[hga]

I can't imagine forging something that big and casting at a foundry wouldn't I think produce what you'd need (maybe, and it would be a cast iron b----, so to speak to do :-). A bit of work with Google came up with this NRC Fact Sheet: http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/pr... which says they "are made of thick steel plates that are welded together" which is what you'd expect. If this was good enough for later 20th century warship armor (which most certainly got put to the ultimate test!) (ADDED:) and submarines (which get put to the test every time they dive) it's good enough for this purpose.

Given that, it wouldn't take too much effort to cobble together what you would need to do it (stuff to hold the work in progress, like the two submarine shipyards we keep alive for the obvious reasons), but it's specialized and low volume enough I'm not be surprised there are only a handful operational in the world right now, and of course post-TMI the US wouldn't have one of them.

[pjscott]

Another fun fact: China and Korea are making large reactors without going through Japan Steel. Waiting in line for the heaviest of heavy forgings isn't necessary to create PWR nuclear reactors, even large ones.