Nuclear weapon

A nuclear weapon (atomic bomb, nuclear warhead) is a weapon whose action is based on nuclear physical reactions – nuclear fission and/or nuclear fusion. Conventional weapons, on the other hand, derive their explosive energy from chemical reactions in which the atomic nuclei remain unchanged. The development of nuclear weapons technology began with the Second World War.

Together with biological and chemical weapons, nuclear weapons are weapons of mass destruction. When a nuclear weapon explodes, a lot of energy is released in the form of heat, shock waves and ionizing radiation. As a result, a nuclear weapon can destroy an entire city and kill hundreds of thousands of people in a very short time. The radiation causes acute radiation sickness and long-term damage to health. Radioactive fallout contaminates larger areas.

Towards the end of the Second World War, nuclear fission opened up the possibility of realizing the explosive power of thousands of tons of TNT in military explosive devices. The further development into the technically more sophisticated fusion bomb promised bombs with several million tons of TNT equivalent in the context of the arms race at the beginning of the Cold War.

The atomic bomb was first developed by the US in the Manhattan Project. On July 16, 1945, the first nuclear weapon test with a nuclear weapon explosion took place under the project name Trinity. On August 6 and 9, 1945, the atomic bombings of Hiroshima and Nagasaki followed, which claimed hundreds of thousands of victims.

Since then, atomic bombs have no longer been used as weapons. Almost 2100 nuclear weapons tests took place. On June 30, 1946, a USAAF plane dropped an atomic bomb on Bikini Atoll in the Pacific.

The Soviet Union also developed nuclear weapons from 1949 onwards. On October 30, 1961, the Soviet Union detonated the Tsar bomb over the island of Novaya Zemlya, the most powerful nuclear weapon ever detonated at 57 megatons.

During the Cold War, there was an arms race between the US and the Soviet Union, at the height of which the two states together possessed around 70,000 nuclear warheads. Its nuclear arsenal had a total yield of more than 800,000 Hiroshima bombs at the end of the Cold War.

The need to produce plutonium or enriched uranium for nuclear weapons construction led to the development and construction of uranium enrichment facilities and the first nuclear reactors. The experience gained accelerated the development of the civil use of nuclear energy. The most widely used method of nuclear reprocessing, PUREX, has its origins in the extraction of weapons-grade plutonium from low-spent fuel and is therefore still criticized today as a dual-use technology, even if no bomb-capable material can be obtained from the commercial spent fuel of reactors of modern designs.

Nuclear weapons were also attributed an inhibiting effect during the Cold War: it was precisely the threat of a total annihilation of humanity that maintained the “balance of terror” and thus avoided direct confrontation. According to some politicians and political scientists, this contributed to the fact that there was no direct war between the two military blocs. Gradually, other states acquired nuclear weapons; today nine states are considered nuclear powers: the USA, Russia, Great Britain, France, China, Israel, India, Pakistan and North Korea (in chronological order).

Together, these states today (January 2019) have approximately 13,865 nuclear warheads; In the mid-1980s, there were about 70,000. This is enough to destroy humanity several times over (so-called overkill). Worldwide, partly also in the USA itself, the use of these weapons of mass destruction, mainly against the civilian population, is condemned as immoral and ethically irresponsible. The development of the atomic bomb is now considered by many to be the darkest chapter in the history of technology and science, and the atomic bomb has become the epitome of the “curse of technology”.

Preventing the proliferation of nuclear weapons is considered a major challenge to international security in the 21st century. Since the first use of nuclear weapons, in view of the catastrophic humanitarian consequences and the danger that nuclear weapons, and in particular nuclear war, pose to humanity, there have been many calls for their complete disarmament. Some international treaties have led to restrictions and reductions in nuclear arsenals (arms control) and nuclear-weapon-free zones.

History of the nuclear weapons

Term

Shortly after the discovery of radioactivity at the end of the 19th century, it became clear that the decay of radioactive elements releases enormous amounts of energy over long periods of time. Soon, therefore, speculation arose about the technical and military use of this new energy. The word atomic bomb was coined by H. G. Wells in his 1914 novel The World Set Free, which used it to describe a weapon that would use induced radioactivity to cause a long-lasting explosion. The term atomic bomb thus emerged two decades before the discovery of nuclear fission, the basis for the nuclear weapons developed since the 1940s, to which the name already introduced in literature was finally transferred. Wells had dedicated his book to the chemist Frederick Soddy, a collaborator of the then leading nuclear physicist Ernest Rutherford.

In 1911, Rutherford used his atomic model to describe the basic structure of atoms consisting of a heavy nucleus and a light shell of electrons. Subsequently, the so-called atomic physical processes, which also include chemical reactions and in which the electron shell is essentially involved, were distinguished from the more energetic processes in the atomic nucleus (such as radioactivity and nuclear fission), which became the subject of nuclear physics.

Therefore, in the newer technical language, terms such as nuclear weapon or nuclear weapon (to Latin nuclearis ‘concerning the nucleus’) and nuclear power plant are often preferred to the atomic bomb and nuclear power plant; sometimes, however, such use is seen as euphemistic. In Germany, for example, the licensing authorities responsible for nuclear energy are sometimes referred to as nuclear supervision, there is an Atomic Energy Act, and a predecessor of the Federal Ministry of Education and Research had the title Atomic Ministry. The conventional names are also common in the language of most other nations, as the name of the International Atomic Energy Agency (IAEA) shows.

The term atomic bomb initially included only nuclear weapons based on fission (A-bomb), in contrast, fusion weapons were called hydrogen bomb (H-bomb); In addition, there are special developments such as the cobalt bomb and the neutron bomb. The terms nuclear weapons and nuclear weapons are generic terms for all types of weapons that exploit energy gains from nuclear reactions.

Beginnings

Robert Oppenheimer and Edward Teller are widely known for their work in the development of nuclear weapons. The first scientist to seriously consider nuclear weapons was probably the Hungarian physicist Leó Szilárd; In September 1933, he considered the possibility of causing atomic nuclei to form an energy-supplying chain reaction by bombardment by neutrons. This idea was still speculative at the time. The German chemist Ida Noddack-Tacke expressed the assumption in 1934 “that when heavy nuclei are bombarded with neutrons, these nuclei decay into several larger fragments”.

