The Coming Nuclear Attack on the US – II

Yesterday I made (or, more correctly, parroted) a prediction that I’d rather not have made at all: Within the lifetimes of most of the readers of this column, a nuclear weapon will be detonated somewhere in the United States.

First, a brief on nuclear weapons. They aren’t that hard to understand and they aren’t that hard to build. For most wannabe nuclear powers, the problem is getting enough ‘fuel,’ or weapons-grade radioactive material. Refining, or enriching, nuclear fuel to a concentration sufficient to produce an effective weapon is not easy. It requires considerable time, knowledge, and sophisticated equipment. The only reason there are so few nuclear powers in the world today is the difficulty in obtaining enough enriched fuel to cobble together a bomb.

Building a nuclear weapon is not difficult.  At its simplest it involves nothing more than slamming two pieces of fuel together quickly enough to achieve a ‘critical mass.’ Any graduate nuclear engineer, given sufficient enriched fuel could, with the assistance of a few Igors, put together a device that would achieve critical mass and produce a nuclear explosion. The trade-off comes in size, weight, and yield.

For example, given sufficient quantities of U-235, a builder could put together a relatively simple “gun bomb” like the one that was dropped on Hiroshima in 1945. “Little Boy,” as the device was called, was grossly inefficient. It contained 64 kg of enriched uranium, of which 0.7 kg underwent nuclear fission, and of this mass only 0.6 grams was transformed into energy. In other words, the U-235 that actually underwent transformation weighed less than a paper clip and yet yielded the explosive power of somewhere between 14,000 and 18,000 tons of conventional explosives. The overall weight of “Little Boy” was about 9000 lbs.

Iranian Nuclear Processing Facility

Needless to say, the efficiencies of modern military-grade weapons are much, much better than they were in 1945. The amount of fuel needed for a high-yield weapon could be less than twenty lbs. provided a fairly sophisticated design were used. Even in an unsophisticated IND, twenty or thirty lbs. of fuel could yield a few kilotons of explosive effect, enough to destroy or damage most things within, say, a mile and produce a fallout plume worth worrying about.

The current physics and design of nuclear weapons is widely available. There’s enough on the internet to instruct someone with reasonable technical skills on the construction of at least a crude bomb. If you’re a geek with nothing else to do, spend some time reading up. You’ll find a lot of very smart people have been up late conjuring ideas that would do more damage with less material. There are dozens of great designs out there.

The most important thing to remember is this: given sufficient fuel any motivated group can build an effective nuclear weapon.

Nuclear Gas Centrifuges

So, where to get the fuel? Most of the weapons-grade nuclear fuel is under the lock and key of the major nuclear powers; fuel rods from nuclear reactors don’t count. They represent a potential source of fuel but would have to undergo considerable and difficult-to-conceal enrichment. There is rumored to be a lot of weapons-grade nuclear fuel in the hands of penurious former Soviet nuclear physicists but, so far, this fuel (if it exists) hasn’t shown up in the nuclear black market in large quantities.

The guys to worry about right now are the ones with unstable or ‘rogue’ governments and military-grade nuclear weapons already on hand. Obviously, the top candidates here are Pakistan and North Korea.

North Korea is ‘hungry’ enough (literally) to sell weapons grade nuclear fuel but is unlikely to do so because, if caught providing it to terrorists, they can kiss their asses goodbye. Hardly anyone would shed a tear.

Pakistan, on the other hand, presents the most eminent danger. They have (according to some estimates) 60-100 military-grade deliverable weapons, a strong Islamic tradition, an unstable and only marginally popular government, and they currently are fending off encroachments from Taliban and/or al Qaeda terrorists. A takeover of the Pakistani government by radical Muslim terrorists is a real possibility. And, with the takeover would come access to nuclear weapons. Even if the bombs themselves prove unusable because of well-engineered ‘fail-safe’ interlocks, the fuel can be extracted and re-used. There’s no danger of the bombs going off accidentally.

Tomorrow: a guess at al Qaeda’s nuclear strategy against the United States.