PNNL

Abstract

Forty years of cold war nuclear weapons production activities have resulted in the by-product of millions of gallons of highly radioactive liquid and solid wastes stored in underground tanks at the Hanford Site in southeastern Washington State. The Department of Energy has contracted the construction of a waste-treatment processing plant to remove the major portions of radioactive isotopes from the liquid waste portion for follow-on processing and vitrification of the high-activity waste separately from the low-activity waste. The plant will use ion exchange processing for 137Cs removal from the supernatant portion of Hanford tank wastes. Currently, SuperLig® 644 (IBC Advanced Technologies, Utah) is the ion exchange resin of choice. However, during pilot-scale testing, significant pressure build-up occurred after multiple load-elute cycles. Current testing activities are evaluating resorcinol-formaldehyde (RF) resin as an alternative to achieve comparable loading and elution performance with improved hydraulic performance. Studies have been conducted with both a ground gel RF resin (Boulder Scientific, Colorado) and a spherical RF resin developed by Microbeads (Trondheim, Norway). The purpose of this testing was then to compare the vertical and radial forces of the expanding resin, the breakage of the resin beads, and the differential pressure across the resin bed during multiple load-elute cycles. These tests were done in a small-scale column with high flow rates to simulate the hydraulic conditions that would be experienced in a full-scale column.