Who made the SG's?
Mitsubishi Heavy Industries, Kobe Japan.
Unit 3 SGs had a big problem...channelheads "delaminated" when SGs undergoing final pressure testing. MHI cut off the channelheads to fix, then welded SGs back together. Appears tube bundles tweaked a bit in the process. Few tubes now wearing funny.
Worried looking Japanese joined by worried looking Waterford folks. Waterford replacement SGs delaminated with cut/weld repair by different Mfr.
Addressing it the nuke way: slow,deliberate, safety first, full disclosure. "No timeline on safety." Davis-Besse lesson...........