Radiation Said to be Observed Near Site of NoKo Nuclear Test
The Beeb is reporting that US now claims to have measured radiation from the apparent failed nuclear test performed by North Korea.

If this is confirmed, we can say with confidence that stone age countries need not apply for membership in the exclusive World Nuclear Club.
More seriously, since North Korea had at maximum 24 kg weapons-grade plutonium, and the critical mass needed for a standard test is at least 6 kg, this leaves them with at most enough plutonium for three more bombs, and possibly only two.
Let’s hope for one more dude dud, and absent a successful (and also technically demanding) uranium enrichment program, they will have managed to successfully make themselves both laughingstocks and render themselves impotent at the same time. (Fuel for one bomb, absent a successful demonstration, does not make much of a deterrent.)