Nuclear Terrorism
Annette Schaper 
The smoke over Manhattan did not reach the size of a mushroom cloud, however, the number of casualties is close to that of a small nuclear explosion. The scenario of nuclear weapons in the hand of terrorists is a nightmare that is being discussed in the media from time to time.
So far, the construction of a nuclear weapon by terrorists was considered to be unklikely. It was believed that that terrorists have an interest to create some sympathy for their cause and to avoid too many innocent victims. After 11 September 2001, this view must be questioned. The terrorists aimed at as many deaths as possible. Future assassinators might develop the perverse ambition to top the number of casualties of 11 September. Weapons of mass destruction, especially nuclear weapons, would be the next step of escalation. In 1998, Bin Laden admitted in an interview that he would not exclude their use and that he perceives it as his "religious duty" to use them.
Will it be possible for terrorists to create a nuclear explosion? Which other kinds of nuclear terrorism could be pursued by them? How can these dangers be prevented? This article undertakes to discuss these questions in a realistic way.
The Know-How
During the Manhattan project in World War II, thousands of the best scientists and workers participated in building the first crude nuclear explosive devices. It took them several years and tremendous efforts. Should this not make it clear that a similar effort would be beyond the rearch for a terrorist group, even a dedicated and rich one like Bin Laden's al Qaeda? However, there is a big difference: the Manhattan physicists did not even know whether a nuclear explosion was possible at all. They had to do all fundamental research and all basic inventions from scratch. Today, in contrast, not only the basics of the functioning of nuclear weapons are public knowledge, but also the details of the underlying theories, non the least because of fifty years experience with civilian nuclear energy. Much information can be found in student textbooks and even on the Internet.[1] Much knowledge contained in these publications is based on declassified information.[2] In contrast to a nuclear reactor, the physics of a simple nuclear explosive device is easy and can be understood by an ordinary physics student after a few years of study.
Engineering
However, there is still a big difference between the theoretical and the practical engineering level which means that a terrorist group would need a few years for experimenting, even if among them are physicists who studied nuclear engineering for several years. Many technical details of the ignition of a nuclear device are still classified and must be reinvented. By experimental work, the ignition technology can be developed even without the nuclear materials plutonium or highly enriched uranium (HEU). But to do so, an experimental site and some laboratories are needed which are hardly mobile because the experiments are rather huge and require many conventional test explosions.
This fact has two important implications: Firstly, a terrorist group cannot build a nuclear explosive device without the protection of a state, e.g. Afghanistan, over several years, because such experiments and their location would soon be noticed by the authorities in the area where they take place. Secondly, once a terrorist organisation completed that work and studied the milling of uranium or plutonium, it can build the device rather quickly when it gets hold of weapon-usable nuclear materials. There is a certain probability that this second step could be performed even without the protection of a state.
Sometimes it is claimed that with HEU not much engineering effort is necessary because it suffices to drop two uncritical masses onto each other which will then combine to an overcritical mass and explode. However, this view must be contradicted: most certainly, such a procedure would result in a very minor explosion with a yield not higher than that of a conventional detonation. Therefore, the terrorists must study how to fire the two parts at each other rather quickly which is less trivial than it seems.
This technology, the so-called guntype method, was used for the Hiroshima bomb, and also by South Africa who had built six nuclear bombs before dismantling them and joining the community of non-nuclear weapon states. If terrorists choose the gun-type method, they need HEU. Plutonium would be of no use for them because it needs a more sophisticated ignition technology, the so-called implosion method, that was used for the Nagasaki bomb and that is currently being employed in the arsenals of all nuclear weapon states.
The implosion method works with both, HEU and plutonium, and - very importantly - with much smaller quantities than the gun-type method. With this method, a hollow sphere of HEU or plutonium is compressed by surrounding conventional explosives that are arranged in a special manner, called "explosive lenses". In contrast to the gun type method, the implosion is much faster and compresses the material to a higher density. As a result, a so-called over-critical mass is created, and the burn-up of the fissile material is more efficient. The development of the explosive lenses needs a series of experiments and is not trivial, although possible. Probably, a terrorist group would need a few years before a workable device were ready. Upon acquisition of the fissile material, completion would then be possible in a rather short time.[3]
Aquisition of Nuclear Materials
What is more difficult than the construction of the ignition mechanism is the acquisition of the nuclear material. It would be impossible for terrorists to produce it on their own, so they would seek to steal it or to buy it on the black market. They would need roughly 20 kg HEU or 10 kg plutonium for one implosion device; the amount for one gun-type device would be very roughly 50 kg.[4] Wordwide there exist about 250 tonnes military plutonium, about 1,700 tonnes military HEU, and additional quantities for civilian purposes.[5] The civilian material in non-nuclear weapon states is subject to safeguards by the International Atomic Energy Agency (IAEA) which have triggered rather high standards of material protection, control, and accountancy. In all EU states, including the nuclear weapon states Britain and France, the stockpiles are additionally subject to Euratom safeguards with equally high standards, and illegal diversion is rather unlikely.
