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Title: Uranium solubility studies during waste evaporation

Abstract

The liquid waste streams from chemical processing of reactor-irradiated targets and fuel are neutralized with excess NaOH and discharged to mild steel waste tanks for interim storage. To reduce the number of tanks required, and thus the cost of waste storage, the supernate is evaporated to about 70% solids, discharged while hot into clean waste tanks. As the solution cools, solids crystallize from the saturated solution and form a solid layer on the bottom of the tank. The supernate is re-evaporated to concentrate the volume further. Evaporation and crystallization are continued until, for tank 41, the tank is almost filled with crystallized salts. In the DWPF processing scheme, these salts will be redissolved in water and {sup 137}Cs precipitated with sodium tetraphenylborate in the in-tank precipitation facility. The decontaminated supernate is now mixed with cement and stored as a solid monolith; the precipitated Cs and the base-insoluble solids are encapsulated in glass for permanent storage. Questions have been raised about the nuclear safety of these operations, particularly for tank 41, where the waste source was waste from the H-Area fuel processing. One scenario for a potential nuclear accident considers that the salts in tank 41 would dissolve in water, butmore » the enriched uranium solids would not dissolve. The uranium is hypothesized to settle to the bottom of the tank and become concentrated enough to reach a critical mass. A second scenario, promulgated by West Valley, is that uranium would precipitate in the evaporator and form a critical mass in the evaporator. To shed some light on the probable behavior of U in the waste system, the solubility of U in synthetic waste was studied. The results are reported here.« less

Authors:
Publication Date:
Research Org.:
Westinghouse Savannah River Co., Aiken, SC (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
10143240
Report Number(s):
WSRC-TR-93-433
ON: DE94010148; TRN: 94:008582
DOE Contract Number:
AC09-89SR18035
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 16 Aug 1993
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; 38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY; 12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; URANIUM; SOLUBILITY; RADIOACTIVE WASTE FACILITIES; SAFETY ANALYSIS; CRITICALITY; RADIATION ACCIDENTS; PROBABILITY; RADIOACTIVE WASTE PROCESSING; SEDIMENTATION; SLUDGES; EXPERIMENTAL DATA; 054000; 400702; 052001; HEALTH AND SAFETY; PROPERTIES OF RADIOACTIVE MATERIALS; WASTE PROCESSING

Citation Formats

Karraker, D.G. Uranium solubility studies during waste evaporation. United States: N. p., 1993. Web. doi:10.2172/10143240.
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Karraker, D.G. Uranium solubility studies during waste evaporation. United States. doi:10.2172/10143240.
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Karraker, D.G. Mon . "Uranium solubility studies during waste evaporation". United States. doi:10.2172/10143240. https://www.osti.gov/servlets/purl/10143240.
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@article{osti_10143240,
title = {Uranium solubility studies during waste evaporation},
author = {Karraker, D.G.},
abstractNote = {The liquid waste streams from chemical processing of reactor-irradiated targets and fuel are neutralized with excess NaOH and discharged to mild steel waste tanks for interim storage. To reduce the number of tanks required, and thus the cost of waste storage, the supernate is evaporated to about 70% solids, discharged while hot into clean waste tanks. As the solution cools, solids crystallize from the saturated solution and form a solid layer on the bottom of the tank. The supernate is re-evaporated to concentrate the volume further. Evaporation and crystallization are continued until, for tank 41, the tank is almost filled with crystallized salts. In the DWPF processing scheme, these salts will be redissolved in water and {sup 137}Cs precipitated with sodium tetraphenylborate in the in-tank precipitation facility. The decontaminated supernate is now mixed with cement and stored as a solid monolith; the precipitated Cs and the base-insoluble solids are encapsulated in glass for permanent storage. Questions have been raised about the nuclear safety of these operations, particularly for tank 41, where the waste source was waste from the H-Area fuel processing. One scenario for a potential nuclear accident considers that the salts in tank 41 would dissolve in water, but the enriched uranium solids would not dissolve. The uranium is hypothesized to settle to the bottom of the tank and become concentrated enough to reach a critical mass. A second scenario, promulgated by West Valley, is that uranium would precipitate in the evaporator and form a critical mass in the evaporator. To shed some light on the probable behavior of U in the waste system, the solubility of U in synthetic waste was studied. The results are reported here.},
doi = {10.2172/10143240},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Aug 16 00:00:00 EDT 1993},
month = {Mon Aug 16 00:00:00 EDT 1993}
}
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DOI:  10.2172/10143240
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