Cold Crucible Vitrification of Defense Waste Surrogate and Vitrified Product Characterization
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Cold Crucible Vitrification of Defense Waste Surrogate and Vitrified Product Characterization A.P. Kobelev,1 S.V. Stefanovsky,1 O.A. Knyazev,1 T.N. Lashchenova,1 E.W. Holtzscheiter,2 J.C. Marra2 1
SIA Radon, 7th Rostovskii lane 2/14, Moscow 119121 RUSSIA, [email protected] 2 Savannah River National Laboratory, Building 773-42A, Savannah River Site, Aiken, SC 29808 USA ABSTRACT In the framework of the contract “Advanced Melter Technology Application to the Defense Waste Processing Facility (DWPF) –Cold Crucible Induction Heated Melter (CCIM)”, vitrification tests with Savannah River Site defense waste surrogate were performed at the SIA Radon facility. Cold crucible melters with inner diameter of 216 mm and 418 mm were used in the testing. Commercially available (USA) frits 200 and 320 were used as glass-forming additives. In three different test campaigns, waste additive mixtures were fed as slurries with ~60 wt.%, ~30 wt.%, and 45 wt.% water content. Maximum slurry capacity and glass productivity under steady-state conditions were 35.4 kg/h and 16.2 kg/h, respectively. Specific glass productivity reached up to ~3000 kg/(m2×day). The average melt process temperature was 12501350 0C. Waste loadings in glass were 45 wt.% in tests 1 and 2 and 50 wt.% in test 3. The glasses produced were found to be homogeneous but contained a magnetite-type phase with the spinel structure due to high iron and manganese content in waste. Spinel was observed in the glassy matrix as individual regular crystals and their aggregates. All the waste uranium entered the vitreous phase. Infra-red spectra consist of strong absorption bands due to bridging Si-O-Si and non-bridging Si-O- bonds, some weak bands due to B-O bonds, and a number of narrow bands due to occurrence of the crystalline phase. The glassy products demonstrate high leach resistance. Normalized release of major glass elements (Na, Li, B, Si) is by 10 to 50 times lower than the values required for repository disposition by EPA. INTRODUCTION Vitrification in Joule-heated ceramic melters (JHCM) is successfully used for solidification of high level wastes in the USA (WVDP [1], DWPF [2]) and Russia (PA “Mayak”) [3]. An alternative to the JHCM is a cold crucible providing for higher process temperatures, higher specific productivity, and longer melter lifetime. The inductive cold crucible melting (ICCM) technology is implemented at SIA Radon, Russia, for vitrification of intermediate-level waste and has been in operation since 1998 [4]. SIA Radon performs collaborative efforts with the US Department of Energy (DOE) to evaluate acceptability of the ICCM technology to vitrification of HLW from DOE sites [5,6]. In the framework of the contract “Advanced Melter Technology Application to the Defense Waste Processing Facility (DWPF) – Cold Crucible Induction Heated Melter (CCIM)” vitrification tests with Savannah River Site defense waste surrogate two tests were performed using a Radon bench-scale facility based on a cold crucible with inner diameter of 216 mm [6]. Slurries to be fed in
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