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The BRINEMIG brine migration code was used to predict rates and quantities of brine migration to a waste package'.emplaced in a high-level nuclear waste repository in salt. The BRINEMIG code is an explicit timemarching finite-difference code which solves a mass balance equation and uses the Jenks equation to predict velocities of brine migration. Predictions were made for the seven potentially acceptable salt sites under consideration as locations for the first U.S. high-level nuclear waste repository. Predicted total quantities of accumulated brine were on the order of 1 m^ brine per waste package or less. In general, less brine accumulation is expected at domal salt sites because of the lower initial moisture contents relative to bedded salt sites. Also, less total accumulation of brine is predicted for spent fuel than for commercial high-level waste because of the lower temperatures generated by spent fuel.

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Previous analytical models for the steady-state radionuclide release rate through perforations in nuclear waste containers into the surrounding medium, are based on a zero wall thickness assumption. In this paper we investigate the effect of the wall thickness on the mass transfer rate through isolated circular holes. We solve the steady-state diffusion equation for the concentration field and derive a model based on the analytical solution. By direct comparison, we show that the zero wall thickness model overpredicts the mass transfer rate by about 1300 percent for a circular hole with 1 cm radius and a wall thickness of 10 cm. As expected, the zero-thickness model becomes even less accurate as the hole radius decreases; it predicts a greater release rate from a large number of small holes than the mass transfer rate from an uncontained waste form cylinder. In contrast, the results predicted by our model remain bounded for isolated holes and never exceed the mass transfer from an uncontained waste form.

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