The Backpack Nuke

The cautionary tale told by David Rosenbaum, an independent nuclear analyst in Washington, is about blackmail on a huge and frightening scale. A terrorist group manages to construct a nuclear weapon and uses it to blast the top off a peak in the Blue Ridge Mountains. The President is then told that other bombs have been planted in three U.S. cities and will be detonated unless he agrees to their terms: a total overseas troop withdrawal, an annual donation of $50 billion for Third World projects and the release of all black and Hispanic prisoners. It sounds like the stuff of spy thrillers. But, warns Theodore Taylor, a former Princeton University physicist who once designed compact nuclear weapons and now is a Washington consultant, the acquisition of plutonium bombs small enough to be smuggled into the U.S. is "a real threat."

Indeed, according to many experts in the field, a well-financed group could build one that could fit into a pickup truck or a station wagon. In fact, the U.S. military has developed a 58-lb. bomb powerful enough to blow up the Golden Gate Bridge. Part of the problem is that the principles of bomb building are well known. In fact, the basic elements of the technology can be found in reference works like the Encyclopedia Americana. The trick is to place two slugs of plutonium close together in a container similar to a gun barrel, then smash the two together with explosives. This triggers the chain reaction that results in a nuclear explosion. However, achieving this involves advanced skills, expensive hardware and sophisticated electronic devices. Also, recovering plutonium from spent reactor fuel is costly and complex.

But neither money nor technical difficulty would necessarily discourage an erratic regime such as Libya's from pouring large amounts into building a small nuclear device. Taylor says that if such a regime could get its hands on enough plutonium, it would require only a few thousand dollars to build a device with a yield of ten kilotons, three kilotons less than that of the bomb that leveled Hiroshima, that could fit into a medium-size car. "I'd give them a pretty good chance, say, one in three, of building one that would work the first time," he says.

However, a terrorist bomb would still be so large that it would probably have to be assembled in the U.S. Making a bomb that could fit into a suitcase, says Taylor, would probably be beyond the capabilities of military designers outside the U.S. and the Soviet Union. The smallest nuclear device developed by the U.S. (SADM). Deployed since 1964, it can be carried by one man and is designed to destroy dams, bridges and similar installations. According to William Arkin, a defense specialist with the Institute for Policy Studies, a private Washington-based research organization, the U.S. has about 400 of these devices in Europe, South Korea, Guam and the U.S. Until recently, the military also produced a 400-lb. nuclear device, the medium atomic demolition munition (MADM), capable of destroying a medium-size city.

One of Washington's most persistent fears is that a determined terrorist group might succeed in stealing plutonium and bomb components. A congressional subcommittee on energy disclosed in 1982 that the guard force at one of the country's weapons plants failed to respond to a mock raid on a plutonium vault until 16 minutes after the "attackers" had left.