Conceptual design of a 3 MWth yttrium hydride moderated heat pipe cooled micro reactor

Micro reactors are gaining substantial interest worldwide due to their capabilities to deliver power to remote and decentralized areas and their long fuel cycles, making them more attractive than other energy sources. This paper presents a conceptual design and steady-state neutronics and thermal-hydraulics analyses results for a heat pipe cooled yttrium hydride moderated micro reactor. The reactor was designed for both terrestrial and space application purposes; hence, size and weight were important. The neutronics analysis calculations were performed to evaluate key safety parameters such as control devices reactivity worth, temperature reactivity coefficients, and power distribution of the reactor core. Burnup calculations were performed using Monte Carlo code MCNP6.2 and verified against Serpent code results. The thermal-hydraulics analyses calculations were performed to evaluate the temperature distribution in a representative unit cell in the reactor core using the STAR CCM+ multi-physics computational fluid dynamics (CFD) software by utilizing the power distribution obtained from neutronics calculations. It was demonstrated that this reactor could be operated safely for more than 11 years, generating 3 MW of thermal power.