Multi-physics Simulation of a Reference Fluoride-Salt-Cooled High-Temperature Reactor with Coupled SAM/Griffin

Abstract

A multi-physics coupled simulation model of a reference pebble bed fluoride-salt-cooled high-temperature reactor (PB-FHR) has been developed with SAM and Griffin codes in this work. This reference PB-FHR design is developed to represent a generic PB-FHR, mostly based on publicly available design information of Kairos Power’s generic FHR (gFHR) and the Hermes demonstration reactor. The SAM thermal hydraulics model of PB-FHR includes a two-dimensional (2-D) axial symmetric core region and external core components in zero- and one-dimensional (0-D/1-D). In addition to the primary loop, a detailed model of the Reactor Cavity Cooling System (RCCS) is also included. The 2-D and 1-D domains are tightly coupled using the single-solve approach developed in SAM. In the pebble bed region, the SAM multiscale pebble model is applied to calculate the pebble and TRISO fuel kernel temperatures. The Griffin neutronics model used in this work is based on a gFHR model which was developed at Idaho National Laboratory in collaboration with the U.S. Nuclear Regulatory Commission. The equilibrium core is attained via the streamline depletion method available in Griffin. The Griffin neutronics model and SAM thermal hydraulics model is coupled with the Comprehensive Reactor Analysis Bundle (CRAB or alternately BlueCRAB) application. Both steady-state and transient scenarios are simulated to demonstrate the model’s suitability for multi-physics simulations.