Comparative Analysis of Accident Tolerant Fuels with Spectrum Shift Regulation in VVER-S Reactor

Abstract Accident Tolerant Fuels (ATF) have emerged as a promising solution to improve safety during reactor accidents by enhancing fuel performance in light water reactors (LWRs). This paper investigates the performance of different ATF concepts, including Chromium-coated Zircaloy (CrZry), advanced steel (FeCrAl), and Silicon Carbide (SiC) as cladding materials, paired with Uranium Dioxide (UO 2 ), Uranium Silicide (U 3 Si 2 ), and Uranium Nitride (UN) fuels, under spectrum shift regulation conditions in a VVER-S reactor. Using the GETERA program, a series of calculations were conducted to compare multiplying factors and isotopic concentrations under spectrum-shifted conditions. The results demonstrate significant differences in fuel cycle characteristics and isotopic behavior, with SiC emerging as the optimal cladding material for maximizing neutron economy and minimizing parasitic absorption.