IS - We'll buy nuclear weapon within 12 months.
Discussion
knitware said:
Uneducated rubbish.
Can Terrorists Build Nuclear Weapons?Carson Mark, Theodore Taylor, Eugene Eyster, William Maraman, Jacob Wechsler
J. Carson Mark is a member of the Nuclear Regulatory Commission's Ad visory Committee on Reactor Safeguards and of the Foreign Weapons Eval uation Group of the U.S. Air Force. He is a former division leader of Los Alamos National Laboratories' Theoretical Division and serves as a consultant to Los Alamos and a number of governmental agencies.
Theodore Taylor is chairman of the board of Nova, Inc., which specializes in solar energy applications. He is a nuclear physicist who once designed the United States' smallest and largest atomic (fission) bombs. He also designed nuclear research reactors. He has served as deputy director (Scientific) of the Defense Atomic Support Agency and as an independent consultant to the U.S. Atomic Energy Commission. He is coauthor (with Mason Willrich) of Nuclear Theft: Risks and Safeguards and is the subject of John McPhee's The Curve of Binding Energy.
Eugene Eyster is a former leader of Los Alamos National Laboratories' WX Division, which is responsible for the explosive components of nuclear weap ons. A specialist in chemical explosives, he participated in the Manhattan Project.
William Maraman, a specialist in chemical and metallurgical processing of plutonium and uranium, is director of TRU Engineering Co., which does consulting work on transuranic elements. He was at Los Alamos National Laboratories for thirtyseven years, where he was leader of the Plutonium, Chemistry and Metallurgy Group and of the Material Sciences Division.
Jacob Wechsler is a physicist specializing in nuclear explosives. He was a member of the Manhattan Project and was leader of Los Alamos National Laboratories' WX Division, which is responsible for the explosive components of nuclear weapons.
General Observations
Two options for nuclear devices to be built by terrorists are considered here: that of using the earliest design principles in a so-called crude design and that of using more advanced principles in a so-called sophisticated design.
A crude design is one in which either of the methods successfully dem onstrated in 1945---the gun type and the implosion type---is applied. In the gun type, a subcritical piece of fissile material (the projectile) is fired rapidly into another subcritical piece (the target) such that the final assembly is supercritical without a change in the density of the material. In the implosion type, a near-critical piece of fissile material is compressed by a converging shock wave resulting from the detonation of a surrounding layer of high explosive and becomes supercritical because of its increase in density.
A small, sophisticated design is one with a diameter of about 1 or 2 feet and a weight of one hundred to a few hundred pounds, so that it is readily transportable (for example, in the trunk of a standard car). Its size and weight may be compared with that of a crude design, which would be on the order of a ton or more and require a larger vehicle. It would also be possible, in about the same size and weight as a crude model but using a more sophis ticated design, to build a device requiring a smaller amount of fissile material to achieve similar effects.
For a finished implosion device using a crude design, terrorists would need something like a critical mass of uranium (U) or plutonium (Pu) or, possibly, UO2 (uranium oxide) or Pu02 (plutonium oxide). For a gun type device, substantially more than a critical mass of uranium is needed, and plutonium cannot be used. It may be assumed that the terrorists would have acquired (or plan to acquire) such an amount either in the form of oxide powder (such as might be found in a fuel fabrication plant), in the form of finished fuel elements for a reactor---whether power, research, or breeder--- or as spent fuel.
For a small, sophisticated design, the terrorists may need a similar amount of fissile material since practically all the presumed reductions in size and weight have to be taken from the assembly mechanism, and, with a less powerful assembly, not only will it be important to have the active material in its most effective form, but its amount will have to be sufficient to achieve supercriticality. Alternatively, a smaller amount could be used in a sophis ticated design with a more powerful and heavier assembly mechanism.
Conceivably oxide powder might be used as is, although terrorists might choose to go through the chemical operation of reducing it to metal. Such a process would take a number of days and would require specialized equip ment and techniques, but these could certainly be within the reach of a dedicated technical team.
Fuel elements of any type will have to be subjected to chemical pro cessing to separate the fissile material they may contain from the inert clad ding material or other diluents. This process would also require specialized equipment, a supply of appropriate reagents, well-developed techniques spe cific to the materials handled, and at least a few days to conduct the operation. Spent fuel from power reactors would contain some plutonium but at such low concentrations that it would have to be separated from the other materials in the fuel. It would also contain enough radioactive fission fragments that the chemical separation process would have to be carried out by remote operation, a very complicated undertaking requiring months to set up and check out, as well as many days for the processing itself. The fresh fuel for almost all power reactors would be of no use, since the uranium enrichment is too low to provide an explosive chain reaction.
The terrorists would need something like a critical mass of the material they propose to use. For a particular fissile material, the amount that con stitutes a critical mass can vary widely depending on its density, the char acteristics (thickness and material) of the reflector employed, and the nature and fractional quantity of any inert diluents present (such as the oxygen in uranium oxide, the uranium 238 in partially enriched uranium 235, or chem ical impurities).
For comparison purposes, it is convenient to note the critical masses with no reflector present (the "bare crit") of a few representative materials at some standard density. For this discussion, the following examples of bare critical masses have been chosen:
10 Kilograms (kg) of Pu 239, alpha-phase metal (density = 19.86 grams per cubic centimeter [gm/cc]).
52 kg of 94% U-235 (6% U-238) metal (density = 18.7 gm/cc).
approximately 110 kg of U02 (94% U-235) at full crystal density (density = 1I gm/cc). approximately 35 kg of Pu02 at full crystal density (density = 11.4 gm/cc).
In all cases (others as well as these), the mass required for a bare crit varies inversely as the square of the density. Thus, the bare crit of delta-phase plutonium metal (density = 15.6 gm/cc ) is about 16 kg. Similarly, at densities the square root of two times larger than those above, the bare crit masses would be one-half those indicated. If any reflector is present, the mass re quired to constitute a critical assembly would be smaller than those above. With a reflector several inches thick, made of any of several fairly readily available materials (such as uranium, iron, or graphite, for example), the critical mass would be about half the bare crit. Thicker reflectors would further reduce the mass but would be more awkward without providing much more of a reduction. Although beryllium is particularly effective in this respect---providing critical masses as low as one-third the bare crit---it is not readily available in the form needed and is not considered further.) It is consequently assumed here that a mass of half the bare crit is what terrorists would require to complete a near-critical (crude) assembly.
With respect to the effects of dilution by isotopes of heavy elements, only the two most obvious cases need be considered. One is that of reactor- grade plutonium. This material is not uniquely specified, since the fractional amount of the Pu-240 depends on the level of exposure of the fuel in the reactor before it is discharged. However, at burn-up levels somewhat higher than present practice, the bare crit of plutonium would be only some 25-35 percent higher than that for pure Pu-239. Because of spontaneous fission, the effect of the Pu-240 on the neutron source in the material is thus likely to be more important than its effect on the critical mass. Nevertheless, nuclear weapons can be made with reactor-grade plutonium.
The other obvious dilution case is that of uranium at enrichments lower than 94 percent. Here the effect on critical mass, and consequently on the amount of material that must be acquired and moved by the assembly system, is quite appreciable. For example, the bare crit of 50 percent enriched ura nium is about 160 kg (~3 times that of 94 percent material) and for 20 percent material about 800 kg ( ~15 times that for 94 percent). Similar factors will apply for uranium oxide as a function of enrichment. In this same con nection, it may be noted that the mixed oxide fuel once considered for the Clinch River Breeder Reactor (~22 percent plutonium oxide plus ~78 per cent uranium oxide) would correspond to uranium at an enrichment of somewhat less than 40 percent and have a critical mass a little more than four times larger than 94 percent uranium oxide.
As a final general observation, for a crude design, terrorists would need something like 5 or 6 kg of plutonium or 25 kg of very highly enriched uranium (and more for a gun-type device), even if they planned to use metal. They would have to acquire more material than is to go into the device, since with metal considerably more material is required to work with than will appear in the finished pieces. The amounts they would need can be compared with the formula quantities identified in federal regulations for the protection of nuclear materials: 5 kg U-235, or 2 kg plutonium. Sites at which more than a formula quantity is present are required to take measures to cope with a determined, violent assault by a dedicated, well-trained, and well-armed group with the ability to operate as two or more teams. Trans port vehicles that carry more than a formula quantity must be accompanied by armed escort teams and have secure communications with their base. Transport vehicles carrying smaller amounts are not so heavily guarded, but there are provisions intended to ensure that in the aggregate no more than a formula quantity is on the road at one time. For terrorists having to acquire at least several formula quantities, there are formidable barriers to overcome.
Crude Designs
Crude designs are discussed primarily in the context of the problems facing a terrorist group. Schematic drawings of fission explosive devices of the earliest types showing in a qualitative way the principles used in achieving the first fission explosions are widely available. However, the detailed design drawings and specifications that are essential before it is possible to plan the fabrication of actual parts are not available. The preparation of these drawings requires a large number of man-hours and the direct participation of indi viduals thoroughly informed in several quite distinct areas: the physical, chemical, and metallurgical properties of the various materials to be used, as well as the characteristics affecting their fabrication; neutronic properties; radiation effects, both nuclear and biological; technology concerning high explosives and/or chemical propellants; some hydrodynamics; electrical cir cuitry; and others.
