PNNL

Abstract

The electrochemical corrosion behavior of low carbon steel was examined in a simulated Yucca Mountain (YM) ground water by varying the electrolyte concentration and temperature under aerated and deaerated conditions. The results show that in deaerated conditions, the corrosion rate is low in the order of 0.6 to 4.5mpy, between 25 to 85oC, respectively. However, in aerated conditions the measured rates were expectedly very high, in the order of 3-55mpy in the above mentioned temperature levels. The rates initially increased up to 45oC, and a decreasing trend was observed with further increase in temperature from 65 to 85oC. The maximum corrosion rate was occurred at 45oC (54.5mpy). The low corrosion rates observed in all deaerated conditions, and in aerated solutions at higher temperatures were due to the preferential adsorption of Mg-species on the steel surface, as identified by XPS analyses. The results also indicate possible localized corrosion behavior of carbon steel in aerated conditions up to 45oC.