عنوان مقاله [English]
A fundamental knowledge of fuel behavior in different situations is required for safe and economic assessment nuclear power generation. Analysis of nuclear fuel pellet rim region is most importance, due to excessive fission gases release, reduce conductivity and high burnup in this region compared to inside regions the pellet. Due to the importance of a fuel rod behavior modelling in high burnup, in this study, the radial distribution of fission products, burnup and actinides atom density and their variations by increasing burnup and other factors such as temperature, enrichment and power density are studied in a fuel pellet of a VVER-1000 reactor in an operational cycle using the MCNPX 2.7 Monte Carlo code. To calculate the radial distribution of temperature and analyze the impact on burnup, the program was written in FORTRAN, which uses heat transfer relationship to investigate the behavior of fuel. The results, has been shown ability to do radius calculations with the model presented in MCNPX2.7 and mentioned program.