With the discovery of neutron-induced uranium nuclear fission in 1938 by Otto Hahn and Fritz Straßmann and its correct theoretical interpretation by Lise Meitner and her nephew Otto Frisch, the most important theoretical foundations and experimental findings were published in 1939, which made nuclear weapons appear possible with sufficient availability of fissile uranium. This possibility was first recognized by the two German-Austrian emigrants Rudolf Peierls and Otto Frisch, who worked at the University of Birmingham. In a secret memorandum from March 1940, they described theoretical calculations for the construction of a uranium bomb and warned urgently against the possibility of Germany building an atomic bomb. As a result, the British MAUD Commission, which was also kept secret, was set up, which recommended research into the construction of an atomic bomb.

Even before the beginning of the Second World War on September 1, 1939, the three physicists Leó Szilárd, Albert Einstein and Eugene Wigner, who had emigrated from Germany to the United States, sent a letter to the then US President Franklin D. Roosevelt in August 1939 to warn him of the possibility of developing an atomic bomb in Germany and to encourage him to develop his own atomic bomb. In the autumn of 1940, Enrico Fermi and Szilárd received money to begin developing a nuclear reactor. When the U.S. government was convinced by the successes of this work that the development of an atomic bomb was basically possible and the war enemy Germany had this possibility, the research was intensified and finally led to the Manhattan Project.

German Nuclear Fission Project

In Nazi Germany during the Second World War, scientists such as Werner Heisenberg, Carl Friedrich von Weizsäcker, Walther Gerlach, Kurt Diebner and Otto Hahn worked on the utilization of nuclear fission to achieve German war aims as part of the German uranium project.

The fear of the USA that Germany could develop its own nuclear explosive device was an important reason for initiating its own atomic bomb program. It was assumed that several research groups, spread over the territory of the German Reich and partly working independently of each other, worked on the development of a German nuclear weapon until the end of the war. After the war, however, it was determined that no nuclear weapons were developed in the uranium project. In the last large-scale experiment, the Haigerloch research reactor, Heisenberg’s research group had not even succeeded in producing a critical nuclear chain reaction in 1945.

However, there is also research in which secret experiments of the research group around Kurt Diebner with radioactive material in connection with explosions are spoken. This is doubted by many physicists and so far no evidence has been provided for the performance of such tests.

Manhattan Project

In 1942, under the code name “Project Y” (as part of the Manhattan Project), the Los Alamos research laboratory in the US state of New Mexico was designed under the greatest secrecy. From 1943 onwards, several thousand people worked there under the scientific direction of Robert Oppenheimer, many of them scientists and technicians.

On July 16, 1945, the first atomic bomb was detonated above ground near Alamogordo (Trinity test). The nuclear fuel used in the bomb was plutonium and had an explosive power of 21 kilotons of TNT equivalent.

Because of the capitulation of Germany at the beginning of May 1945, i.e. 21/2 months before the Trinity test, no atomic bomb was used in Germany. The first and so far only air raids with atomic bombs were carried out on 6 and 9 August 1945 against the Japanese cities of Hiroshima and Nagasaki.

Operation against Hiroshima and Nagasaki

On August 6, 1945, 21 days after the first successful test at Alamogordo, the bomber Enola Gay dropped the first atomic bomb (explosive: uranium-235), called Little Boy, over the coastal city of Hiroshima, where it detonated at 08:15 local time about 600 m above the ground. Around 90,000 people died immediately, another 50,000 people died of radiation sickness within days to weeks.

On August 9, 1945, the bomber Bockscar was to drop the second atomic bomb (explosive: Plutonium-239), called Fat Man, over Kokura. When there was still poor visibility after three approaches and fuel became scarce, the commander switched to the alternative destination, the coastal city of Nagasaki. Since the cloud cover was too dense there as well, the city center was missed by several kilometers. In addition, because the urban area is hillier than Hiroshima’s, which hindered the spread of the blast wave, there were fewer casualties – although Fat Man’s explosive power was slightly more than 50% stronger than Little Boy’s. Nevertheless, 36,000 people died immediately in this attack; another 40,000 people were irradiated to such an extent that they died within days to weeks.

For a long time, it was assumed that tens of thousands more people had died over the course of years and decades from long-term effects of radiation exposure. Studies from Germany, the USA and Japan have revised these estimates significantly downwards: according to this, slightly more than 700 deaths can be attributed to nuclear contamination.

The significance and necessity of the atomic bomb missions are still controversial today. Proponents have argued that the operation reduced the duration of the war and thus saved millions of lives. Others have argued that the use of atomic bombs was ethically indefensible; the war would have ended in a short time even without the use of atomic bombs and there would have been alternatives that had been rejected, not used or not considered.

Development after the Second World War

For three years, the USA was the only state to have operational nuclear weapons and used them to carry out tests underwater, for example. In 1948 they had about 50 operational warheads. In view of its military inferiority to the Soviet Union in conventional terms, a massive nuclear retaliation against the USSR was first drafted in early 1948 in the “Halfmoon” plan, which initially provided for 133 atomic bombs on 70 Soviet cities, but soon afterward in a reduced version the existing 50 atomic bombs on 20 Soviet cities.

Meanwhile, Britain and the Soviet Union were working on their own atomic bombs. The Soviet Union was already informed about the atomic bomb program by Klaus Fuchs during the Second World War. The Soviet atomic bomb project led to the successful detonation of the first own atomic bomb on 29 August 1949, which Great Britain did not succeed until 2 October 1952 and France on 13 February 1960. In 1962, Britain allowed the United States to conduct the Dominic test series on Christmas Island Kiritimati in the Pacific. The People’s Republic of China detonated its first atomic bomb on October 16, 1964, at the Lop Nor nuclear test site in the Xinjiang Autonomous Region. This nuclear weapon was developed using Soviet technology.

Soldiers as test subjects

The adjacent picture shows an American troop experiment with soldiers at a short distance from the nuclear explosion in 1951 in the USA; it documents the partly careless, partly ignorant handling of radioactivity at that time.

Some 20,000 British soldiers were also transferred to test sites in Australia (12 tests), Kiritimati (6 tests) and Malden Island (3 attempts) without being informed.

The mostly young soldiers were instructed to protect their eyes with their hands or elbows during the tests. The soldiers, who are referred to as Atomic Veterans as witnesses to those tests, reported the explosions as incomparably frightening experiences. They reported that the radiation released was so bright and penetrating that the blood vessels and bones of their own hands and arms became visible through the skin. The ensuing heat wave of the explosion felt like body-piercing fire.

