Heat Generation by Radioactive Wastes

Generalized numerical and anaytical methods were developed for estimating temperatures resulting from the storage of high-level wastes. Parametric relationships were considered, and solutions for the packed-bed, multi-region, variable-geometry, and variable-effective thermal conductivity systems were evaluated. Solutions of the heat equation in one space dimension were obtained for plane, cylindrical, and spherical geometries. Three computer codes were developed, tested for accuracy, and compared. The codes represent three approximations to the actual physical situation. An auxilary code was written to provide an estimate of the waste that could be put into a cavity when a maximum permissible temperature is specified. The accuracy of the solutions depends chiefly on the values of the input data and the variations of the parameters affecting the finite mesh and boundary conditions. The size of storage sites, the concentration of wastes, and the age of wastes have the greatest effect on the magnitude of the temperature.