But problems arise from states whose protective measures are below these standards, the most prominent being Russia. In recent years, several thefts of nuclear weapon-usable material were reported, including quantities of a few kilograms. In 1998, Russian officials confirmed a conspiracy inside a nuclear weapon facility with the purpose to steal 18.5 kg HEU. The diversion was prevented just before the material left the plant.[6] It is possible that there were additional cases which have never been discovered. The standards for material accountancy and protection in Russia are still far below those in the West, although international efforts to work on the problems have been initiated.
Countries of Concern
It is not possible that terrorists produce weapon-usable materials by themselves. This could be done only by a state with appropriate recources. But it may be doubted whether such a clandestine program would remain undetected for a long time. Acquisition and construction activities are being monitored more intensively than some decades ago. All enrichment and reprocessing activities release traces in the environment that can be detected in case of suspicion. IAEA safeguards have been reformed since Iraq's clandestine acquistion program were detected. As a result, much more information is gathered and more international collaboration takes place.
Nevertheless, in addition to Russia, some other countries might be sources of nuclear materials for terrorists. An example is Iraq. Although all enrichment plants were destroyed after the Gulf war and all known nuclear material was transfered from the country, the IAEA controls ceased some years ago but the weapon-relevant knowledge is still present. There are warnings that Iraq might be able to produce a bomb within months if it gets hold of nuclear material, e.g. by smuggling. It cannot be excluded that Iraq in such a case might sponsor terrorists to deliver such a bomb.[7]
Before South Africa stopped its nuclear weapon ambitions, it might have been a source of smuggeled nuclear material. Meanwhile, it is subject to IAEA safeguards.[8] There is a certain likelihood that criminals still possess HEU originating from South Africa. Indeed, in 1993 and 1994, allegedly there was an attempt by Bin Laden to buy South African HEU. This was testified by a former aide of Bin Laden, Jarmal Ahmad al-Fadl, a Sudanese who was involved in the early stages of this purchase. It is unknown whether the deal was completed.[9]
Iran is also frequently named as a potential nuclear weapon aspirant, especially by US sources. During the last decade, several suspicious events have been reported, including rumours that the Iranian government tried to buy HEU, and Iranian interest in enrichment technologies. But no suspicion has ever been confirmed. Meanwhile it may be assumed that there is a strong fraction that is interested in normalization of Iran's relation with the West and would therefore oppose any support of terrorists.
Nuclear Weapons and Materials from Pakistan?
A special case is Pakistan that possesses a small arsenal of nuclear weapons and that has produced substantial quantities of HEU. Not much is known about the security of its nuclear complex. The Pakistani government would not support terrorists. But the Taliban and fundamentalists find many sympathies in the population. It is not clear whether even insiders would support them. In October 2001, two retired Pakistani nuclear physicists were arrested. They had taken part in programs to build up Pakistan's nuclear capacity.[10] They sympathize with the Taliban and had recent intensive contacts. However, it was not clear whether they had passed on nuclear materials. The case is still pending, but apparently there will be no conviction. According to the Carnegie Endowment for International Peace, already a year ago, Pakistan asked the US for support in order to improve the physical protection of nuclear material which indicates that there might be problems. It is unknown where the nuclear weapons are hidden because it is likely that the storage sites might not withstand an attack. They are not equipped with so-called permissive actions links, that would prevent any unauthorized use.
Smuggling of Complete Warheads?
During the last years, there had been frequent rumours about Bin Laden's acquisition activities of complete warheads, specifically very small and light devices, so-called atomic demolition munitions (ADMs) or nicknamed rucksack bombs, originating from Russia. In September 1997, General Alexander Lebed, who at that time was in charge of investigating the accountancy of Russian warheads, claimed that 100 ADMs were missing. He asserted they had been stationed in other Soviet republics and not been returned after the break-up of the Soviet Union. This allegation was disputed by other Russian officials, but some of them even claimed that weapons like ADMs never existed. However, some of these denials were not very convincing, and it must be assumed that such weapons exist. There had also been rumors that Bin Laden's organisation was successful in acquiring them. As an example, the Israeli secret service reported in 1998 that an agent in Kazakhstan has been paid 2 million pounds for the promise to deliver a rucksack bomb within two years. It is not clear how much truth is in these rumors, whether indeed bombs are missing and whether they are already in the hands of terrorists.
