These two documents, posted by the US Nuclear Regulatory Commission on June 25, 2018, discuss predictions related to amount of iodine-129 and technetium- 99 in the solidified waste to be left forever in the ground at SRS.
Evaluation of I-129 Concentration Data to Improve Liquid Waste Inventory Projections, February 2018 – linked here
For future modeling, this report recommends similar values: for “realistic” models 15.9 Ci is recommended; this value represents I-129 already disposed at SDF plus the total soluble inventory in the tank farms. For “compliance” models an inventory of 16.6 Ci is recommended; this value represents I-129 already disposed at SDF plus the total soluble and insoluble inventory in the tank farms. Finally, for “defense-in-depth” models an inventory of 24.4 Ci is recommended; this value represents I-129 already disposed at SDF plus the total tank farm inventory increased by 50%.
Evaluation of Tc-99 Concentration Data to Improve Liquid Waste Inventory Projections, March 2018 – linked here
For future modeling, this report recommends similar values: for “realistic” models 2.24E+04 Ci is recommended; this value represents Tc-99 already disposed at SDF plus the total soluble inventory within the tank farms. For “compliance” models an inventory of 3.30E+04 Ci is recommended; this value represents Tc-99 already disposed at SDF plus the total soluble
inventory within the tank farms, increased by 50% to account for potential uncertainty. Finally, for “defense-in-depth” models an inventory of 3.55E+04 Ci is recommended; this value represents Tc-99 already disposed at SDF plus the total soluble inventory and half of the total insoluble inventory.