Neutronics Analysis of Accident – Tolerant Cladding and Pellet Materials

SCALE software and two kinds of approximated methods are used for lattice and reactor core analysis respectively, based on which the neutron economy evaluation is performed for the accident -tolerant cladding materials including SiC, advanced steel alloy and Mo, and new pellet materials like U3Si2, U15N and U- Mo. The analysis results indicate that the metallic claddings have noticeable neutronie penalty, which should be compensated by thinner cladding or high fuel enrichment. High density pellets like U3Si2 can generally improve the neutron economy; however U15 N has no obvious economic advantage due to its high 238U content.