The Real Sum of All Fears

It is not a matter of “if” but “when” one of our cities confronts a nuclear emergency. Monday’s announcement of the May 8 arrest in Chicago of an alleged Al Qaeda operative accused of planning to build a radioactive “dirty bomb” suggests that the date for a domestic nuclear crisis is rapidly approaching.

Less obvious, however, is the kind of nuclear terrorist threat about which we should be most concerned.

There are four varieties of nuclear terrorism. In addition to the seizure of a nuclear weapon by a renegade military faction--the preferred scenario for Hollywood thrillers--these threats include the theft of nuclear material for the purpose of fashioning a nuclear explosive device, the attack on or sabotage of civilian nuclear power installations or spent fuel storage sites and the matching of highly radioactive nuclear material with conventional explosives to create radiological dispersal devices or, in common parlance, “dirty bombs.”

All of these nuclear terrorist threats are real, all merit the urgent attention of the U.S. government and the international community and all require the significant expenditure of resources to reduce the likelihood and impact of their occurrence.

The threats themselves, however, are different and vary significantly in their probability of occurrence, their consequences for human and financial loss and the ease with which their likelihood of occurrence can be reduced.

The most immediate threat is apt to arise from the use of a conventional explosive to disperse radioactive debris.

Millions of tons of radioactive material exist globally, much of it in the form of spent nuclear fuel. Highly radioactive sources also are used widely for radiotherapy and diagnoses, to irradiate food, for agricultural purposes and in industry.

It is estimated that in the U.S. alone there are several million devices using radioactive material. No reliable inventory of these materials exists, and a large percentage of them are no longer in use, have been discarded or are lost. “Orphan” sources from other countries have turned up repeatedly on the black market and are known to have been acquired by Chechen rebels in Russia.

The risk of nuclear sabotage also is a serious one. Although not widely know in the West, there were at least four episodes in the mid-1990s in which nuclear power plants in the post-Soviet states were the targets of terrorist actions. Three of them involved the Ignalina nuclear power plant in Lithuania and one had to do with the Kursk nuclear power station in Russia. There is good reason to believe that U.S. nuclear power plants also are vulnerable to armed assault, cyberterror (to disable the plants’ safety devices) and insider malevolence.

Were individuals or groups to succeed in acquiring a sufficient amount of highly enriched uranium, one also could not rule out their ability to manufacture a crude but effective nuclear bomb.

What has changed since Sept. 11 is not that it has suddenly become easier to fashion a nuclear bomb--it hasn’t--but that we now must assume that there are organizations that covet fissile material for the purpose of detonating nuclear explosives in our cities. The main obstacle in their path is obtaining highly enriched uranium.

Finally, although less likely than the other nuclear terrorist scenarios, we must take seriously the need to guard against the theft of intact nuclear weapons. Of particular concern are relatively small tactical nuclear weapons, of which thousands exist, none covered by formal arms control accords.

Today there is an urgent need to assess the full range of nuclear terrorist threats and invest finite resources where they can have the greatest impact.

It will be years before we can secure all of Russia’s highly enriched uranium against theft, and it may never be possible to control every radiological source that might find its way into a dirty bomb. But it should be possible in a matter of months to beef up security at U.S. nuclear power plants and prepare the public psychologically for the manageable dangers from a radiological bomb attack.

These must be our immediate priorities as we pursue a more comprehensive plan to compare, assess and combat the multiple threats posed by the different faces of nuclear terrorism.

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William C. Potter is director of the Monterey Institute Center for Nonproliferation Studies. Leonard Spector directs the center’s Washington, D.C., office.