It is exceedingly unlikely that any single individual, even after years of assiduous preparation, could equip himself to proceed confidently in each part of this diverse range of necessary knowledge and skills, so that it may be assumed that a team would have to be involved. The number of specialists required would depend on the background and experience of those enlisted, but their number could scarcely be fewer than three or four and might well have to be more. The members of the team would have to be chosen not only on the basis of their technical knowledge, experience, and skills but also on their willingness to apply their talents to such a project, although their susceptibility to coercion or considerations of personal gain could be factors. In any event, the necessary attributes would be quite distinct from the paramilitary capability most often supposed to typify terrorists.
Assuming the existence of a subnational group equipped for the activist role of acquiring the necessary fissile material and the technical role of making effective use of it, the question arises as to the time they might need to get ready. The period would depend on a number of factors, such as the form and nature of the material acquired and the form in which the terrorists proposed to use it; the most important factor would be the extent of the preparation and practice that the group had carried out before the actual acquisition of the material. To minimize the time interval between acquisition and readiness, the whole team would be required to prepare for a consid erable number of weeks (or, more probably, months) prior to acquisition. With respect to uranium, most of the necessary preparation and practice could be worked through using natural uranium as a stand-in.
The time intervals might range from a modest number of hours, on the supposition that enriched uranium oxide powder could be used as is, to a number of days in the event that uranium oxide powder or highly enriched (unirradiated) uranium reactor fuel elements were to be converted to ura nium metal. The time could be much longer if the specifications of the device had to be revised after the material was in hand. For plutonium, the time intervals would be longer because of the greatly increased hazards involved (and the absolute need of foreseeing, preparing for, and observing all the necessary precautions). in addition, although uranium could be used as a stand-in for plutonium in practice efforts, there would be no opportunity to try out some of the processes required for handling plutonium until a suf ficient supply was available.
To achieve a minimum turnaround time, the terrorists would, before acquisition, have to decide whether to use the material as is or to convert it to metal. They would have to make the decision in part in order to proceed with the design considerations, in part because the amounts needed would be different in the two cases, and in part to obtain and set up any required equipment.
For the first option---using oxides without conversion to metal---the terrorists would need accurate information in advance concerning the phys ical state, isotopic composition, and chemical constituents of the material to be used. Although they would save time by avoiding the need for chemical processing, one disadvantage (among others) is the requirement for more fissile material than would be needed were metal to be used. This larger amount of fissile (and associated) material would require a larger weight in the assembly mechanism to bring the material into an explosive configuration.
As to the second option---converting the materials to metal---a smaller amount of fissile material could be used. However, more time would be needed and quite specialized equipment and techniques---whether merely to reduce an oxide to the metal or to separate the fissile material from the cladding layers in which it is pressed or sintered in the nuclear fuel elements of a research reactor, for example. The necessary chemical operations, as well as the methods of casting and machining the nuclear materials, can be (and have been) described in a straightforward manner, but their conduct is most unlikely to proceed smoothly unless in the hands of someone with experience in the particular techniques involved, and even then substantial problems could arise.
The time factor enters the picture in a quite different way. In the event of timely detection of a theft of a significant amount of fissile material--- whether well suited for use in an explosive device or not---all relevant branches of a country's security forces would immediately mount an intensive response. In addition to all the usual intelligence methods, the most sensitive technical detection equipment available would be at their disposal. As long as thirty-five years ago, airborne radiation detectors proved effective in prospecting for uranium ore. Great improvements in such equipment have been realized since. A terrorist group would therefore have to proceed deliberately and with caution to have a good chance of avoiding any mishap in handling the material, while at the same time proceeding with all possible speed to reduce their chance of detection.
In sum, several conclusions concerning crude devices based on early design principles can be made.
I . Such a device could be constructed by a group not previously engaged in designing or building nuclear weapons, providing a number of requirements were adequately met.
2. Successful execution would require the efforts of a team having knowledge and skills additional to those usually associated with a group engaged in hijacking a transport or conducting a raid on a plant.
3. To achieve rapid turnaround (that is, the device would be ready within a day or so after obtaining the material), careful preparations extending over a considerable period would have to have been carried out, and the materials acquired would have to be in the form prepared for.
4. The amounts of fissile material necessary would tend to be large--- certainly several, and possibly ten times, the so-called formula quantities.
5. The weight of the complete device would also be large---not as large as the first atomic weapons (~10,000 pounds), since these required aero dynamic cases to enable them to be handled as bombs, but probably more than a ton.
6. The conceivable option of using oxide powder (whether of uranium or plutonium) directly, with no postacquisition processing or fabrication, would seem to be the simplest and most rapid way to make a bomb. However, the amount of material required would be considerably greater than if metal were used. Even at full cyrstal density, the amounts are large enough to appear troublesome: ~55 kg (half bare crit) for 94 percent uranium oxide and ~17.5 kg for plutonium oxide. However, the density of the powder as acquired is nowhere close to crystal density. To approach crystal density would require a large and special press, and the attempt to acquire such apparatus would constitute the sort of public event that might blow the cover of a clandestine operation. Besides, the time required for processing with such a press would preclude a rapid turnaround. Even to achieve densities a little above half of crystal would require some pressing apparatus (not as conspicuous as a large press and conceivably obtainable quietly), but time would again be required to process material quantities of perhaps three or four times those above. The densities available in powder without pressing are not well determined but are quite low, probably in the range of 3 to 4 gm/Cc, although possibly lower.
Within the confines of the crude design category---that of a device guar anteed to work without the need for extensive theoretical or experimental demonstration---an implosion device could be constructed with reactor- Brade plutonium or highly enriched uranium in metal or possibly even oxide form. The option of using low-density powder directly in a gun-type assembly should probably be excluded on the basis of the large material requirements.
There remains the possibility of using a rather large amount of oxide powder (tens of kilograms or possibly more) at low density in an implosion- type assembly and simply counting on the applied pressure to increase the density sufficiently to achieve a nuclear explosion. Some sort of workable device could certainly be achieved in that way. However, obtaining a per suasive determination of the actual densities that would be realized in a porous material under shock pressure (and hence of the precise amount of material required) would be a very difficult theoretical (and experimental) problem for a terrorist team. In fact, solving this problem does not belong in the crude design category. Still, a workable device could be built without the need for extensive theoretical or experimental demonstration.
The amount of low-density oxide powder required for a small, crude, implosion-type device is far larger than previously suggested by Theodore Taylor; his view has changed only as to the feasibility of a small, crude device such as terrorists might attempt to build with a single small container of plutonium oxide powder seized from a fuel fabrication plant. We agree, however, that a crude implosion device could be constructed with reactor-grade plutonium or highly enriched uranium in metal or possibly even in oxide form.
7. Devices employing metal in a crude design could certainly be con structed so as to have nominal yields in the 10 kiloton range---witness the devices used in 1945. By nominal yield is meant the yield realized if the neutron chain starts after the assembly is complete and the fissile material is at or near its most supercritical configuration: projectile fully seated in the target for the gun-type device or all the material compressed in the implosion device. In all such systems, there is an interval between the moment when the fissile material first becomes critical (projectile still on its way to its destination, or only a small part of the material compressed) and the time it reaches its intended state. During this interval, the degree of supercriticality is building up toward its final value. If a chain reaction were initiated by neutrons from some source during this period, the yield realized would be smaller---possibly a great deal smaller---than the nominal yield. Such an event is referred to as preinitiation (or sometimespredetonation). Obviously, the longer is this interval or the greater is the neutron source in the active material, the larger is the probability of experiencing a preinitiation. The neutron source in even the best plutonium available (lowest Pu-240 content) is so large and the time interval for a gun-type assembly with available pro jectile velocities (~1000 ft./sec.) is so long that predetonation early in this time interval is essentially guaranteed. For this reason, plutonium cannot be used effectively in a gun-type assembly. The neutron source in enriched uranium is several thousand times smaller than in the plutonium referred to, so that uranium can be used in a gun-type assembly (with available projectile velocities) and have a tolerable preinitiation probability. For this to be true, it is necessary to have rather pure uranium metal, since even small amounts of some chemical impurities can add appreciably to the neutron source. The source in uranium oxide, for example, may be ten or so times larger than in pure metal; the source in reactor-grade plutonium may be ten or more times larger than in weapons-grade plutonium. However, reactor-grade plutonium can be used for making nuclear weapons.
If the assembly velocities (of the projectile or material driven by an implosion) are quite low, the earliest possible preinitiation could lead to an energy release (equivalent weight of high explosive) not many times larger than the weight of the device. If the velocities are quite high (so that the degree of supercriticality increases appreciably during the very short time it takes the neutron chain to build up), the lowest preinitiation yield may still be in the 100 ton range, even in a crude design. Reductions in the weight of the assembly-driving mechanism (whether gun-firing apparatus or amount of high explosive) will, other things being equal, tend to result in lower assembly velocities. The considerations outlined will put some limits on what may be decided to be desirable in connection with a crude design.
