Idaho National Engineering Lab nuclear reactor component preheat failure

Teaching anecdote from a welding-engineer friend. The Monday-morning piece was supposed to be preheated to 150°F; touch-test revealed it had been preheated Friday and allowed to cool over the weekend. Used as the punchline illustrating that preheat must be present at the moment of welding, not just nominally performed.

One of my favorite stories: I was talking to a friend who was a welding engineer at Idaho National Engineering Lab out in Idaho Falls. He had gone through a shop where they were building some nuclear reactor components out of carbon steel. It was a Monday morning. I don't know if it was a pressure vessel or whatever, but he went up, and he knew the thing was supposed to be preheated to about 150 degrees, because he was a welding engineer. He didn't feel warm — if you stand next to something that weighs a few tons and it's 150 degrees, you can tell. He put his hand up to it, and he actually touched it. You can't — if you put your hand on 150 degrees you won't leave it there very long, you won't burn it immediately but you won't leave it there. And he realized it wasn't preheated. He went over and asked the welder, well, did you preheat this? He says, oh, we did that on Friday. Okay. It cooled down over the weekend, so there was no effect of preheat.