There's also a very strong bias towards keeping what you learn secret by default because you don't want to let your adversary learn your means and methods, e.g.

There's also a very strong bias towards keeping what you learn secret by default because you don't want to let your adversary learn your means and methods, e.g. particular spies, "national technical means" like surveillance aircraft back then and satellites nowadays, how you do analysis, all the way up to the scope of your efforts. I'd add that this disaster doesn't seem to implicate the US nuclear industry at all, sounds like it was part of their plutonium breeding effort, which is for weapons. Back then and for a very long time Oak Ridge would enrich natural uranium to, what, 5% U-235, and then it goes into a separate cycle which could and no doubt someday will include reprocessing (although not for weapons grade plutonium, too much Pu-238 and Pu-240 if you let it brew long enough), but didn't then nor does it today.