17 June 2006

Plutonium lessons from Korea

By Jacqui McCarney

It would be funny it wasn't so tragic. In 2002 the United States accused North Korea of enriching uranium to make nuclear weapons. Sound familiar? The tragedy in this case was that the North Koreans weren't anywhere near being able to enrich uranium sufficiently to make a nuclear weapon, but, as a consequence of the accusation, the North Koreans suddenly were able to make nuclear weapons.

Confused? You should be. To understand the story you have to know how to make a nuclear bomb. Not in every detail, but at least the basics. There are two types of nuclear bomb; one is made from uranium – very highly enriched uranium to be precise – and the other is made from plutonium. The difference between uranium and plutonium, and where they come from, is extremely significant.

Let's start with uranium. The stuff you use for nuclear weapons and nuclear reactors, uranium 235, is less than 1% of the uranium that you find in the ground. To get a concentrated amount of uranium 235 you therefore have to separate the U235 from the rest of the uranium. To do this you have to use a complex machine called a centrifuge cascade. The centrifuge cascade relies on very precise engineering, a constant supply of electricity, bearings that can withstand a huge amount of work without degrading, very specialised materials and an extremely well controlled environment. It takes over a thousand centrifuges, operating constantly for a year, to produce enough very highly enriched uranium for one nuclear bomb. At this point it is worth noting that Iran currently only has a 164 centrifuge pilot project which has only just become operational after several years work. They plan to make a bigger centrifuge cascade, but it won’t be ready any time soon, and there are plenty of technical hurdles to be overcome in the process. Making nuclear weapons from uranium is no easy task.

Another way to make a nuclear weapon is with plutonium. All you need, to make plutonium, is some old fuel rods from your local nuclear reactor, a few chemicals and some large stainless steel tanks. Every used fuel rod contains a few grams of plutonium but you need at least 20 odd kilograms of the stuff to make a nuclear weapon. That's quite a few fuel rods, but, if you happen to have your very own nuclear reactor, you will also have access to several thousand fuel rods. Anyone with a nuclear power station therefore, can make plutonium without too much difficulty. Anyone with a few kilograms of plutonium, could make a nuclear weapon.

Let's return to North Korea. It's important to know that North Korea has built and operates its own nuclear reactor and therefore has access to plutonium. Until recently the plutonium in the used fuel rods was carefully monitored by international inspectors. Then the United States accused the Koreans of enriching uranium. The basis of the accusation was the fact that the Koreans had tried to buy the materials to make a centrifuge cascade (remember what that is?). They might have tried, but there is no evidence, according to the US establishment journal Foreign Affairs, that they actually succeeded in buying the parts, let alone in putting them together and successfully operating the highly complex machine; according to Johnathan Pollack, chairman of the Strategic Research Department at the US Naval War College "North Korea confronted daunting obstacles had it decided to build an enriched uranium weapon, or even to acquire the production capabilities that might ultimately permit such an option".

For the Bush administration though it was enough to call an end to the Agreed Framework which allowed inspectors to monitor the Korean nuclear programme in return for economic benefits from the United States. So the Bush administration was able to call a halt to providing economic aid to North Korea. The downside for the international community was that it also meant that the nuclear inspectors had to leave the country too. Suddenly no one was monitoring the North Korean nuclear reactor and those piles of used fuel rods containing that oh so deadly plutonium.

Two years later the North Koreans announced they had made a nuclear weapon. No one doubted that they would have been able to extract the plutonium from the used fuel rods now that no one was looking. The Bush administration's accusation that North Korea was enriching uranium for nuclear weapons was a gross exaggeration that has seriously back fired. For Bush and his advisers the devil is clearly in the axis of evil, for the rest of us the lesson is clear; the devil is in the detail.

My thanks to Liam Carroll for his help and research with this column.