You seem to be desperately angling for somebody to say that the evil reactor management orders one of the workers to be sacrificed by going into the highly radioactive reactor vessel. Why?
Almost all largely workable decades ago before we had e.g. laser welding, modern remote welding, industrial robots, etc. Of course things are better now. (Also, of course, we'd have to learn a lot operationally to actually do it).
Still, obviously these are procedures one would like to not have to employ, as they're likely to be very expensive and troublesome. They provided ample fuel for your concern trolling while I slept and couldn't answer, though, and then for you to "conclude" that there was no answer because the person answering in my stead didn't offer one. Yuck.