In case terrorists got hold of such weapons, it is not clear whether indeed there are no devices built in to prevent unauthorized use. Terrorists would then only have the option to dismantle the weapons in order to use the material for building their own device. The question then is whether the nuclear material is still weapon-usable. Weapons plutonium normally must be reprocessed within five to ten years. This certainly has not been done with "forgotten" Russian nukes, so that the energy of a nuclear explosion with this material would probably be rather small.
Other Means of Nuclear Terrorism
A technically much simpler variant of nuclear terrorism would be a radiological weapon. It would disperse highly radioactive material by a conventional explosion and contaminate wide areas. Instead of HEU or plutonium whose acquisition is difficult and which are not very radioactive, terrorists would probably use high-level waste from reprocessing plants or highly radioactive sources from civilian industry. The accountancy of high-level waste is much more difficult and the security provisions are worse than for weapon-usable materials. Any diversion poses a health risk - which is no concern for dedicated terrorists willing to commit suicide - but it is much easier to overcome its security than that of weapons materials. A variant would be to contaminate drinking water.
A scenario that has been widely discussed during the last weeks is the suicide crash of a passenger jet on a nuclear plant. Sabotage and attacks on nuclear reactors happened before. In Russia, it is feared that Chechenian terrorists might plan an attack on a nuclear plant. In 1972, three kidnappers threatened to crash a plane into a nuclear plant at Oak Ridge in the US. Indeed, the containment of nuclear reactors in most countries is not designed to withstand the crash of a freshly fueled jumbo jet, as has recently been acknowledged by the IAEA. Although the radioactive core would probably not be destroyed, it is likely that the cooling system would not work any more which would lead to a Chernobyl-like accident. However, the containment must be hit by the plane in a perpendicular way. This needs a much more sophisticated art of flying than hitting a large building.
European Actions and Perceptions
After the terror attacks of September 11, the Europeans first stated their "unreserved" solidarity with the American people. However, some parliamentarians and politicians also expressed some caution: They demanded that the culprits of this crime should be judged, but only by an international court. They also warned of military actions that would fuel even more terrorism. A vicious circle of violence should be avoided. In the public discussions following since, the "unreserved" solidarity is viewed with increasing scepticism. The reason is that the Europeans perceive US military actions as too unilateral and not sufficiently sanctioned by the UN.[11]
Efforts to combat nuclear trafficking also exist. On December 17, 1999 the EU Council adopted a Joint Action For Nonproliferation and Disarmament in the Russian Federation, using the Cooperative Threat Reduction (CTR) program of the United States as model. The utilization of the Joint Action instrument, a legal tool to guarantee the thorough coordination of EU Commission and member states policies, proves the willingness of the members to act in a systematic and unified way in an ostensibly important field. The EU declares its readiness in the Joint Action "to promote cooperative risk reduction activities and the safe and secure dismantlement of WMD-related resources in Russia" and "to provide a legal and operational framework for an enhanced European Union role in cooperative risk reduction activities in the Russian Federation through project-orientated cooperation".[12] For the Joint Action, a total budget of EUR 8.9 Mio has been set up for the years 1999 and 2000, including funds from the Commission budget. Most of the European projects concentrate on safeguards, a topic in which Europe is in a good position for successful projects.
In addition to several European national activities aiming at CTR and nuclear disarmament, the EU runs the program Tacis (Technical aid for the CIS countries) and substantially contributes to the International Science and Technology Center (ISTC). The total budget of both, Tacis and ISTC, amounts to several hundreds of millions EUR, and therefore is comparable to the US CTR activities. However, its largest fraction is devoted to general scientific or safety-related projects; security related projects constitute only a small part, with a budget of only a few tens of millions EUR. Nevertheless, the Joint Action triggered a higher priority which might evolve even more in the future.
Why is the European financial contribution to the battle against nuclear proliferation so low? In the European public debates, the topics of combatting nuclear terrorism and stemming nuclear proliferation hardly play a prominent role. Also general economic collaboration with Russia is uncontested and promoted as Russia is seen as a future market; collaboration in nuclear safety is also highly valued, because the Europeans fear future Chernobyls. Collaboration in nuclear non-proliferation, however, touches upon nuclear weapon policies. On this topic, integration within the EU has only just started. It is especially difficult, because there are two nuclear weapon states, others that promote nuclear energy, some reject nuclear energy altogether, some do allow the stationing of NATO nuclear weapons on their soil while others don't. The topic of nuclear weapons touches especially on sensitive souvereignty issues with the consequence that collaboration on nuclear non-proliferation has also evolved only very slowly. Nevertheless, it is the duty of all developed countries to share their burden on non-proliferation and nuclear disarmament - an insight which is developing only slowly.
