A set of reactive chemical transport calculations was conducted with the Subsurface Transport Over Reactive Multi-phases (STORM) code to evaluate the long-term performance of a representative low-activity waste glass in a shallow subsurface disposal system located on the Hanford Site. One-dimensional simulations were conducted out to times of 20,000 yr. The simulations predict a lower release rate for the new trench design (0.605 ppm/yr) than for the old trench design (0.726 ppm/yr). Because the glass corrosion rate is significantly higher at the backfill/glass interfaces, having one less interface with the 3-layer design offsets the effect of the slightly higher pH relative to the 4-layer design. The differences between the old and new trench designs were much less significant than differences due to differences in recharge rate.
Revised: October 12, 2009 |
Published: September 20, 2002