SUMMARY

The Systems for Nuclear Auxiliary Power (SNAP) program produced systems that were small and compact, optimized for space travel causing them to have unique characteristics and be regarded as the original microreactors, sharing many attributes of modern microreactor designs such as comparable dimensions and power output, similar material composition, similar working fluids, and overall representative reactor physics phenomena.
The Nuclear Energy Advanced Modeling and Simulation (NEAMS) program aims to develop high-fidelity tools to aid the design and deployment of advanced systems, such as microreactors. As part of this program the Multiphysics Object Oriented Simulation Environment (MOOSE) framework has been developed to enable an integrated multiphysics approach. However, with the development of these tools and frameworks arises the need for verification and validation aswell as a benchmarking. The goal of this work is to present computational tools that we have developed to streamline the collection and integration of data into multiphysics sequences using models of the SNAP 8 Experimental Reactor. The focus is on the criticality configuration experiments under dry conditions (no coolant, low power) with additional relevant reactivity worth experiments. This work intends to provide reproducible benchmark models that are aligned with microreactor technology to facilitate the verification and validation of nuclear safety codes for microreactor applications. A 2-stage sequence is applied here with the Monte Carlo code Serpent used for the generation of few-group cross sections and Griffin as the transport eigenvalue solver. This work provides the procedure adopted for the pre-generation of a few group parameters, generation of unstructured mesh geometry, and selection of transport solver parameters. The results from Griffin are compared against the reference Serpent for various experimental configurations.