Concept of feed water iron control operation and application status in Japan

Recent status of the feed iron control operation in Japanese BWR and ABWR plants will be reviewed. Iron control operation for the Fe/Ni ratio control have been generally applied in the low crud plants and confirmed to be effective for the radioactivity reduction in reactor water. In recent iron control operation, more effective iron control conditions have been investigated in order to get the radioactivity reduction effects with minimum iron crud input in a reactor. It will be shown that optimum control of the installed fuel surface conditions is the important key technology to realize the effective iron control operations. (author)