{"id":24145,"date":"2016-01-11T10:45:35","date_gmt":"2016-01-10T23:45:35","guid":{"rendered":"http:\/\/www.aspistrategist.ru\/?p=24145"},"modified":"2016-01-11T10:08:37","modified_gmt":"2016-01-10T23:08:37","slug":"the-north-korean-nuclear-test","status":"publish","type":"post","link":"https:\/\/www.aspistrategist.ru\/the-north-korean-nuclear-test\/","title":{"rendered":"The North Korean nuclear test"},"content":{"rendered":"
<\/a><\/p>\n Pyongyang conducted its fourth nuclear test on 6 January. Technically, we know comparatively little about the device that it tested. In terms of seismic signature the blast seems to have been from a bomb about 7 kilotons in size. But seismic signature is an imprecise way of measuring yield, so we should probably allow a factor of two in either direction. That means the bomb\u2019s yield was somewhere between 3.5 and 14 kilotons.<\/p>\n Was it\u2014as North Korea claimed\u2014a hydrogen bomb? We don\u2019t know. It might have been a plain fission device or a \u2018boosted\u2019 fission device (with deuterium or tritium emplaced to \u2018boost\u2019 the yield). Frankly, unless it proves possible to detect radionuclides from air-sampling in the vicinity of the test site\u2014and that would require leakage from the test shaft\u2014it seems unlikely we\u2019ll know what sort of device it was. Air-sampling aircraft didn\u2019t detect any tell-tale radionuclides in the weeks after the third test. (The Comprehensive Nuclear Test Ban Treaty Organisation did report<\/a> a finding of noble gases xenon-131m and xenon-133 about two months after the test, a finding it described as \u2018consistent with a nuclear fission event occurring more than 50 days before the detection\u2019.)<\/p>\n True, the yield suggests it wasn\u2019t a full-sized hydrogen bomb. But North Korea has already said it wasn\u2019t, so no prizes there. Even in a hydrogen bomb, the most interesting reactions take place during triggering: the detonation of the primary fission weapon and the initiation of fusion. Boy scouts learn to light fires, not to build the biggest fires they can. So too for a weapon designer\u2014once the fire\u2019s burning it\u2019s comparatively easy to add more wood. So it might have been a test of a prototype hydrogen bomb with relatively little fusion fuel.<\/p>\n It might also have been a test of a boosted fission weapon. Pyongyang has long sought ways to miniaturise its nuclear weapons, the better to place them atop its ballistic missiles. Some media reports<\/a> in recent months have suggested the North Koreans have been trying to build weapons that use less than 6kg of plutonium, and so they might have been testing a device doing so, perhaps using boosting to help the detonation along.<\/p>\n