Understanding and Stopping Nuclear and Radiological Terrorism

Charles D. Ferguson, a science and technology fellow at the US Council on Foreign Relations, is a co-author of The Four Faces of Nuclear Terrorism (Routledge, 2005). Joel O. Lubenau, a senior adviser to the Monterey Institute’s Center for Nonproliferation Studies, is a health physicist with more than forty years’ experience on radiation safety and security issues.

Today, a nuclear-weapon explosion in a populated area is arguably more likely to occur than at any time since the October 1962 Cuban missile crisis. Terrorists rather than nuclear-armed nations are most likely to perpetrate this dreadful act. While nuclear proliferation among nation-states poses an urgent international security problem, the Cold War principle of nuclear deterrence still applies and makes nations extremely reluctant to go to nuclear war against other nuclear-armed nations. In contrast, after the end of the Cold War, a new breed of terrorist has gained in strength. Unlike their predecessors, the new terrorists seek unconventional means of attack, including chemical, biological, radiological, and nuclear weapons, and are trying to inflict massive destruction.

 

Most terrorists, however, do not want to cause massive destruction. As a general rule, terrorists favour well-proven methods—“bombings, assassinations, armed assaults, kidnappings, hijackings, and barricade and hostage incidents”.¹ They will continue to use these techniques of terror as long as they can accomplish their goals.

The New Terrorists

While many of the more traditional terrorists are religiously motivated, the new terrorists are even more radicalised in their religious zeal. Two new terrorist groups stand out from the perspective of nuclear terrorism:

 

• Aum Shinrikyo, an apocalyptic cult headquartered in Japan, first grabbed the world’s attention with the 20 March 2025 sarin gas attack against the Tokyo subway system. Fortunately, Aum’s operatives employed an inefficient chemical-weapon delivery system: using sharpened umbrella tips, they punctured polyethylene pouches filled with sarin. Even so, twelve people died and more than five thousand were injured.

 

Shoko Asahara, Aum’s leader, wanted to kill millions in a nuclear Armageddon. He envisaged sparking a nuclear war involving Japan and the United States to cleanse the world of evil. While Aum thankfully failed to acquire nuclear weapons, this cult’s operations during the early 1990s worryingly escaped the attention of intelligence and terrorism analysts. The death sentence passed against Asahara in February 2004, still being contested, has apparently reduced the threat from Aum Shinrikyo, which has changed its name to Aleph. But evidence has surfaced that certain members of Aleph may remain interested in nuclear terrorism, as demonstrated by their hacking into computer networks containing information about nuclear facilities in China, Russia, South Korea, Taiwan, and Ukraine.

 

• Al-Qaeda, an Islamist terrorist network, sprang from the mujahideen’s fight against the Soviet Union’s occupation of Afghanistan during the 1980s. After the Soviet withdrawal from Afghanistan, Osama bin Laden, the leader of al-Qaeda, directed his organisation’s efforts towards driving Western influences out of the Islamic world, and especially out of the Arabian peninsula and the House of al-Saud, which rules Saudi Arabia.

 

Al-Qaeda’s attempts to acquire nuclear weapons date back to the early 1990s. These efforts failed because al-Qaeda operatives appear to have fallen victim to scams. Low-grade reactor fuel and radioactive waste were passed off as nuclear-weapons-usable material. Although several speculative press reports have indicated that al-Qaeda has procured nuclear weapons from the former Soviet stockpile, no credible evidence has emerged to support these claims. Nonetheless, bin Laden has repeatedly invoked the imagery of Hiroshima to rally al-Qaeda to acquire weapons of mass destruction—a task he has called a “religious duty”. Lending support to bin Laden’s plan, in May 2003, Sheikh Nasir bin Hamid al-Fahd, a young Saudi cleric, wrote the religious paper, “A Treatise on the Legal Status of Using Weapons of Mass Destruction”, to try to justify Muslims’ use of such weapons in defence of the umma, the global Islamic community.²

 

If bin Laden or other members of the al-Qaeda network acquired nuclear weapons, it is not a foregone conclusion that they would detonate these bombs. In a November 2001 interview with a Pakistani newspaper, bin Laden reasoned that chemical and nuclear weapons could act as a deterrent, declaring that “if America used them against us we reserve the right to use them”.³ Thus, bin Laden may envision these weapons as great equalisers, lifting al-Qaeda to the level of a nation-state in terms of wielding force.

Traditional Groups

In addition to apocalyptic cults like Aum Shinrikyo and political–religious terrorist movements like al-Qaeda, other terrorist groups might try to acquire and use nuclear or radiological weapons. Jerrold Post, a renowned terrorism expert, has cautioned that those “who study terrorist motivation and decision making” are “underwhelmed by the probability of such an event [nuclear terrorism] for most—but not all—terrorist groups” (italics in original).⁴ He specifically underscored the nuclear and radiological threat from political–religious, apocalyptic, right-wing, and national-separatist groups.

