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Title: Spectroscopic investigation of the formation of PuO{sub 2}Cl{sup +} and PuO{sub 2}Cl{sub 2} in NaCl solutions and application for natural brine solutions

Abstract

The chloride complexation of the PuO{sub 2}{sup 2+} ion has been studied in acidic NaCl solutions with electrolyte concentrations as high as 5 mol kg{sup {minus}1} at 23 C by using conventional absorption spectrophotometry. Plutonyl and its complexes have ionic strength-dependent molar absorptivities that were determined in NaClO{sub 4}, the first essential step in the quantitative analysis of chloride complexation. The distributions of species for the Pu complexes, PuO{sub 2}{sup 2+}, PuO{sub 2}Cl{sup +}, and PuO{sub 2}Cl{sub 2}{degree}, formed under the conditions investigated, were determined by peak-fitting of optical absorption spectra. The apparent stability constants of the Pu(VI) chloro complexes were calculated at each NaCl concentration. Specific ion-interaction theory parameters were determined for the plutonyl chloro complexes and the electrolyte constituents, then compared with the literature data. The calculated values for log {beta}{degree} were determined to be 0.23 {+-} 0.03 and {minus}1.7 {+-} 0.2 for the mono and bis chloro complexes, respectively. Spectra of Pu(VI) in brines representative of waters at the Waste Isolation Pilot Plant, the licensed nuclear waste repository in a salt formation at Carlsbad, NM, USA, were measured and modeled by using the thermodynamic data and ion interaction parameters were determined. In these brines, less than 10%more » of the total Pu(VI) concentration exists as the Pu(VI) aquo ion, whereas about 90% is present as Pu(VI) chloro complexes.« less

Authors:
; ;
Publication Date:
Research Org.:
Los Alamos National Lab., NM (US)
Sponsoring Org.:
USDOE
OSTI Identifier:
20003988
Resource Type:
Journal Article
Journal Name:
Geochimica et Cosmochimica Acta
Additional Journal Information:
Journal Volume: 63; Journal Issue: 19-20; Other Information: PBD: Oct 1999; Journal ID: ISSN 0016-7037
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 05 NUCLEAR FUELS; BRINES; PLUTONIUM COMPOUNDS; OXYCHLORIDES; STABILITY; WIPP; RADIONUCLIDE MIGRATION

Citation Formats

Runde, W, Reilly, S D, and Neu, M P. Spectroscopic investigation of the formation of PuO{sub 2}Cl{sup +} and PuO{sub 2}Cl{sub 2} in NaCl solutions and application for natural brine solutions. United States: N. p., 1999. Web. doi:10.1016/S0016-7037(99)00275-6.
Runde, W, Reilly, S D, & Neu, M P. Spectroscopic investigation of the formation of PuO{sub 2}Cl{sup +} and PuO{sub 2}Cl{sub 2} in NaCl solutions and application for natural brine solutions. United States. doi:10.1016/S0016-7037(99)00275-6.
Runde, W, Reilly, S D, and Neu, M P. Fri . "Spectroscopic investigation of the formation of PuO{sub 2}Cl{sup +} and PuO{sub 2}Cl{sub 2} in NaCl solutions and application for natural brine solutions". United States. doi:10.1016/S0016-7037(99)00275-6.
@article{osti_20003988,
title = {Spectroscopic investigation of the formation of PuO{sub 2}Cl{sup +} and PuO{sub 2}Cl{sub 2} in NaCl solutions and application for natural brine solutions},
author = {Runde, W and Reilly, S D and Neu, M P},
abstractNote = {The chloride complexation of the PuO{sub 2}{sup 2+} ion has been studied in acidic NaCl solutions with electrolyte concentrations as high as 5 mol kg{sup {minus}1} at 23 C by using conventional absorption spectrophotometry. Plutonyl and its complexes have ionic strength-dependent molar absorptivities that were determined in NaClO{sub 4}, the first essential step in the quantitative analysis of chloride complexation. The distributions of species for the Pu complexes, PuO{sub 2}{sup 2+}, PuO{sub 2}Cl{sup +}, and PuO{sub 2}Cl{sub 2}{degree}, formed under the conditions investigated, were determined by peak-fitting of optical absorption spectra. The apparent stability constants of the Pu(VI) chloro complexes were calculated at each NaCl concentration. Specific ion-interaction theory parameters were determined for the plutonyl chloro complexes and the electrolyte constituents, then compared with the literature data. The calculated values for log {beta}{degree} were determined to be 0.23 {+-} 0.03 and {minus}1.7 {+-} 0.2 for the mono and bis chloro complexes, respectively. Spectra of Pu(VI) in brines representative of waters at the Waste Isolation Pilot Plant, the licensed nuclear waste repository in a salt formation at Carlsbad, NM, USA, were measured and modeled by using the thermodynamic data and ion interaction parameters were determined. In these brines, less than 10% of the total Pu(VI) concentration exists as the Pu(VI) aquo ion, whereas about 90% is present as Pu(VI) chloro complexes.},
doi = {10.1016/S0016-7037(99)00275-6},
journal = {Geochimica et Cosmochimica Acta},
issn = {0016-7037},
number = 19-20,
volume = 63,
place = {United States},
year = {1999},
month = {10}
}