Core shroud replacement of Fukushima-Daiichi Unit #3

The core shroud replacement of a boiling water reactor (BWR) was successfully completed at Fukushima-Daiichi Unit #3 (1F3) of the Tokyo Electric Power Company (TEPCO) in Japan. The core shroud and other core internal components made of type 304 stainless steel (SS) were replaced with the ones made of low carbon type 316L SS to improve Intergranular Stress Corrosion Cracking (IGSCC) resistance. This project was the first application of the replacement procedure developed for the welded core shroud, and employed various advanced technologies. The outline of the core shroud replacement project and applied technologies are discussed in this paper.