Ion exchange distribution coefficients for {sup 137}Cs and {sup 99}Tc removal from Hanford tank supernatants AW-101 (Envelope A) and AN-107 (Envelope C)

The current BNFL Inc. flow sheet for the pretreatment of the Hanford High-Level tank wastes includes the use of Superlig{reg_sign} materials in a dual column system for the removal of {sup 137}Cs and {sup 99}Tc from the aqueous fraction of the waste. The Superlig{reg_sign} materials include the cesium selective Superlig 632and Superlig 644 for removal of {sup 137}Csband Superlig 639 for the removal of {sup 99}Tc present as TcO{sub 4}{sup {minus}}. These materials have been developed and supplied by IBC Technologies, Inc., American Fork, UT. The objectives of this work were to: Evaluate the equilibrium behavior of the Superlig materials for the removal of {sup 137}Cs and {sup 99}Tc (as pertechnetate) from AW-101 (Envelope A) and AN-107 (Envelope C) clarified supernatants; Obtain information of the composition of ion exchange feed streams and the pertechnetate/nonpertechnetate fraction in the samples; and Determine some of the Superlig material physical properties including particle size distribution, dry density and water content. To evaluate the equilibrium behavior, batch contacts at a phase ratio of 100 (5 mL of waste solution: 0.05g of exchanger) were conducted with each of the Superlig materials and each of the waste envelope samples. In order to obtain equilibrium data that bounds the expected feed compositions, some of the envelope subsamples were spiked with either CsNO{sub 3} or {sup 99}Tc as pertechnetate. The fraction of nonpertechnetate in the AN-107 sample was estimated by contacting some of the AN-107 sample with a large excess of Superlig 639 (phase ratio of about 1)