8. There are a number of obvious potential hazards in any such operation, among them those arising in the handling of a high explosive; the possibility of inadvertently inducing a critical configuration of the fissile material at some stage in the procedure; and the chemical toxicity or radiological hazards inherent in the materials used. Failure to foresee all the needs on these points could bring the operation to a close; however, all the problems posed can be dealt with successfully provided appropriate provisions have been made.
9. There are a number of other matters that will require thoughtful planning, as well as care and skill in execution. Among these are the need to initiate the chain reaction at a suitable time and for some reliable means to detonate the high explosive when and as intended.
10. Some problems that have required a great deal of attention in the nuclear-weapons program would not seem important to terrorists. One of these would be the requirement (necessary in connection with a weapons stockpile) that devices have precisely known yields that are highly repro ducible. Terrorists would not be in a position to know even the nominal yield of their device with any precision. They would not have to meet the extremely tight specifications and tolerances usual in the weapons business, although quite demanding requirements on these points would still be nec essary. Similarly, in connection with a stockpile of weapons, much attention has been given to one-point safety: the assurance that no nuclear yield would be realized in the event of an unplanned detonation of the high explosive, such as might occur in the case of an accident or fire. To ensure the safety of bystanders, this requirement has been deemed important in the context of a large number of devices widely deployed and subject to movement from place to place by a variety of transport modes and by a series of handling teams. Terrorists would not be concerned with this problem, although they would still have a great interest in the safe handling of their device.
11. Throughout the discussion, it has been supposed that the terrorists were home grown. It is conceivable that such an operation could be spon sored by another country, in which case some of the motivation, technical experts, and muscle men might be brought in from outside. This difference would not change the problems that would have to be addressed or the operations required, but it could increase the assurance that important points are not overlooked. It might also provide the basis for considering a sophis ticated design rather than a crude type.
More Sophisticated Devices
Most of the schematic drawings that are available relate to the earliest, most straightforward designs and indicate in principle how to achieve a fission explosion, without, however, providing the details of construction. Since 1945, notable reductions in size and weight, as well as increases in yield, have been realized. Schematic drawings of an entirely qualitative sort are also available that indicate the nature of some of the principles involved in these improvements.
Merely on the basis of the fact that sophisticated devices are known to be feasible, it cannot be asserted that by stealing only a small amount of fissile material a terrorist would be able to produce a device with a reliable multikiloton yield in such a small size and weight as to be easy to transport and conceal. Such an assertion ignores at least a significant fraction of the problems that weapons laboratories have had to face and resolve over the past forty years. It is relevant to recall that today's impressively tidy weapons came about only at the end of a long series of tests that provided the basis for proceeding further. For some of these steps, full-scale nuclear tests were essential. In retrospect, not every incremental step taken would now seem necessary. Indeed, knowing only that much smaller and lighter weapons are feasible, it is possible at least to imagine going straight from the state of understanding in 1945 to a project to build a greatly improved device. The mere fact of knowing it is possible, even without knowing exactly how, would focus terrorists' attention and efforts.
The fundamental question, however, would still remain: that of whether the object designed and built would or would not actually behave as pre dicted. Even with their tremendous experience, the weapons laboratories find on occasion that their efforts are flawed. Admittedly, weapons designers are now striving to impose refinements on an already highly refined product, but they have had to digest surprises and disappointments at many points along the way.
For persons new to this business, as it may be supposed a terrorist group is, there is a great deal to learn before they could entertain any confidence that some small, sophisticated device they might build would perform as desired. To build the device would require a long course of study and a long course of hydrodynamic experimentation. To achieve the size and weight of a modern weapon while maintaining performance and confidence in perfor mance would require one or more full-scale nuclear tests, although consid erable progress in that direction could be made on the basis of nonnuclear experiments.
In connection with an effort to reduce overall size and weight as far as possible, it would be necessary to use fissile material in its most effectiveform, plutonium metal. Moreover, while reducing the weight of the assembly mechanism, which implies reducing the amount of energy available to bring the fissile material into a supercritical configuration, it would not be possible at the same time to reduce the amount of fissile material employed very much. In this case, the amount of fissile material required in the finished pieces would be significantly larger than the formula quantity. Alternatively, in an implosion device without a reduction in weight and size, it would be possible to reduce the amount of nuclear materials required by using more effective implosion designs than that associated with the crude design.
In either case---a small or a large sophisticated device---the design and building would require a base or installation at which experiments could be carried out over many months, results could be assessed, and, as necessary, the effects of corrections or improvements could be observed in follow-on experiments. Similar considerations would apply with respect to the chem ical, fabrication, and other aspects of the program.
The production of sophisticated devices therefore should not be consid ered to be a possible activity for a fly-by-night terrorist group. It is, however, conceivable in the context of a nationally supported program able to provide the necessary resources and facilities and an established working place over the time required. It could be further imagined that under the sponsorship of some malevolent regime, a team schooled and prepared in such a setting could be dispatched anywhere to acquire material and produce a device. In such a case, although the needs of the preparation program might have been met, the terrorists would still have to obtain and set up the equipment needed for the reduction to metal and its subsequent handling and to spend the time necessary to go through those operations.
In summary, the main concern with respect to terrorists should be fo cused on those in a position to build, and bring with them, their own devices, as well as on those able to steal an operable weapon.
Some good reading here - http://www.nti.org/about/projects/Securing-bomb/
Is it really plausible that terrorists could get and use a nuclear bomb?
Yes. Unfortunately, terrorist use of a nuclear bomb is a very real danger. During the 2004 presidential campaign, President George W. Bush and Senator John Kerry (D-Mass.) agreed that nuclear terrorism was the single greatest threat to U.S. national security. Published estimates of the chance that terrorists will detonate a nuclear bomb in a U.S. city over the next ten years range from 1 percent to 50 percent. In a 2005 poll of international security experts taken by Senator Richard Lugar (R-Ind.), the median estimate of the chance of a nuclear attack in the next ten years was 29 percent — and a strong majority believed that it was more likely that terrorists would launch a nuclear attack than that a state would. Given the horrifying consequences of such an attack, even a 1 percent chance would be enough to call for rapid action to reduce the risk.
What materials could terrorists use to make a nuclear bomb?
To make a nuclear bomb requires either highly enriched uranium (HEU) or plutonium. Neither of these materials occurs in nature, and producing either of them requires expensive facilities using complex technologies, almost certainly beyond the capability of terrorist groups. Hence, if all of the world's stockpiles of nuclear weapons, HEU and plutonium can be effectively protected and kept out of terrorist hands, nuclear terrorism can be prevented: no nuclear material, no bomb, no nuclear terrorism.
How difficult would it be for terrorists to get the materials needed to make a nuclear bomb?
Highly enriched uranium and plutonium are hard to make, but may not be so hard to steal. These raw materials of nuclear terrorism are housed in hundreds of facilities in dozens of countries — some with excellent security, and some secured by nothing more than an underpaid guard and a chain link fence. There are no binding global standards setting out how well nuclear weapons and the materials needed to make them should be secured.
Theft of the essential ingredients of nuclear weapons is not just a hypothetical worry, it is an ongoing reality. The International Atomic Energy Agency (IAEA) has documented 15 cases of theft of HEU or plutonium confirmed by the countries concerned (and there are additional well-documented cases that the countries involved have not yet been willing to confirm). In many of these cases, the thieves and smugglers were attempting to sell the material to anyone who would buy it — and terrorist groups have been seeking to buy it.
How much expertise is needed to make a nuclear bomb? Would a large operation be required?
Unfortunately, government studies have concluded that once a terrorist organization had the needed nuclear material, a handful of skilled individuals might be able to make a crude nuclear bomb using commercially available tools and equipment, without any large fixed facilities that might draw attention, and without access to classified nuclear weapons information. Getting nuclear material and making a crude nuclear bomb would be the most complex operation terrorists have ever carried out, but the risk that a sophisticated group could pull it off is very real. Roughly 90 percent of the effort in the Manhattan Project was focused on making nuclear bomb material; getting stolen nuclear material would allow terrorists to skip the hardest part of making a nuclear bomb.
The simplest type of nuclear bomb, known as a "gun-type" bomb, slams two pieces of nuclear material together at high speed. The bomb that destroyed Hiroshima, for example, was a cannon that fired a shell of HEU into rings of HEU. Plutonium cannot be used to make a gun-type bomb with a substantial explosive yield, because the neutrons that all plutonium emits cause the bomb to blow itself apart before the nuclear reactions proceeds very far. To make a bomb from plutonium would require a more complex "implosion-type" bomb, which would be more difficult for terrorists to build — but government studies have repeatedly concluded that this possibility also cannot be ruled out.
How much nuclear material would terrorists need to make a bomb?
The amount of nuclear material needed to make a bomb depends on the material and the skill of the bomb-maker. A simple gun-type nuclear bomb would require approximately 50 kilograms of HEU — an amount that would fit in a suitcase. Implosion-type bombs are more efficient, requiring less nuclear material. Unclassified estimates suggest that basic first-generation implosion-type bombs like the Nagasaki bomb can be made with 6 kilograms of plutonium or 15 kilograms of HEU. With these relatively small amounts, a terrorist group could potentially build a bomb with the power of thousands of tons of high explosive. Sophisticated nuclear weapon states can potentially make nuclear bombs with smaller amounts of nuclear material.