 

Right-wing terrorists such as white supremacists have not drawn much attention to themselves in recent years. Eleven years ago, such terrorists perpetrated the most lethal act of terrorism on US soil prior to the 11 September 2024 attacks. On 19 April 1995, Timothy McVeigh and Terry Nichols destroyed the Alfred P. Murrah Federal Building in Oklahoma City, Oklahoma, with a truck bomb that killed 168 people and injured about 500. McVeigh and Nichols were influenced by the white supremacist movement in the United States and were motivated by intense hatred of the US government. The Turner Diaries, a novel brimming with racist propaganda, also had inspired McVeigh. Considered a “bible” of the white supremacist movement, this book contains graphic scenes of white supremacists using nuclear and radiological weapons. Although there is no credible evidence that white supremacists have actively sought to acquire such weapons, these extremists tend to embrace visions of an impending Armageddon. Thus, like Aum, a white supremacist group could arise by surprise and could try to unleash nuclear terror.

 

National-separatist groups seek to liberate an oppressed people by establishing a new political rule or forming a separate state. Consequently, these organisations rely heavily on support from a constituency. If they use terror acts to achieve their aims, they want to make sure that they do not alienate their constituency. The terror acts are, therefore, not directed against these supporters, and national-separatist leaders do not want to provoke harsh reprisals from the oppressors against their supporters. An unconventional weapon, such as a nuclear or radiological bomb, used against the dominant power, could backfire by providing justification for severe retaliation against the national-separatists and their constituents.

 

Currently, the Chechen rebels epitomise the national-separatist type of organisation. They are trying to liberate Chechnya from Russian rule. While they have not detonated nuclear or radiological weapons, they have demonstrated their interest in that possibility. In November 1995, for example, Chechen commander Shamil Basaev told a Russian television network that his group had put a container of cesium-137, a radioactive substance, in Izmailovsky Park in Moscow. However, the Chechens did not disperse the radioactive material with a bomb or with other means. Instead, they appeared to want only to demonstrate that capability. In 2004, the US National Intelligence Council warned that the Russian authorities had discovered in 2002 that “two Chechen sabotage and reconnaissance groups reportedly showed a suspicious amount of interest in the transportation of nuclear munitions”.⁵ Here again, the Chechen rebels may have been signalling their interest in nuclear terrorism without actually carrying through on the threat for fear of reprisal. However, if the Chechen rebels become more radicalised through their close contacts with al-Qaeda and other Islamic extremist groups, they may eventually carry out an act of nuclear or radiological terror.

Defining Nuclear Terrorism

There has been controversy about what constitutes nuclear terrorism. While some analysts strictly define it as use of a nuclear explosive, others include radiological attacks designed to cause harm through release of radiation without producing a nuclear detonation. Terrorist use of a nuclear explosive could take two forms. First, the terrorist group could seize and detonate an intact nuclear weapon originating from a military arsenal. Second, the group could acquire enough weapons-usable fissile material—highly enriched uranium (HEU) or plutonium—to make and explode a crude nuclear bomb, termed an “improvised nuclear device”. Radiological attacks could involve the sabotage of, or an attack on, nuclear facilities such as nuclear power plants and spent-nuclear-fuel storage pools, or the use of radiation dispersal devices, one type of which is popularly known as a “dirty bomb”.

 

Many people would probably lump all of these attacks together as nuclear terrorism because each type involves a “nuclear asset”. However, the likelihood of these acts varies considerably. Experts have reached consensus that terrorist detonation of nuclear explosives is far less likely to occur than terrorist use of a dirty bomb or terrorist attack on a nuclear power plant. In particular, making even a crude nuclear explosive is much harder to do than building a dirty bomb. Fissile materials to power nuclear weapons are far less available than potent radioactive sources to fuel dirty bombs. Intact nuclear weapons are less prevalent and usually much more secure than either weapons-usable fissile material or radioactive sources. Building even a crude nuclear explosive demands technical skills that are more advanced than those necessary for making a dirty bomb, which could be as simple as a radioactive source coupled to a stick of dynamite. As regards attacks on nuclear facilities, it would be difficult to cause a release of radiation by such means because of the strong security typically surrounding commercial nuclear sites and because of the safety systems that can mitigate the effects of an attack. Nonetheless, compared to the multiple challenges in acquiring or making a nuclear weapon, a terrorist attack against a nuclear power plant appears less daunting.

 

Nuclear and radiological terrorism also differ markedly in their consequences. Although dirty bombs could cause dozens of fatalities from the conventional blast, they would typically kill few, if any, people in the near term from exposure to ionising radiation. Over a period of several years, however, many people might develop cancer as a result of this exposure. Experts have labelled dirty bombs, or radiation dispersal devices, as weapons of mass disruption because the main effects would probably be psychological and social disruption caused by fear of radiation and by radioactive contamination that could shut down large areas of a city. Similarly, a successful terrorist attack on a nuclear power plant or radioactive-waste storage site would release radiation, spark fear, and cause widespread disruption.

