How to Build a Bomb

Two new books due out trace the flow of information from the first atomic bomb project to various others. Laid out in detail are facts known to insiders, but not widely in the consciousness of the public, including China’s proliferation decision of 1982, the early date of Pakistan’s nuclear program – their first test was in 1990 – and the trail from the US, to the USSR, to China, to France, to Israel, to South Africa.

The reality of bomb building is that it is not hard to build a bomb in concept. It is, however, expensive, and difficult to hide getting the fissile material – the actual fuel for a bomb. It is also a matter of detail. There is an enormous amount of precision work, particularly in the “fuses” – the extremely tight synchonization of parts that must happen at almost as close to exactly the same moment as is humanly measurable. Being off by fractions of a fraction of a fraction of a second, is enough to prevent a weapon from working. As with anything else, knowing that someone else has done something makes people more willing to pay to find out how to do it, than to pay to re-do it.

The hurdles to bomb building are in the incredible level of detail that is required, and the ability to see the results of actions. It is this open minded skepticism, and ability to make distant connections, which allows a country to thread the needle. Let me take an example from the US bomb building program.

The original design of the atomic program was a “gun” type of device. This is conceptual the most simple: two sub-critical, that is below the point of spontaneous explosion, wedges of fissile material are aimed at each other. The “bullet” is a hollow point that fires into a shaped opening in a larger “target”, the bullet mushrooms out on impact, creating a super-critical zone that sends a shockwave out, compressing the remaining fissile above critical and finishing the explosion. It is the high tech equivalent of dropping a boulder on some one. It works fine if it doesn’t miss. However, such a design is both unsafe, and does not lead to the hydrogen bomb, which works on an internal implosive core.

The gun design was pursued by the Manhattan project, until it was realized that the plutonium being mass produced had too much Pu-240 in it. This small amount would have meant that it was very possible that there would be a chain reaction started before the two wedges collided, resulting in a “fizzle.” Since the point of the gun design was that it was almost assured to work, the program shifted to designing the more complex implosive type in June of 1944, the resulting delay would make the weapon unavailable until 1945. It also threw the actual invasion of Japan into the works. Previously, while planning for the invasion was being done precisely to cover the fact that it was not believed to be necessary, suddenly it assumed an urgency.

The realization that a small impurity in the plutonium supplied could shift the core direction of the entire atomic design, is the kind of “heads up” thinking that occurs at dozens of points in the production of an atomic weapon, and then in making it possible to deliver that weapon to a target reliably. Creating a nuclear explosion is not difficult, creating a nuclear weapon is, for the same reason that murdering someone is not difficult, but getting away with it is. It takes precise timing to not be around when the consequences come out.

This is what prevents the horror scenario of buying “raw” fissile materials on some kind of black market and making a gun. A plutonium gun type weapon has a high chance of not working, or worse, working early. Even tiny impurities can change the characteristics of the fissiles by enough to make simple designs unworkable. The implosion design is far more complex, but far more robust. This is why, when given a choice, states prefer to get the intricacies of the implosion design solved for them – because extracting and purifying enough U-235 for the simple gun design, just to detonate a weapon of some kind, is generally not thought to be worth while, since it is also known to be a largely dead end technology: both weaponization, that is putting an atomic device on a missile of some kind, and thermo-nuclear, that is the fusion bomb – require implosion anyway.

But these objects exist primarily in the the context of the stable bi-polar, or uni-polar world. Many nations have had their nuclear programs closed, often by being bribed by existing nuclear states. Proliferated programs often are done with the intention of “selling the razor blades.” Bombs are cheap, it is the fissiles that are expensive. Sell the bomb for little, and then offer to sell the fissiles at a dear cost.

The permanent nuclear powers – and let us add India and Pakistan to that list since they are both beyond the point of turning back, even if they dismantle their present weapon inventories – have a vested interest in this remaining so. But in a multi-polar world, having an atomic device, even a dead end one, assumes an importance that it does not have in a uni-polar world. In the uni-polar or bi-polar world, the main powers have huge incentives, and disincentives, for nations to have or pursue atomic weapons. Only those nations which have overwhelming security paranoia, large resources, access to technical expertise, and political insularity, have done so. Absent all of these parts, it is more profitable to abandon than maintain a program. Currently North Korea and Iran are “pre-nuclear” states, but only just. It is likely that, if pressed, North Korea could assemble a bomb rather quickly, since they have conducted tests of the implosive shell without atomic arming. Iran is farther away.

Thus as we enter the multi-polar world, the bi-polar and uni-polar experience changes in it’s shape. Instead of underlining how few nations are willing to spend the massive amount of money required to build a from scratch atomic device, it emphasizes how easy it is for weapons to be proliferated, and how many states are willing to reach for them if the bar is set, not at the high level of making an obvious and massive commitment, with it’s attendant international isolation, but at the relatively lower commitment of creating the “atomic bureaucracy” required to build and maintain an arsenal.

With the decaying of the incentives of the US hegemony, this is going to look more and more attractive in the not very long run to more and more states.