Reducing the Risks
It cannot be excluded that terrorist groups already possess nuclear explosive devices. In this case, strategies to prevent their use are difficult. Nevertheless, there are several measures that might be helpful to reduce the risks in the future.
First of all, this is international collaboration and assistance for the protection of nuclear materials in Russia. The already existing programs must be strengthened, and their funding must get a higher priority in the western world. An international plan for the disposition of Russian plutonium from dismantled weapons failed recently, due to lacking interest and finances.
So far, there is no international treaty that obliges states to protect their weapon-usable material from theft and sabotage. It is therefore necessary to create more binding commitments and to raise international standards, especially in countries that are not subject to international safeguards. It will als be necessary to work with the three de-facto nuclear weapon states India, Pakistan, and Israel to enhance the security of their nuclear weapons and installations.
In addition, it is recommended to collaborate with the IAEA which is running several work programs for risk reduction. They include a database on threats of nuclear terrorism and training programs for physical protection and threat assessment.
A special problem is the lacking transparency of existing warheads, especially so-called tactical nuclear weapons. Some of them are older systems and much less secured against theft or unauthorized use than so-called strategic weapons. In 1993, all five nuclear weapon states rejected a proposal by the German Foreign Minister to create a nuclear weapon register with the United Nations. A treaty that creates transparency and aims at limiting or reducing the number of tactical nuclear weapons would also reduce the risk of theft and unauthorized use.
An example is: Carey Sublette, Nuclear Weapons Frequently Asked Questions, Version 2.25: 9 August 2001, www.fas.org/nuke/hew/Nwfaq/Nfaq0.html.- US Department of Energy, Office of Declassification, Restricted Data Declassification Policy 1946 to the Present (RDD-6), January 1, 2000, www.osti.gov/opennet/rdd-6.pdf.
- Alexander Kelle, Annette Schaper, Bio- und Nuklearterrorismus - eine kritische Analyse der Risiken nach dem 11. September 2001 (Biological and nuclear terrorism - a critical analysis of the risks after 11 September 2001, in German), HSFK-Report 10-2001, Frankfurt, 2001.
- These are rough estimates. They take into account that the fissile material will be surrounded by a reflector which reduces the critical mass, and that there are material losses in the production process (A. Schaper, Zur Waffentauglichkeit verschiedener Uranbrennstoffe (Weapons usability of several uranium fuels), working paper for the Expert Commission on the research reactor FRM II of the German Federal Ministry of Education and Research, 5 March 1999).
- David Albright/Frans Berkhout/William Walker, Plutonium and Highly Enriched Uranium 1996 - World Inventories, Capabilites and Policies, SIPRI (Oxford University Press), 1997, updated on the web site of the Institute of Science and International Security (ISIS): www.isis-online.org.
- Matthew Bunn, The Next Wave: Urgently Needed New Steps to Control Warheads and Fissile Material, Carnegie Endowment for International Peace and Harvard Project on Managing the Atom, Washington DC, April 2000, http://ksgnotes1.harvard.edu/BCSIA/Library.nsf/pubs/Nextwave.
- Albright/Berkhout/Walker, op.cit.
- Adolf von Baeckmann, Garry Dillon, Demetrius Perricos, Nuclear Verification in South Africa, IAEA Bulletin, Vol. 37, No. 1, March 1995.
- Kimberly McCloud and Matthew Osborne, WMD Terrorism and Usama Bin Laden, CNS Report, 14 March 2001, http://cns.miis.edu/pubs/reports/binladen.htm.
- BBC News, 25 Oct. 2001, Pakistan holds nuclear scientists, http://news.bbc.co.uk/hi/english/world/south_asia/newsid_1619000/1619252.stm.
- The scepticism was boosted after President George W. Bush's State of the Union remarks labeling Iran, Iraq and North Korea as an axis of evil. On the subsequent German debate see Ralf Beste, Christoph Schulte, Eingeschränkte Solidarität (Reserved Solidarity), Der Spiegel, 9/2002, p. 30, March 1, 2002.
- EU Council, Joint Action for Non-Proliferation and Disarmament in the Russian Federation of 17 December 1999, Preamble (2), www.eur.ru/eng/neweur/user_eng.php?func=rae_disarmament April 17th, 2002.
