Work

Temperature-dependent corrosion of structural alloys for molten salt reactors in NaCl-MgCl2 molten salt

Year: 2026

Type: article

Abstract: The corrosion behavior of Inconel 600, SS316H, and Hastelloy C276 was investigated in molten NaCl-MgCl 2 eutectic salt by 500 h static immersion tests at 550 °C and 650 °C. Mass change measurements, SEM-EDS, and XRD were combined to relate alloy degradation to surface and subsurface microstructural evolution. At 550 °C, all three alloys showed relatively shallow, surface-confined attack without detectable crystalline corrosion products, indicating dissolution-dominated behavior. At 650 °C, corrosion became strongly alloy-dependent: Inconel 600 developed a continuous MgO-rich surface deposit and limited subsurface damage with net mass gain, SS316H experienced dissolution-dominated attack with deep void formation and no protective deposit, and Hastelloy C276 formed a thick but non-uniform spinel layer coupled with significant internal degradation. These results demonstrate a temperature-driven transition from simple dissolution to mixed dissolution-precipitation and show that nominal Cr content alone is insufficient to predict corrosion resistance in molten chlorides, underscoring the need to consider full alloy chemistry and salt impurity effects in materials selection for chloride-based molten salt systems.

Source: Nuclear Engineering and Technology

DOI: 10.1016/j.net.2026.104739

Authors: Seok Min Yoon, Eun-Young Choi, Chang Hwa Lee, Taeho Kim

Institutions: Korea Atomic Energy Research Institute, Korea University of Science and Technology

Language: English

Topic: Molten salt chemistry and electrochemical processes

Subfield: Electrochemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $200

Funder: Ministry of Science and ICT, South Korea