The shock wave also indirectly led to bruises and broken bones, as soldiers were thrown away by the shock wave. Almost all soldiers involved in the tests suffered physical and mental damage. Some soldiers were unable to conceive after the tests; Overall, a much higher infantile mortality rate and more frequent malformations were observed in the descendants of the soldiers. Many of those veterans became chronically ill and had various forms of cancer. According to reports, in almost all of the people present at those tests, the long-term damage was a factor in their later cause of death.

Development of the hydrogen bomb

The further development of nuclear weapons led to the hydrogen bomb. The USA detonated its first hydrogen bomb (codenamed Ivy Mike) on 31 October/1 November 1952. It released 10.4 megatons of TNT equivalent energy, 800 times that of the Hiroshima bomb.

The Soviet Union detonated its first hydrogen bomb on August 12, 1953, at the Semipalatinsk nuclear test site. On November 22, 1955, it detonated its first portable H-bomb. The United States first tested a thermonuclear hydrogen bomb based on the Teller-Ulam design during Operation Redwing (May 4 to July 21, 1956) on May 20, 1956. On October 30, 1961, the Soviet Union detonated the Tsar bomb on the island of Novaya Zemlya, the most powerful nuclear weapon ever detonated at 57 MT.

Britain detonated its first hydrogen bomb in 1957 (Operation Grapple), China detonated the first on 17 June 1967 at the Lop Nor test site (Test No. 6) and France detonated on 24 August 1968 at Fangataufa Atoll (Canopus).

Britain joined the ban on atmospheric nuclear weapons testing in 1962. Thereafter, all tests were carried out underground in cooperation with the USA at the Nevada Test Site (24 tests), most recently in 1991. In total, Great Britain carried out 45 trials.

Post-Cold War development of nuclear weapons

After the collapse of the Soviet Union in the early 1990s, experts doubted the military sense of nuclear weapons, since any target can be destroyed even with conventional weapons of the desired size. The greatest danger of nuclear armament is the use of terrorists because they could cause great damage with little effort if nuclear weapons were used; Nuclear weapons, on the other hand, are completely unsuitable in the fight against terrorism.

Regardless of this development, the USA and Russia, as the successor state of the Soviet Union, remained the states with the most nuclear weapons. Their arsenal will continue to be maintained; it received less and less public attention after the end of the Cold War.

The development of such small nuclear weapons has been regarded by experts as a danger, since their use would hardly attract attention. Instead of destroyed cities and thousands of deaths, the world public would only see a small crater. As a consequence, the inhibition threshold to use nuclear weapons and thus wage wars comparatively cheaply – without loss of own soldiers and without too negative an image – would decrease. The Nuclear Non-Proliferation Treaty would also be called into question, which could have unforeseeable consequences (abolition of the Treaty).

Construction

The technical development of nuclear weapons since the 1940s has produced a wide variety of different variants. A distinction is made between nuclear bombs according to the nuclear fission or fission principle (“classical” atomic bomb) and the nuclear fusion principle (hydrogen or H-bomb).

In a nuclear fission bomb, a supercritical mass of fissile material is brought together for triggering. How high this mass is depends on the material, geometry and construction. The smallest critical mass can be achieved with a spherical shape of the fissile material, the most commonly uranium-235 or plutonium-239 are used. Supercriticality leads to a nuclear fission chain reaction with a rapidly increasing nuclear reaction rate. The energy thus released causes the material to explosive evaporation.

In the fusion bomb, a nuclear fission bomb is first detonated. The pressures and temperatures generated inside the bomb are sufficient to ignite the fusion reaction with the Li contained in it. With the deuterium present and the tritium produced in the said reaction, the thermonuclear reaction is initiated.

Explosion

In order to detonate atomic bombs, i.e. to set the nuclear fission process in motion, several different systems were developed.

Authorization and command

The command sequences are controlled via so-called nuclear cases.

Gun Design

The simplest principle is to shoot a nuclear explosive device, which is subcritical on its own, onto a second, also subcritical one, with a conventional explosive charge in order to combine the two parts into a supercritical mass.
Either two hemispheres of fissile material are shot at each other with two explosive capsules or a cylindrical body of fissile material is shot at a ball with a corresponding hole.

Such a construction of an atomic bomb is called gun design. The atomic bomb Little Boy dropped by the USA on Hiroshima on August 6, 1945, was built according to this system and had an explosive force of 13 kilotons of TNT.

Implosion

Another method is implosion, in which the fissile material is present as a hollow sphere. This is surrounded by a layer of explosives, which are ignited during the explosion by a number of electric detonators in such a way that the resulting pressure wave compresses the fissile material in the center. This implosion increases its density, creating a supercritical state.

Both the Alamogordo test bomb and the atomic bomb dropped on Nagasaki on August 9, 1945, were implosion bombs. These had an explosive force of 20 kilotons of TNT.

Nuclear weapons parameters

The energy released when a nuclear weapon explodes is usually expressed in kilotons. A kiloton ton, abbreviated kT, is the energy released by the detonation of 1000 tons (1 Gg) of TNT (about 4·10¹² J). Therefore, it is also referred to as TNT equivalent. For various reasons, however, the explosive power of conventional and nuclear weapons via this unit can only be roughly equated. In the case of very strong explosions, such as hydrogen bombs, the explosive force is given in megatons, MT for short. This unit corresponds to the energy of one million tons (1 Tg) of TNT.

However, pure explosive power alone is not a measure of the effectiveness of a nuclear weapon. Depending on the type, area of application and explosion height of the weapon, various other factors are important. Among others, the following parameters are used:

• Total radius of destruction: the radius around the explosion center in which all animal and human life, as well as all buildings, plants, etc., are completely destroyed. Depending on the size of the bomb, this can be up to 10 km. The experimental Soviet Tsar bomb in its strongest version had a total radius of destruction of up to 20 km. This is followed by other radii in which the destructive power of the bomb decreases, e.g. the radius at which the chance of survival is above 50%; Then the one where it is above 80%, and so on.
• Millions dead: Number killed in the explosion in a metropolitan area. This size depends very much on the location. In particular, the population density and the construction of the city have a very large influence on the number of deaths. During the Cold War, model calculations were made for the use of powerful nuclear weapons against key targets, including Moscow, Leningrad, Washington, D.C. and New York. Today, there are corresponding simulations that assume a terrorist attack with a small nuclear weapon (a few kilotons).
• Number of warheads: Many nuclear missiles have multiple nuclear warheads, which are then separated from the launcher at high altitude and spread over a large area. A single missile can devastate huge areas in this way, for example, the Soviet SS-18 Satan – depending on the equipment – can distribute its warheads over an area of up to 60,000 km². (For comparison: Bavaria has an area of 70,552 km².) In modern missiles, the individual warheads are controllable in such a way that a single target can be attacked with each warhead.

