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DURABILITY TESTING OF FLUIDIZED BED STEAM REFORMER WASTE FORMS FOR SODIUM BEARING WASTE AT IDAHO NATIONAL LABORATORY

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Crawford,-C; Carol-JantzenFluidized Bed Steam Reforming (FBSR) processing of Sodium Bearing Waste simulants was performed in December 2006 by THOR sup s sup m Treatment Technologies LLC (TTT) The testing was performed at the Hazen Research Inc. (HRI) pilot plant facilities in Golden, CO. FBSR products from these pilot tests on simulated waste representative of the SBW at the Idaho Nuclear Technology and Engineering Center (INTEC) were subsequently transferred to the Savannah River National Laboratory (SRNL) for characterization and leach testing. Four as-received Denitration and Mineralization Reformer (DMR) granular/powder samples and four High Temperature Filter (HTF) powder samples were received by SRNL. FBSR DMR samples had been taken from the ''active'' bed, while the HTF samples were the fines collected as carryover from the DMR. The process operated at high fluidizing velocities during the mineralization test such that nearly all of the product collected was from the HTF. Active bed samples were collected from the DMR to monitor bed particle size distribution. Characterization of these crystalline powder samples shows that they are primarily Al, Na and Si, with > 1 wt% Ca, Fe and K. The DMR samples contained less than 1 wt% carbon and the HTF samples ranged from 13 to 26 wt% carbon. X-ray diffraction analyses show that the DMR samples contained significant quantities of the Al sub 2 O sub 3 startup bed. The DMR samples became progressively lower in starting bed alumina with major Na/Al/Si crystalline phases (nepheline and sodium aluminosilicate) present as cumulative bed turnover occurred but 100% bed turnover was not achieved. The HTF samples also contained these major crystalline phases. Durability testing of the DMR and HTF samples using the ASTM C1285 Product Consistency Test (PCT) 7-day leach test at 90 C was performed along with several reference glass samples. Comparison of the normalized leach rates for the various DMR and HTF components was made with the reference glasses and the Low Activity Waste (LAW) specification for the Hanford Waste Treatment and Vitrification Plant (WTP). Normalized releases from the DMR and HTF samples were all less than 1 g/m sup 2. For comparison, normalized release from the High-Level Waste (HLW) benchmark Environmental Assessment (EA) glass for Si, Li, Na and B ranges from 2 to 8 g/m sup 2. The normalized release specification for LAW glass for the Hanford WTP is 2 g/m sup 2. The Toxicity Characteristic Leach Test (TCLP) was performed on DMR and HTF as received samples and the tests showed that these products meet the criteria for the EPA RCRA Universal Treatment Standards for all of the constituents contained in the starting simulants such as Cr, Pb and Hg (RCRA characteristically hazardous metals) and Ni and Zn (RCRA metals required for listed wastes).