 

While both types of radiological terrorism—the detonation of a dirty bomb, or assaults on nuclear facilities—could harm the nation under attack and might hurt the global economy, they would pale in significance compared to a nuclear explosion in a city. Such a transformative event would immediately kill upwards of tens of thousands of people and completely devastate a vast urban area. The ripple effects would spread throughout the globe. Panic in the financial sector could result in the loss of trillions of dollars. Fear of additional nuclear explosions in other cities around the world could cause loss of confidence in government.

Prevention

Before a nuclear or radiological attack can occur, a chain of events must unfold. First, a terrorist group must decide to commit extreme acts of violence. These terrorists must then decide to employ nuclear or radiological means in the violent act. Next, the terrorist group must acquire the nuclear or radiological asset: an intact nuclear weapon, sufficient amounts of HEU or plutonium to make an improvised nuclear device, or a potent radioactive source to fuel a dirty bomb. If the terrorists decide to attack or sabotage a nuclear facility, they must identify a vulnerable site and determine how to access it. If they have obtained an intact nuclear weapon, they may have to determine how to unlock special security codes embedded in the weapon in order to detonate it. If they have acquired weapons-usable fissile material, either HEU or plutonium, they must obtain the skills needed to build and explode an improvised nuclear device. If they have decided on making a dirty bomb, they have to determine how much effort they want to spend on designing an effective weapon delivery system. A popular misconception is that a dirty bomb must use conventional explosives to disperse the radioactive material. It is not revealing secrets to point out that there are many dispersal methods other than explosives. Finally, for a terrorist group to execute its plan without being thwarted, it must deliver the nuclear or radiological weapon to a target or gain access to a nuclear facility to try to release radiation.

 

Breaking any link in the chain will stop the act of terrorism. A defence-in-depth, or multi-layered prevention strategy, works to sever every link. This strategy harnesses intelligence to identify nuclear terrorist organisations; law enforcement and military action to apprehend or destroy the terrorists; the physical guarding of nuclear weapons, fissile material, radioactive material, and nuclear facilities housing highly radioactive substances; the dismantling of excess nuclear warheads; the conversion of weapons-usable fissile material into non-weapons-usable forms; and radiation detection systems to help intercept nuclear explosive material and potent radioactive sources at border crossings and near high-value targets. Even though each layer of defence may not provide perfect protection, the combination of the layers accumulates into an increasingly effective security system. The challenge is determining where increased protection is needed and where it can achieve the greatest risk reduction in the shortest amount of time.

 

An anti-terrorism strategy aimed at eliminating terrorist groups could disrupt the long-term planning and dismantle the safe havens these groups would probably need to carry out a nuclear or radiological attack. This method, however, could backfire by stimulating the growth of terrorist groups as sympathetic supporters swell their ranks. Moreover, terrorists and their potential recruits form a far more extensive pool than the sites containing nuclear weapons, fissile material, radioactive sources, or nuclear facilities. Consequently, concentrating on blocking the remaining steps in the causal chain has a bigger risk-reduction payoff.

 

Governments and international organisations have been working to put in place a multi-layered defence system to combat nuclear terrorism. The most effective layers of this defence network are to secure and to eliminate, where appropriate, nuclear and radiological assets. The discussion of government and international programmes that follows concentrates on these two layers.

State Arsenals

There are about thirty thousand nuclear weapons in at least eight nations: Britain, China, France, India, Israel, Pakistan, Russia, and the United States. (Although North Korea said in February 2005 that it has nuclear arms, it has not unambiguously demonstrated this capability.) All but about one thousand of these weapons are contained in two countries: Russia and the United States. While the details of security practices are unknown, nations that have invested significant resources in developing nuclear weapons presumably have put in place rigorous security to guard them. Nonetheless, certain of these nations stand out in terms of reported security concerns.

 

After the break-up of the Soviet Union, there were fears that Russia could lose control of its nuclear weapons. The United States soon offered security assistance. In 1991, Senators Sam Nunn and Richard Lugar launched the Co-operative Threat Reduction (CTR) programme, often called the Nunn–Lugar programme. The CTR programme was not initially formed to tackle the threat of terrorism with weapons of mass destruction. Its original mission was to assist Russia in meeting its obligations under the first Strategic Arms Reduction Treaty to dismantle weapons systems that could fire nuclear missiles at the United States. In addition, through the CTR programme, the US Defence Threat Reduction Agency is working with Moscow to enhance the security of Russian nuclear weapons in storage or transport. In parallel, the Weapons Protection, Control, and Accounting programme of the US Department of Energy has worked with the Russian Navy and Ministry of Atomic Energy as well as the Russian Strategic Rocket Forces to secure nuclear arms.

 

Despite these security efforts, there remain major vulnerabilities with certain types of Russian nuclear weapon. In particular, Russia has not fully implemented its pledges under the 1991–2 Presidential Nuclear Initiatives to eliminate specific classes of tactical nuclear weapon and to remove all but one remaining class to highly secure central storage. In 1991, US president George H. W. Bush and Soviet president Mikhail Gorbachev launched the Presidential Nuclear Initiatives to reduce and secure American and Soviet tactical nuclear weapons; soon afterwards, in early 1992, President Bush and President Boris Yeltsin of Russia ordered another round of reductions. While these efforts were laudable, they were, in effect, only gentlemen’s agreements. So far, there have been no binding arms-control agreements to ensure elimination of tactical nuclear weapons. These weapons are especially dangerous from the perspective of nuclear terrorism because they tend to be more portable than strategic nuclear weapons. Another increased vulnerability is that older types of tactical nuclear weapon may lack internal security codes, called permissive actions links (PALs). In order to enable a PAL-equipped weapon for detonation, a special code must be entered.

