Determination of a surrogate for plutonium electrorefining

Journal Article · Sat Aug 12 00:00:00 EDT 2023 · Journal of Nuclear Materials

DOI:https://doi.org/10.1016/j.jnucmat.2023.154680· OSTI ID:2282427

Chipman, Greg ^[1]; Johnson, Bryant ^[1]; Choi, Suhee ^[2]; Zhang, Chao ^[3]; Simpson, Michael ^[2]; Rappleye, Devin ^[1]

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1. Brigham Young Univ., Provo, UT (United States)
2. Univ. of Utah, Salt Lake City, UT (United States)
3. Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

Conducting research experiments on plutonium electrorefining is difficult due to the significant hazards and regulations associated with nuclear materials. Finding a surrogate for plutonium electrorefining studies would enable more fundamental research to be conducted. Potential surrogates were first identified by determining the physical properties required to conduct electrorefining at the same conditions commonly used in plutonium electrorefining, a molten metal and molten CaCl₂ at 1123 K. Ce-CeCl₃, In-InCl₃, and Pb-PbCl₂ were the only potential surrogates identified using these constraints. Sn-SnCl₂ was also tested at these same conditions. More potential surrogates were identified by changing the matrix salt and operating temperature. This expanded the potential surrogate list to also include Zn-ZnCl₂, Sn-SnCl₂, and Bi-BiCl₃. Zn-ZnCl₂ was used with the LiCl-CaCl₂ (65:35 mol%) eutectic at 773 K. Sn-SnCl2 and Bi-BiCl₃ were used with the LiCl-KCl-CaCl₂ (50.5:44.2:5.3 mol%) eutectic at 673–773 K. Ce electrorefining in molten CaCl₂ resulted in a difficult to separate colloid mixture of Ce, Ca and Cl. Electrorefining rates for In in molten CaCl₂ were too slow due to InCl₃ volatilizing out of the molten salt. Only trace amounts of SnCl₂ was retained in the CaCl₂ at 1123 K resulting in impractical electrorefining rates. Zn metal product was successfully collected in the LiCl-CaCl₂ eutectic molten salt, but the metal obtained did not coalesce into one piece. Sn and Bi were successfully electrorefined in the LiCl-KCl-CaCl₂ eutectic molten salt and coalesced into product rings with high yields and coulombic efficiencies. Finally, while a surrogate could not be identified using the same conditions as plutonium electrorefining, two possible surrogates, Sn-SnCl₂ and Bi-BiCl₃, were found that could imitate the physical configuration (i.e., molten salt on top of molten metal) of plutonium electrorefining at a reduced temperature using the eutectic LiCl-KCl-CaCl₂ salt at 673–773 K in place of CaCl₂ at 1123 K.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
• Sponsoring Organization: USDOE; USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC52-07NA27344
• OSTI ID: 2282427
• Alternate ID(s): OSTI ID: 2369053
• Report Number(s): LLNL--JRNL-845481; 1065340
• Journal Information: Journal of Nuclear Materials, Journal Name: Journal of Nuclear Materials Vol. 586; ISSN 0022-3115
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Actinide
Electrorefining
Materials science
Nuclear science and engineering
Plutonium
Pyroprocessing
Surrogate