Iron-Enriched Basalt and its Application to Three-Mile Island Radioactive Waste Disposal

Demonstration tests were performed on iron-enriched basalt (IEB), a dissolution and immobilization medium for TMI radioactive wastes. Zeolite of the type used for cesium and strontium decontamination of TMI containment water was mixed with 20 wt% additives and melted at 1500°C to form IEB. Cesium volatility from the IEB melts was low. Leaching tests in 90°C deionized water showed leach rates of 6 µg/cm2·d for both cesium and strontium. IEB melts were used to dissolve Type 304 SS pellets and UO2 pellets clad with zircaloy in order to simulate immobilization of TMI core debris. Bubbling air through the melts greatly enhanced the dissolution of these components.