Initial Laboratory-Scale Melter Test Results for Combined Fission Product Waste

Abstract

SUMMARYPacific Northwest National Laboratory (PNNL) and Savannah River National Laboratory performed a joint study to develop acceptable glasses for the combined alkali and alkaline-earth fission products (CS) + lanthanide fission products (LN) + transition metal fission products (TM) waste streams and CS + LN combined waste streams. Glass CSLNTM-C-2.5 was selected as the baseline glass for the CS + LN + TM waste stream as it had the highest MoO 3 -loaded glass that did not crystallize during slow cooling and it had properties within acceptable tolerances for glass processing and waste form performance (Crum et al., 2009).To obtain an initial understanding on the processability of this selected glass composition, initial smallscale melter tests were performed. This report summarizes the melter feed processing in a 3"-diameter laboratory-scale melter at PNNL as well as techniques that could be employed to improve the efficiency of vitrifying such a waste stream. Two experiments were run (including a shakedown test) in the melter with the same feed, representative of the actual waste stream. Reaction vessel and off-gas line solid condensates were analyzed to perform a mass-balance of the most volatile components -Cs and Mo. The analysis of the condensates showed that volatile components (i.e., Cs, Mo) evolved during the melting process at reasonable concentrations. From these studies, it is apparent that a recuperator for the volatile compounds should be considered. Initial Laboratory-Scale Melter Test Results for Combined Fission Product Waste

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