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Title: Characterization of Uranium Solids Precipitated with Aluminosilicates

Abstract

At the Savannah River Site (SRS), the High-Level Waste (HLW) Tank Farms store and process high-level liquid radioactive wastes from the Canyons and recycle water from the Defense Waste Processing Facility. The waste is concentrated using evaporators to minimize the volume of space required for HLW storage. Recently, the 2H Evaporator was shutdown due to the crystallization of sodium aluminosilicate (NAS) solids (such as cancrinite and sodalite) that contained close to 10 weight percent of elementally-enriched uranium (U). Prior to extensive cleaning,the evaporator deposits resided on the evaporator walls and other exposed internal surfaces within the evaporator pot. Our goal is to support the basis for the continued safe operation of SRS evaporators and to gain more information that could be used to help mitigate U accumulation during evaporator operation. To learn more about the interaction between U(VI) and NAS in HLW salt solutions, we performed several fundamental studies to examine the mechanisms of U accumulation with NAS in highly caustic solutions. This larger group of studies focused on the following processes: co-precipitation/structural incorporation, sorption, and precipitation (with or without NAS), which will be reviewed in this presentation. We will present and discuss local atomic structural characterization data about Umore » that has been co-precipitated with NAS solids (such as amorphous zeolite precursor material and sodalite) using X-ray absorption fine-structure (XAFS) spectroscopic techniques.« less

Authors:
Publication Date:
Research Org.:
Savannah River Site (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
821126
Report Number(s):
WSRC-MS-2003-00898
TRN: US0400641
DOE Contract Number:  
AC09-96SR18500
Resource Type:
Conference
Resource Relation:
Conference: WM 04 Conference, Tucson, AZ (US), 02/29/2004--03/04/2004; Other Information: PBD: 9 Jan 2004
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; ABSORPTION; CRYSTALLIZATION; EVAPORATORS; FINE STRUCTURE; PRECIPITATION; RADIOACTIVE WASTES; SHUTDOWN; SODIUM; SORPTION; STORAGE; STORAGE FACILITIES; URANIUM; WASTE PROCESSING; WASTES; ZEOLITES

Citation Formats

DUFF, MC. Characterization of Uranium Solids Precipitated with Aluminosilicates. United States: N. p., 2004. Web.
DUFF, MC. Characterization of Uranium Solids Precipitated with Aluminosilicates. United States.
DUFF, MC. Fri . "Characterization of Uranium Solids Precipitated with Aluminosilicates". United States. https://www.osti.gov/servlets/purl/821126.
@article{osti_821126,
title = {Characterization of Uranium Solids Precipitated with Aluminosilicates},
author = {DUFF, MC},
abstractNote = {At the Savannah River Site (SRS), the High-Level Waste (HLW) Tank Farms store and process high-level liquid radioactive wastes from the Canyons and recycle water from the Defense Waste Processing Facility. The waste is concentrated using evaporators to minimize the volume of space required for HLW storage. Recently, the 2H Evaporator was shutdown due to the crystallization of sodium aluminosilicate (NAS) solids (such as cancrinite and sodalite) that contained close to 10 weight percent of elementally-enriched uranium (U). Prior to extensive cleaning,the evaporator deposits resided on the evaporator walls and other exposed internal surfaces within the evaporator pot. Our goal is to support the basis for the continued safe operation of SRS evaporators and to gain more information that could be used to help mitigate U accumulation during evaporator operation. To learn more about the interaction between U(VI) and NAS in HLW salt solutions, we performed several fundamental studies to examine the mechanisms of U accumulation with NAS in highly caustic solutions. This larger group of studies focused on the following processes: co-precipitation/structural incorporation, sorption, and precipitation (with or without NAS), which will be reviewed in this presentation. We will present and discuss local atomic structural characterization data about U that has been co-precipitated with NAS solids (such as amorphous zeolite precursor material and sodalite) using X-ray absorption fine-structure (XAFS) spectroscopic techniques.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2004},
month = {1}
}

Conference:
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