Rather than stealing nuclear material and making a bomb, could terrorists steal and use an already assembled nuclear weapon?
Possibly. Nuclear weapons are generally better secured than some stocks of HEU and plutonium are. Nevertheless, the United States is spending hundreds of millions of dollars beefing up security for its own nuclear weapons complex sites, and hundreds of millions more helping Russia improve security for its warhead sites.
A stolen nuclear weapon might be very difficult for a terrorist group to detonate. Many nuclear weapons are equipped with electronic locks making it impossible to set off the weapon without putting in the appropriate code or figuring out a way to bypass the lock. Unfortunately, on older Russian tactical nuclear weapons, such locks are thought to be absent in some cases and relatively easily bypassed in others. U.S. strategic nuclear weapons also do not incorporate such locks, and some other countries' weapons may also lack them. In addition, modern nuclear weapons are typically equipped with devices that prevent the weapon from going off until it has passed through its expected flight sequence — such as a period of rocket-powered flight followed by coasting through space and reentering the atmosphere, in the case of a long-range ballistic missile. While designed more for safety than security, these devices would also make it more difficult to detonate most stolen weapons. If terrorists could not figure out how to detonate a stolen weapon, they might choose to cut it open and use the nuclear material inside to try to make a bomb of their own.
Are there "suitcase nukes" on the loose?
Probably not. In the 1990s, Gen. Alexander Lebed, then the national security advisor to Russian President Boris Yeltsin, said that more than 100 nuclear weapons designed to be carried by one person — so-called "suitcase nukes" — could not be accounted for and might be missing. The Russian Ministry of Defense firmly denied that any weapons were missing, and Lebed ultimately backed off from his initial statements. Ultimately enough information was released to make a reasonably convincing case that none of these man-portable nuclear weapons were missing. It is clear, however, that both the United States and the Soviet Union did in fact manufacture nuclear weapons designed to be carried and used by one or two people. In the United States, all such weapons have been dismantled, and some Russian statements indicate that the same is now true in Russia.
Once a nuclear bomb or nuclear material has been stolen, could we stop it from being smuggled?
The chances would not be very good, unfortunately. The amounts of HEU or plutonium needed for a bomb are small and easy to smuggle. These materials are not radioactive enough to require any special equipment to carry them, or to make them easy to detect. After they have left the site where they are supposed to be, they could be anywhere, and all the later lines of defense are variations on searching for needles in haystacks. With hundreds of millions of people and vehicles crossing U.S. borders every year, making sure no one gets in with a suitcase of potential bomb material is an immense challenge. Even if governments screened every container coming across their borders with a radiation detector, terrorists would not be likely to send their nuclear bomb material through one of the readily-observable radiation detectors, but would use one of the many other possible routes to avoid inspection. Moreover, if HEU was shielded with lead, detectors now being deployed would not be able to detect the weak radiation it emits (unless it was contaminated with the isotope U-232, and the detector was designed to look for the gamma rays from that decay chain). If the United States cannot stop the flow of illegal drugs and illegal immigrants across its borders, it is unlikely that it will succeed in stopping nuclear material. Even an assembled nuclear bomb might fit in the hold of a yacht, in a truck, or in a small plane.
What would happen if terrorists set off a nuclear bomb in a major city?
Terrorist use of a nuclear bomb would be an historic catastrophe. If a crude nuclear bomb with an explosive equivalent of 10,000 tons of TNT (10 "kilotons" in the language of nuclear weapons) were set off at Grand Central Station on a typical work-day, some 500,000 people might be killed, and hundreds of thousands more would be injured, burned, and irradiated. The direct economic damage would likely be in the range of $1 trillion, and the reverberating economic effects throughout the United States and the world would come to several times that figure. In 2005, then-UN Secretary General Kofi Annan warned that such an attack "would stagger the world economy and thrust tens of millions of people into dire poverty," causing "a second death toll throughout the developing world." The terrorists would surely claim they had more bombs already hidden in U.S. cities, potentially provoking widespread panic and economic disruption. In short, America and the world would be changed forever.
What terrorist groups are known to be seeking nuclear weapons?What do we know about their attempts?
Al Qaeda has been seeking nuclear weapons and the material needed to make them for more than a decade. Osama bin Laden and his followers have repeatedly attempted to acquire stolen nuclear material and to recruit nuclear expertise. In 2001, for example, bin Laden and his deputy Ayman al-Zawahiri met at length with two senior Pakistani nuclear scientists and discussed nuclear weapons. As early as 1993, al Qaeda attempted to purchase what it believed was HEU in the Sudan. In the 1990s, the Japanese terror cult Aum Shinrikyo, which launched the nerve gas attack in the Tokyo subway, also attempted to get nuclear weapons. Russian officials have confirmed that Chechen terrorist teams have carried out reconnaissance at Russian nuclear warhead storage sites, and in 2005, the Russian Minister of the Interior warned that Russia had intelligence that Chechen groups were planning "attacks against nuclear and power industry installation" intended to "seize nuclear materials and use them to build weapons of mass destruction." Some Chechen factions are closely linked to al Qaeda.
Has any terrorist group succeeded in acquiring nuclear material?
Despite various terrorist claims, there is no convincing evidence that any terrorist group has yet succeeded in getting a nuclear bomb or the HEU or plutonium needed to make one.
What has been done to reduce the risk of nuclear theft and terrorism?
A wide range of programs in the United States and elsewhere are making real progress in reducing the global danger of nuclear terrorism — but much more remains to be done. Through Nunn-Lugar cooperative threat reduction programs and related efforts, security has been dramatically improved at scores of buildings and bunkers with either nuclear weapons or the materials needed to make them in the former Soviet Union and in other countries around the world. Hundreds of kilograms of HEU have been removed from potentially vulnerable nuclear sites around the world. HEU-fueled research reactors are being converted to run on low-enriched uranium (LEU) fuel that cannot be used in a nuclear bomb, and their HEU is being removed. As a second line of defense, radiation detectors are being installed at key ports and border crossings around the world — and at U.S. border crossings and elsewhere within the United States. Hundreds of tons of potential nuclear bomb material are actually being destroyed (for example, by blending HEU with other uranium to produce LEU reactor fuel that cannot be used in a bomb); remarkably, roughly one of every 10 light bulbs in the United States is powered with fuel from dismantled Russian nuclear weapons. These programs continue to be excellent investments in U.S. and world security.
But important gaps remain. Security upgrades have not yet been completed for scores of nuclear material buildings and warhead sites in Russia — and for some, there is no agreement to cooperate on security upgrades. Upgrades in China are just beginning, and India has not yet agreed to cooperate on nuclear security improvements. Only a small fraction of the world's HEU-fueled research reactors have had all their HEU removed. Most of the HEU the United States itself shipped to countries around the world for use as research reactor fuel is not yet eligible for the U.S. offer to take it back. A dangerous gap remains between the urgency of the threat and the scope and pace of the U.S. and international response.
What is highly enriched uranium? What is enrichment?
Highly enriched uranium is uranium that contains 20 percent or more of the isotope uranium-235 (U-235 for short). Because it easily fissions, uranium-235 is useful in powering nuclear reactors or nuclear bombs.
Natural uranium mined from the ground contains only 0.7 percent U-235 and cannot sustain the explosive nuclear chain reaction needed for a nuclear bomb. To make HEU, the uranium has to be "enriched" -- that is, the concentration of U-235 has to be increased. Separating the atoms of U-235 from the atoms of U-238 (which make up more than 99 percent of natural uranium) requires complex and difficult technology, since these atoms have the same chemical properties and differ only slightly in weight. Terrorist groups would almost certainly not have the technical or financial means to enrich their own uranium. Unfortunately, the same technologies used to make LEU for peaceful reactor fuel can also be used to make HEU for nuclear weapons — which is why Iran's pursuit of uranium enrichment technology is raising international concern.
What is plutonium and where is it found?
Plutonium is a man-made radioactive element that can be used in nuclear fuel or nuclear weapons. It is extremely heavy, with 94 protons in its nucleus. Plutonium is produced when an atom of U-238 absorbs a neutron, typically in a nuclear reactor. All current nuclear power reactors produce plutonium in their spent fuel, though this plutonium cannot be used in nuclear weapons until it has been chemically separated from the uranium and the intensely radioactive fission products in the spent fuel, a step known as reprocessing. As with uranium enrichment, it is extremely unlikely that terrorists could build and operate their own nuclear reactor and reprocessing facility to produce plutonium for a bomb. Plutonium-239, the most common isotope and the one most useful in nuclear weapons, has a half-life of 24,000 years (meaning that half of it will have decayed after that time, half of the remainder after another 24,000 years, and so on). Over geologic time, therefore, plutonium has decayed away and little of it exists in nature.
What are weapons-grade uranium and weapons-grade plutonium?
