a heavy water-cooled and heavy water-moderated pressure channel design, offering an alternative to fossil fuel-dependent heating and cooling plants, thereby reducing environmental impact and pollution. This article outlines the initial steps in developing a detailed neutron diffusion model for the TEPLATOR core using COMSOL Multiphysics software. The study focuses on developing and evaluating a two-group steady-state neutron diffusion model for the two-dimensional reactor geometry to analyze spatial neutronic dynamics under various control rod positions. Neutronic parameters were computed using the Serpent Monte Carlo neutron transport code and integrated into the diffusion model as multi-group constants. Calculations were conducted for the Beginning-of-Cycle (BOC) scenario. The obtained values of effective multiplication factor (keff) from both the developed COMSOL diffusion model and Serpent codes remain consistent, with differences ranging from 242 pcm to 643 pcm across different control rod position scenarios. Additionally, the computational time of the developed diffusion model is significantly shorter than that of the Serpent code. Furthermore, the effectiveness of the diffusion model for practical design investigations and sensitivity analyses of the TEPLATOR reactor core is demonstrated by presenting steady-state neutron flux and power distribution calculated by the diffusion model, which was compared with Serpent code computations.