and everything is dandy now. The whole work took about 5.5 hours on October 9, according to Yomiuri. No information of the radiation exposure for the workers who had to work in the high-radiation Reactor 1 building.
TEPCO, which has caused the worst nuclear disaster in the world since Chernobyl (if not ever), is not at all interested in finding out WHY hydrogen gas was in the pipe.
The information that it was TIG welding came from the independent journalist Ryuichi Kino, who attends almost all TEPCO press conferences.
From TEPCO's handouts for the press on October 10:
(Pipe cutting operation)
(After the pipe was cut: the bottom part was welded shut, but I see duct tape on the top part...)
Good weld, I think. But my understanding is that TIG welding takes more time than other types of welding. I wonder what the radiation exposure for the welder was. I hope he was paid extremely well.
This bottom part of the pipe connects to the Suppression Chamber. The top part is where TEPCO will attach the "gas management" system.