Assessment of thermodynamic stability of sapphire in eutectic molten chloride environment

Journal Article · 17 January 2022 · Journal of the American Ceramic Society

DOI: https://doi.org/10.1111/jace.18354 · OSTI ID:1983758

Thyagatur, Anugraha  ^[1]; Gakhar, Ruchi  ^[2]; Chidambaram, Dev ^[1]; Calderoni, Pattrick  ^[2]; Buric, Michael ^[3]; Mushongera, Leslie T. ^[1]

---

1. University of Nevada, Reno, NV (United States)
2. Idaho National Laboratory (INL), Idaho Falls, ID (United States)
3. National Energy Technology Lab. (NETL), Morgantown, WV (United States)

The continued development of molten salt reactors requires highly efficient and stable instruments that can efficiently track monitor conditions of the molten salt during long-term application operation in both the fuel and coolant/heat transfer fluid loops. Sapphire (Al₂O₃) fibers have shown tremendous potential by enabling radiation resistance and a broader operational range of temperature . Thermodynamic modeling using the ThermoCalc and the SGTE Molten Salts (SALT1) and Pure Substances (Pure5) database is done performed to understand the compatibility of Al₂O₃ fibers with NaCl-MgCl₂ eutectic molten salt in the temperature range of 600 to 1000°C. The thermodynamic calculations show that sapphire fibers are not expected to be compatible with long term exposure to molten chloride salts within this temperature range. Furthermore, various pure metallic elements were evaluated as potential cladding materials for part of the Al₂O₃ fibers. Based on the thermodynamic analysis, molybdenum (Mo) and nickel (Ni) could be effective cladding materials to enhance the stability of Al₂O₃ in NaCl and MgCl₂ chloride salt molten bath in the desired temperature range. The presence of a metallic cladding leads to the suppression of aluminum dissolution from Al₂O₃, thus improving its stability in chloride salts. Additionally, it is also shown that Al₂O₃ remains stable up to 2300 K in the presence of pre-existing Al₂MgO₄ and Al₂NiO₄ in the eutectic molten chloride bath environment.

• Research Organization: Idaho National Laboratory (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE Advanced Research Projects Agency - Energy (ARPA-E); USDOE Office of Nuclear Energy (NE)
• Grant/Contract Number: AC07-05ID14517
• OSTI ID: 1983758
• Report Number(s): INL/EXT-21-62675-Rev000
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 5 Vol. 105; ISSN 0002-7820
• Publisher: American Ceramic SocietyCopyright Statement
• Country of Publication: United States
• Language: English