SIMMER-III Code Assessment for Material Expansion Dynamics During Core Disruptive Accidents in Sodium-Cooled Fast Reactors Available to Purchase

The sodium-cooled fast reactor (SFR) severe accident analysis computer code SIMMER-III has been developed and assessed comprehensively and systematically in a code assessment (verification and validation) program which consists of a two-step effort: Phase 1 for fundamental or separate-effect assessment of individual code models; and Phase 2 for integral assessment of key physical phenomena relevant to SFR safety. This paper describes the achievement of the code assessment on material expansion dynamics in the framework of the Phase 2 assessment program. Detailed descriptions are given for two representative experimental analyses (VECTORS and OMEGA), which are intended to validate high speed multi-phase flow dynamics in pin bundle structure and large vapor bubble expansion dynamics into a coolant pool, respectively. Through the assessment program, the SIMMER-III code has proved to be basically valid both numerically and physically, with current applicability to integral reactor safety calculations.