In-tank processes for destruction of organic complexants and removal of selected radionuclides

Technical basis for classification of low-activity waste fraction from Hanford site tanks

“…In-tank mixers are required to keep the floc in suspension and available to the soluble TRU for adsorption. 14s demonstrated from laboratory testing, precipitation of FqO,.xH,O from CC waste rrmoves 84 to 96 percent of the 241Arn and 60 to 75 percent of the soluble plutonium (Schulz 1995). The development work also indicates that approximately 50 percent of the soluble strontium may also be removed by the ferric hydroxide precipitation process (0.28 MCi of ihe 0.57 MCi soluble %r).…”

“…An analysis of DST radionuclide removal requirements on a tank-by-tank basis (Schulz 1995) has determined that no additional removal of soluble "Sr is required for any tank to meet the NRC Class C criteria. The "Sr concentration in glasses made from supernatant liquid in at least 21 of the DSTs will contain less than 150 Ci "Sr/m3 without pretreatment, which is below the Class B limit for "Sr.…”

“…Recent radionuclide removal tests indicates that "Sr is effectively removed from CC waste (95 percent removal) by addition of 0.1 molar nonradioactive Sr(N03), to precipitate Sr,(PO,), (Schulz 1995).…”

“…An analysis of DST radionuclide removal requirements on a tank-by-tank basis (Schulz 1995) has determined that only three DSTs (241-AN-102, 241-AN-107 and 241-AY-101) require some removal of soluble TRU from supernatants to meet the NRC Class C requirement of less than 100 nCi TRU/g glass. These three tanks are classified as CC wastes and contain an estimated 0.0054 MCi (56 percent) of the totall soluble TRU.…”

“…The analysis of DST radionuclide removal requirements (Schulz 1995) indicates that TRU removal for the three CC waste DSTs (241-AN-102, 241-AN-I07 and 241-AY-101) can be attained with additions of NaOH as demonstrated by laboratory testing (Herting 1993, 1994a. 1994b, Washington 1990).…”