The objective of this calculation is to evaluate the peak temperatures due to thermal loading and boundary conditions of the TAD Waste Package design under nominal Monitored Geologic Repository conditions.

The purpose of this calculation is to characterize the criticality safety aspects of N-Reactor fuel stored in a Department of Energy spent nuclear fuel (DOE-SNF) canister that contains four Multi-Canister Overpacks (MCO's). These calculations will be done to support the analysis that will be done to demonstrate concept viability related to pre-emplacement storage and use in the Monitored Geologic Repository (MGR) environment for the pre-closure time frame.

This report presents a two-phased approach to develop and analyze a “thermal envelope” to represent the postclosure response of the repository to the anticipated range of repository design thermal loadings. In Phase 1 an estimated limiting waste stream (ELWS) is identified and analyzed to determine the extremes of average and local thermal loading conditions. The coldest thermal loading condition is represented by an emplacement drift loaded exclusively with high-level radioactive waste (HLW) and/or defense spent nuclear fuel (DSNF).