Application of the Serpent–OpenFOAM Coupled Code System to the SEALER Reactor Core

In this work the Monte Carlo neutron transport code Serpent 2 is coupled with a CFD solver from the OpenFOAM toolbox for multi-physics calculations of a small modular reactor core. The coupling is implemented with the multi-physics interface available in Serpent and all data between the two codes is exchanged with OpenFOAM fields files. The coupled neutronics/thermal-hydraulics problem is solved with Picard iteration. As a test case the small lead-cooled fast reactor SEALER is simulated in steady state at full power. Only active core is modelled and 1/6 symmetry of the core is utilized in solving the coupled problem in one sixth of the active core with reflecting boundary conditions. Serpent and OpenFOAM models of SEALER are described separately in detail and some initial results of the coupled calculation are presented. Based on the test calculation general difficulties related to coupled Monte Carlo--CFD calculations are discussed along with more specific issues related to fast and liquid metal cooled systems such as SEALER.