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.

1. Introduction
2. Experimental
    2.1 Salts and Their Dehydration
    2.2 Analysis of Hygroscopicity and MoistureConcentration of Salts
3. Results and Discussion
    3.1 Measurements of Hygroscopicity of the Salts
    3.2 Moisture Concentration Measured in Saltsin air and Ar-filled Glove box
4. Conclusions
CRediT Authorship Contribution Statement
Conflict of Interest
Acknowledgements
REFERENCES

• Eun-Young Choi(Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon 34057, Republic of Korea, University of Science and Technology, 217, Gajeong-ro, Yuseong-gu, Daejeon 34113, Republic of Korea) Corresponding author
• Seol Kim(Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon 34057, Republic of Korea, University of Science and Technology, 217, Gajeong-ro, Yuseong-gu, Daejeon 34113, Republic of Korea)
• Seok Min Yoon(Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon 34057, Republic of Korea, University of Science and Technology, 217, Gajeong-ro, Yuseong-gu, Daejeon 34113, Republic of Korea)
• Taeho Kim(Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon 34057, Republic of Korea, University of Science and Technology, 217, Gajeong-ro, Yuseong-gu, Daejeon 34113, Republic of Korea)
• Taeho Kim(Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon 34057, Republic of Korea)