In principle, any HEU can fuel a nuclear bomb. However, the greater the concentration of U-235, the less HEU is needed for the bomb. Weapons-grade uranium consists of 90 percent or greater U-235. Despite this definition, however, nuclear bombs can be and have been made with less enriched material. The average enrichment of the HEU used in the Hiroshima bomb was roughly 80 percent.
Weapon-grade plutonium typically contains 93 percent or more plutonium-239 (Pu-239), the isotope most useful in nuclear weapons. The plutonium in the spent fuel discharged from typical power reactors is "reactor-grade," containing larger concentrations of Pu-240 and Pu-241, which are more troublesome for weapons designers. Nevertheless, government studies have concluded that any state or group that could make a bomb from weapon-grade plutonium could also make a bomb from reactor-grade plutonium.
How much HEU and plutonium exists in the world?
World stockpiles of separated plutonium and HEU, the essential ingredients of nuclear weapons, amount to well over 2,300 tons — enough to manufacture over 200,000 nuclear weapons. These materials exist in more than 40 countries, though Russia and the United States have by far the largest stockpiles. The global HEU stockpile is overwhelmingly military, but the 65 tons of the HEU stockpile that is in civilian use is enough for hundreds of nuclear bombs. The global stockpile of plutonium for military uses is in the range of 250 tons, and there are now more than 250 tons of separated plutonium in the civilian sector worldwide as well.
How many states have nuclear weapons?
Nine. Eight countries have demonstrated nuclear weapons capability by having conducted one or more nuclear tests. These states are China, France, India, North Korea, Pakistan, Russia, the United States, and the United Kingdom. In addition, Israel is widely believed to possess an arsenal of nuclear weapons.
How many states have abandoned nuclear weapons?
South Africa is the only state to have built its own nuclear arsenal and then completely dismantled it — the first case of real nuclear disarmament. The last apartheid government under President F. W. de Klerk made this dismantlement decision and completed the dismantlement before handing over power to African National Congress led by Nelson Mandela in the early 1990s. Also in the mid-1990s, Belarus, Kazakhstan and Ukraine agreed to relinquish nuclear weapons left on their soil when the Soviet Union collapsed (though these states never had complete control of these weapons).
Many other states have started nuclear weapons programs and then verifiably abandoned them, concluding that it was in their national interest not to have nuclear weapons. Indeed, there are more states that have started nuclear weapons programs and given them up than there are states with nuclear weapons — so efforts to stop the spread of nuclear weapons succeed more often than they fail.
How many nuclear weapons are there in the world?
While there is no official census of the total number of nuclear weapons, the Natural Resources Defense Council (NRDC) compiles some of the best unofficial estimates. According to the NRDC, nine states possess about 26,000 intact nuclear weapons. Russia and the United States have 97 percent of the world's nuclear weapons. About 12,500 of the world's nuclear weapons are considered operational, with the rest in reserve or awaiting dismantlement. In the United States, NRDC estimates that there are nearly 10,000 total intact warheads, of which just over 5,700 are operational. Russia has been very guarded about revealing the size of its stockpile but is believed to have something in the range of 15,000 intact warheads, with over 5,600 operational. The United Kingdom has about 200 warheads. France holds about 350 warheads. China is thought to possess around 200 warheads. NRDC estimates that India has roughly 85 warheads, and Pakistan in the range of 60 warheads. For Israel, NRDC cites a Defense Intelligence Agency estimate of 60 to 80 warheads. Finally, NRDC estimates that North Korea may have roughly ten warheads, though no one knows for sure.
What about a "dirty bomb"? How is that different from a nuclear bomb?
A "dirty bomb" simply spreads radioactive material over an area, to create panic and force people to evacuate. In most dirty bomb scenarios, there would be few if any immediate deaths from radiation — most of the impact would be from economic disruption, if many blocks of a city had to be evacuated for an extended time. This stands in stark contrast to an actual nuclear bomb, whose blast and fire could incinerate the heart of any major city and kill tens or hundreds of thousands of people.
A dirty bomb — more formally known as a radioactive dispersal device (RDD) — would be far easier for terrorists to make, potentially as simple as putting radioactive material in a box with conventional explosives and setting it off. Unlike the plutonium or HEU needed for a nuclear bomb, radioactive materials that might be used in a dirty bomb exist at tens of thousands of locations all over the world: many hospitals, for example, use large radioactive sources. In other words, the probability of a dirty bomb attack is substantially higher than the probability of a terrorist attack with a nuclear bomb, but the consequences of a dirty bomb attack would be far lower.
What about sabotage of a major nuclear facility?
Terrorists might attempt to sabotage a nuclear facility in any number of ways, from attack by a group of outsiders on the ground, to insider sabotage, to attempting to crash a plane into the facility. In most countries, nuclear facilities that would have major consequences if sabotaged are guarded and equipped with strong buildings and containment vessels and redundant safety systems. Although most nuclear power plants were not specifically designed against the possibility of a large plane crash, government and industry studies have concluded that most types of possible crashes would not lead to radioactive releases. Nevertheless, if terrorists managed to overcome these protections, they could potentially cause a devastating radioactive release, which might cause hundreds of fatalities in the weeks after an attack, thousands of longer-term deaths, and contamination of a wide area. Sabotage of a major nuclear facility is probably in between nuclear bombs and dirty bombs in both probability and consequences.
Is it really plausible that terrorists could get and use a nuclear bomb?
Yes. Unfortunately, terrorist use of a nuclear bomb is a very real danger. During the 2004 presidential campaign, President George W. Bush and Senator John Kerry (D-Mass.) agreed that nuclear terrorism was the single greatest threat to U.S. national security. Published estimates of the chance that terrorists will detonate a nuclear bomb in a U.S. city over the next ten years range from 1 percent to 50 percent. In a 2005 poll of international security experts taken by Senator Richard Lugar (R-Ind.), the median estimate of the chance of a nuclear attack in the next ten years was 29 percent — and a strong majority believed that it was more likely that terrorists would launch a nuclear attack than that a state would. Given the horrifying consequences of such an attack, even a 1 percent chance would be enough to call for rapid action to reduce the risk.
What materials could terrorists use to make a nuclear bomb?
To make a nuclear bomb requires either highly enriched uranium (HEU) or plutonium. Neither of these materials occurs in nature, and producing either of them requires expensive facilities using complex technologies, almost certainly beyond the capability of terrorist groups. Hence, if all of the world's stockpiles of nuclear weapons, HEU and plutonium can be effectively protected and kept out of terrorist hands, nuclear terrorism can be prevented: no nuclear material, no bomb, no nuclear terrorism.
How difficult would it be for terrorists to get the materials needed to make a nuclear bomb?
Highly enriched uranium and plutonium are hard to make, but may not be so hard to steal. These raw materials of nuclear terrorism are housed in hundreds of facilities in dozens of countries — some with excellent security, and some secured by nothing more than an underpaid guard and a chain link fence. There are no binding global standards setting out how well nuclear weapons and the materials needed to make them should be secured.
Theft of the essential ingredients of nuclear weapons is not just a hypothetical worry, it is an ongoing reality. The International Atomic Energy Agency (IAEA) has documented 15 cases of theft of HEU or plutonium confirmed by the countries concerned (and there are additional well-documented cases that the countries involved have not yet been willing to confirm). In many of these cases, the thieves and smugglers were attempting to sell the material to anyone who would buy it — and terrorist groups have been seeking to buy it.
How much expertise is needed to make a nuclear bomb? Would a large operation be required?
Unfortunately, government studies have concluded that once a terrorist organization had the needed nuclear material, a handful of skilled individuals might be able to make a crude nuclear bomb using commercially available tools and equipment, without any large fixed facilities that might draw attention, and without access to classified nuclear weapons information. Getting nuclear material and making a crude nuclear bomb would be the most complex operation terrorists have ever carried out, but the risk that a sophisticated group could pull it off is very real. Roughly 90 percent of the effort in the Manhattan Project was focused on making nuclear bomb material; getting stolen nuclear material would allow terrorists to skip the hardest part of making a nuclear bomb.
The simplest type of nuclear bomb, known as a "gun-type" bomb, slams two pieces of nuclear material together at high speed. The bomb that destroyed Hiroshima, for example, was a cannon that fired a shell of HEU into rings of HEU. Plutonium cannot be used to make a gun-type bomb with a substantial explosive yield, because the neutrons that all plutonium emits cause the bomb to blow itself apart before the nuclear reactions proceeds very far. To make a bomb from plutonium would require a more complex "implosion-type" bomb, which would be more difficult for terrorists to build — but government studies have repeatedly concluded that this possibility also cannot be ruled out.
How much nuclear material would terrorists need to make a bomb?
The amount of nuclear material needed to make a bomb depends on the material and the skill of the bomb-maker. A simple gun-type nuclear bomb would require approximately 50 kilograms of HEU — an amount that would fit in a suitcase. Implosion-type bombs are more efficient, requiring less nuclear material. Unclassified estimates suggest that basic first-generation implosion-type bombs like the Nagasaki bomb can be made with 6 kilograms of plutonium or 15 kilograms of HEU. With these relatively small amounts, a terrorist group could potentially build a bomb with the power of thousands of tons of high explosive. Sophisticated nuclear weapon states can potentially make nuclear bombs with smaller amounts of nuclear material.