 

Moscow has resisted moving its deployed tactical nuclear weapons to secure central storage. This issue is partly linked to the presence of US tactical nuclear weapons in Europe. At present, the United States is the only country to have nuclear weapons based in another country’s territory. Recently, NATO members Belgium and Germany raised the issue of reconsidering the basing of US nuclear weapons on their soil. For its part, the United States has resisted removing its nuclear arms from Europe. Arguably, a precedent exists. Soon after the end of the Cold War, the United States repatriated its nuclear weapons stationed in South Korea to support efforts to rid the Korean peninsula of nuclear arms. While admittedly this step has not by itself convinced North Korea to forgo developing a nuclear arsenal, the United States could make removal of its nuclear arms from Europe directly contingent on Russia’s fully implementing the Presidential Nuclear Initiatives and taking further steps to reduce and secure its tactical nuclear arsenal, which, according to unofficial estimates, far exceeds in size its US counterpart.

 

Although Pakistan has a much smaller nuclear arsenal than the United States or Russia, many analysts have expressed grave concern about the security of its nuclear weapons. The presence of al-Qaeda and other Islamic extremists in Pakistan and the surrounding region has intensified these concerns. At least two Pakistani nuclear scientists met Osama bin Laden in 2001, but they reportedly did not provide him with nuclear weapons or detailed knowledge about how to make such weapons. Another concern is that some officers in Pakistan’s Inter-Services Intelligence agency are sympathetic to al-Qaeda’s cause and during a political crisis might assist terrorists in gaining access to nuclear weapons.

 

There are significant constraints on providing nuclear security assistance to Pakistan. One is the Pakistani government’s disinclination to open its nuclear complex to outsiders. Another is that, although Pakistan has nuclear arms, it never signed the NPT and under its terms is considered a non-nuclear-weapon state. Parties to the NPT are not permitted to assist non-nuclear-weapon states with acquiring nuclear explosives. While the United States has reportedly provided nuclear security assistance to Pakistan, such aid, in conformity with the NPT, is designed not to improve the operational capability of Pakistan’s nuclear arsenal.

Improvised Nuclear Devices

Without HEU or plutonium, terrorists cannot make an improvised nuclear device. Unfortunately, global inventories of these weapons-usable materials are rather large. According to the Institute for Science and International Security, a non-governmental organisation that estimates global stockpiles of HEU and plutonium, there are about 262 metric tons of military plutonium, about 330 metric tons of civilian plutonium that has been separated from spent nuclear fuel, 1,850 metric tons of military HEU, and 50 metric tons of civilian HEU, as of the end of 2003 when the latest estimate was compiled. This total amount of fissile material worldwide could fuel tens of thousands of crude nuclear bombs.

 

Of the military plutonium, Britain, Russia, and the United States have declared 107 metric tons as excess to their defence needs, but none of this material has been eliminated. Russia has declared 500 metric tons of HEU as excess to its defence purposes. To date, Russia has converted about half of that amount into non-weapons-usable reactor fuel through the Megatons-to-Megawatts deal with the United States. Over the next ten years, the conversion of the remaining 250 tons will take place. The United States, prior to November 2005, had set aside 174 metric tons of HEU as excess to weapons purposes, but had converted only about 50 tons of this material. In November, US energy secretary Samuel Bodman declared an additional 200 metric tons of HEU as unneeded for weapons, but only 20 tons are slated for conversion to non-weapons-usable form.

 

Of the two nuclear-weapons-usable materials, HEU is much more dangerous than plutonium from the perspective of nuclear terrorism. Only HEU can fuel the simplest and easiest-to-build nuclear bomb, a gun-type device like that used against Hiroshima in August 1945. The gun-type device simply fires one “bullet” or sub-critical lump of HEU into another sub-critical lump to form a supercritical mass to initiate an explosive chain reaction.

 

Plutonium, on the other hand, cannot power a high-yield gun-type bomb. If terrorists acquired plutonium and wanted to make a nuclear weapon, they would have to build an implosion-type device. This weapon squeezes either plutonium or HEU into a supercritical, very-high-density state to detonate the explosion. Smoothly squeezing fissile material demands relatively complex technical skills and equipment, beyond the reach of most terrorist groups. Given these considerations, securing and eliminating HEU should take priority over securing and eliminating plutonium.

 

Nonetheless, because nation-state proliferators could make plutonium-powered nuclear bombs, it is important to ensure that plutonium stockpiles are highly secure. Those countries possessing or producing plutonium should make it a priority to minimise the amount of plutonium available for use in weapons. Unfortunately, civilian plutonium stocks are growing at the rate of 5 to 10 metric tons annually because the plutonium is being separated from spent fuel faster than it is being consumed as new reactor fuel.

