3-D MODELLING OF A SUPERPHéNIX BENCHMARK WITH SERPENT AND PARCS FOR COUPLED SIMULATION WITH PARCS/ATHLET

摘要

Most of the safety criteria for Sodium cooled Fast Reactors (SFR) are local core parameters.Thus, application of 3-D neutron kinetic and thermal-hydraulic coupled codes includingdetailed modelling of core expansion effects is mandatory for best estimate evaluations ofsafety margins. A recently published benchmark related to Superphénix offers the opportunityto validate codes and methods for SFR safety assessment. This requires the generation of fewgroupcross-sections. Since whole core Serpent Monte Carlo models for production of suchcross-section libraries would be computationally costly (and the standard 2-D approach mayintroduce unnecessary large approximations), 3-D models of each sub-assembly type ininfinite radial lattice configurations have been created with Serpent. To simplify the handlingof temperature dependent geometric changes, a pre-processor for generation of temperaturedriven expansion of geometry and material densities has been developed and implemented inthe GRS core simulator KMACS. These cross-sections are then used to evaluate effectivemultiplication factors and 3-D distributions of power density using PARCS for different coreconfigurations. The results are compared with the reference calculation and with experimentaldata provided with the benchmark. In the next step, a simple ATHLET parallel channel opencore model has been developed for coupled PARCS/ATHLET first transient test calculations.This paper describes in detail the models and techniques used for the generation of the fewgroupparameterized cross section libraries, the PARCS model and the ATHLET open coremodel and first transient test calculations.