Deliquescence of eutectic LiCl-KCl diluted with NaCl for interim waste salt storage

Conference · Sun Sep 19 04:00:00 EDT 2021

OSTI ID:1923698

Howard, Jerry ^[1]; Harward, Allison ^[1]; Simpson, Mike ^[1]; Carlson, Krista ^[1]; Patterson, Michael D ^[2]; Decke, Claire ^[1]; Fredrickson, Guy L ^[2]; Yoo, Tae-Sic ^[2]; Gardner, Levi ^[3]

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1. University of Utah
2. Idaho National Laboratory
3. Argonne National Laboratory

Molten eutectic LiCl-KCl salt is a widely used electrolyte for electrorefining uranium from spent nuclear fuel. Due to the hygroscopic nature of this salt, careful handling and storage of solidified waste electrorefiner (ER) salt is required to avoid deliquescence and corrosion of container materials. This study investigated a potential processing path for reducing the deliquescence through dilution with NaCl. The hydration behavior of LiCl-KCl salts diluted with NaCl was evaluated in terms of mass gain due to mass of water absorption, visual evidence of deliquescence, and visual evidence of corrosion to stainless steel containers in a humid air environment. Pure eutectic LiCl-KCl exhibited a 50 mass% increase due to water absorption and showed signs of deliquescence after 24 hours. 89 mass% NaCl was required in order to prevent deliquescence. Dilution with 89% NaCl was also found to protect corrosion to stainless steel crucibles. Corrosion, thus, appears to require deliquescence. While NaCl dilution greatly decreases steady state hydration and eliminated deliquescence, storage volume is increased ~10x.

• Research Organization: Idaho National Laboratory (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE)
• DOE Contract Number: AC07-05ID14517
• OSTI ID: 1923698
• Report Number(s): INL/CON-21-62048-Rev000
• Country of Publication: United States
• Language: English

Related Subjects

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
Corrosion
Molten Salt
Nuclear waste