Today North Korea tested, apparently successful, a nuclear device. The size of the explosion was given as 10,000 to 20,000 tons of TNT equivalent. That is much bigger than the last test which resulted in a ‘fizzle’ with only 500 tons TNT equivalent. NoKo also launched three surface to air missiles with a range of some 130km.
This was likely a test of a “Fat Man” type device, comparable to the first second nuclear bomb. It is the easiest to build plutonium design and the most likely one to work without more intensive engineering and testing. It is also a bulky design that is difficult to fit on the missiles North Korea has.
As far as known, today’s detonation left North Korea with enough Plutonium for two to six more bombs. It may restart reprocessing old nuclear fuel from its sole reactor and get material for another one within six month. It would have to restart the half dismantled reactor to produce more which would take some three to four years. North Korea may have an Uranium enrichment program, another possible way to nukes, but this program is likely not at industrial scale.
Everyone and his brother is condemning today’s test including the Russians and the Chinese. The UN Security Council will meet and release some harsh words. But I doubt that any new sanctions will be issued.
Even if North Korea manages to put a nuclear device on a missile it is unlikely that it would use it in a first strike. There would be nothing to gain but devastation for itself and the certain end for its regime. Under attack the calculation would be different.
The concerned global parties about a North Korean nuclear strike are South Korea, Japan, the U.S. and China. South Korea and the especially the U.S. troops stationed there would be a likely aim for a defensive strike. Japan and U.S. garrisons there are another possible target. China does not fear a North Korean weapon. But it has two other concerns.
The first is a nuclear armed Japan. Japan is a latent nuclear state. It has the material and the know how to build a few nukes over a weekend or two. It also has the means to deliver them. If Japan officially takes up nuclear arms China would feel endangered. The Japanese occupation is not forgotten.
The second Chinese fear is a collapse of the North Korean regime followed by a ‘peaceful’ invasion from South Korea and the U.S. troops there that would come to ‘help’ the ‘poor North Korean people’. This would put U.S. troops directly at its border.
Therefore I believe that China will block any attempt to put even more sanctions on North Korea.
But next to a nuclear strike there is another fear out there. North Korea could, in theory, export a nuclear device to interested party. As it has so few, the price would certainly be very high and I find it unlikely that anyone who can pay that price is interested in acquiring one or two weapons. But who knows? The U.S. will certainly play along that fear to further it aims.
It could argue that to prevent proliferation all ships must be searched when they enter and leave North Korea’s territorial waters. If the UN security council would agree to that it would set a precedent that could later be used to essentially blockade Iran.