Laboratory development of methods for centralized treatment of liquid low-level waste at Oak Ridge National Laboratory

Abstract

11.3 Effect of processing delays and coagulant polymers on strontium and cesium removal from simulated newly generated liquid low-level waste. .. . 11.4 Strontium and cesium removal from diluted simulated newly generated liquid low-level waste with a SrCl, + ferric sulfate strike and a KCCF strike. .. .

Removal of technetium-99 from simulated Oak Ridge National Laboratory Newly-Generated Liquid Low-Level Waste

“…In addition to ?9r andI3' Cs, significant radionuclides will include lMRu and 99Tc. Principal chemical constituents for the NGLLLW have been reported by Arnold et al (1994); the composition for a synthetic surrogate solution, based upon current process knowledge and anticipated future laboratory activities, is given in Table 1.…”

“…Proposed flowsheets for the treatment of NGLLLW are presented in Arnold et al (1994). Opportunities for treatment of technetium in the waste stream include the as-received waste (pH -13), or after pH adjustment and co-precipitation of Sr at a pH value near 8-9.…”

“…Volumetric loading efficiencies for the stabilization of spent anion exchange resin in waste forms are -50% for grout and -90% for VES (Morgan and Bostick, 1992). Assuming disposal of spent Dowexm 1-X8 resin laden with -1 0 mg T c per cm3 (or -170 Ci/m3; see section 4.2 ), the stabilized waste forms would contain -85 Ci/m3 (grout) to -150 C i / d (VES), well in excess of the draft criterion of 5.5E-06 Curd for disposal of 99Tc as Class LII solid waste at the Oak Ridge Reservation (Arnold, et al, 1994).…”

FY 1995 separation studies for liquid low-level waste treatment at Oak Ridge National Laboratory

“…The NGLLLW flow sheet was tested with NGLLLW simulants representing (1) the less caustic waste that currently is generated after an operational change at the Radiochemical Engineering Development Center (REDC), (2) NGLLLW that is contaminated with organic complexants that have been associated with previous transuranic processing activities at ORNL, and (3) LLLW in which NGLLLW is blended with MVST supemate. Results from these studies indicate that strontium removal from LLLW is more efficient as the carbonate content in the waste is reduced.…”

“…These treatment options included (1) placing the NAC process at the head of the NGLLLW flow sheet, (2) denitnfylng the waste at the completion of the NGLLLW flow sheet, and (3) treating NGLLLW blended with MVST Supernate. The final nitrate content, radionuclide activity, and volumes of secundary solid and liquid waste produced were compared for these treatment scenarios.…”