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Title: Non-Aqueous Electrochemical Fluorination of Used Nuclear Fuel as an Advanced Separation Process

Abstract

Development of efficient and environmentally benign methods to reprocess used nuclear fuel (UNF) will enable technologies for a nuclear renaissance. Electrochemical and fluorination methods for reprocessing UNF have been proposed, but combinations of electrochemical and fluorination methods have not been investigated. Electrochemical fluorination may reduce waste volumes compared to the main large-scale aqueous methods for processing used nuclear fuel. A non-aqueous electrochemical fluorination reprocessing method has been developed and demonstrated that enables gas phase uranium recovery while allowing for potential control of the reaction using a single process. Thermodynamic modeling showed a galvanic reaction between UNF and a fluorinating agent, such as NF3, in a molten fluoride electrolyte was possible and could selectively fluorinate U to UF6. To verify the model results, a reactor system for electrochemical fluorination was constructed along with vessels for product collection and analysis. Initial trials of the electrochemical reaction were performed and characterized by several electrochemical methods. The electrochemical oxidation of U using NF3 as an oxidizing agent was demonstrated and UF6 as a reaction product was detected.

Authors:
ORCiD logo [1];  [1];  [1]; ORCiD logo [1]
  1. Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)
Publication Date:
Research Org.:
Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)
Sponsoring Org.:
USDOE; SRNL Laboratory Directed Research and Development (LDRD) Program
OSTI Identifier:
1512421
Report Number(s):
SRNL-STI-2019-00219
Journal ID: ISSN 0013-4651
Grant/Contract Number:  
AC09-08SR22470
Resource Type:
Accepted Manuscript
Journal Name:
Journal of the Electrochemical Society
Additional Journal Information:
Journal Volume: 166; Journal Issue: 8; Journal ID: ISSN 0013-4651
Publisher:
The Electrochemical Society
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; electrochemical engineering; molten salts; FLiNaK; galvanic cell; uranium hexafluoride

Citation Formats

Martínez-Rodríguez, Michael J., Olson, Luke C., Gray, Joshua R., and García-Díaz, Brenda L. Non-Aqueous Electrochemical Fluorination of Used Nuclear Fuel as an Advanced Separation Process. United States: N. p., 2019. Web. doi:10.1149/2.0261908jes.
Martínez-Rodríguez, Michael J., Olson, Luke C., Gray, Joshua R., & García-Díaz, Brenda L. Non-Aqueous Electrochemical Fluorination of Used Nuclear Fuel as an Advanced Separation Process. United States. doi:10.1149/2.0261908jes.
Martínez-Rodríguez, Michael J., Olson, Luke C., Gray, Joshua R., and García-Díaz, Brenda L. Mon . "Non-Aqueous Electrochemical Fluorination of Used Nuclear Fuel as an Advanced Separation Process". United States. doi:10.1149/2.0261908jes. https://www.osti.gov/servlets/purl/1512421.
@article{osti_1512421,
title = {Non-Aqueous Electrochemical Fluorination of Used Nuclear Fuel as an Advanced Separation Process},
author = {Martínez-Rodríguez, Michael J. and Olson, Luke C. and Gray, Joshua R. and García-Díaz, Brenda L.},
abstractNote = {Development of efficient and environmentally benign methods to reprocess used nuclear fuel (UNF) will enable technologies for a nuclear renaissance. Electrochemical and fluorination methods for reprocessing UNF have been proposed, but combinations of electrochemical and fluorination methods have not been investigated. Electrochemical fluorination may reduce waste volumes compared to the main large-scale aqueous methods for processing used nuclear fuel. A non-aqueous electrochemical fluorination reprocessing method has been developed and demonstrated that enables gas phase uranium recovery while allowing for potential control of the reaction using a single process. Thermodynamic modeling showed a galvanic reaction between UNF and a fluorinating agent, such as NF3, in a molten fluoride electrolyte was possible and could selectively fluorinate U to UF6. To verify the model results, a reactor system for electrochemical fluorination was constructed along with vessels for product collection and analysis. Initial trials of the electrochemical reaction were performed and characterized by several electrochemical methods. The electrochemical oxidation of U using NF3 as an oxidizing agent was demonstrated and UF6 as a reaction product was detected.},
doi = {10.1149/2.0261908jes},
journal = {Journal of the Electrochemical Society},
number = 8,
volume = 166,
place = {United States},
year = {2019},
month = {4}
}

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