Real-time corrosion monitoring system under in situ conditions of crystalline groundwater

Autor: Leena Carpen, Pauliina Rajala, Tuomo Kinnunen
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: Carpen, L, Rajala, P & Kinnunen, T 2018, ' Real-time corrosion monitoring system under in situ conditions of crystalline groundwater ', Paper presented at European Corrosion Congress, EUROCORR 2018, Krakow, Poland, 9/09/18-13/09/18 pp. 114552 .
VTT Technical Research Centre of Finland-PURE
Popis: An in situ corrosion monitoring system was developed to monitor real-time corrosion rates of two stainless steel grades (EN 1.4301 and EN 1.4404). The corrosion monitoring system relied on linear polarization resistant (LPR) method. Besides the electrochemical coupons, the monitoring system contained gravimetric specimens to confirm the results of electrochemical measurements. The results of this study can be used when evaluating risks of the microbially induced corrosion of metallic materials in the underground radioactive waste repository.Low and intermediate level radioactive waste (LLW and ILW) is produced during the operation, maintenance and decommissioning of nuclear power plants. The metallic waste includes pipes, valves, filters and tools, the majority of which is made of various stainless steels and carbon steel. In Finland at Olkiluoto nuclear power plant site, the LLW and ILW have been disposed of in a geological repository located at the depth of 60 of 95 m below surface since 1992.Surprisingly, higher corrosion rates were detected in the molybdenum contained stainless steel type EN 1.4404 compared to the lower alloyed type EN 1.4301. This indicates possible role of microbial activity in corrosion. Microbial community from groundwater has been earlier analyzed and a vast bacterial and archaeal community was discovered. The microbial community involved microbial groups linked frequently to MIC. Here, thick biofilm was detected on surfaces of both steel grades. Results during the exposure of two years are presented and discussed here.
Databáze: OpenAIRE