PNNL

Abstract

Spherical resorcinol formaldehyde (SRF) resin is planned to be used to remove cesium (137Cs) from the aqueous phases of Hanford tank wastes in preparation for their vitrification at the Waste Treatment and Immobilization Plant. SRF is an elutable organic ion exchanger that is projected to be used in up to 30multiple process cycles (load/elute/regeneration) before being disposal . Only two full process cycles have been tested using SRF on Hanford tank waste. This paper describes the test results of six complete load/elute cycles using the SRF in a lead/lag column format with 12 liters of Hanford tank waste supernatant collected from Tank AP-105. The testing exposed the SRF to the combined sources of degradation: chemical attack from dissolved oxygen, nitric acid, and tank waste components; physical stress from resin expansion and contraction; and beta and gamma radiolytic exposure. Process conditions, dictated by Washington River Protection Solutions, featured loading until the lag column effluent reached 10% of the waste acceptance criteria (a Cs decontamination factor of 6,000). Under these conditions the lead column was nearly fully loaded and the lag column was loaded with about 20% of the input Cs. Variations in process flowrates and elution volumes were investigated as part of the testing. Characteristics examined included degradation with cycling, mass transfer zones as a function of flowrate, Cs leakage into the ensuing process cycle, and analyte mass fractionation.