The amount of plutonium in tank C-106 now exceeds the site criteria for fissile material control. The sludge retrieved from tank C-106 may therefore need to be transferred into two different double shell tanks to avoid violating a mass criticality safety limit. Entrained gases can be released from the sludge when it is sprayed with 120 psi sluicing fluid, or when the slurry goes through the vertical centrifugal suction pump and booster pump which transfers the slurry into tank AY-102. The rate at which entrained gases may be released is also a concern, as is the formation of a large vapor bubble in the waste which could splash waste up into the air inlet or exhaust risers in the dome. The amount of organic material in tank C-106 is not believed to be large, but the actual amount is unknown.
Organic material can be in the sludge and the hardpan.
There is also no automatic process control of the flow. The amount of gas that can be tolerated in the transfer line is unknown. The potential for solids to plug the pumps or the lines during operations, or after pump shutdown, has not been fully evaluated. Specific procedures to clear plugged equipment or lines or replace failed equipment, have not been developed. If the failed heel jet in tank C-106 could be replaced much of the heel might be removed.