Product Consistency Leach Tests of Savannah River Site Radioactive Waste Glasses
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PRODUCT CONSISTENCY LEACH TESTS OF SAVANNAH RIVER SITE RADIOACTIVE WASTE GLASSES
NED E. BIBLER* and JOHN K. BATES** *Savannah River Laboratory, Westinghouse Savannah River Co., Aiken, SC, 29802 "**Argonne National Laboratory, 9700 S. Cass Ave., Argonne, IL, 60439. ABSTRACT The Product Consistency Test (PCT) is a glass leach test developed at the Savannah River Site (SRS) to confirm the durability of radioactive nuclear waste glasses that will be produced in the Defense Waste Processing Facility. The PCT is a seven day, crushed glass leach test in deionized water at 90 0 C. Final leachates are filtered and acidified prior to analysis. To demonstrate the reproducibility of the PCT when performed remotely, SRS and Argonne National Laboratory have performed the PCT on samples of two radioactive glasses. The tests were also performed to compare the releases of the radionuclides with the major nonradioactive glass components and to determine if radiation from the glass was affecting the results of the PCT. The test was performed in triplicate at each laboratory. For the major soluble elements, B, Li, Na, and Si, in the glass, each investigator obtained relative precisions in the range 2-5% in the triplicate tests. This range indicates good precision for the PCT when performed remotely with master slave manipulators in a shielded cell environment. When the results of the two laboratories were compared to each other, the agreement was within 20%. Normalized concentrations for the nonradioactive and radioactive elements in the PCT leachates measured at both facilities indicated that the radionuclides were released from the glass slower than the major soluble elements in the glass. For both laboratories, the normalized releases for both glasses were in the general order Li-B-Na>Si>Cs-137>Sb-125>Sr-90. The normalized releases for the major soluble elements and the final pH values in the tests with radioactive glass are consistent with those for nonradioactive glasses with similar compositions. This indicates that there was no significant effect of radiation on the results of the PCT. INTRODUCTION A crushed glass leach test, the Product Consistency Test (PCT) [1,2], has been developed at the Savannah River Site (SRS) to confirm the durability of the nuclear waste glasses that will As be produced by the Defense Waste Processing Facility (DWPF). the name of the test implies, the primary purpose of the PCT is to measure the consistency of the durability of the radioactive glasses that the DWPF will produce during its several years of Durability of the glasses will be determined by operation. measuring the amounts of soluble elements such as B, Li, Na, K, and Si that are released from the glass to deionized water when the glasses are leached following the PCT procedure. Mat. Res. Soc. Symp. Proc. Vol. 176. @1990 Materials Research Society
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At SRS, the DWPF will solidify into solid borosilicate glass the -30 million gallons of caustic slurries of high-level radioactive waste. Eventually, this glass will be permanently placed
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