Aw, yeah. Well known in the nuclear engineering world. Playing with fire. And this wasn't the only time such an accident occurred. There was another one at Hanford. BZZZZT! Blue flash of light. Oops.

Playing with plutonium is not like playing with uranium. You need a lot more uranium to get critical so it's inherently less sensitive to human mistakes and fumbles. A plutonium pit is so small that human errors are easier to make.

Yeah, that would have been bad, since a lot of smart people were nearby. But a naked plutonium pit, while you can make it go supercritical by hand, it won't "detonate" like in a bomb. You won't get an explosion. You'll only get "fizzles". To get the instantaneous detonation of a bomb, you need the compression from the explosives surrounding the pit, which aren't even present, much less detonated correctly.

The plutonium pit bomb design is actually quite excellent. (If you're intent on building bombs. The wisdom of building these things is another discussion. Lol.) It's inherently safe.

In other words, if I gave you a plutonium pit, there's no way you could make it go off like a bomb without doing lots of precision engineering of chemical explosives and setting off those explosives in a precise way. So, that's a good thing about this design that we universally use in every bomb we have.

Lol. Engineers think differently and have two contexts: real life, and engineering. The real life side of me would prefer that these things didn't exist at all. The engineering side of me think's it's fascinating and cool.