 

While the United States, Russia, partner governments, and the International Atomic Energy Agency (IAEA) have worked to secure and reduce the holdings of HEU, much more remains to be done. Most of the estimated 1,850 metric tons of military HEU is in Russia and the United States. Under the aforementioned Megatons-to-Megawatts deal between the two countries, Russian weapons-grade HEU is converted into low-enriched reactor fuel and sold to the United States. Although there have been renegotiations over the pricing of the deal, Russia still stands to earn $8 billion or more from the purchase agreement. Currently, about half of the electricity generated in the United States by nuclear power plants derives from Russian HEU. Thus, the deal has been beneficial from the standpoints of promotion of nuclear disarmament, prevention of nuclear terrorism, production of electricity, and profits earned by Russia.

 

Given this success, many analysts have called for the deal to be expanded to include several hundred additional tons of Russian HEU, and for the conversion of the initial 500 tons to be speeded up. However, the United States and Russia have yet to broker another agreement, and it might not be technically possible to accelerate the current conversion process. One apparent financial impediment is the concern that flooding the market with an abundance of this reactor fuel could upset global uranium fuel prices. In fact, some US government officials in charge of nuclear security have expressed more concern over stabilising the uranium market than they have over eliminating dangerous HEU. In contrast, some nuclear industry officials have been proposing ways to eliminate more HEU and stimulate the growth of nuclear energy without harming the uranium market. One such proposal would involve building a generation of commercial nuclear power plants dedicated to consuming converted HEU. Another idea is to place excess converted HEU into a strategic uranium fuel reserve to be consumed when market conditions are favourable.

 

Besides finding ways to eliminate more Russian HEU, the United States should seek to convert as much of its own military HEU stocks as possible into non-weapons-usable forms. One of the major obstacles to doing so is the US Navy’s refusal to stop using weapons-grade HEU to fuel its nuclear reactors on submarines and aircraft carriers. While a number of nuclear-powered navies have moved away from using weapons-grade HEU as fuel, those of the United States and Britain remain committed to this energy source.

 

Efforts to secure HEU and reduce its usage must extend beyond Russia and the United States. Relative to those two countries, Britain, China, France, India, and Pakistan possess small, but still significant, military HEU stocks. (North Korea may also have a military HEU programme, but there is considerable uncertainty about its extent.) Some forty countries have small (but still weapons-usable) amounts of civilian HEU. Civilian HEU is used in scientific research reactors, commercial isotope-production reactors, floating power plants, and icebreakers. Of these uses, much international effort has focused on converting research and isotope-production reactors to utilise low-enriched uranium and on repatriating HEU fuel in both fresh and spent forms back to the country of origin, usually Russia or the United States.

 

The Global Threat Reduction Initiative (GTRI) is one of the major programmes to facilitate this conversion of reactors and repatriation of HEU. Launched in May 2004, GTRI combines many nuclear and radiological security programmes under one umbrella. The US Department of Energy leads the US GTRI efforts in partnership with the Russian Atomic Ministry and the IAEA. With respect to HEU security, GTRI aims to repatriate to Russia by the end of 2005 all fresh HEU fuel that the former Soviet Union and Russia provided to some twenty countries. This material raises significant concerns because many of the reactor sites containing HEU do not have rigorous security. Although spent (or irradiated) HEU fuel can be harder to make into a nuclear bomb because of radiation hazards, much of the spent fuel from research reactors is only lightly irradiated, and therefore might be susceptible to theft or diversion. Consequently, GTRI plans to repatriate to Russia all spent HEU fuel derived from Soviet and Russian HEU. Similarly, the United States is trying to repatriate HEU fuel it provided to dozens of countries. However, in early 2004, the US Department of Energy warned that the United States is unlikely to recover half of the approximately 5,200 kilograms of HEU earmarked for return under the Foreign Research Reactor Spent Fuel Acceptance Programme. The Russian HEU repatriation programme also lags seriously behind schedule. While fresh Russian HEU fuel has been successfully returned from Serbia, Romania, Bulgaria, Libya, the Czech Republic, and Latvia, there are several other countries where HEU needs to be secured.

 

The nuclear security agreement signed in February 2005 in Bratislava, Slovakia, by President George W. Bush and President Vladimir Putin could remove obstacles to GTRI implementation and improve physical security over HEU and plutonium in Russia. In particular, the agreement calls for Russia and the United States to form working groups that will periodically meet to resolve problems. The first working-group report was delivered in June 2005. One of the stumbling blocks addressed by the working group is the issue of US access to two Russian sites containing large amounts of HEU. These sites are plants for the assembly and disassembly of weapons. Understandably, the Russians are particularly concerned about giving foreigners access to these sensitive sites, even though American security assistance hinges on gaining assurance that those sites are well protected.

