This is my first experimental post to go with today’s daily wordpress writing prompt: Critical
Also interesting to see how the whole ping-back thing works… Meanwhile, this is just a story.
My name is Ju-Won Park, and I am in charge of the Nuclear program for the Democratic People’s Republic of Korea.
I believe in my country, and I consider myself a patriotic citizen. I know that history doesn’t remember men like me in a favorable light – the US scientist Oppenheimer, or Lavrentiy Beria of the USSR. There is a darkness to their legacy. The duality of man is not an easy thing to understand, let alone come to terms with.
I have heard of “the great filter” – the idea that advanced civilizations aren’t visible to our searching because they will tend to destroy themselves. But I have also studied MAD – the legacy of Mutually Assured Destruction has created a new age of peace, and I know that my people can find a way out of the darkness they’ve found themselves trapped within. They are resilient and resourceful, and more than anything they want something to believe in.
Our legacy as effective nuclear weapons engineers is complicated. I walk a fine line. Our first test in 2006, was one of fear. Our fear was that we would be killed and our replacements would not be so careful. Our military masters had come to a point of panic and demanded a test. Thankfully, our device fizzled a perfect amount, yielding about half a kiloton.
I understand your confusion. Let me explain. A super-critical reaction, you see, it’s a delicate thing. There is pressure, time, energy… The speed of light comes into play. Every nanosecond that goes by means that a beam of energy could escape from the perimeter of your reaction, and thus won’t build a bigger chain by reacting other fissionable elements. It’s a geometry problem, really. 2 becomes 4, 4 becomes 8; this doubling is very powerful, imagine instead of 2 atoms we’re talking about 2 kilotons becoming 4 kilotons in a single nanosecond. Every nanosecond means doubling the size of the explosion.
In a critical reaction of a power generation mass, the reaction is in total balance, creating even and reliable energy. A larger device will have too much mass, and be too close to criticality, producing a hum of warmth. It won’t sit on a shelf until you need it, and will be too “hot” to handle. It will cook your electronics and your detonators won’t work correctly – it will be the same as for power generation, but without water to turn a steam turbine and capture all that energy, the energy is simply a curse upon itself.
There’s a sweet spot in size where the highly enriched stuff isn’t too hot, and will have enough to capture its own neutrons to carry forward a runaway reaction – if you get the right arrangement. No matter what you do, such a reaction will eventually stop doubling but only because it will expand outward as the energy builds. Like a balloon being blown up with air, the surface area will thin out and the neutrons start to escape. In Hiroshima, less than 2 percent of the available material had fissioned, converting mass to energy in that famous equation – so powerful that 2 percent was devastating: 16 kilotons.
A lot of this has to do with a tamper. You’ve got to slow the expansion of the explosion, and give it something to … well, push against. Nothing could be better than depleted uranium, a heavy, dense material, with a unique property that it can also be part of the reaction – another bonus, it doesn’t produce any extra neutrons prior to the super-critical reaction. It pushes back on the explosion, keeps it from expanding before it’s doubled enough to make enough energy for your purposes. But how much energy? There was a test, “Castle Bravo” the American’s called it, where the device produced 2.5 times more energy than was anticipated. This was a failure in success.
Balance. It’s all about balance. Some of the high explosives don’t do well if they’re bombarded by radiation, heat, and even x-rays that come from the core. You’ve got to balance the explosive forces against each other. The detonators have to have nanosecond precision. The gun type style is easier than this type of design, that’s what we used in the past.
Our results were perfect balance. We created a credibility for the military to flog on the world stage, but at the same time our lack of higher yield gave room to diplomats who could claim the threat was smaller, not so grave as the saber rattling might suggest. We were modest. Our second test, in 2009, yielded a higher amount of total energy, almost 2 and a half kilotons. This test was too difficult to fail, as we lengthened the barrel to reduce the amount of pre-critical interference.
In some ways, it was easy to use the military’s instincts against them. They would ask for larger chunks of uranium thinking that would make a bigger explosions, and later when they asked we could turn the blame back on them by pointing out that too much fission had occurred prior to detonation – at some point you’re just banging together pieces of lead. Still, only 1/8th the yield of the Hiroshima weapon. Perfect balance. A successful failure.
The real goals for me are to keep capabilities limited in terms of weapons, but we also need to move forward with power generation if we’re going to develop enough to build a stronger country and move past this dark age. Have you seen the picture from space showing our entire political geographical region shrouded in darkness? This lack of modern progress has meant our country faces the possibility of famine and disease. It must not be so. In order to convince the military to spend money on what is, essentially, a public works project, you must dangle the carrot of something in front of them. This started with my predecessors. Pragmatic people.
Do you judge me for this? Your space shuttle has the same provenance. Something benign and built seemingly as part of a peaceful mission. It has an absurd mission funded as a military capability, to capture soviet satellites or, in the twinkle of Nixon’s eyes, intercept ICBM’s. As such it was drastically overbuilt to abort from a polar orbit with an enormous cargo bay full of treasure. Without this funding from the military, and the promise of such a nefarious use, it would never have had the funding to exist.
In my country we are caught in a similar, but more grim form of the prisoner’s dilemma. We must balance our capabilities against the specter of our own total destruction. Now we’ve started to tackle new challenges, but only because this provides us knew plausible ways to avoid developing something more terrible. In 2013 we continued our plodding advance – this time 5 kilotons. Still, modest. Still, in balance. 1/3rd the yield of the “little boy” dropped on Hiroshima. We repeated this result, simply for consistency in 2016 – this time with a more complicated device. We kept these variables in balance. Fusion and fission. In September, finally, we could delay no more, and we hit 10 kilotons. Our political system faced severe challenges at this time, but we continued, we made old methods of refinement more difficult, and the production of heavy water (water with hydrogen that has extra neutrons) will prove a new industrial challenge more difficult for the kind of large scale that would threaten any other countries in a meaningful way.
Miniaturization in my field means producing something that doesn’t produce a large amount of radiation. Beryllium, plutonium, even palladium – there are chemical purification and industrial processes at work here that may never be fully solved. Even in the west, with all the industrial power and education and sophistication, frequently refined designs succeed and fail in the confines of a computer program. The legacy of your own tests of real bombs and the attacks on Japan weigh far more heavily than my own, thousands of above and underground explosions. From me, there’s comparatively nothing to fear.
If I am successful, I may be considered a monster. If I fail, the toll may be much worse. I must have the kind of success that is tinged with failure. Balance. The world must be in balance.