Experimental Study on Corrosion Behavior of Pure Copper in the Presence of Cement

Kawasaki, Manabu*; Taniguchi, Naoki ; Kawakami, Susumu

In geological disposal of high-level radioactive waste in soft rock, the cement material will be used as concrete support to ensure the mechanical stability of underground tunnel. The pH in ground water becomes high by the contact with cement. Therefore, the influence of cement on the corrosion of copper which is one of the candidate materials for overpacks was investigated. The anodic polarization measurement and immersion test in reducing environment were carried out, using the solution simulating the seawater(SSW) in contact with ordinary portland cement(OPC) and low alkaline cement (HFSC). The anodic polarization curves on SSW and SSW + HFSC were active dissolution type and, the polarization curve of SSW + OPC, was active dissolution / passivation transition type. The polarization curves in bentonite were active dissolution type. These results were consistent with results that have already reported. As the results of immersion test, corrosion rates became small with time. The growth of corrosion for 90day and one year immersion test was small and the average corrosion depth was in the order 0.1um. Within the test conditions, the influence of cement materials on the corrosion of was not significant.