During the operation of Pressurized Heavy Water Reactor (PHWR), corrosion oxide layers are formed on the surface of carbon steel SA 106 Grade B (GR.B), primary coolant system material. These oxide layers can be effectively removed using the common chemical decontaminant, oxalic acid (OA). However, the base metal of the structural material may also undergo corrosion, increasing the concentration of metal ions, such as ferrous ions, in the decontamination solution. The increased concentration of metal ions leads to an increased use of cation exchange resins in wastewater treatment, thereby increasing the amount of secondary wastes. Therefore, minimizing the corrosion of the base metal during chemical decontamination is crucial. In this study, imidazole (IM) and 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) were selected for their effectiveness in reducing carbon steel corrosion in acidic environments. Their efficiency as corrosion inhibitors was evaluated under actual decontamination conditions in OA solution. When [BMIM]Cl was added to OA, the corrosion depth of carbon steel decreased from 0.641 μm to 0.406 μm, and the corrosion rate decreased from 1.924 μm/h to 1.218 μm/h, both representing a reduction of 36.7%. In conclusion, this study suggests that [BMIM]Cl is a good candidate as a corrosion inhibitor to be further evaluated under chemical decontamination process.

Exploring corrosion inhibitor of carbon steel SA 106 GR.B for chemical decontamination treatment
    Abstract
    1 Introduction
    2 Materials and methods
        2.1 Materials
        2.2 Corrosion experiments of carbon steel specimens
        2.3 Evaluation of corrosion behavior of carbon steel
    3 Results and discussion
    4 Conclusions
    Acknowledgements 
    References

• Bum Kyoung Seo(Decommissioning Technology Division, Korea Atomic Energy Research Institute, Daejeon 34057, Korea)
• Sion Kim(Decommissioning Technology Division, Korea Atomic Energy Research Institute, Daejeon 34057, Korea, Nuclear Science and Technology, University of Science and Technology, Daejeon 34113, Korea)
• Kamal Asghar(Decommissioning Technology Division, Korea Atomic Energy Research Institute, Daejeon 34057, Korea, Nuclear Science and Technology, University of Science and Technology, Daejeon 34113, Korea)
• Miguta Faustine Ngulimi(Decommissioning Technology Division, Korea Atomic Energy Research Institute, Daejeon 34057, Korea, Nuclear Science and Technology, University of Science and Technology, Daejeon 34113, Korea)
• Changhyun Roh(Decommissioning Technology Division, Korea Atomic Energy Research Institute, Daejeon 34057, Korea, Nuclear Science and Technology, University of Science and Technology, Daejeon 34113, Korea) Corresponding author