Neutronic analysis of fuel assembly design in Small-PWR using uranium mononitride fully ceramic micro-encapsulated fuel using SCALE and Serpent codes

Abstract

One of proposed Accident Tolerant Fuel (ATF) concept is fully ceramic micro-encapsulated fuel (FCMF). FCMF using uranium mononitride (UN) has better safety aspects than UO2 pellet fuel although it might not have a better neutronic performance due to the presence of matrix and high neutron-induced interaction of 14N. Before implementing UN-FCMF technology in Small-PWR, further research must be taken place to make sure the proposed design of fuel assembly has inherent safety features and maintain the fuel performance. This study focusses on the neutronic analysis of UN-FCMF based fuel assembly using Serpent and SCALE codes. It is shown in the proposed fuel assembly design has inherent safety features with respect to the fuel temperature reactivity coefficient, void reactivity coefficient, and moderator temperature reactivity coefficient. It is noted that the use of FCMF leads to a lower ratio of burnup to 235U enrichment ratio compared to the UO2/Zr fuel. Keywords: Small-PWR, Fully ceramic micro-encapsulated fuel, Uranium mononitride, SCALE, Serpent