Lee Unho, Kim Min Wook, Na Jisu, Lee Mingyu, Kim Sung Joong, Kim Dong-Joo, Yoon Young Soo
Department of Materials Science and Engineering, Gachon University, 1342, Seongnam-daero, Sujeong-gu, Seongnam-si 13120, Republic of Korea.
Department of Nuclear Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea.
Materials (Basel). 2025 Apr 3;18(7):1653. doi: 10.3390/ma18071653.
The molten salt reactor is a fourth-generation nuclear power plant considered a long-term eco-friendly energy source with high efficiency and the potential for green hydrogen production. The selection of alloys for such reactors, which can operate for more than 30 years, is a primary concern because of corrosion by high-temperature molten salt. In this study, three Fe- and Ni-based alloys were selected as structural material candidates. Corrosion immersion tests were conducted in NaCl-KCl molten salt for 48 h at 800 °C and 40% RH conditions in an air environment. In the absence of moisture and oxygen removal, ClNaK salt-induced damage was observed in the investigated alloys. The corrosion behavior of the alloys was characterized using various techniques, including scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and Auger electron spectroscopy. The results show that the corrosion process can be explained by salt-induced surface damage, internal ion migration, and depletion to the surface. The corrosion rate is high in SS316L (16Cr-Fe), N10003 (7Cr-Ni), and C-276 (16Cr-Ni), in decreasing order. Based on the corrosion penetration, ion elution, and interfacial diffusion results, C-276 and N10003 are good candidates for structural materials for MSRs. Therefore, Ni-based alloys with high Cr content minimize surface damage and ion depletion in unpurified molten salt environments. This indicates that Ni-based alloys with high Cr content exhibit highly corrosion resistance.
熔盐反应堆是一种第四代核电站，被认为是一种高效且具有绿色制氢潜力的长期环保能源。由于高温熔盐的腐蚀作用，对于这种可运行30多年的反应堆，合金的选择是首要关注点。在本研究中，选择了三种铁基和镍基合金作为结构材料候选物。在800°C和40%相对湿度的空气环境中，于NaCl-KCl熔盐中进行了48小时的腐蚀浸泡试验。在没有去除水分和氧气的情况下，在所研究的合金中观察到了ClNaK盐引起的损伤。使用各种技术对合金的腐蚀行为进行了表征，包括扫描电子显微镜、能量色散X射线光谱、X射线光电子能谱和俄歇电子能谱。结果表明，腐蚀过程可以通过盐诱导的表面损伤、内部离子迁移和向表面的耗尽来解释。SS316L（16Cr-Fe）、N10003（7Cr-Ni）和C-276（16Cr-Ni）的腐蚀速率依次降低且较高。基于腐蚀穿透、离子洗脱和界面扩散结果，C-276和N10003是熔盐反应堆结构材料的良好候选物。因此，高Cr含量的镍基合金可最大限度地减少未净化熔盐环境中的表面损伤和离子耗尽。这表明高Cr含量的镍基合金具有高度的耐腐蚀性。
