Multi-Physics Modelling of Small Modular Reactors With Serpent 2 and Thermal Hydraulics Solvers

Abstract

In this research the goal is to solve coupled problems with neutronics and thermal hydraulics. The focus is on SMRs. The neutronics are solved with Serpent 2, a Finnish state-of-the-art Monte Carlo neutronics code developed at VTT. Thermal-hydraulics are solved with the COSY (COmponent/SYstem-scale) ther\-mal-hydraulics tool also developed at VTT. The coolant flow solution is based on a porous-media three-field flow model on unstructured grid. The code also solves axial and radial temperature distributions in the fuel and the cladding using finite volume method as well as the radial expansion of the fuel rods. Using the coupled code system a SMR core in a steady state at full power with multiphase flow will be modelled. The idea is to demonstrate that a steady state coupled neutronics/thermal hydraulics problem can be solved using the Serpent-COSY coupling and assess the computational cost of the solution.