Long term thermal analysis of high level radioactive waste burial in Basalt

A 1,000 year temperature history of high level radioactive wastes (spent fuel) is calculated for containers buried in a deep underground repository carved out of basalt. The discussion is based on work performed for the Basalt Waste Isolation Project (BWIP). The analysis uses a grid/boundary conformance technique to permit an accurate representation of the geometry by a reasonable number of modes. This technique is more commonly used for analysis of complex aerodynamic shapes; the present application to a multi-dimensional semi-infinite conduction problem is thought to be unique. The method used permits use of a micro-computer at the conceptual design stage; thereby saving significant computer dollars. A generalized finite difference heat transfer program is used. Extension of the technique to more detailed evaluations showing gradients along the cylinder axes, and in particular near the cylinder ends, can be expected to result in similar efficiencies and inherent accuracies