Criticality and Burnup Analysis of Accident-Tolerant Fuels in High-Temperature Test Reactor

Abstract This study aims to investigate the feasibility of implementing accident-tolerant fuels (ATFs) in high-temperature gas-cooled reactors (HTGRs). Endeavors to reinforce risk management in nuclear safety have led to an increased emphasis on investigating ATFs. These specialized fuels are engineered to endure higher operational temperatures than conventional fuel rods, thereby offering superior thermal stability during accidents. In this study, all the computation was performed by using the MCNP6.2 computer code in conjunction with ENDF/B-VII continuous energy library. Five distinct fuel configurations were investigated: the original UO2 tri-isotropic (TRISO) particle design, UC and UN fuels with TRISO particle design; UC fuel with titanium nitride (TiN) coating, and UN fuel with zirconium carbide (ZrC) coating. The effective multiplication factor (keff) and the burnup performance during 660 equivalent full power days (EFPD) was computed to prove the advantage of utilizing higher uranium density ATFs, with the potential to enhance fuel cycle economy. Additionally, the neutron flux, moderator-to-fuel ratio and temperature coefficient was presented and analyzed in this paper.