These are not fixed units but only benchmarks on the basis of which the damage of a nuclear weapon can be estimated. Depending on the intended use, other variables may also be interesting, such as mechanical, thermal and electromagnetic power, or the resulting fallout and long-term effects. Sometimes only technical variables such as dimensions and weight are important. In order to get an accurate picture of the effect of a single bomb, detailed knowledge of a wide variety of data is necessary.

The most powerful nuclear weapons designed as regular military warheads are hydrogen bombs with up to 25 MT explosive power (warhead for SS-18 ICBM or Mk-41 bomb for B-52 bombers). The most powerful nuclear weapon currently in use is probably the warhead of the Chinese DF-5A intercontinental ballistic missile with 3 MT (for comparison: The explosion disaster in Beirut had an explosive force of about 0.001 MT or 1 kT).

Typically, however, it is significantly less, such as 100 kT for the most common American nuclear weapon W-76-0. Without nuclear fusion, i.e. only with fission of uranium or plutonium nuclei, 500 kT (American Ivy King test – Mk-18 bomb) to 800 kT (strongest French test) are achieved. Fat Man dropped over Nagasaki, had only 20 kT explosive power. Some modern nuclear weapons also allow a selection of explosive force, so the American B83 bomb can be detonated with a few kT up to 1.2 MT.

Classification

Strategic nuclear weapon

Strategic nuclear weapons are nuclear weapons with high explosive power, which are not used on the battlefield, but are intended to destroy targets in the enemy’s rear, such as entire cities or missile silos of intercontinental ballistic missiles. Their explosive power ranges from the kiloton range to theoretically more than 100 megatons of TNT in the hydrogen bomb.

The nuclear triad consists of intercontinental ballistic missiles, submarine-launched ballistic missiles and strategic bombers.
The distribution of nuclear weapons on several types of platforms is intended to ensure the effectiveness of nuclear power in the event of a conflict.

Strategic nuclear weapons are:

• free-falling nuclear bombs dropped directly on the target by aircraft (usually long-range bombers);
• land-based intercontinental ballistic missiles (ICBMs) with nuclear warheads stationed in silos or mobile on the mainland;
• land-based intermediate-range missiles (MRBM, IRBM) with nuclear warheads, mounted in silos or on mobile launchers. A particular problem of these weapons is the extremely short flight and thus reaction time of only a few minutes. They are therefore considered particularly susceptible to the unintentional triggering of a nuclear strike, since after radar-based (mis)detection of such a missile, there is practically no time to trigger political decision-making processes. Examples of these missiles are the Jupiter missiles stationed by the US in Turkey in the 1950s and the missiles that the USSR wanted to station in Cuba – which triggered the Cuban Missile Crisis at the time. Today, such weapons are only deployed by states that lack the technology of intercontinental ballistic missiles, such as Pakistan or Israel.
• Submarine-launched ballistic missiles (SLBMs) with nuclear warheads;
• airborne ballistic missiles (ALBM) with nuclear warheads, launched from aircraft;
• Cruise missiles with nuclear warheads, which can be fired from aircraft (ALCM), warships or submarines, are primarily intended for “tactical” use.

Depending on the design, a missile can also transport several nuclear warheads (so-called MIRV design, Multiple Independently Targetable Re-entry Vehicles) and thus devastate radii of several hundred kilometers.

Tactical nuclear weapon

Tactical nuclear weapons (also called nuclear battlefield weapons) are to be used similarly to conventional weapons to combat enemy forces. Their sphere of action and usually also the explosive power are significantly lower than with strategic weapons. The smallest tactical nuclear weapon in military service has an explosive power of about 0.3 kT (for comparison: Little Boy had an explosive power of about 13 kT and Fat Man of about 21 kT). The small effective radius should allow use relatively close to one’s own positions.

Tactical nuclear weapons existed and still exist in various forms:

• Nuclear artillery shells (such as W9), which can be fired by artillery pieces, see M65 gun, later self-propelled howitzer M109;
• Davy Crockett, an infantry grenade with propellant unit (RPG)
• Short-range tactical surface-to-surface missiles (e.g. Honest John, FROG, Lance);
• Atomic Demolition Munitions, colloquially ‘nuclear mines’;
• nuclear free-falling bombs (e.g. B61);
• air-to-air missiles to combat aircraft, such as the AIM-26 Falcon;
• surface-to-air missiles (e.g. Bomarc, Nike) to combat aircraft;
• anti-submarine missiles (e.g. RUR-5 ASROC);
• nuclear depth charges for use against submarines (e.g. B57);
• nuclear-armed anti-ship missiles in order to be able to eliminate entire groups of launchers at one stroke;
• nuclear-armed torpedoes (such as the Soviet Shkval torpedo); Nuclear torpedoes were to be used autonomously by the Soviet submarine crews even without orders from Moscow and thus had a low threshold before deployment.

The term “tactical” can be misunderstood insofar as even these weapons can cause severe destruction and release considerable radioactivity, which would have devastating effects in the event of war. NATO’s “Flexible Response” nuclear strategy assumed that the use of tactical nuclear weapons could be controlled. If conventional ordnance proved to be too weak, the use of tactical nuclear weapons would make it possible to repel attacks on NATO territory without the conflict having to escalate into a comprehensive nuclear exchange ( so-called all-out war). On the Soviet side, this theory was rejected from the beginning. It was considered impossible to limit it once nuclear weapons had been used. France was also very skeptical about the concept.

In 2022, after blatant threats from Russia after the Russian invasion of Ukraine, the concept of the tactical nuclear bomb hit the headlines. Tactical military objectives could never be achieved with such a weapon, because the use of nuclear weapons would always have strategic political consequences, according to Oliver Thränert of the Center for Security Studies at ETH Zurich. In this respect, the term ‘tactical nuclear weapon’ is “misleading”.

Special nuclear weapons

Neutron bomb

Neutron bombs are tactical nuclear weapons that produce a lower explosive force (about 1 kT) but stronger neutron radiation compared to conventional design.

