PNNL

Abstract

Following the 2011 accident at the Fukushima Daiichi Nuclear Power Plant (1F), a significant amount of spent media and slurry/sludge were generated from water cleanup processing which has been stored at 1F as secondary wastes. These wastes will eventually require some level of processing before disposal. Vitrification has been one of the preferred solutions for the disposal of highly radioactive waste around the world. Studies were performed to evaluate the durability of a series of 1F secondary waste glasses. The glass compositions formulated for this work are appropriate for GeoMelt® In-Container Vitrification (ICV)™ with high chemical durability and relatively high waste loadings, ranging from 60 to 92 wt.%. Durability of various selected glasses was evaluated using Materials Characterization Center test number 1 (MCC-1 – ASTM C1220). The tests were performed in deionized water at 90°C for 7 to 365 days and showed a good performance, equal or better than most well-characterized reference waste glasses from US, Japan, and France. The MCC-1 data were combined with those found in literature and models were fitted to the experimental data for release fraction. This model demonstrates the relative effects of key glass components on resistance to corrosion under these conditions. This initial study identifies the key compositional parameters which determine the reaction of glass with water.