If the maniacs who blew up the federal office building in Oklahoma City had had better technology, the scene of that tragedy would not be marked by remnants of a collapsed building. Most likely, all that would be left would be a plaque designating the site where a city once stood.
A plutonium-powered nuclear bomb--small enough to be hidden under the back seat of a compact car--could have reduced Oklahoma City to a large crater.
Many believe that is an unlikely scenario because the construction of a nuclear weapon is not as simple as some have suggested, but just about any sober-minded physicist will admit it is a possibility.
The end of the Cold War and the collapse of the Soviet Union may have reduced the threat of a nuclear attack, at least for the time being, but the threat of nuclear weapons falling into the hands of terrorists or mad dictators or the mentally deranged remains very real.
Thomas B. Cochran of the Natural Resources Defense Council in Washington has estimated that a beer can could hold enough plutonium to build seven nuclear bombs.
The world has been spared so far because plutonium-239 is produced in nuclear reactors and not readily available to terrorists. And though enriched uranium can also be used for nuclear bombs, the process that concentrates this naturally occurring isotope into weapons-grade materials is highly complex, expensive and requires processing facilities that are hard to hide.
Yet nuclear materials are increasingly being found in unauthorized hands. Germany, for example, has reported an increase in the number of such cases to 267 in 1994 from 41 in 1991. Most did not involve weapons-grade materials. Even smoke detectors and various industrial processes use radioactive substances, and in some cases that material has been used to fake possession of nuclear fuel for blackmailing purposes.
Some incidents, however, are very disturbing.
On May 10, 1994, for example, police in Tengen, Germany, found 6 grams of plutonium-239 in the home of a businessman. In August, police arrested a Colombian dentist and two Spaniards in Munich who had 363.4 grams of high-grade plutonium in their possession. Although the police were accused of contributing to the latter case by enticing the men to smuggle the material out of Moscow, the incident is unsettling.
The situation will get worse before it gets better. The Bulletin of the Atomic Scientists recently estimated that Russia alone has about 12,000 nuclear warheads. A report in Scientific American last month said the former Soviet Union has hundreds of tons of enriched uranium and plutonium housed in more than 1,000 sites.
Scientists alone cannot solve this problem--it involves politics, international safeguards, policing agencies and a wide range of activities that lie outside the domain of science. Yet science has a role, and several key players have suggested recently that the best solution must go beyond protecting stockpiles from theft.
It might make more sense, they suggest, to make excess nuclear materials less useful to terrorists by making the fuel more difficult to fabricate into weapons.
The National Academy of Sciences concluded recently that one way to reduce the stockpile of weapons-grade fuel would be to burn it in existing reactors. But critics say that would take decades, and public hostility over such a program could be prohibitive.
The academy also suggested that nuclear fuel could be converted into a form of glass and the glass then buried in a nuclear waste site. But the site would have to be guarded for thousands of years, longer than any government has survived on this planet.
Meanwhile, Alex DeVolpi, a physicist with the Arms Control and Nonproliferation Program at Argonne National Laboratory near Chicago, has come up with a proposal that is so simple it probably will not be taken seriously.
DeVolpi believes the solution might be to contaminate weapons-grade material so that it would be far more difficult to use for illicit purposes. That could be done, he says, by mixing it with spent reactor fuel.
He admits it would be possible to decontaminate the fuel and separate out the plutonium, but says it would be so difficult that only the more advanced countries would have the technological expertise to do so.
He and his colleagues at Argonne are working on the technology required to "melt" the weapons-grade fuel and mix it with spent reactor cores, and he said in a recent report that it appears doable.
The end product would still have to be guarded, but at least the incentive to steal it would be greatly reduced, he says.
Clearly, he adds, something has to be done, and quickly.
"In a world in which fissile material could be purchased under the counter, all bets are off," he says.
Lee Dye can be reached by electronic mail at firstname.lastname@example.org