Special Analysis: Revised 14C Disposal Limits for the Saltstone Disposal Facility

The Saltstone Special Analysis calculated a limit for 14C based on the atmospheric pathway of 52 pCi/mL using some very conservative assumptions. This was compared to the estimated Low Curie Salt concentration of 0.45 pCi/mL and since the limit was two orders of magnitude greater than the estimated concentration, the decision was made that no further analysis was needed. The 14C concentration in Tank 41 has been found to be much greater than the estimated concentration and to exceed the limit derived in the Special Analysis. A rigorous analysis of the release of 14C via the air pathway that considers the chemical effects of the Saltstone system has shown that the flux of 14C is significantly less than that assumed in the Special Analysis. The net result is an inventory limit for 14C that is significantly higher than that derived in the Special Analysis that will also meet the performance objectives of DOE Order 435.1