Editors note by Ian Greenhalgh:
Once again, Jeff Smith delivers a truly devastating information bomb, one that will lay waste to entire paradigms that have become increasingly anachronistic in the modern age. For almost everyone, when they think of nuclear weapons they picture the 1950s newsreels of colossal hydrogen bombs blasting immense mushrooms clouds into the stratosphere and spreading deadly fallout over huge areas. That type of bomb still exists, but are unlikely to ever be used, they have existed for almost 70 years and no-one has ever dared to use one and I doubt anyone ever will.
However, those are very obsolete and outdated weapons, what we need to be concerned about today is four or five generations evolved from those old megatonne H-bombs – a totally different type of weapon that does not require a critical mass and therefore requires only a tiny amount of fissile material by comparison and best of all doesn’t produce a huge amount of nasty fallout and ionising radiation.
In fact, they produce no EMP, virtually no harmful fallout and only a small amount of radiation that is gone within hours. The yield of these bombs is, of course, much smaller, in the low kilotonne range, starting around 0.5kt and scaling upwards by adding more fissile material. All these factors make these weapons far more usable than the old megatonne monsters.
Now for the really scary part – these small clean neutron bombs are also very simple and cheap to manufacture, so much so that even non-state actors such as Islamic State could feasibly manufacture them in a decent machine shop.
Then it gets even worse – you can make these things out of the used fuel rods from nuclear reactors – something that is common and, given the political situation in some countries that contain nuclear reactors, quite readily available on the black market – certainly far easier to obtain than any ‘weapons grade’ material, which has been closely monitored for decades.
This scenario totally undermines all the years of political anti-proliferation negotiations, all the treaties and international monitoring agencies, all of it is now irrelevant due to the new designs of the 4th and 5th generation as described here by Jeff.
by Jeff Smith
Note below 1KT all charts stop. There is a reason why. Below 1KT you don’t need a “critical Mass” because you just hold it together longer. 32 neutron chain reaction is equal to 1KT or more in yield. So a much smaller amount will still go bang.
Critical Mass
Scientists define criticality as a measure of the ability of nuclear material to sustain a fission chain reaction. If a system is subcritical, it cannot sustain a fission chain reaction. If a system is supercritical, the fission chain reactions grow greatly. A system that is “critical” is the bounding case – this means that it sustains a chain reaction with a constant rate. The critical mass of fissile material depends on many factors:
- Purity of material
- Shape of material
- Density of material
- Temperature of material
- Surrounding materials
The “bare sphere critical mass” of weapons-grade uranium and weapons-grade plutonium is approximately 52 kg and 10 kg (respectively).
The critical mass of fissile material informs the most fundamental question of nuclear weapon design. The question which scientists have asked for the first time at the beginning of the Manhattan Project and which every nuclear weapon state has asked since then is: how much fissile material is necessary for a nuclear weapon? The class of nuclear weapon design (see section nuclear weapon design ) determines the amount which is needed. For a
gun-assembled design, more fissile material is necessary than for an implosion device, for example.
gun-assembled design, more fissile material is necessary than for an implosion device, for example.
The International Atomic Energy Agency defines “significant quantities” of uranium and plutonium as 25 kg and 8 kg (respectively). However, the figures which are below show that it is possible to produce reasonable nuclear yields with much less nuclear material than this, even if the technical capability is low.
Full article > https://tinyurl.com/y7te2o6h
