The Neutronics Codes FENNECS and FRENETIC: Code-to-code Benchmarking on Lead and Sodium-cooled Fast Reactors

Compared to light water-cooled reactors, the operating experience for liquid metal-cooled reactors (LMRs) and so the amount of available measurement data is very limited. Therefore, code-to-code benchmarking of different deterministic neutron kinetics codes using the same neutronic data in terms of macroscopic cross section libraries plays an important role in elaborating the capabilities of the codes to simulate the safety relevant neutronic characteristics of LMRs and providing insight into potential limitations due to specific modeling approximations. This present paper is the initial step to do such comparisons by starting with steady-state stand-alone neutronics code-to-code comparisons considering the Lead-cooled Fast Reactor concept ALFRED and a Sodium-cooed Fast Reactor (SFR) with metallic fuel. The deterministic neutronic codes used are FENNECS and FRENETIC, while the Serpent Monte Carlo code is used as a reference. For ALFRED, the obtained steady-state FRENETIC and FENNECS simulations exhibit some differences with respect to the Serpent calculations. For the SFR, systematic studies of different set of group constants, including or excluding the scattering multiplication reaction and considering the super homogenization (SPH) method, are carried out. The outcomes of this analysis suggests that the SPH corrections should be evaluated consistently with the numerical scheme implemented in the code used to simulate the full-core behaviour.