Evaluation of sludge screening limit for Tank Farm Low Level Waste

摘要

High Level Waste (HLW) generated during Separations processing in the F- and H-Canyons is transferred to the 241-F/H Tank Farms for storage in 61 underground, carbon steel tanks. The waste is an aqueous solution containing dissolved sodium salts and insoluble metal oxides/hydroxides. As the waste is collected in a receipt tank, the insoluble solids settle to form the sludge phase. The supernatant solution is decanted to an evaporator to reduce the volume. The evaporator concentrate is transferred to another waste tank and is cooled, causing the sodium salts to precipitate from solution and form the saltcake phase. Eventually, the soluble and insoluble components will be separately prepared for processing within the DWPF for final disposal. As a result of routine and non-routine activities that are part of managing these highly radioactive wastes, secondary solid waste is generated. Low level waste (LLW) such as protective clothing, plastic sheeting, plastic huts, etc. are connected for disposal in B-25, B-12 and other waste containers. The wastes are transferred to the E-Area Vaults (EAV) for disposal, and must comply with the Waste Acceptance Criteria (WAC) for disposal of LLW. Compliance with the WAC includes manifesting the quantities of certain radioisotopes and declaring that the waste containers are not hazardous. However, solid waste is not amenable to routine smearing and analysis to determine the required information. This report documents the evaluation to ensure that LLW contaminated with sludge at 10,000 dpm/100 cm(sup 2) of alpha emitters is nonhazardous. The hazardous constituent present in the greatest ratio to its Resource Conservation and Recovery Act (RCRA) limit is identified, and the concentration of that component in the leachate from a TCLP test is calculated. Finally, implications of this evaluation on screening LLW in the field are identified. (Atomindex citation 26:006427)