Above all, it was hoped that this would increase effectiveness against armored forces: For the destruction of tanks, a bomb usually has to explode in the immediate vicinity, as the armor provides protection against pressure and heat. On the other hand, it hardly protects against neutron radiation, as neutrons penetrate even heavy materials almost unhindered. The explosion of a neutron bomb could therefore kill the crew of a tank instantaneously without destroying the tank itself. However, the neutron radiation generates secondary radioactivity in the target area, which makes the site and the material remaining there permanently unusable.

In addition, neutron bombs can be used to render enemy nuclear weapons (e.g. approaching missiles) unusable by destroying the ignition or control electronics.

The development and stationing of neutron bombs, including in Germany, were initially justified in such a way that a war waged with them devastates land and infrastructure less than conventional nuclear weapons, even with the greater number of explosions required.
However, model calculations soon showed that this was hardly true in practice. Because in the effectively irradiated area, the pressure and heat effect would already be deadly, buildings and facilities would also be destroyed and the material radioactive by capture. A “clean” alternative to the classic atomic bomb would thus not be achieved.

The neutron weapon’s approach of killing people and obtaining equipment, such as tanks, was sharply criticized by many people in Western Europe from 1977 onwards. Egon Bahr spoke of a “symbol of the perversion of human thought”. Furthermore, it was criticized that death by a neutron bomb was particularly cruel. People exposed to strong neutron beams would die an agonizing and slow death. Victims would suffer from hair loss, paralysis, loss of sensory perception and articulation, spasms, uncontrolled diarrhea, and fluid loss for several weeks until they finally die. From 1977, the peace movement unfolded a campaign against the neutron bomb, first in the Netherlands, then also in West Germany.

In addition, critics feared that the neutron bomb would lower the threshold for the use of nuclear weapons and thus increase the risk of an escalation into war with more powerful nuclear bombs.

About 800 neutron explosive devices have been built in the USA since 1974. The last neutron bombs were officially scrapped in 1992.

For a stationing location in Germany in the 1980s, see Sondermunitionslager Gießen.

Mini-Nuke

So-called mini-nukes are nuclear weapons with an explosive force of less than five kilotons. The new research on small, technically advanced nuclear weapons is planned in the USA. The U.S. Senate lifted a ten-year-old ban on the development of mini-nukes in May 2003. This decision was weakened in Congress by a resolution authorizing research but maintaining a ban on the development or manufacture of new low-yield nuclear weapons.

Suitcase bombs, for example for use by secret services or terrorists, have been described and are also presented on the High Energy Weapons Archive; however, it is also emphasized that the physical feasibility is more than doubtful (for example, too high quantities of conventional explosives would have been necessary for ignition). On the other hand, the weight of the American W-54 warhead to the Davy Crockett light gun was already only 23 kilograms. The egg-shaped weapon from the 1950s had a diameter of only about 27 cm at 40 cm length and reached a maximum explosive force of about 0.02 kT TNT equivalent.

Furthermore, in the 1950s and 60s, NASA developed propulsion technology using small nuclear explosive devices, as it was to be used for manned or unmanned missions. Although the concept was discarded, the documents of the Orion project are still under lock and key, mainly to prevent misuse by, for example, terrorists.

Bunker breakers

Nuclear bunker-busting weapons are designed to penetrate deep into the earth to destroy underground and hardened bunkers. It is impossible that the bombs, dropped from the air, can penetrate deep enough below the surface and the explosion takes place completely underground. Thus, a bomb crater is created and highly radioactive material is ejected into the air. Likewise, large-scale destruction around the actual target is to be feared by the vibrations generated.

There is already a “bunker buster” in the U.S. arsenal: the B-61-11, which, according to the Nuclear Posture Review (NPR) of U.S. nuclear weapons policy published in January 2002, has an explosive force size of more than five kilotons and is therefore not a “mini-nuke”. From a height of a good 13,000 meters, this weapon penetrates only up to seven meters into the earth and 2-3 meters into the frozen ground. The US has about 50 of these bombs at its disposal.

Dirty bomb

In the case of a dirty bomb, the effect of the explosion is further increased with the large scale and years of contamination by radioactive fallout. This is achieved by building up the weapon or by a nuclear explosion on the ground (for the latter, see nuclear weapon explosion). Especially the cobalt bomb was called a dirty bomb. In this design, a cobalt jacket is attached to the actual explosive device. This metal is converted by the explosion into ⁶⁰Co, a highly radiating isotope with a relatively long half-life, which should rain down as dust and contaminate the affected area for a long time.

At the beginning of the 21st century, the term dirty bomb was recoined. It now refers to an explosive device made of conventional explosives, to which radioactive material has been added, which is to be distributed as widely as possible by the explosion. A nuclear explosion does not take place. It is believed that terrorists could use such IEDs to spread terror.

The International Atomic Energy Agency also warns that terrorists could acquire radioactive material, e.g. from successor states of the Soviet Union. There, as in the USA, substances from industry, research institutions or hospitals are repeatedly lost. Since the material for a dirty bomb can be extracted from civil nuclear technology, the entire nuclear technology is also counted among the dual-use products.

An example of the consequences of a dirty bomb is the Goiânia accident in Brazil in 1987, in which thieves broke into an empty hospital and stole a container containing radioactive ¹³⁷caesium chloride and took it home. Out of curiosity and ignorance, many people in their environment handled the bluish fluorescent material and carried parts of the substance around with them. Several residential districts were affected, and eventually, four people died of radiation sickness, ten others needed intensive medical treatment, 85 buildings had to be demolished or decontaminated.

Nuclear weapons in Europe

All states in Europe have ratified the Nuclear Non-Proliferation Treaty, which entered into force on 5 March 1970. According to the treaty, the possession of nuclear weapons (from the states located in Europe) is only permitted to Great Britain, France and the Soviet Union or their successor state Russia. The European nuclear powers, like the other European countries, are not allowed to pass on nuclear weapons. In addition, under the Germany Treaty, which entered into force on 5 May 1955, the Federal Republic of Germany committed itself to the victorious powers of the Second World War to refrain from building nuclear weapons. This renunciation was reaffirmed in 1990 in the Two Plus Four Treaty.

The nuclear weapons stored in Europe (cf. special ammunition stockpiles) were drastically reduced after the end of the Cold War. Between 1990 and 1996, around 208 NATO nuclear weapons silos were built at European air bases. Originally, 438 NATO bunkers were planned for this purpose, but they were no longer needed. The bunkers controlled by the US armed forces for bombs, which were available to NATO forces in an emergency, had not all been stocked. By 1998, Britain had reduced its arsenal of drop bombs at the bases. From 1996, the other arsenals were emptied.

