Flow accelerated corrosion of carbon steel containing chromium under water chemistry conditions of boiling water reactor applying mitigation techniques of corrosive environment

Abstract

ABSTRACT The effects of exposure to oxygenated water on flow accelerated corrosion of carbon steel containing chromium were investigated by alternately and repeatedly exposing specimens to low dissolved oxygen water with <3 μg L−1 of dissolved oxygen and oxygenated water with 30–50 μg L−1 at 190°C and 2 m s−1 flow velocity. First, carbon steel ingot and several carbon steel ingots containing chromium were prepared in a vacuum melting furnace and hot forged. The forged ingots were machined to make tube test specimens. After exposure to the oxygenated water condition, the thinning rate of carbon steel containing chromium under the low dissolved oxygen condition was found to depend on chromium concentration. For carbon steel containing less than 0.052 wt% chromium, thinning rate after exposure to the oxygenated water condition was almost the same as that before exposure to the oxygenated water condition. That is, no adverse effects by exposure to the oxygenated water condition were observed. For carbon steel containing more than 0.13 wt% chromium, thinning rate decreased to the undetected level by exposure to the oxygenated water condition. That is, corrosion resistance was improved by exposure to the oxygenated water.