Evaluation of Transportation and Acceptance Strategies Associated with the Potential Yucca Mountain Waste Management System

This paper describes the development and use of an integrated model to explore the impact of design parameters and operational decisions on storage and transportation aspects of the preclosure activity period for the potential repository at Yucca Mountain (YM), Nevada. The model provides an opportunity to perform analyses of various YM preclosure "scenarios." Storage and transportation aspects of the preclosure system are evaluated with the goal of identifying important design parameters and understanding system interactions, thereby providing a tool to recognize trade-offs and dependencies between storage demands at the waste generation sites and the repository.

This application of the model explores changes in assumptions regarding the following parameters: (a) year the transportation, aging, and disposal (TAD) canister becomes available; (b) year that YM opens; (c) thermal limit for emplacement; (d) thermal limit for transportation; and (e) utility strategies for selecting assemblies for dry storage loading.

The response variables measured are (a) dry storage containers loaded because of lack of capacity in the spent nuclear fuel pools, (b) TAD canisters that could potentially be loaded before YM opens (assuming utilities begin using the TAD canister as soon as it is commercially available), (c) pools from which shipments to YM originate each year, (d) years aboveground aging is required at YM, and (e) containers in the aging facility at YM each year.

Results indicate that allowing utilities to trade allocations, prioritizing the trading based on least remaining capacity in the spent nuclear fuel pools, could reduce dry storage demands at the utility sites, decrease the number of pools making shipments each year, and increase the efficiency of the transportation system. This type of prioritization for allocations can provide these improvements without adversely impacting the required aboveground aging at YM in the case that younger fuel is sent first. Consequently, there may be incentive for utilities to negotiate the trading of allocations if they wish to reduce their expected dry storage demands after shipments commence to YM.