Over at DefenseTech, I’ve got a post comparing recent defector claims that North Korea has a one ton nuclear device with current US intelligence community assessments as read by Paul and yours truly.
Late Update: I now have the full text of the report. They guy says that North Korea’s bomb uses 4 kg of the Pu. That’s the bare minimum for an all Pu pit. I don’t believe this guy. More in a bit …
I tend to agree that this report doesn’t make sense. Is the 1-ton number the weight of the bomb or its yield? And, as you note at Defense Tech, simple generally means heavy.
I’m tending toward the idea that North Korea has no nuclear weapons. Bits and pieces, some attempts at plutonium casting (flashing from which was shown to Sig Hecker during his visit), but not whole, working weapons. This is just gut feel, accompanied by the fact that they haven’t tested, despite the bluster.
Well, 4 kg isn’t really the minimum; Cochran and Paine claimed in 1995 that you could go as low as 1-3 kg to get 1 kT depending on the sophistication of the design. On the other hand, Albright, Berkhout, and Walker say a “first bomb” could be 8 kg on p. 306 of Pu&HEU 1996. I’m going with the latter; Nagasaki was 6 kg of Pu, but it was heavy.
So a 1000-kg first-design untested bomb with 4 kg of Pu? If it’s got a decent yield, we oughta be hiring these guys to design our Reliable Replacement Warhead if it’s got any decent yield.
I was planning a post the Cochrane and Paine estimate as it related to North Korea.
I ought to have said “bare minimum assuming a Nagasaki-like yield.” Since Pyongyang presumably has more than 4 kg of Pu, there would be no reason to economize on a bomb with a 1 kt yield.
But, yes, if Pyongyang just wanted a bomb that fissioned, damn the yield, then I’d believe it had only 4 kg of Pu.