Nuclear Terrorism

Nuclear Weapons

Nuclear weapons are devices that release energy stored in the atomic nucleus, the central, positively charged core of all atoms. The first nuclear weapons used uranium, a dense metal mined from the earth in many parts of the world, and plutonium, a man-made metal produced by irradiating uranium in nuclear reactors. The nuclei of these atoms can be made to fission, or divide, liberating vast quantities of energy in the process. Each fission also releases a few neutrons. If there is a sufficiently large mass of uranium or plutonium present, called a “critical mass,” those extra neutrons stimulate more nuclei to fission in an explosive chain reaction in which energy released by vast numbers of fissioning nuclei is transformed into heat, radiation, and shock waves. This vast release of energy creates a nuclear explosion.

Fortunately, it is not easy to make a nuclear weapon, despite the fact that numerous books, articles, and websites purport to give information about how it can be done. The most difficult part of making a nuclear weapon involves obtaining the necessary fissionable material, an isotope (or variety) of uranium known as U-235 (because the total number of protons and neutrons in its nucleus is 235). It is very difficult to separate the lighter variety, the U-235 needed to make bombs, from the heavier variety, U-238. Bomb-builders who have obtained U-235 can then make a bomb from it directly, or they can use it to build a nuclear reactor that uses neutrons to irradiate U-238 and make plutonium-239 (Pu-239), another bomb material that fissions readily. The bomb dropped on Hiroshima in August 1945 used U-235, and the one employed at Nagasaki several days later used Pu-239.

The project to build the first U.S. nuclear weapons during World War II was a massive undertaking requiring the full resources of a powerful nation. Could terrorists do it? What is the probability that they have both the skills and technology needed to take the next step? Could they make a fission bomb or perhaps even a thermonuclear weapon? Several possible scenarios will be considered.

A Terrorist Threat Assessment

It can be said with complete confidence that a terrorist organization that did not have the support of a government could not produce the fissionable uranium or plutonium for a fission bomb from raw materials. Nor would it be possible for a group of non-state actors to take irradiated nuclear fuel from a reactor and extract plutonium from it. The technologies involved are too complex, dangerous, and expensive for a small group to master.

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