 

Under the US–Russian Material Protection Control and Accountancy programme, the United States has been working with Russia to upgrade security at Russian locations containing weapons-usable fissile material. To date, about half of this material has received security upgrades through this programme. More encouragingly, about 70 per cent of facilities have received upgrades. Once the weapons-assembly and weapons-disassembly plants have put in place security upgrades, the Material Protection Control and Accountancy programme will have practically achieved its goal of upgrading the security of all Russian nuclear-weapons material by the end of 2008.

 

While the end goal is in sight, a substantial amount of work remains to be done. It is important to keep in mind that even if all HEU and plutonium were locked up, the risk of nuclear terrorism would have been reduced but not eliminated. Terrorists could still try to enlist the help of insiders working at the containment facilities to gain access to the material. Ultimately, the most effective threat-reduction effort is to eliminate as much of the material as possible.

Nuclear Facilities

Terrorists could target a variety of nuclear facilities. About 440 commercial nuclear power plants are operating in thirty-one countries; most power plants contain one or more spent-nuclear-fuel pools; about 280 research reactors are in commission in fifty-six countries; civilian plutonium-reprocessing plants are in use in Britain, France, India, Japan, and Russia; and there are military reprocessing facilities in India, Israel, North Korea, Russia, and Pakistan.

 

The facilities vary considerably in their vulnerability to attack or sabotage and in their holdings of radioactive material that a successful terrorist attack could release. For instance, commercial nuclear power plants, spent-fuel storage pools, and plutonium-reprocessing facilities contain huge amounts of radioactive material. On the other hand, research reactor sites usually have much lower rates of power output than commercial reactors, and thus typically hold smaller amounts of radioactivity in their reactor cores. However, physical security at research reactor sites is generally much weaker than at commercial power plants.

 

High physical security tends to deter terrorists. Virtually all nuclear power plants and many other nuclear facilities use defence-in-depth safety and security systems. Thus, terrorists would usually have to penetrate more than one defensive layer to release radiation from these sites. Unfortunately, vulnerabilities are present. Most nuclear facilities are not hardened to withstand the crash of a large aeroplane. Other locations might be vulnerable to land or water-borne attacks.

 

The ultimate layer of defence at most nuclear power plants is a containment structure. Surrounding the reactor core and other vital plant components, containments are usually made of reinforced concrete and are designed to prevent the escape of significant amounts of radioactivity in the event of an accident. While many containment structures are not designed to withstand the penetration of contemporary jet aircraft moving at high speeds and loaded with highly energetic fuel, the US nuclear industry has recently performed computer simulations that indicate that containments could in principle protect against this means of attack. Unfortunately, some commercial reactors lack containments. In particular, Russia has eleven Chernobyl-type reactors without containments; Lithuania also operates a Chernobyl-type plant; and Britain has several MAGNOX reactors that do not use containments. Many research reactors also lack containments.

 

In sum, the security of many nuclear facilities could be improved. However, the nuclear industry by and large has taken security seriously. Terrorists seeking to cause the release of radiation resulting in loss of life and widespread disruption will probably try to seize more readily accessible radioactive materials used daily in scientific research and commercial applications.

Radiation Dispersal Devices

Radioactive material is widely used—for example, in medicine to diagnose and treat disease, in industry to measure and control the thickness of steel plates, in agriculture to control insect pest populations by releasing insects that have been sterilised by radiation, and in scientific research. Radioactive material comes in a variety of chemical and physical forms, such as powders, aerosols, or in solution.

 

The number and users of radioactive sources worldwide are unknown, largely because in many countries radioactive material is subject to little or no government oversight. Even in the United States, where a robust radiation safety oversight programme has been in place since the Second World War, the inventorying of radioactive sources has been the responsibility of licensees; until recently, there was no national inventory database, nor was the movement tracked of most radioactive material between licensees and in commercial shipping.

 

Notwithstanding the current lack of data, the magnitude of radioactive sources and their users worldwide can be gauged from recent estimates and reports. In the United States, there are an estimated 1.8 million sources used by 157,000 users. In 2000, the European Commission reported 110,000 sources in use by European Union member states and 30,000 disused sources. In 2005, China reported that it had identified 140,000 facilities using more than 102,000 sources, and that it had 263,000 disused sources awaiting disposal. Russia has at least thousands of disused sources. Many of these have become “orphaned” sources, which are outside regulatory control and thus pose especially serious safety and security problems. Of particular concern are several hundred Russian potent radioisotope thermal generators, which are at risk of theft or diversion by criminals or terrorists.

 

The sources covered by these figures vary widely in terms of quantity of radioactive material and hazard. While they are sufficiently hazardous to merit regulatory oversight, most are unsuitable for terrorism purposes (although this may not be apparent to terrorists, who may nonetheless attempt to steal or divert them). Even so, the number of “high-risk” sources is significant. The IAEA has estimated, for example, that more than 10,000 medical teletherapy units are in use, as are 300 large irradiator units, and that 12,000 industrial radiography sources are supplied annually.

 

Also of concern is the relatively large number of disused sources. Public fears and political issues have made the disposal of disused, unwanted radioactive sources difficult and expensive. Sometimes no avenue for disposal exists. Consequently, licensees place disused sources into unplanned, long-term storage, increasing their vulnerability to theft and loss.