Rather than stealing nuclear material and making a bomb, could terrorists steal and use an already assembled nuclear weapon?
Possibly. Nuclear weapons are generally better secured than some stocks of HEU and plutonium are. Nevertheless, the United States is spending hundreds of millions of dollars beefing up security for its own nuclear weapons complex sites, and hundreds of millions more helping Russia improve security for its warhead sites.
A stolen nuclear weapon might be very difficult for a terrorist group to detonate. Many nuclear weapons are equipped with electronic locks making it impossible to set off the weapon without putting in the appropriate code or figuring out a way to bypass the lock. Unfortunately, on older Russian tactical nuclear weapons, such locks are thought to be absent in some cases and relatively easily bypassed in others. U.S. strategic nuclear weapons also do not incorporate such locks, and some other countries' weapons may also lack them. In addition, modern nuclear weapons are typically equipped with devices that prevent the weapon from going off until it has passed through its expected flight sequence — such as a period of rocket-powered flight followed by coasting through space and reentering the atmosphere, in the case of a long-range ballistic missile. While designed more for safety than security, these devices would also make it more difficult to detonate most stolen weapons. If terrorists could not figure out how to detonate a stolen weapon, they might choose to cut it open and use the nuclear material inside to try to make a bomb of their own.
Are there "suitcase nukes" on the loose?
Probably not. In the 1990s, Gen. Alexander Lebed, then the national security advisor to Russian President Boris Yeltsin, said that more than 100 nuclear weapons designed to be carried by one person — so-called "suitcase nukes" — could not be accounted for and might be missing. The Russian Ministry of Defense firmly denied that any weapons were missing, and Lebed ultimately backed off from his initial statements. Ultimately enough information was released to make a reasonably convincing case that none of these man-portable nuclear weapons were missing. It is clear, however, that both the United States and the Soviet Union did in fact manufacture nuclear weapons designed to be carried and used by one or two people. In the United States, all such weapons have been dismantled, and some Russian statements indicate that the same is now true in Russia.
Once a nuclear bomb or nuclear material has been stolen, could we stop it from being smuggled?
The chances would not be very good, unfortunately. The amounts of HEU or plutonium needed for a bomb are small and easy to smuggle. These materials are not radioactive enough to require any special equipment to carry them, or to make them easy to detect. After they have left the site where they are supposed to be, they could be anywhere, and all the later lines of defense are variations on searching for needles in haystacks. With hundreds of millions of people and vehicles crossing U.S. borders every year, making sure no one gets in with a suitcase of potential bomb material is an immense challenge. Even if governments screened every container coming across their borders with a radiation detector, terrorists would not be likely to send their nuclear bomb material through one of the readily-observable radiation detectors, but would use one of the many other possible routes to avoid inspection. Moreover, if HEU was shielded with lead, detectors now being deployed would not be able to detect the weak radiation it emits (unless it was contaminated with the isotope U-232, and the detector was designed to look for the gamma rays from that decay chain). If the United States cannot stop the flow of illegal drugs and illegal immigrants across its borders, it is unlikely that it will succeed in stopping nuclear material. Even an assembled nuclear bomb might fit in the hold of a yacht, in a truck, or in a small plane.
What would happen if terrorists set off a nuclear bomb in a major city?
Terrorist use of a nuclear bomb would be an historic catastrophe. If a crude nuclear bomb with an explosive equivalent of 10,000 tons of TNT (10 "kilotons" in the language of nuclear weapons) were set off at Grand Central Station on a typical work-day, some 500,000 people might be killed, and hundreds of thousands more would be injured, burned, and irradiated. The direct economic damage would likely be in the range of $1 trillion, and the reverberating economic effects throughout the United States and the world would come to several times that figure. In 2005, then-UN Secretary General Kofi Annan warned that such an attack "would stagger the world economy and thrust tens of millions of people into dire poverty," causing "a second death toll throughout the developing world." The terrorists would surely claim they had more bombs already hidden in U.S. cities, potentially provoking widespread panic and economic disruption. In short, America and the world would be changed forever.
What terrorist groups are known to be seeking nuclear weapons?What do we know about their attempts?
Al Qaeda has been seeking nuclear weapons and the material needed to make them for more than a decade. Osama bin Laden and his followers have repeatedly attempted to acquire stolen nuclear material and to recruit nuclear expertise. In 2001, for example, bin Laden and his deputy Ayman al-Zawahiri met at length with two senior Pakistani nuclear scientists and discussed nuclear weapons. As early as 1993, al Qaeda attempted to purchase what it believed was HEU in the Sudan. In the 1990s, the Japanese terror cult Aum Shinrikyo, which launched the nerve gas attack in the Tokyo subway, also attempted to get nuclear weapons. Russian officials have confirmed that Chechen terrorist teams have carried out reconnaissance at Russian nuclear warhead storage sites, and in 2005, the Russian Minister of the Interior warned that Russia had intelligence that Chechen groups were planning "attacks against nuclear and power industry installation" intended to "seize nuclear materials and use them to build weapons of mass destruction." Some Chechen factions are closely linked to al Qaeda.
Has any terrorist group succeeded in acquiring nuclear material?
Despite various terrorist claims, there is no convincing evidence that any terrorist group has yet succeeded in getting a nuclear bomb or the HEU or plutonium needed to make one.
What has been done to reduce the risk of nuclear theft and terrorism?
A wide range of programs in the United States and elsewhere are making real progress in reducing the global danger of nuclear terrorism — but much more remains to be done. Through Nunn-Lugar cooperative threat reduction programs and related efforts, security has been dramatically improved at scores of buildings and bunkers with either nuclear weapons or the materials needed to make them in the former Soviet Union and in other countries around the world. Hundreds of kilograms of HEU have been removed from potentially vulnerable nuclear sites around the world. HEU-fueled research reactors are being converted to run on low-enriched uranium (LEU) fuel that cannot be used in a nuclear bomb, and their HEU is being removed. As a second line of defense, radiation detectors are being installed at key ports and border crossings around the world — and at U.S. border crossings and elsewhere within the United States. Hundreds of tons of potential nuclear bomb material are actually being destroyed (for example, by blending HEU with other uranium to produce LEU reactor fuel that cannot be used in a bomb); remarkably, roughly one of every 10 light bulbs in the United States is powered with fuel from dismantled Russian nuclear weapons. These programs continue to be excellent investments in U.S. and world security.
But important gaps remain. Security upgrades have not yet been completed for scores of nuclear material buildings and warhead sites in Russia — and for some, there is no agreement to cooperate on security upgrades. Upgrades in China are just beginning, and India has not yet agreed to cooperate on nuclear security improvements. Only a small fraction of the world's HEU-fueled research reactors have had all their HEU removed. Most of the HEU the United States itself shipped to countries around the world for use as research reactor fuel is not yet eligible for the U.S. offer to take it back. A dangerous gap remains between the urgency of the threat and the scope and pace of the U.S. and international response.
What is highly enriched uranium? What is enrichment?
Highly enriched uranium is uranium that contains 20 percent or more of the isotope uranium-235 (U-235 for short). Because it easily fissions, uranium-235 is useful in powering nuclear reactors or nuclear bombs.
Natural uranium mined from the ground contains only 0.7 percent U-235 and cannot sustain the explosive nuclear chain reaction needed for a nuclear bomb. To make HEU, the uranium has to be "enriched" -- that is, the concentration of U-235 has to be increased. Separating the atoms of U-235 from the atoms of U-238 (which make up more than 99 percent of natural uranium) requires complex and difficult technology, since these atoms have the same chemical properties and differ only slightly in weight. Terrorist groups would almost certainly not have the technical or financial means to enrich their own uranium. Unfortunately, the same technologies used to make LEU for peaceful reactor fuel can also be used to make HEU for nuclear weapons — which is why Iran's pursuit of uranium enrichment technology is raising international concern.
What is plutonium and where is it found?
Plutonium is a man-made radioactive element that can be used in nuclear fuel or nuclear weapons. It is extremely heavy, with 94 protons in its nucleus. Plutonium is produced when an atom of U-238 absorbs a neutron, typically in a nuclear reactor. All current nuclear power reactors produce plutonium in their spent fuel, though this plutonium cannot be used in nuclear weapons until it has been chemically separated from the uranium and the intensely radioactive fission products in the spent fuel, a step known as reprocessing. As with uranium enrichment, it is extremely unlikely that terrorists could build and operate their own nuclear reactor and reprocessing facility to produce plutonium for a bomb. Plutonium-239, the most common isotope and the one most useful in nuclear weapons, has a half-life of 24,000 years (meaning that half of it will have decayed after that time, half of the remainder after another 24,000 years, and so on). Over geologic time, therefore, plutonium has decayed away and little of it exists in nature.
What are weapons-grade uranium and weapons-grade plutonium?
