Considerations in the selection of a high-level waste canister

The design of the high-level waste (HLW) canister is highly significant in all phases of the high-level waste management system including solidification of the waste at the reprocessor, transportation, and permanent disposal at the federal repository. The purpose of this preliminary study is to identify these considerations and interactions, to provide background data for a detailed study which will evaluate these interactions, and to form the basis for the selection of specific design parameters for the canister. Preliminary estimates of the ranges of HLW canister constraints are summarized. Short-cooled wastes or calcination lead to canister sizes on the order of 6 to 16 inches. The in-can melter (ICM) might be limited to canisters in the range of 12 to 18 inches due to the weight of the glass, but this also depends on the length of the canister. Large diameter cans require more heating of the ICM to melt the waste and glass frit in the center of the canister, and this could lead to a diameter limit for the ICM. The drill used for emplacement holes in the repository may limit the maximum canister diameter in the range of 20 to 24 inches, depending on the retrievability concept chosen and the clearances required. The largest size canister a truck cask could handle is about 15 feet long by 24 inches in diameter. The minimum size canister required for disposing of unprocessedspent fuel would be 15 feet long by 12 inches in diameter. The room height in the repository might limit the canister length to a range of 12 to 15 feet, depending on the amount of end shielding and handling clearances necessary. In summary, a first look at the potential canister envelope indicates a range of 6 to 24 inches in diameter and 8 to 15 feet in length