The US and Britain stored up to 5,000 nuclear weapons in German bunkers during the Cold War, including the Zebra package intended for use inside Germany. It is believed that an estimated 480 nuclear weapons are stored in Europe today as part of nuclear sharing, 20 of them at the German Büchel Air Base. There, the Luftwaffe trained the use of nuclear weapons by Tornado fighter-bombers as part of nuclear sharing. The German air bases in Memmingen and Nörvenich no longer had any nuclear weapons from 1995 onwards. It is also assumed that the 130 warheads were withdrawn from Ramstein Air Base.

The two Western European nuclear powers, Great Britain and France, began converting parts of their arsenals to sea-based systems in the 1960s and 1970s respectively. Today, both states maintain four ballistic nuclear submarines, each of which can be equipped with 16 nuclear missiles each. France has only 60 warheads ready for use by bombers, Great Britain has had exclusively sea-based systems since 2000. As a result of this change, the number of deposits on air bases was also reduced. Sea-based warheads now account for the majority of nuclear weapons deployed in Europe. The British warheads are stored entirely at Clyde Naval Base, the French at Brest.

Shortly after the American atomic bombings, Switzerland began a study on the production of its own weapons. After initial secrecy until 1958, the Swiss nuclear weapons program was uniquely legitimized by two referendums in 1962 and 1963, continued in the form of planning and only definitively stopped in 1988, although Switzerland had already signed the Nuclear Non-Proliferation Treaty in 1969. In 1995 it was agreed to be extended indefinitely, and in 2016 the remaining 20 kg of weapons-grade plutonium were transported from the Swiss warehouse to the USA.

NATO airbases with nuclear weapons

(Status: 2011, for number of weapons and storage systems, as of 2022, regarding the places with stored nuclear weapons)

• Great Britain
  • Lakenheath (33 WS3 storage systems, currently no weapons stored)
• Netherlands
  • Volkel (eleven WS3 storage systems, 10–20 B61-3/4 bombs)
• Belgium
  • Small Brogel (eleven WS3 storage systems, 10–20 B61-3/4 bombs)
• Germany
  • Büchel Air Base (eleven WS3 storage systems, 10–20 B61-3/4 bombs)
  • Ramstein Air Base (55 WS3 storage systems, training facility, currently no weapons stored)
• Italy
  • Aviano (18 WS3 storage systems, 50 B61-3/4 bombs)
  • Ghedi-Torre (eleven WS3 storage systems, 10–20 B61-3/4 bombs)
• Greece
  • Araxos (eleven WS3 storage systems, currently no weapons stored)
• Turkey
  • Balıkesir (eleven WS3 storage systems, currently no weapons stored)
  • Incirlik Air Base (25 WS3 storage systems, 60–70 B61-3/4 bombs)
  • Akıncı (Mürted) (eleven WS3 storage systems, currently no weapons stored)

Current status

• – Red: Nuclear powers in the Nuclear Non-Proliferation Treaty (China, France, Russia, UK, USA)
• – Dark red: Nuclear powers outside the NPT (India, North Korea, Pakistan)
• – Pink: Undeclared nuclear powers outside the Nuclear Non-Proliferation Treaty (Israel)
• – Orange: Suspected nuclear weapons program (Iran, Saudi Arabia)
• – Purple: Member States of Nuclear Sharing
• – Turquoise: Former nuclear powers
• – Blue: Nuclear weapons program abandoned

The five permanent members of the UN Security Council are considered official nuclear powers. They are listed in the Nuclear Non-Proliferation Treaty as states with nuclear weapons.

Two states have so far made public the number of their nuclear warheads.

• United Kingdom: 225 (as of 2010)
• USA: The nuclear forces of the United States comprise 3750 warheads. (including non-operational as of 2021)

The exact number of nuclear warheads is often unclear and needs to be estimated. The Federation of American Scientists announced the following figures for 2009:

• China: ≈ 180
• France: ≈ 300
• United Kingdom: ≈ 160
• Russia: ≈ 13,000 (4,830 operational)
• USA: 9,400 (2,700 operational)

India, Pakistan, Israel and North Korea are not listed in the NPT, but still possess nuclear weapons and delivery systems (2008 figures):

• India: ≈ 50
• Israel: ≈ 80
• Pakistan: ≈ 60
• North Korea: < 10

The Carnegie Endowment for International Peace published the following information for 2007 in the Proliferation Report:

• China: 410
• France: 350
• UK: 200
• Russia: ≈ 16,000
• United States: ≈ 10,300

as well as

• India: ≈ 75 to 110
• Israel: ≈ 100 to 170
• Pakistan: ≈ 50 to 110

Although not officially confirmed for a long time, it is considered indisputable that Israel has also been in possession of nuclear weapons since the 1970s. Mordechai Vanunu, then a technician at the Negev nuclear research center, revealed the existence of Israel’s nuclear weapons project in 1986 and was kidnapped from Rome to Israel by the Mossad. On December 11, 2006, Israeli Prime Minister Olmert admitted to German broadcaster Sat.1 that Israel was a nuclear power. However, this was later denied by him. Previously, there were protests at home and abroad in response to this statement. In January 2007, Iranian media reported that Israel was planning a nuclear attack on Iran, which was denied by Tel Aviv.

North Korean nuclear weapons

North Korea also declared in the spring of 2005 that it had developed nuclear weapons as a deterrent; however, the statement was and is doubted from various sides. However, it was and is undisputed that North Korea has an ambitious program to acquire nuclear weapons. On October 3, 2006, the North Korean government announced its intention to conduct nuclear bomb tests.

On 9 October 2006 at 10:36 local time, a successful underground nuclear weapons test was carried out in Hwadaeri near Kilju and later confirmed by seismic measurements in Russia and the USA. According to South Korean estimates, the yield was over 800 tons of TNT. Russia’s Defense Ministry, on the other hand, assumes 5 to 15 kilotons of TNT. (For comparison: The Hiroshima bomb had an explosive force equivalent to 13 kilotons of TNT).

However, it is still not clear whether the detonation of 9 October 2006 was indeed a nuclear explosion. It is possible that the demolition could also have been carried out by conventional means in order to increase political pressure on the international community. By spy planes of the USA, there is evidence of a very slightly increased radioactivity in the atmosphere above the test area, which, however, was so weak that it was only discovered on the second attempt.