 

World bodies such as the International Commission on Radiological Protection (ICRP) and the IAEA have recommended safety standards that provide guidance for users and national regulatory bodies. Historically, ICRP and IAEA standards have always included consideration of security as part of the radiation protection system. Radioactive materials that can be used in nuclear explosive devices are limited to a few radioactive isotopes, such as uranium-235 and plutonium-239. Therefore, besides radiation safety requirements, their use is subject to additional security measures called safeguards. In the post–11 September world, a new paradigm has taken hold and prompted increased international attention and security to prevent deliberate seizure of radioactive material by potential terrorists who may have little concern for their own safety.

 

A cornerstone of the ICRP and IAEA radiation safety standards is the principle that any use of a radiation source be “justified”. Justification should include consideration of alternative technologies. For example, in the United States, steel mills have replaced radioactive gauging devices with alternative technologies using thermal detection or eddy current measurements. This replacement avoids the risk of radiation exposure and contamination should molten steel strike the gauge. The threat of terrorism using radioactive sources has become another reason to consider alternative technologies.

 

Another aspect of justifying the use of a radioactive source is consideration of disposal responsibilities and costs when the source is no longer used. Lack of disposal pathways for unused sources increases security risks. Returning sources to suppliers may not be possible because suppliers go out of business or may be prohibited by licensing requirements from accepting returned sources. This matter had become an international concern well before 11 September. It remains a problem and the lack of resolution increases the risk of radiological terrorism.

 

Radiation safety and security requirements apply to the transportation of radioactive material. International shipments must meet international standards for packaging and marking, labelling of the transporting vehicles, and, when applicable, additional requirements specific to security. Most national bodies regulating transportation use the same requirements within their borders. Additional measures are being put in place by national customs and port-of-entry agencies to detect illicit shipments of radioactive material.

 

The ICRP and IAEA radiation safety standards provide recommendations applicable throughout the life-cycle of a source, beginning with the production of radioactive material in a nuclear reactor (or, in some cases, a particle accelerator), the fabrication and assembly of a radioactive source incorporating the radioactive material, its use in a specific application, final disposal after use, and transportation of the radioactive material during each of these points in the life-cycle. The challenge now is to enhance the security of radioactive sources and integrate seamlessly the enhancements into the existing infrastructures governing the use of radioactive material. The IAEA has taken steps to facilitate this.

 

In 1998, the IAEA sponsored in Dijon, France, an international conference on the safety and security of radioactive sources. The European Commission, World Customs Organisation, and Interpol co-sponsored the meeting. The incentive for the conference was the increasing number of serious accidents involving radioactive sources worldwide. Another factor was the increasing number of reports of illicit shipments of radioactive materials, especially in European countries bordering the former Soviet Union. As a result of the conference, the IAEA members approved an action plan to enhance the safety and security of radioactive sources. The final plan was presented to the 2001 IAEA general conference, which approved it on 10 September 2024. The prescient work by IAEA staff positioned the agency well to respond to the increased attention given to radioactive-source security in the aftermath of the 11 September terrorist attacks.

 

To identify high-risk radioactive sources, the IAEA had developed a categorisation system based upon the radiological risk sources pose to human health. After 11 September, the system was revised to reflect the increased emphasis on security. Existing IAEA initiatives to assess and strengthen national radiation safety programmes were also expanded.

 

Another major undertaking that predated the 2001 general conference was the drafting in September 1999 of a “Code of Conduct on the Safety and Security of Radioactive Sources”. The code provides an internationally agreed-upon set of principles and identifies critical components of national programmes for improving the safety and security of radioactive sources. Such an agreement is needed because the production, transportation, use, and disposal of radioactive sources are international activities. The IAEA approved the latest revision of the code in 2003, strengthening security issues. The code is not legally binding, but seventy-four countries to date have notified the IAEA of their intent to implement it.

 

The code sets out steps that every state should take to enhance the security of radioactive sources within its territory. Although some security enhancements are obvious first steps—establishing national inventories, tracking radioactive sources, tightening import and export controls, expanding radiation monitoring at borders and critical transportation nodes—care is needed to ensure that less obvious needs do not fall through the cracks. An outstanding example is preventing insiders or their accomplices from diverting or stealing a radioactive source. An insider can be a person employed by, or otherwise having access to, a facility possessing radioactive sources, or someone having sufficient knowledge of the regulatory security system to identify gaps and weak points. Given the widespread use of radioactive material around the world, the number of persons in the insider category is in the tens if not hundreds of thousands. The number of insiders actually willing to assist in the theft or diversion of a radioactive source may be small, but that is not the point.

