Field test of ELOMIX radioactive waste treatment process for decontamination solutions

The objective of the Electrochemical Ion Exchange process is to reduce the volume of waste arising from LOMI decontamination operations. This is achieved by using the conventional ion exchange resin as an intermediate, rather than a final waste form. Radioactive and metallic constituents removed during the decontamination are converted by the process to a metallic form. Laboratory work on the concept of Electrochemical Ion Exchange has been taking place since May 1989. In October 1990 a small pilot scale ELOMIX cell, was operated successfully on a side stream of actual decontamination solution at Commonwealth Edisons Dresden Unit 2 Nuclear Plant. This was reported in EPRI report NP-7277 (May 1991). Following the Dresden demonstration a second unit was constructed to undertake a further demonstration test on a larger scale prior to construction of commercial scale equipment. The objectives of the test were to demonstrate operation in a pressurized system with a multiple (as opposed to single) compartment cell, to develop process control capability, to address waste handling issues and demonstrate clean-up and transportability. It was agreed that the unit would be operated at an on-site demonstration at Gulf States Utilities River Bend Plant. This demonstration took place in May 1992, and is described in this report. The test successfully achieved the objectives. In particular the demonstration has given confidence that an ELOMIX cell can be operated and then cleaned up to radiation levels low enough to permit transportation to another site, and that the metallic waste can be transferred hydraulically in much the same way as ion exchange resin. Thisreport discusses the implications of the test and covers the recommendations for future work to cover the remaining R ampersand D issues. A program of work is now under way to cover these issues before the construction and operation of commercial scale equipment