Design Methodology of a Pressurized Irradiation Test Apparatus for Stirling Convertor Organics in the Fission Surface Power Project

The NASA Fission Surface Power project is undertaking risk reduction efforts to achieve the goal of placing a fission reactor on the lunar surface in the early 2030s. Stirling engines are one option for reactor power conversion; however, the organic/polymer components used may be susceptible to radiation damage. A combined effects test at prototypic temperatures, pressures, and mixed-radiation doses is needed to evaluate the components' ability to meet mission exposure levels. This paper describes the design methodology of a low-activation pressure vessel to simulate a Stirling engine environment and test organic components into a research reactor. Calculations and modeling were used to verify the design. MCNP was used to model the sample dosage and confirm material selection. Irradiation testing is planned for FY 2025.