Range of Parameters For PWR SNF in a 21 PWR WP

This calculation file uses the MCNP neutron transport code to determine the range of parameters for Pressurized Water Reactor Spent Nuclear Fuel contained with a 21 PWR waste package (WP). Four base geometry patterns were considered in this work and included the following: intact fuel assemblies with intact WP internal components, intact fuel assemblies with degraded WP internal components, degraded fuel assemblies with intact WP internal components, and degraded fuel assemblies with degraded WP internal components. For the degraded fuel assemblies, the pitch of the fuel rods was varied such that the largest range of neutronics parameters could be obtained. The calculations involed in this work span an initial U235 wt% range from 2 to 5. The burnup values corresponding to k-eff values of .92 and .99 are found for each enrichment and geometry configuration. Results of this work will be used to support efforts of the Yucca Mountain Project in predicting the range of various parameters for which the MCNP code must be benchmarked.