Validation of Burnup Calculation Code SWAT4 by Evaluation of Isotopic Composition Data of Mixed Oxide Fuel Irradiated in Pressurized Water Reactor

This paper provides validation results of SWAT4, the revised version of SWAT3.1, by the analysis of PIE data of MOX fuel irradiated in a pressurized water reactor.SWAT4 is a system that combines the point burnup system ORIGEN2 and neutron transport calculation solvers, the continuous energy Monte Carlo code MVP or MCNP5, and the deterministic neutronics calculation code SRAC2006.The calculation results of SWAT4 have generally same trends with the case of UO2 fuel analyses. For major uranium and plutonium isotopes, deviations less than 5% were obtained. This means that SWAT4 has the same accuracy to predict isotopic compositions of irradiated MOX fuel with the case of UO2 fuel. The radial distribution of isotopes in a pellet was also analyzed, whose results were compared with that measured by SIMS. SWAT4 predicted well the isotope and burnup distributions in an irradiated MOX pellet.