The relativistic multigroup diffusion equations describing superthermal electron transport in laser fusion plasmas were derived in an earlier UCRL. A successful numerical scheme based on these equations which is now being used to model laser fusion experiments is described.

Four different models of the migration process have been reviewed to determine their suitability as a working model. While there are several common factors in the models additional factors are included to account for several possible effects. The detail of each model leads to a certain degree of difficulty in applying the model to the problem at hand. One model predicts that inclusions smaller than 0.1 mm dimension probably will not migrate. The other models do not consider size as a factor. Thermal diffusion (Soret effect) is considered insignificant in three models, while in the fourth model it is added to the concentration diffusion term. The following conclusions are made: (1) Temperature is the most significant parameter in all models and must be known as a function of time, and distance from the canister. (2) All four models predict about the same migration velocity for a given set of conditions. For 100/sup 0/C and 1/sup 0/C/cm thermal gradient, the individual values are 3.0, 4.8, 5.6 and 6.4 mm/y. (3) The diffusion of ions through the brine inclusions is the rate controlling mechanism. (4) The difference between the thermal gradients in the liquid and in the solid should always be considered, …

When canisters containing radwastes are emplaced in a repository the heat produced by the decaying radwaste will cause moderate thermal gradients to develop which will cause the brine present in a halite medium (salt deposits) to accumulate around the canister. Four different models of the migration process have been reviewed to determine their suitability as a working model. One model predicts that inclusions smaller than 0.1 mm dimension probably will not migrate. The other models do not consider size as a factor. Thermal diffusion (Soret effect) is considered insignificant in three models, while in the fourth model it is added to the concentration diffusion term. The following conclusions can be made: Temperature is the most significant parameter in all models and must be known as a function of time, and distance from the canister. All four models predict about the same migration velocity for it is a given set of conditions; for 100/sup 0/C and 1/sup 0/C/cm thermal gradient, it is 3.0, 4.8, 5.6 and 6.4 mm/y. Diffusion of ions through the brine inclusions is the rate controlling mechanism. The difference between the thermal gradients in the liquid and in the solid should always be considered and is a function …