All Stocks of Weapons-Usable Nuclear Materials Worldwide Must be Protected Against Global Terrorist Threats

Support for this research was provided by the Nuclear Threat Initiative and by the Hewlett Foundation as part of the American Academy of Arts and Sciences' Global Nuclear Future initiative.

The possibility that terrorists could get and detonate a nuclear bomb poses a real and urgent risk to international security. No one knows the real probability of such an attack.  But the evidence of terrorist efforts to get the nuclear materials and expertise needed to make a crude nuclear explosive is sufficiently troubling, and the consequences of such an event sufficiently grave, to justify urgent action to reduce the risk.

Nuclear Terrorism is a Genuine Danger

Several unfortunate facts shape the risk the world faces.  First, some terrorists are actively seeking to acquire nuclear weapons, and the plutonium or HEU needed to make them.  Osama bin Laden has called the acquisition of nuclear weapons or other weapons of mass destruction a "religious duty", and al-Qaeda operatives have attempted to buy nuclear material and recruit nuclear expertise.  Two senior Pakistani nuclear weapon scientists associated with Ummah Tameer e-Nau (UTN) network, for example, personally met with bin Laden and Zawahiri to discuss nuclear weapons.  In the 1990s, the Japanese terror cult Aum Shinrikyo, which launched the nerve gas attack in the Tokyo subway in 1995, also sought nuclear weapons.  There is clear evidence that Chechen terrorists have pursued radiological "dirty bombs," and at least suggestive indications of their interest in actual nuclear bombs as well -- and there are deep links between some Chechen terrorist factions and al Qaeda. With at least two terrorist groups having pursued nuclear weapons in the last two decades, the world should not expect that they will be the last.

Second, repeated assessments by the U.S. government and other governments have concluded that it is plausible that a sophisticated terrorist group could make a crude nuclear explosive -- capable of destroying the heart of a major city -- if they got enough plutonium or HEU. A "gun-type" bomb made from HEU, in particular, is basically a matter of slamming two pieces of HEU together at high speed.

One study by the now-defunct congressional Office of Technology Assessment summarized the technical reality: "A small group of people, none of whom have ever had access to the classified literature, could possibly design and build a crude nuclear explosive device... Only modest machine-shop facilities that could be contracted for without arousing suspicion would be required." Indeed, even before the revelations from Afghanistan, U.S. intelligence concluded that "fabrication of at least a 'crude' nuclear device was within al-Qa'ida's capabilities, if it could obtain fissile material."

The hardest part of making a nuclear bomb is producing the needed plutonium or HEU -- a task that took up more than 90% of the effort in the U.S. Manhattan Project.  Making their own nuclear material is almost certainly beyond terrorist nuclear capabilities -- so if the stocks controlled by states can be appropriately secured and kept out of terrorist hands, nuclear terrorism can be prevented.

It is important to understand that making a crude, unsafe, unreliable bomb of uncertain yield that might be carried in the back of a large van is a dramatically simpler task than designing and building a safe, secure, reliable, and efficient weapon deliverable by a ballistic missile, which a state might want to incorporate into its arsenal.  Terrorists are highly unlikely to ever be able to make a sophisticated and efficient weapon, a task that requires a substantial nuclear weapons enterprise -- but they may well be able to make a crude one.  Their task would be easier if they managed to recruit knowledgeable help, which they have been actively attempting to do.

Third, there is a real risk that terrorists could get the plutonium or HEU needed to make a nuclear bomb.  Important weaknesses in nuclear security arrangements still exist in many countries, creating weaknesses that outsider or insider thieves might exploit.  HEU-fueled research reactors, for example, sometimes located on university campuses, often have only the most minimal security measures in place.  One recent review of research reactors that had received U.S.-sponsored security upgrades identified research reactors that were wholly dependent on off-site response forces to respond to a theft attempt, but had never exercised the capabilities of those forces; a reactor that conducted no search of vehicles leaving the site for potential nuclear contraband; a reactor for which the national regulatory agency had not established any nuclear security requirements; and a reactor where no background checks were performed before allowing access to nuclear material. In countries such as Pakistan, even substantial nuclear security systems are challenged by immense adversary threats, both from nuclear insiders - some with a demonstrated sympathy for Islamic extremists - and from outside attacks that might include scores or hundreds of armed attackers.  In the end, all countries where these materials exist - including the United States and Russia - must regularly reassess whether the security they have in place is sufficient to meet the evolving threat.

As a result of such security weaknesses, there have been 18 incidents of theft or loss of HEU or separated plutonium confirmed to the IAEA by the states concerned. Most recently, in February 2006, Russian citizen Oleg Khinsagov was arrested in Georgia (along with three Georgian accomplices) with 79.5 grams of 89% enriched HEU, claiming that he had kilograms more available for sale. What we do not know, of course, is how many thefts may have occurred that were never detected; it is a sobering fact that nearly all of the stolen HEU and plutonium that has been seized over the years had never been missed before it was seized.  There have also been alarming intrusions. In 2007, for example, at the Pelindaba nuclear facility in South Africa, where hundreds of kilograms of weapon-grade HEU are located, two teams of armed men attacked from opposite sides of the site: one of the teams got through a 10,000-volt security fence, disabled intrusion detectors without detection, proceeded to the emergency control center (where they shot one of the workers on duty), and spent 45 minutes inside the guarded perimeter without ever being engaged by site security forces.

Fourth, it would be extremely difficult to stop terrorists from smuggling nuclear material or a crude nuclear weapon to its target. A nuclear bomb might be delivered, intact or in ready-to-assemble pieces, by boat or aircraft or truck.  The length of national borders, the diversity of means of transport, the vast scale of legitimate traffic across borders, and the ease of shielding the radiation from plutonium or especially from HEU all operate in favor of the terrorists. Building the overall system of legal infrastructure, intelligence, law enforcement, border and customs forces, and radiation detectors needed to find and recover stolen nuclear weapons or materials, or to interdict these as they cross national borders, is an extraordinarily difficult challenge.

Fifth, even a single terrorist nuclear bomb would be a catastrophe that would change history.  The heart of a major city could be reduced to a smoldering radioactive ruin, leaving tens or hundreds of thousands of people dead. Terrorists -- either those who committed the attack or others -- would probably claim they had more bombs already hidden in other cities (whether they did nor not), and the fear that this might be true could lead to panicked evacuations, creating widespread havoc and economic disruption.  Some countries may feel that nuclear terrorism is really only a concern for the countries most likely to be the targets, such as the United States.  In reality, however, such an event would cause devastating economic aftershocks throughout the world -- global effects that in 2005 then-UN Secretary-General, Kofi Annan warned would push "tens of millions of people into dire poverty," creating "a second death toll throughout the developing world."

It is also important to emphasize that the nuclear industry itself has a huge interest in preventing nuclear terrorism.  A terrorist nuclear bomb, or a major sabotage of a nuclear facility -- a "security Chernobyl" -- would doom any prospect for gaining the public, government, and utility support needed for large-scale growth of nuclear power, putting tens or hundreds of billions of dollars in future revenue at risk.  In some countries, it might even lead to pressures to close major operating facilities.

The good news is that there is no convincing evidence that any terrorist group has yet gotten a nuclear weapon or the materials and expertise needed to make one.  Moreover, making and delivering even a crude nuclear bomb would be among the most technically challenging and complex operations any terrorist group has ever carried out.  There would be many chances for the effort to fail.  But given a history of terrorist efforts to get a nuclear bomb, and the dire consequences should they ever succeed, there can be no room for complacency.  All countries must take action to reduce the risks of nuclear theft and terrorism to the lowest practicable level.

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