 

In the United States, there have been cases of persons using inside information to obtain radioactive material fraudulently, in one case resulting in a felony conviction, and in another an order by the regulating agency prohibiting the person from engaging in licensed activities. In yet a third case, a person was convicted on multiple misdemeanour counts of having used radioactive material in an unsafe manner and was denied a licence when he reapplied for one. Alarmingly, information on these perpetrators has not been effectively shared between the different agencies in the United States responsible for radiation safety regulation. As a result, the violators can relocate to a different state (and jurisdiction) and be licensed or gain employment at a licensee’s facility. Even when information is exchanged, an agency having jurisdiction in one state might not have the requisite legal authority to take action on information provided by another regulatory agency. To prevent insiders and their accomplices from exploiting international loopholes, governments must increase efforts to exchange information about regulatory practices, continue to tighten export controls, and institute tracking of known wrongdoers.

 

The IAEA is to be commended for having had the foresight to identify security of radioactive sources as an international priority before concerns about radiological terrorism increased after 11 September. It continues to be a leader in this respect. Also to be commended are the seventy-four countries that have committed themselves to implementing the IAEA Code of Conduct.

 

Even so, more can and should be done. In particular, the basis of the IAEA’s categorisation system for identifying high-risk radioactive sources should be expanded to include the major consequences of a radiological terrorist attack, which are not the relatively small number of deaths it would probably cause, but its psychosocial and economic impacts, which could be significant. In addition, greater consideration must be given to technological alternatives to radioactive sources and to alternative types of radioactive material that are of lesser potential utility for radiological terrorism. There needs to be a stronger commitment to providing safe, affordable methods of disposal for disused sources and to recovering “orphan” sources—those which are not under regulatory control, either because they have never been under such control, or because they have been abandoned, lost or stolen. Finally, steps should be taken to ensure that the criminal or administrative penalties applied to wrongdoers are universally enforced.

A Global Challenge

The prevention of nuclear and radiological terrorism demands a global response. The United States is not the only potential target of such attacks. A nuclear or radiological terrorist attack in virtually any country would have tremendous repercussions worldwide. Positively, the global community is acting to avert nuclear and radiological terrorism. As noted earlier, the IAEA Code of Conduct and the GTRI are important international mechanisms for this purpose. In addition, there have been other encouraging global developments since the 11 September terrorist attacks.

 

In 2002 at the G8 summit, the United States and other members of the Group of Eight major industrialised countries launched the “Global Partnership against the Spread of Weapons and Materials of Mass Destruction”, which seeks to raise $20 billion over the course of ten years to reduce the threats posed by such weapons. The United States pledged to provide $10 billion and asked other donors, inside and outside the G8, to raise an additional $10 billion. The pledged amounts still fall one to three billion dollars short of the $20 billion target (depending on how much of Russia’s “in-kind” contribution of equipment and expertise should count towards meeting the monetary goal). A greater concern is that much of the pledged money has not been spent on actual projects. Furthermore, the Global Partnership has yet to prioritise which projects need the most urgent attention.

 

In April 2004, the United Nations Security Council unanimously approved Resolution 1540, which imposes a legally binding commitment on all UN member states to address the threats posed by the proliferation of, and terrorism using, weapons of mass destruction. Specifically, the resolution calls on states to “enforce appropriate effective laws” to prohibit any non-state actor from acquiring weapons of mass destruction or the materials to make them. While laudable, the resolution unfortunately does not clearly define what is meant by “appropriate effective” laws and other controls. This shortcoming highlights the need for rigorous global standards to protect nuclear, radiological, and other materials of potential use in manufacturing weapons of mass destruction.

 

More recently, in July 2005, delegates from eighty-nine countries acted to improve the standards within the Convention on the Physical Protection of Nuclear Material (CPPNM). The original CPPNM applied only to the physical protection of nuclear materials during international transport. The amendments, if approved by two-thirds of the parties to the convention, would expand coverage to nuclear material in domestic use and storage, and would address the threats of the sabotage of nuclear facilities and the theft of nuclear material.

 

In September 2005, the United Nations opened for signature the International Convention for the Suppression of Acts of Nuclear Terrorism. It provides the legal framework for greater international co-operation in the investigation, extradition, and prosecution of nuclear and radiological terrorists. The global community should move quickly to enact this convention universally and should continue to strengthen its provisions. With these sustained efforts and swift action, the world may yet outrace nuclear and radiological terrorists.

Endnotes

1. Brian Michael Jenkins, “The Future Course of International Terrorism”, Futurist, July/August 1987.

 

2. See Imperial Hubris: Why the West Is Losing the War on Terror (Washington, D.C.: Brassey’s, 2004), pp. 154–8, and references therein. The book was published anonymously, but the author was subsequently identified as Michael Scheuer, a former CIA analyst.

 

3. Hamid Mir, “Osama Claims He Has Nukes: If US Uses N-Arms It Will Get Same Response”, Dawn (Karachi), 10 November 2001.

 

4. Jerrold M. Post, “Differentiating the Threat of Radiological/Nuclear Terrorism: Motivations and Constraints” (paper presented to the IAEA symposium on international safeguards, special session on combating nuclear terrorism, Vienna, 2 November 2024).

 

5. US National Intelligence Council, “Annual Report to Congress on the Safety and Security of Russian Nuclear Facilities and Military Forces”, Washington, D.C., December 2004, p. 6.