The effect of sulfate reducing bacteria and acetogenic bacteria on the corrosion of carbon steel in crystalline groundwater

摘要

During the operation and decommissioning of nuclear power plants, low- and intermediate-level waste (LLW and ILW) is produced. The majority of metallic waste is made of carbon steel and various stainless steels. In Finland, this LLW and ILW is transferred to underground repository. It is known that microbes can accelerate several corrosion mechanisms of steels, such as general corrosion and localized corrosion as well as degradation of concrete. Microbially induced corrosion (MIC) in deep bedrock is important when evaluating long-term safety of disposal of radioactive waste. A laboratory system simulating the repository environment for studying the corrosion of decommissioning waste designed and developed in earlier studies was utilized here. Microbially induced corrosion was studied using new electrochemical technologies, such as multi-electrode arrays sensors, and molecular biology methods in the laboratory. In this work, the results from laboratory studies on carbon steel are reported. The tests were performed in natural anoxic groundwater sourced from an underground drill hole at the disposal site. Test environments were further supplemented with sulfate reducing bacteria and acetogenic bacteria enriched from the disposal site. The results of this study can be used when evaluating risks associated with MIC of metallic materials in underground storage of LLW and ILW.