In principle, any HEU can fuel a nuclear bomb. However, the greater the concentration of U-235, the less HEU is needed for the bomb. Weapons-grade uranium consists of 90 percent or greater U-235. Despite this definition, however, nuclear bombs can be and have been made with less enriched material. The average enrichment of the HEU used in the Hiroshima bomb was roughly 80 percent.
Weapon-grade plutonium typically contains 93 percent or more plutonium-239 (Pu-239), the isotope most useful in nuclear weapons. The plutonium in the spent fuel discharged from typical power reactors is "reactor-grade," containing larger concentrations of Pu-240 and Pu-241, which are more troublesome for weapons designers. Nevertheless, government studies have concluded that any state or group that could make a bomb from weapon-grade plutonium could also make a bomb from reactor-grade plutonium.
How much HEU and plutonium exists in the world?
World stockpiles of separated plutonium and HEU, the essential ingredients of nuclear weapons, amount to well over 2,300 tons — enough to manufacture over 200,000 nuclear weapons. These materials exist in more than 40 countries, though Russia and the United States have by far the largest stockpiles. The global HEU stockpile is overwhelmingly military, but the 65 tons of the HEU stockpile that is in civilian use is enough for hundreds of nuclear bombs. The global stockpile of plutonium for military uses is in the range of 250 tons, and there are now more than 250 tons of separated plutonium in the civilian sector worldwide as well.
How many states have nuclear weapons?
Nine. Eight countries have demonstrated nuclear weapons capability by having conducted one or more nuclear tests. These states are China, France, India, North Korea, Pakistan, Russia, the United States, and the United Kingdom. In addition, Israel is widely believed to possess an arsenal of nuclear weapons.
How many states have abandoned nuclear weapons?
South Africa is the only state to have built its own nuclear arsenal and then completely dismantled it — the first case of real nuclear disarmament. The last apartheid government under President F. W. de Klerk made this dismantlement decision and completed the dismantlement before handing over power to African National Congress led by Nelson Mandela in the early 1990s. Also in the mid-1990s, Belarus, Kazakhstan and Ukraine agreed to relinquish nuclear weapons left on their soil when the Soviet Union collapsed (though these states never had complete control of these weapons).
Many other states have started nuclear weapons programs and then verifiably abandoned them, concluding that it was in their national interest not to have nuclear weapons. Indeed, there are more states that have started nuclear weapons programs and given them up than there are states with nuclear weapons — so efforts to stop the spread of nuclear weapons succeed more often than they fail.
How many nuclear weapons are there in the world?
While there is no official census of the total number of nuclear weapons, the Natural Resources Defense Council (NRDC) compiles some of the best unofficial estimates. According to the NRDC, nine states possess about 26,000 intact nuclear weapons. Russia and the United States have 97 percent of the world's nuclear weapons. About 12,500 of the world's nuclear weapons are considered operational, with the rest in reserve or awaiting dismantlement. In the United States, NRDC estimates that there are nearly 10,000 total intact warheads, of which just over 5,700 are operational. Russia has been very guarded about revealing the size of its stockpile but is believed to have something in the range of 15,000 intact warheads, with over 5,600 operational. The United Kingdom has about 200 warheads. France holds about 350 warheads. China is thought to possess around 200 warheads. NRDC estimates that India has roughly 85 warheads, and Pakistan in the range of 60 warheads. For Israel, NRDC cites a Defense Intelligence Agency estimate of 60 to 80 warheads. Finally, NRDC estimates that North Korea may have roughly ten warheads, though no one knows for sure.
What about a "dirty bomb"? How is that different from a nuclear bomb?
A "dirty bomb" simply spreads radioactive material over an area, to create panic and force people to evacuate. In most dirty bomb scenarios, there would be few if any immediate deaths from radiation — most of the impact would be from economic disruption, if many blocks of a city had to be evacuated for an extended time. This stands in stark contrast to an actual nuclear bomb, whose blast and fire could incinerate the heart of any major city and kill tens or hundreds of thousands of people.
A dirty bomb — more formally known as a radioactive dispersal device (RDD) — would be far easier for terrorists to make, potentially as simple as putting radioactive material in a box with conventional explosives and setting it off. Unlike the plutonium or HEU needed for a nuclear bomb, radioactive materials that might be used in a dirty bomb exist at tens of thousands of locations all over the world: many hospitals, for example, use large radioactive sources. In other words, the probability of a dirty bomb attack is substantially higher than the probability of a terrorist attack with a nuclear bomb, but the consequences of a dirty bomb attack would be far lower.
What about sabotage of a major nuclear facility?
Terrorists might attempt to sabotage a nuclear facility in any number of ways, from attack by a group of outsiders on the ground, to insider sabotage, to attempting to crash a plane into the facility. In most countries, nuclear facilities that would have major consequences if sabotaged are guarded and equipped with strong buildings and containment vessels and redundant safety systems. Although most nuclear power plants were not specifically designed against the possibility of a large plane crash, government and industry studies have concluded that most types of possible crashes would not lead to radioactive releases. Nevertheless, if terrorists managed to overcome these protections, they could potentially cause a devastating radioactive release, which might cause hundreds of fatalities in the weeks after an attack, thousands of longer-term deaths, and contamination of a wide area. Sabotage of a major nuclear facility is probably in between nuclear bombs and dirty bombs in both probability and consequences.
I think the saving grace to all this is simple cause an effect. Let's say al quad had wanted a nuke before 9/11 they had huge number of followers and resources in Afghanistan maybe They could have stolen one from Pakistan (I am guessing the location of the nukes is known). So they pinch a nuke and then they use it kills 1 million people....what would be the response ground offensive air strikes....or a f
kin nuke but a much bigger one sent back so kandahr glows in the dark for next.1000 years.
A nuke would change the game no more avoid civilian deaths precision air strikes etc etc WMD use I think is a line in the sand even IS leaders don't want to cross.
kin nuke but a much bigger one sent back so kandahr glows in the dark for next.1000 years.A nuke would change the game no more avoid civilian deaths precision air strikes etc etc WMD use I think is a line in the sand even IS leaders don't want to cross.
drivetrain said:
Gecko1978 said:
I think the saving grace to all this is simple cause an effect. Let's say al quad had wanted a nuke before 9/11 they had huge number of followers and resources in Afghanistan maybe They could have stolen one from Pakistan (I am guessing the location of the nukes is known). So they pinch a nuke and then they use it kills 1 million people....what would be the response ground offensive air strikes....or a fkin nuke but a much bigger one sent back so kandahr glows in the dark for next.1000 years.
A nuke would change the game no more avoid civilian deaths precision air strikes etc etc WMD use I think is a line in the sand even IS leaders don't want to cross.
They wouldn't give a toss about retaliation, the more the better. They're trying to fulfil a religious prophecy, they want Armageddon.kin nuke but a much bigger one sent back so kandahr glows in the dark for next.1000 years.A nuke would change the game no more avoid civilian deaths precision air strikes etc etc WMD use I think is a line in the sand even IS leaders don't want to cross.
k about God etc it's a means to an end. The end being ruling say the middle east etc. So a nuclear strike is not going to allow that dream etc.Gecko1978 said:
or a fkin nuke but a much bigger one sent back so kandahr glows in the dark for next.1000 years.
A fission bomb is indeed dirty and causes widespread contamination.kin nuke but a much bigger one sent back so kandahr glows in the dark for next.1000 years.Since the 70s, the superpowers have had Fusion nukes, which rely on the enormous energy released by fusing hydrogen into helium. Much, much, much bigger bang capable of levelling several hundred square mile, but with no lingering after-effects.
Kandahar would be razed into the weeds but it wouldn't be glowing in the dark
My background is in the R.A.F. and a subsequent civilian career in engineering, I also have a physics degree.
I have to say that there is simply no real info on the central physics package of a nuclear weapon available out side of deeply secret governmental research.
In service yellow sun/green grass/red snow, ( the second two referring to the 'innards'), were the earliest weapons we studied, yet absolutely nothing was known by us, not even a hint of the detailed inner workings.
Its possible to conjecture about green grass because of the 'balls', but nothing firm is known.
I've been to Aldermaston and 'the other place' and from conversation with boffins I doubt any one person has the expertise to build a workable device.
No real data is available, even those websites and physicists who talk about 'gun designs' and 'tampers' are flying blind.
By 'workable' I mean a guaranteed successful shot.
A 'dirty' bomb is very possible though.
One thing that, MUST be considered by any terrorist organisation deploying a nuke against any nuclear armed country is that if a sponsoring state is established to be behind an attack then nuclear retaliation is almost certain.
In my opinion no terrorist organisation is willing to risk nuclear obliteration for any aim, witness the aftermath of 9/11 and think how much greater the response would have been had that been an act of nuclear terrorism.
I have to say that there is simply no real info on the central physics package of a nuclear weapon available out side of deeply secret governmental research.
In service yellow sun/green grass/red snow, ( the second two referring to the 'innards'), were the earliest weapons we studied, yet absolutely nothing was known by us, not even a hint of the detailed inner workings.
Its possible to conjecture about green grass because of the 'balls', but nothing firm is known.
I've been to Aldermaston and 'the other place' and from conversation with boffins I doubt any one person has the expertise to build a workable device.
