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Title: EXPECTED IMPACT OF HANFORD PROCESSING ORGANICS OF PLUTONIUM DURING TANK WASTE SLUDGE RETRIEVAL

Abstract

This document evaluates the potential for extracting plutonium from Hanford waste tanks into residual organic solvents and how this process may have an impact on criticality specifications during the retrieval of wastes. The two controlling factors for concentrating plutonium are the solubility of the plutonium in the wastes and the extraction efficiency of the potential organic extractants that may be found in these wastes. Residual Hanford tank sludges contain plutonium in solid forms that are expected to be primarily insoluble Pu(IV) hydroxides. Evaluation of thermodynamic Pourbaix diagrams, documentation on solubility studies of various components in waste tank matrices, and actual analysis of plutonium in tank supernates all indicate that the solubility of Pu in the alkaline waste is on the order of 10{sup -6} M. Based on an upper limit plutonium solubility of 10{sup -5} M in high pH and a conservative distribution coefficient for organic extractants of <0.01 (the E{sub a}{sup 0} for plutonium in 30% TBP at 0.07 M HNO{sub 3}), the estimated concentration for plutonium in the organic phase would be <1 x 10{sup -7} M. This is well below the process control criteria. A significant increase in plutonium solubility or the E{sub a}{sup o} would havemore » to occur to raise this concentration to the 0.01 M concern level for organics. Measured tank chemical component values, expected operating conditions, and the characteristics of the expected chemistry and extraction mechanisms indicate that concentration of plutonium from Hanford tank residual sludges to associated process organic extractants is significantly below levels of concern.« less

Authors:
;
Publication Date:
Research Org.:
CH2M (US)
Sponsoring Org.:
ENVIRONMENTAL MANAGEMENT (US)
OSTI Identifier:
823762
Report Number(s):
RPP-20041, Rev.0
DE-AC27-99RL14047; TRN: US0401812
DOE Contract Number:  
AC27-99RL14047
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 18 Mar 2004
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; CRITICALITY; HYDROXIDES; ORGANIC SOLVENTS; PLUTONIUM; PROCESS CONTROL; RADIOACTIVE WASTE PROCESSING; SLUDGES; SOLUBILITY; THERMODYNAMICS; HANFORD RESERVATION; WASTE RETRIEVAL; EXTRACTION

Citation Formats

TROYER, G L, and WINTERS, W I. EXPECTED IMPACT OF HANFORD PROCESSING ORGANICS OF PLUTONIUM DURING TANK WASTE SLUDGE RETRIEVAL. United States: N. p., 2004. Web. doi:10.2172/823762.
TROYER, G L, & WINTERS, W I. EXPECTED IMPACT OF HANFORD PROCESSING ORGANICS OF PLUTONIUM DURING TANK WASTE SLUDGE RETRIEVAL. United States. doi:10.2172/823762.
TROYER, G L, and WINTERS, W I. Thu . "EXPECTED IMPACT OF HANFORD PROCESSING ORGANICS OF PLUTONIUM DURING TANK WASTE SLUDGE RETRIEVAL". United States. doi:10.2172/823762. https://www.osti.gov/servlets/purl/823762.
@article{osti_823762,
title = {EXPECTED IMPACT OF HANFORD PROCESSING ORGANICS OF PLUTONIUM DURING TANK WASTE SLUDGE RETRIEVAL},
author = {TROYER, G L and WINTERS, W I},
abstractNote = {This document evaluates the potential for extracting plutonium from Hanford waste tanks into residual organic solvents and how this process may have an impact on criticality specifications during the retrieval of wastes. The two controlling factors for concentrating plutonium are the solubility of the plutonium in the wastes and the extraction efficiency of the potential organic extractants that may be found in these wastes. Residual Hanford tank sludges contain plutonium in solid forms that are expected to be primarily insoluble Pu(IV) hydroxides. Evaluation of thermodynamic Pourbaix diagrams, documentation on solubility studies of various components in waste tank matrices, and actual analysis of plutonium in tank supernates all indicate that the solubility of Pu in the alkaline waste is on the order of 10{sup -6} M. Based on an upper limit plutonium solubility of 10{sup -5} M in high pH and a conservative distribution coefficient for organic extractants of <0.01 (the E{sub a}{sup 0} for plutonium in 30% TBP at 0.07 M HNO{sub 3}), the estimated concentration for plutonium in the organic phase would be <1 x 10{sup -7} M. This is well below the process control criteria. A significant increase in plutonium solubility or the E{sub a}{sup o} would have to occur to raise this concentration to the 0.01 M concern level for organics. Measured tank chemical component values, expected operating conditions, and the characteristics of the expected chemistry and extraction mechanisms indicate that concentration of plutonium from Hanford tank residual sludges to associated process organic extractants is significantly below levels of concern.},
doi = {10.2172/823762},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2004},
month = {3}
}

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