Evaluation of zeolite mixtures for decontaminating high-activity-level water at the Three Mile Island unit 2 nuclear power station

Mixtures of Linde Ionsiv IE-96 and Ionsiv A-51 zeolites were evaluated for use in the Submerged Demineralizer System (SDS) that was installed at the Three Mile Island Unit 2 Nuclear Power Station to decontaminate approx. 2780 m3 of high-activity-level water (HALW). The original SDS flowsheet was conservatively designed for removal of cesium and strontium and would have required the use of approx. 60 SDS columns. Mixed zeolite tests, which were made on a 10-5 scale, indicated that the appropriate ratio of IE-96/A-51 was 3:2. A mathematical model was used to predict the performance of the mixed zeolite columns in the SDS configuration and with the intended method of operation. Actual loading results were similar to those predicted for strontium and better than those predicted for cesium. The number of SDS columns needed to process the HALW was reduced to approx. 10. (author)