Inspection of the steam generator heat transfer tubes for FBR Monju restart

Takahashi, Kenji; Shiina, Akira; Onizawa, Takahiro; Ibaki, Shoji; Yamaguchi, Toshihiko ; Tagawa, Akihiro 

Japanese prototype FBR Monju will restart its operation for the first time since the sodium leak accident in 1995. Concerning heat transfer tubes of the steam generator (SG) units, presumable deteriorations were studied and the integrity is confirmed when they have no lack of thickness by corrosion after the long-term suspension. It was impossible to test the tubes directly, then three tests were applied, which were ECT, VT (visual test) and leak test. ECT is to check for the lack of thickness caused by regional corrosion. VT checked for the global corrosion and the bottom of the tube. Leak test checked for pin-holes (penetrating holes). Total evaluation proved no significant lack of thickness and pin-holes in the tube.