Neutronic analysis of alternative ceramic fuels in the next generation of VVER-1000/V446 reactor

Abstract

One of the most important issues in nuclear fuel management is burnup increase, which impacts significantly on the reactor cycle length. Burnup enlargement specifically leads to reducing the cost of electricity generation and increasing efficiency. In the present study, the neutronic analysis of some alternative ceramic fuels includingUN, 15UN, and UChas been performed forthe VVER-1000/V446 reactor, comparing with the conventional UO2. Being single-ligand, the alternative fuels’ density of heavy metals such as uranium is greater than UO2’s one. Therefore, the absorption and fissionamounts in thesefuels will be higher than theones in UO2 fuel. By modellingVVER-1000/V446 reactor with MCNPX2.6 Monte Carlo code, we showed that the excess reactivity value for UC fuel (169.173 ∆K/K) increased compared to UO2 fuel (165.526). Due to the ultra-high burnup, the reactor cycle length is 398 days for 15UN fuel, while it is 270, 308, and 130 days for UO2, UC, and UN fuels, respectively, and has increased by 47%. Therefore, the use of alternative fuels has advantages like plant construction cost reduction,excess reactivity, discharge burn up, making them suitable substitution of conventional UO2 for the next generation of LWRs.