Low enriched nuclear thermal propulsion neutronic, thermal hydraulic, and system design space analysis

Abstract

Nuclear thermal propulsion is the high thrust, high specific impulse rocket engine technology of choice for future missions to Mars and beyond. Current designs are focusing on low enriched uranium fuel systems to reduce development costs and regulatory concerns. These designs require careful examination to identify an engine that is able to satisfy NASA’s requirements. Previous work has focused on low enriched, but for limited cases of fuel options and without a fully integrated computational framework and assumed boundary conditions. The current study relies on and extends previous publicly available NASA studies by accounting for UN fuel embedded in Molybdenum and Molybdenum-Tungsten matrices. Integrated system framework that considers various engine’s components was developed. The performance of the engine is evaluated using T/H analysis of all the major components, such as the reactor-core, pumps, turbines, and pipes. Neutronic calculations are performed using the Serpent code, in which both the neutron and gamma transport were enabled to provide accurate spatial power distributions. The results show that using an integrated system analyses approach yields a systematic assessment and identifies an ideal design space for future higher fidelity analysis to achieve mission needs set by NASA.