How Big Was the North Korean Bomb?

There are a number of different types of nuclear bombs but the two that are of interest for those nations entering or thinking of entering the nuclear club are the basic uranium bomb and the basic plutonium bomb.

The problem with uranium is that it takes a great deal of time and technology to enrich uranium (or isolate the isotope U-235); but once the uranium is acquired, the device for setting off a nuclear explosion is a relatively simple cannon closed at both ends. Plutonium is created in atomic reactors and once a sufficient amount is created, it is relatively easy to isolate chemically from other materials (assuming that precautions against radiation are taken). North Korea has a stockpile of plutonium but not, as far as I've read, stockpiles of enriched uranium. If a device was detonated, it's assumed to be a plutonium-type bomb.

The problem with plutonium is that the bomb device itself is a great deal more complicated than the one for uranium and requires precision machining, explosive packing, high quality switches that all combine to create an implosion (an inward-directed explosion). A mistake anywhere can result in a) a lethal radiation for those putting the bomb together, b) an outright dud, or c) a small misfired explosion.

It's not clear what happened in North Korea but we're hearing reports that it was a 1-kiloton explosion, far less than the first plutonium bomb set off by the United States in 1945 in New Mexico. A small misfired explosion is considered a likely explanation.

Jeremy Manier of the Chicago Tribune has a useful article that explains some of the possibilities and issues around the North Korean test:

When North Korea detonated what it said was a nuclear device Monday, the blast set off seismic sensors as far away as Wyoming and Norway and sparked a round of urgent study by scientists around the world.

But determining just what caused the seismic spike is such a delicate art that after five days of intense work, analysts still cannot say for sure whether the test was a success or a dud—and there is a remote possibility the blast was not nuclear.

The job requires analysis of data drawn from hundreds of monitoring stations worldwide, including seismic monitors so sensitive that they can detect rumblings from mine cave-ins halfway around the world. Getting an accurate read on the bomb's power is complicated by the fact that some forms of seismic waves are detectable only at a great distance.

One seismic clue the scientists may look for is whether the bomb caused its underground cavern to collapse. That could be one sign of a significant nuclear blast, said David Albright, president of the Institute for Science and International Security in Washington.

Monitors are also watching air samplers that can pick out radioactive particles or gases released by a nuclear blast, though those devices are subject to the whims of the winds over North Korea.

France's defense minister has called North Korea's bomb a dud—a "failed explosion"—but other analysts said that conclusion is premature. Marine Gen. Peter Pace, chairman of the Joint Chiefs of Staff, said Thursday that U.S. intelligence officials had "not yet determined ... what exactly they tested."

There have been false alarms in the past about nuclear tests so I appreciate that the experts are taking their time. Then again, if France says the test was a dud, we have to wonder why they reached such a conclusion so quickly while US experts are still taking their time.

In the end, the real issue remains the failure of the Bush Administration to talk to our enemies, an obvious diplomatic strategy that has been productive since the end of World War Two. When the leader of the free world refuses to negotiate or even hold discussions with our enemies, it is equivalent to refusing to show up for work. There is a reason President John Kennedy installed the red phone.