Waste Package Heat-Transfer Analysis: Model Development and Temperature Estimates for Waste Packages in a Repository Located in Basalt

摘要

The Office of Waste Package Studies of the Basalt Waste Isolation Project is conducting an ongoing study of waste package heat-transfer processes as part of the development of waste package-design requirements. The objective of these heat-transfer studies is to provide the temperature estimates necessary to predict the physical, chemical, and hydrothermal environment of the waste package during geologic isolation in a repository located in basalt. Heat-transfer analyses were performed for three nuclear waste types which exhibit different characteristics - commercial and defense high-level waste (both immobilized in borosilicate glass) and spent-fuel elements. The waste-isolation system parameters used in these analyses reflect the current conceptual designs for a high-level nuclear waste repository constructed in basalt. Details of the thermal properties of the host rock and waste package relevant to a repository in Columbia River basalt and the relevant properties of the waste forms themselves are presented and discussed. The physical layout of the nuclear waste repository was modeled using the heat-transfer computer code, HEATING5. The first step in this analysis was to evaluate repository temperatures using one-, two-, and three-dimensional models with a homogenized heat source. Next, the results of the one-, two-, and three-dimensional models were integrated to produce an accurate estimate of waste package/host rock-interface temperatures as a function of time. (ERA citation 07:042572)