A second nuclear weapons test apparently succeeded on 25 May 2009, whereby an explosive force of 20 kilotons is said to have been reached. On January 6, 2016, North Korea announced that a successful test of a hydrogen bomb had been conducted. However, experts doubt that it was really a successful test of a hydrogen bomb, as the energy released was too low for a hydrogen bomb explosion. Either the test failed or it was only a hybrid nuclear bomb.

Programs of Iran

Iran is accused of striving for nuclear weapons, above all by Israel and the USA. However, there is no proof of this. According to its own statements, Iran is working on the civilian utilization of nuclear power for energy production.

Diplomats in Vienna, the headquarters of the International Atomic Energy Agency (IAEA), told the FAZ in 2015 that Iran had already installed 1,000 centrifuges for uranium enrichment at the Natanz plant a few weeks ago. This is a significant increase, as Iran initially had only 164 centrifuges in operation twice after the start of enrichment a year ago. On April 12, 2007, the government in Tehran even reported that it had a total of 3,000 centrifuges in operation, which had achieved enrichment at an industrial level.

The number of centrifuges is considered important because it shows the progress of Iran’s nuclear program. Western governments fear that Iran wants to acquire the capability to build nuclear weapons under the guise of a civilian nuclear program. About 3000 centrifuges are considered necessary to produce the material for one or two atomic bombs a year.

Programs or Past Ownership

With the collapse of the Soviet Union, there were three other successor states of the USSR with nuclear weapons in addition to Russia: Ukraine, Belarus and Kazakhstan. Ukraine was at times the country with the third-largest nuclear arsenal in the world. All these states were parties to the START 1 Treaty, which was signed by the Soviet Union and the USA in 1991 and entered into force in 1995. Ukraine, Belarus and Kazakhstan committed themselves to the NPT Treaty and pledged to destroy their nuclear arsenals. Kazakhstan and Belarus became nuclear-weapon-free by 1996. The last Ukrainian warhead was destroyed in Russia in October 2001.

South Africa developed a nuclear weapon under the apartheid government, probably with Israeli help, and may have conducted a test off the coast in September 1979. Shortly before the end of apartheid, South Africa destroyed its six nuclear weapons in order to join the Nuclear Non-Proliferation Treaty in 1991 and thus reintegrate into international society. By 1994, all South African nuclear weapons facilities had been dismantled.

Argentina, Brazil, Libya and Switzerland had nuclear weapons programs in the past, but abandoned and officially ended them. The government of Sweden discussed after 1945 whether it wanted to develop nuclear weapons and decided against it.

Accidents

Between 1950 and 1980, 32 accidents involving American nuclear weapons alone were reported. According to research by Eric Schlosser, between 1950 and 1968, the US government recorded at least 700 “significant” accidents and incidents involving around 1250 nuclear weapons. Especially in the 1950s and 1960s, many weapons had to be dropped by bombers during emergency landings. Some of the weapons were never found again because they were dropped (but not detonated) in the oceans. Greenpeace estimates that about 50 nuclear bombs were lost. Eleven bombs are officially missing the USA. Radioactive contamination has been detected in several cases.

Crashes of nuclear bombers and other accidents are very problematic because the impact can scatter the fissile material in the environment, even if the bomb does not ignite. In the case of plutonium, this is particularly dangerous because it also has chemical toxicity.

See also:

• Accidents involving intercontinental ballistic missiles
• Accidents involving nuclear weapons on board the B-36 bomber
• Accidents involving nuclear weapons on board the B-47 bomber
• Nuclear weapons accidents on board the B-50 bomber
• Accidents involving nuclear weapons aboard the B-52 strategic bomber
• Accidents involving nuclear weapons on board the Douglas C-124 transport aircraft
• Loss of a nuclear weapon and a Douglas A-4
• Loss of a nuclear weapon on board the Martin P5M flying boat
• This is a list of nuclear missile accidents since 1945.

However, not only in the event of accidents but also as part of the disposal process within normal production, massive amounts of radioactive material were released into the environment (Mayak, Lake Karachay), especially in the Soviet Union.

Disarmament and arms limitation

Because of the enormous destructive power of nuclear bombs, there have always been efforts to abolish and generally ban all nuclear weapons in order to prevent humanity from being destroyed. However, the Cold War and the power interests of individual nations prevented a rapid departure from weapons of mass destruction. Nevertheless, some agreements were enforced, each signaling a major step towards a nuclear-weapon-free world. Whether the treaties are actually as effective as desired, however, is doubted.

On October 10, 1963, the Test Ban Treaty came into force, in which some major powers agreed not to detonate nuclear weapons in water, space and atmosphere. Underground tests should not exceed a certain strength. So far, 120 nations have acceded to this agreement.

The Nuclear Non-Proliferation Treaty was signed on 1 July 1968 by the USA, the Soviet Union and Great Britain and entered into force in 1970. After North Korea withdrew its signature in 2003, the treaty is valid in 188 states. The signatory states also include the People’s Republic of China and France (both in 1992). Accession to the Non-Proliferation Treaty means that signatory states are obliged to submit at regular intervals to the checks carried out by the International Atomic Energy Agency to ensure compliance with the Treaty. Article VI, however, states that states undertake to conduct negotiations “in the near future” that guarantee “complete disarmament”.

The Comprehensive Nuclear-Test-Ban Treaty (CTBT) has been open for signature since 1996. It will not enter into force until it has been ratified by a certain group of countries, including the United States. Ratifications by some important countries are still pending. The United States, in particular, rejects arms controls.

Compliance with the contracts is verified by various techniques: seismic measuring stations react to even the smallest vibrations and enable a fairly accurate location of underground detonations. They can also clearly distinguish the seismographic signatures of earthquakes and nuclear weapons tests. Hydroacoustics can detect and locate underwater explosions. Special microphones and radionuclide detectors can detect, identify and locate atmospheric nuclear explosions. The measuring stations are distributed all over the world. When the contract enters into force, there will also be the possibility of on-site inspection. The implementation of the treaty is being prepared by the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO).

Bilateral treaties between the USA and the Soviet Union or Russia with the aim of limiting or disarming strategic nuclear weapons are the SALT I and II talks (1969 to 1979) which led, among other things, to the ABM Treaty (1972), the INF Treaty (1987), START I and II (1991 and 1993) and the SORT Treaty (2002).

