Corrosion of stainless steel in high temperature water and its fundamental chemistry

The field taken up here as the object of the corrosion in high temperature water is BWR plants. Concerning the safety of the plants, corrosion is particularly important, and the recent advance on this problem is so conspicuous that it has become the motive power for the development in this field. In the past, the stress corrosion cracking of stainless steel piping in BWR plants and the corrosion of inconel steam generator tubes in PWR plants occurred. As there problems were the important problems related to the fate of the plants, the countermeasures were taken in relatively short period as the results of having carried out the energetic research. Also there is the problem that the constituent eluted from plant structural materials is activated and increases the radioactivity in the whole plants, and the effort to reduce it has been made. In order to understand the corrosion in high temperature water, the basic knowledge on the equilibrium among reaction substances in metal-water system, the rate of electrode reaction, the properties of high temperature water and dissolved substances and so on. On a number of the basic matters on corrosion, the present status and problems are outlined. (Kako, I.)