The Role of Inert Atmospheres in Precision Analysis of Moisture in Molten Chloride Salts

Eun-Young Choi^*,a,b, Seol Kim^a,b, Seok Min Yoon^a,b, Taeho Kim^a,b, Chang Hwa Lee^a

^aKorea Atomic Energy Research Institute, Daedoek-daero 989-111, Yuseong-gu, Daejeon 34057, Republic of Korea
^bDepartment of Nuclear Science and Technology, University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon 34113, Republic of Korea

Received 2025-02-25 ; Revised 2025-03-14 ; Approved 2025-03-14

Abstract

The corrosivity of molten salt presents a major challenge for the commercialization of molten salt reactors, which utilize molten salt as both fuel and coolant. To protect structural materials of molten salt reactors, minimizing moisture—the primary source of corrosion—is crucial, necessitating precise moisture concentration measurements. This study examines the role of an inert gas atmosphere in analyzing moisture in molten chloride salts. Four chloride salts with different hygroscopic properties (NaCl, KCl, MgCl₂ and ZnCl₂) were tested. Each was analyzed in three states: as-received and dried by heating for 6 and 12 hours. Karl Fischer titration was employed to measure the moisture concentrations in salts under both air and an argon-filled glove box. Results showed consistently lower and more stable moisture concentrations in the inert atmosphere, highlighting the necessity of an argon environment for accurate moisture analysis in molten salts.

Key Words : Molten salt, Dehydration, Moisture concentration, Karl Fischer titration, Inert gas atmosphere