Dismantling

Uranium-based nuclear bombs contain highly enriched uranium. One speaks only from an enrichment level of 85% of weapons-grade uranium. Natural uranium has 0.7% uranium-235; for use in light water reactors, the uranium must be enriched to 3-4% ²³⁵U content (reactor-grade). Highly enriched uranium is therefore a valuable raw material.

The plutonium from plutonium bombs, on the other hand – a very problematic substance due to its long half-life and high radiotoxicity – cannot be destroyed: “The plutonium can only be disposed of in the form of a final disposal after mixing with other nuclear waste or by processing into MOX elements”.

Between 1993 and 2013, the US and Russia successfully cooperated on the megatons-to-megawatt disarmament project. By converting 500 tons of Russian nuclear weapons material into electricity, the US covered 10% of its electricity generation for 20 years, and Russia received a total of $17 billion.

Campaigns for abolition

Numerous international campaigns are campaigning for the abolition of all nuclear weapons, including:

• International Campaign to Abolish Nuclear Weapons (ICAN)
• International Physicians for the Prevention of Nuclear War / Physicians in Social Responsibility (IPPNW)
• Büchel is everywhere! Nuclear-weapon-free.now
• Parliamentary Network on Nuclear Disarmament and Non-Proliferation (PNND)

Numerous appeals for nuclear disarmament and arms control were also addressed to politics by the physicists – such as the Franck Report, the Russell-Einstein Manifesto, which led to the founding of the Pugwash movement, the Mainau rally or the declaration of the Göttingen Eighteen. The German Physical Society (DPG) has also pointed out the dangers associated with the existence of nuclear weapons in a number of resolutions and called for the reduction of existing arsenals and the conclusion of a Comprehensive Nuclear-Test-Ban Treaty. In its resolution of April 2010, the DPG initially advocates the renunciation of the first use and withdrawal of all nuclear weapons remaining in Germany and Europe.

In addition, in principle, all Christian churches speak out against the use of any kind of nuclear weapons, partly also against possession. It was only in 2006 that the World Council of Churches again called for the elimination of all nuclear weapons.

Starting with Catholic philosophers in Britain in the early 1960s, ethical concerns were raised against the strategy of nuclear deterrence. For many people, the use of a nuclear weapon was immoral, as it necessarily entails the death of civilians and the poisoning of the earth. It has been argued that if the use of nuclear weapons is immoral, so is the strategy of nuclear deterrence, which includes the conditional intention to commit an immoral act.

In the Catholic Church, the Second Vatican Council (1965) refers to the transgression of a just defense in the use of so-called scientific weapons, since the application of these can “cause enormous and uncontrollable destruction”. The Pastoral Constitution Gaudium et Spes also pronounces a prohibition of total war, which “aims indiscriminately at the destruction of entire cities or vast territories and their populations”. (GS 80)

The violation of the principles of discrimination and proportionality are the main criticisms of the use of nuclear weapons.

On 27 March 2017, the UN General Assembly decided to begin negotiations on a treaty banning nuclear weapons. The aim is an “unambiguous political commitment” to the goal of a world free of nuclear weapons. This is intended as a first, quickly achievable step towards a nuclear weapons convention that includes concrete disarmament measures. However, only two-thirds of the 193 member states will initially take part in the negotiations. The nuclear powers and almost all NATO countries, including Germany, are not involved.

Literature

Nonfiction

• The UN Study: Nuclear Weapons. C.H.Beck, München 1982, ISBN3-406-08765-5.
• Peter Auer: Von Dahlem nach Hiroshima. The history of the atomic bomb. Aufbau, Berlin 1995, ISBN3-351-02429-0.
• Klaus Fuchs, Ruth Werner, Eberhard Panitz: Treffpunkt Banbury oder Wie die Atombombe zu den Russen kam. Das neue Berlin, Berlin 2003, ISBN3-360-00990-8.
• Robert Jungk: Heller als tausend Sonnen. 1958 und Strahlen aus der Asche, Alfred Scherz Verlag, 1959
• Rainer Karlsch, Zbynek Zeman: Urangeheimnisse. Links, Berlin 2002, ISBN3-86153-276-X.
• Hubert Mania: Chain reaction. The history of the atomic bomb. Rowohlt Verlag, Reinbek bei Hamburg 2010, ISBN978-3-498-00664-8.
• Richard Rhodes: The Making of the Atomic Bomb 1995, ISBN0-684-81378-5, german Greno, Nördlingen 1988; Volk und Welt, 1990, ISBN3-353-00717-2 (Standardwerk).
• Joseph Rotblat: Strahlungswirkungen beim Einsatz von Kernwaffen, Berlin 1996, ISBN3-87061-544-3.
• Helmut Simon (foreword): Atomwaffen vor dem Internationalen Gerichtshof. Lit, Münster 1997, ISBN3-8258-3243-0.
• Wolfgang Sternstein: Abolish nuclear weapons!. Meinhardt, Idstein 2001, ISBN3-933325-05-6.
• Mark Walker: The Uranium Machine. Mythos und Wirklichkeit der deutschen Atombombe. Siedler, Berlin 1990, ISBN3-88680-359-7.
• Egmont R. Koch: Atomwaffen für Al Qaida. “Dr.No” and the network of terror. Aufbau Verlag, Berlin 2005, ISBN3-351-02588-2.
• Kenneth W. Ford: Building the H Bomb – A Personal History. World Scientific, Singapore 2015, ISBN978-981-4632-07-2.

Book

• Michael Light: 100 suns. Knesebeck, München 2003, ISBN3-89660-190-3.

Novels and plays

• Heinar Kipphardt: In der Sache J. Robert Oppenheimer. Rowohlt, Reinbek 1996, ISBN3-499-12111-5.
• Masuji Ibuse: Black Rain. Fischer-Taschenbuch-Verlag, Frankfurt am Main 1985, ISBN3-596-25846-4.

References (sources)

Vulnerability of populations and the urban health care systems to nuclear weapon attack, Healthgeographics; ‘We Were Guinea Pigs’: Soldiers Explain What Nuclear Bomb Blasts Feel Like, Vice; Article Kernwaffe, Wikipedia; Matthias Schulz: Nuclear Exaggeration: Is Atomic Radiation as Dangerous as We Thought?, Spiegel Online, 2007; Hans M. Kristensen, Robert S. Norris: Status of World Nuclear Forces.