A generalized model for determining the thermal response to a nuclear waste repository

A generalized integral method for determining unsteady, one-dimensional heat conduction in multi-layer systems with arbitrary thermophysical properties has been developed. Temperature distributions within each sublayer are represented with approximating polynomials, and the source of heat can exist at any location in the system. The recurrence relations between coefficients of temperature profiles are generalized so that any number of sublayers can be handled. Although the model is a general one, it has been applied to temperature independent thermal properties in this study to illustrate the efficiency of the computations. The model is exercised for the stratigraphy of the proposed National High Level Nuclear Waste Repository at Yucca Mountain, Nevada. Results indicate that the model provides a powerful tool for both bounding the coupled thermal and hydrologic performance of the repository and assessing thermal uncertainties over both short and long time scales of repository operations.