Spent Fuel Critical Experiment Device Criticality Calculation

With the development of nuclear power, the nuclear critical safety problem becomes more and more significant. The burnup credit technology has been applied to analysis of the nuclear critical safety. This has significantly enhanced the capacity of storing, transportation, reprocessing and improved the economy of back end fuel cycle. It is very important to carry out critical experiment on spent fuel for selecting calculation code packages and validating calculation methods using burnup credit technology. Before building the spent fuel critical experimental facility, massive detailed critical calculation should be performed.This paper consults the burnup analysis method of burup credit technology, selects a series of burnup parameters(the concentration of soluble boron, moderator density, fuel pellet temperature and control rod operation). Using the SCALE code package, we carried out the calculations and sensitive analysis to each parameter, determined its change range. Based on appropriate simplification of fuel operation history, varying spent fuel compositions are calculated with design parameters of spent fuel of 3.0% initial fuel enrichment in Qinshan 300MWe nuclear power station. In the process of spent fuel isotope yield calculations, the simple accumulation of spent fuel composition influences of each burnup parameter is taken, but the coupling effect of each parameter is not considered.Based on investigating and studying in the domestic and foreign critical experimental facilities, according to the certain design principle, existing fuel condition, using the spent fuel compositions which is resulted from previous calculation, the reactor core geometry arrangement of spent fuel critical experiment facility is determined by a lot of critical calculations using the CASMO+MCNP code system. A number of parameters, such as water level coefficient, control rod value, is calculated. The result indicates that the reactor core arrangement satisfies the critical and control request, and can meet the purpose of spent fuel critical experiments.The reactor core critical calculation of spent fuel critical experimental facility has been basically completed in this paper. Furthermore, there is a lot of work to do for the design of reactor core. It provided the basis for constructing the spent fuel critical experimental facility and development studies of burnup credit technology.