Characterization of Radionuclides in Purex Waste Sludges from the F-Area High Level Waste Tanks (U)

Sludge-contaminated waste consists of waste contaminated with both insoluble species (the sludge fraction) and entrained supernate. The WCS is based on the assumption that approximately 70% of the weight of what is commonly referred to as sludge is interstitial supernate; the remaining approximately 30% consists of the insoluble species (Reference 1). Development of a method for characterization of sludge-contaminated waste must consider both fractions. Separate waste cuts may contain sludge and supernate fractions in varying proportions due to the nature of the job generating the waste and the variability in waste handling techniques. Development of a distribution representative of all sludge-contaminated waste cuts must allow for varying fractions of sludge and supernate contamination. This document will develop a radionuclide distribution in accordance with the methodology outlined in WSRC 1S SRS Waste Acceptance Criteria Manual, Procedure 2.02, Revision 8 for the sludge fraction of sludge-contaminated waste generated in the F-Area Tank Farm This distribution was based on the assumption that sludge-contaminated waste from F-Area Tank Farm Waste Tanks could be co-mingled, and the actual contamination present on waste in a series of containers from these tanks will be representative of the mean radionuclide distribution. The original characterization was based primarily on process knowledge and fill histories (Reference 6). A single, comprehensive characterization for supernate has been developed previously (Reference 9). This document also describes the methodology for application of radionuclide distributions representative of the sludge and supernate fractions of sludge-contaminated waste to individual waste packages. Most of the waste contaminated with sludge from the F-Area Tank Farm will be categorized as Low Level Waste (LLW) and disposed of in the E-area trenches. The waste does, however, have the potential to be categorized as TRU and/or mixed waste. Quantification of hazardous constituents and determination of whether the waste is classified as mixed is dependent on the amount of sludge present on the waste matrix and the nature of the waste matrix, and will be performed on a case-by-case basis. Quantification of radionuclides present in each waste package will be performed as described in Section 5.0. The radionuclide distribution developed for LLW contaminated with sludge from the F-Area Tank Farm can also be applied to waste classified as transuranic. [Neither WSRC 1S SRS Waste Acceptance Criteria Manual, Procedure 3.06, ''E-Area TRU Pads Transuranic Waste Acceptance Criteria'', Revision 11, nor Appendix A:23, ''TRU Waste Container Characterization Form (OSR 29-90) Instruction'' specifies a methodology for determination of the isotopic distribution in TRU Waste; simply that the methodology be documented.]