No real data is available, even those websites and physicists who talk about 'gun designs' and 'tampers' are flying blind.
By 'workable' I mean a guaranteed successful shot.
A 'dirty' bomb is very possible though.
One thing that, MUST be considered by any terrorist organisation deploying a nuke against any nuclear armed country is that if a sponsoring state is established to be behind an attack then nuclear retaliation is almost certain.
In my opinion no terrorist organisation is willing to risk nuclear obliteration for any aim, witness the aftermath of 9/11 and think how much greater the response would have been had that been an act of nuclear terrorism.
I'm not worried. NK have been ploughing people and money into this for decades and still can't get it right and as someone else mentioned the betting money is the first fundamentalist nuke going off in India.
And to be frank, I'm actually more concerned about the response if this did happen, than the event itself.
And to be frank, I'm actually more concerned about the response if this did happen, than the event itself.
ChemicalChaos said:
A fission bomb is indeed dirty and causes widespread contamination.
Since the 70s, the superpowers have had Fusion nukes, which rely on the enormous energy released by fusing hydrogen into helium. Much, much, much bigger bang capable of levelling several hundred square mile, but with no lingering after-effects.
Kandahar would be razed into the weeds but it wouldn't be glowing in the dark
Thermonuclear or "H" weapons are a combined fission/fusion cycle, no pure fusion devices are known to exist; furthermore the major source of fallout is small, rapidly moving bits of the former environment that have been rendered radioactive by the enormous neutron flux generated by the exploding device. They really are not cleaner in any meaningful sense.Since the 70s, the superpowers have had Fusion nukes, which rely on the enormous energy released by fusing hydrogen into helium. Much, much, much bigger bang capable of levelling several hundred square mile, but with no lingering after-effects.
Kandahar would be razed into the weeds but it wouldn't be glowing in the dark
ChemicalChaos said:
A fission bomb is indeed dirty and causes widespread contamination.
Since the 50s, the superpowers have had Fusion nukes, which rely on the enormous energy released by fusing hydrogen into helium. Much, much, much bigger bang capable of levelling several hundred square mile, but with no lingering after-effects.
Kandahar would be razed into the weeds but it wouldn't be glowing in the dark
Fixed that for you.Since the 50s, the superpowers have had Fusion nukes, which rely on the enormous energy released by fusing hydrogen into helium. Much, much, much bigger bang capable of levelling several hundred square mile, but with no lingering after-effects.
Kandahar would be razed into the weeds but it wouldn't be glowing in the dark
Hydrogen bombs do leave radiation behind, just ask any Japanese fisherman...
jimreed said:
I've been to Aldermaston and 'the other place' and from conversation with boffins I doubt any one person has the expertise to build a workable device.
No real data is available, even those websites and physicists who talk about 'gun designs' and 'tampers' are flying blind.
By 'workable' I mean a guaranteed successful shot.
If you’re taking about a basic fission bomb then I totally disagree. Anyone with a good grounding in reactor physics can work out the parameters you need for a viable bomb. All of the data you need is available. Anyone with a reasonable understanding of explosives and a bit of freedom to experiment could work out how to meet the parameters. The US government did the experiment back in the 60’s. Take a couple of keen physics grads who know nothing classified and see if they can work it out. Look up the “Nth country experiment”. These days it’d be even easier.No real data is available, even those websites and physicists who talk about 'gun designs' and 'tampers' are flying blind.
By 'workable' I mean a guaranteed successful shot.
If it’s a discussion about terrorists rather than countries, it’s likely to be a moot point anyway. The only way they could get their hands on enough fissile material is to buy or steal 3 or 4 modern weapons. It seems a bit perverse to take them to pieces to make one crap bomb.
jimreed said:
My background is in the R.A.F. and a subsequent civilian career in engineering, I also have a physics degree.
I have to say that there is simply no real info on the central physics package of a nuclear weapon available out side of deeply secret governmental research.
In service yellow sun/green grass/red snow, ( the second two referring to the 'innards'), were the earliest weapons we studied, yet absolutely nothing was known by us, not even a hint of the detailed inner workings.
Its possible to conjecture about green grass because of the 'balls', but nothing firm is known.
I've been to Aldermaston and 'the other place' and from conversation with boffins I doubt any one person has the expertise to build a workable device.
No real data is available, even those websites and physicists who talk about 'gun designs' and 'tampers' are flying blind.
By 'workable' I mean a guaranteed successful shot.
A 'dirty' bomb is very possible though.
One thing that, MUST be considered by any terrorist organisation deploying a nuke against any nuclear armed country is that if a sponsoring state is established to be behind an attack then nuclear retaliation is almost certain.
In my opinion no terrorist organisation is willing to risk nuclear obliteration for any aim, witness the aftermath of 9/11 and think how much greater the response would have been had that been an act of nuclear terrorism.
People like I.S capitalise and thrive on instability, nuclear armageddon would provide the ideal scenario for IS advances - a vulnerable, weakened and desperate populace, governance in total disarray, modern infrastructure destroyed. Being bombed back into the stone age is probably what they want.I have to say that there is simply no real info on the central physics package of a nuclear weapon available out side of deeply secret governmental research.
In service yellow sun/green grass/red snow, ( the second two referring to the 'innards'), were the earliest weapons we studied, yet absolutely nothing was known by us, not even a hint of the detailed inner workings.
Its possible to conjecture about green grass because of the 'balls', but nothing firm is known.
I've been to Aldermaston and 'the other place' and from conversation with boffins I doubt any one person has the expertise to build a workable device.
No real data is available, even those websites and physicists who talk about 'gun designs' and 'tampers' are flying blind.
By 'workable' I mean a guaranteed successful shot.
A 'dirty' bomb is very possible though.
One thing that, MUST be considered by any terrorist organisation deploying a nuke against any nuclear armed country is that if a sponsoring state is established to be behind an attack then nuclear retaliation is almost certain.
In my opinion no terrorist organisation is willing to risk nuclear obliteration for any aim, witness the aftermath of 9/11 and think how much greater the response would have been had that been an act of nuclear terrorism.
anonymous said:
[redacted]
I hate hypothosising on things like this as I doubt there are more than a handful of people in the world who would know the true responce. But lets say someone detonated a nuclear device in the UK they kill 100,000 etc. An lets say IS did it. So we sail a sub to the nearest point needed then fire a nuke or 11 at Ramadi (IS main strong hold).We kill 100,000 or more its not the stone age its end of days type stuff. No desperate population to rule with a medievil like grip etc no new country rising up in the name of Allah etc. just a lot of very dead people land that's toxic for 1000's of years and the possibility of even more deaths as we bomb conventionally other towns who harbour IS supporters.
Now given that do you think Iran, Jordan, Quatar Saudi etc want that to happen and would they do anything to prevent that happening on their doorstep like maybe stop funding IS and or increasing support militarially agaist them (Iran are sort of hero squad in that respect). So IS and a nuke I think is far fetched no one wants end of the world they want to rule a world (that night be a medievil hell hole for sure) even if its a small part of it.
Re a dirty bomb, this is probably the most likely and terrifying thing that a country like us faces.
Forget about mushroom clouds and atomised tourists in Trafalgar Sq, they're just not about that.
All you need is some properly radioactive material and something to detonate and spread it over a wide area. If this was done in central London or any other relatively compact capital the results would be economically devastating.
Firstly every worker would have to leave. The risk of contracting some form of cancer would increase several fold. Even if the risk triples there isn't a company on earth who would ask or expect their staff to stay put.
Then there would be the clean up. That would cost billions and take a long time.
Then there would be the cost of people's attitudes. Where would you draw a line? If something went off in the city would you still be happy sitting at your desk in Holborn while the offices over the road at St Paul's are abandoned?
A bomb like this could kill a few people yes, but the economic fallout would be crippling. Set 3 off together in London/Birmingham/Manchester and you could bankrupt the country in a day.
As for the material, go over to Georgia, Ukraine etc and see how much stuff you could buy in a few days. Collect up a number of old xray machines and you're halfway there. This material is all over the place, far easier to get than anything near fissile and pretty much available to the bloke with the deepest pockets.
Forget about mushroom clouds and atomised tourists in Trafalgar Sq, they're just not about that.
All you need is some properly radioactive material and something to detonate and spread it over a wide area. If this was done in central London or any other relatively compact capital the results would be economically devastating.
Firstly every worker would have to leave. The risk of contracting some form of cancer would increase several fold. Even if the risk triples there isn't a company on earth who would ask or expect their staff to stay put.
Then there would be the clean up. That would cost billions and take a long time.
Then there would be the cost of people's attitudes. Where would you draw a line? If something went off in the city would you still be happy sitting at your desk in Holborn while the offices over the road at St Paul's are abandoned?
A bomb like this could kill a few people yes, but the economic fallout would be crippling. Set 3 off together in London/Birmingham/Manchester and you could bankrupt the country in a day.
As for the material, go over to Georgia, Ukraine etc and see how much stuff you could buy in a few days. Collect up a number of old xray machines and you're halfway there. This material is all over the place, far easier to get than anything near fissile and pretty much available to the bloke with the deepest pockets.
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