Fission Surface Power—A Conceptual 350-kW(thermal) Microreactor Designed for Lunar Power Around SpaceX Falcon Heavy Mass Constraints

Abstract

A fast spectrum surface fission power microreactor for lunar deployment is conceptualized and modeled utilizing the primary design drivers of the SpaceX Falcon Heavy mass constraints, a 10-year operation lifetime, high-assay low-enrichment uranium fuel enrichment, a 100-kW(electric) system power rating, and a Stirling conversion cycle. The reactor is demonstrated to remain subcritical during launch accidents resulting in oceanic submersion and throughout control system failures in the highest reactivity positions. Neutron shielding requirements for the high-leakage core were satisfied with 40 cm of natural enrichment LiH at 100% solid density, while photon shielding for the reactor at full power exceeded the in the National Aeronautics and Space Administration scope of work design requirement 18960 DR-3 of 5 rem·y−1 at rates of 30 rem·y−1 for a 1-km standoff. A conversion cycle was approximated using an experimental carbon-carbon thermal radiator coupled with published analytical and experimental results for free-piston Stirling systems.