Sarov

Nizhni Novgorod Region

Gymnazia № 2

Nuclear Disarmament:

Challenges, Opportunities and Next Steps

Student: Teacher:

Denis Kalyapin Alexandra Krasina

Grade 10

2009

Benchmark I – Background Knowledge

Contents

1. Introduction

2. History of NW

1. Nuclear physics before World War II
2. Creation and development of NW
3. Stockpiles of NW

3. Physical processes of creation and use of NW

1. Nuclear processes
2. Types of NW
3. Effects of NW
4. NW testing

4. Motivation to acquire NW

1. The first five NWS

2. Nuclear Non-proliferation Treaty

3. New declared nuclear powers

4. States alleged to have or develop NW

5. Conclusion

6. Reference materials

I. Introduction

My tasks in this work are:

1. to reveal the history of Nuclear Weapons (NW) paying special attention to

• fundamental discoveries in nuclear physics in the first half of the 20^th century,

• the people and places that were important in the development of NW and

• their current location;

2. to show the physical essence of NW describing

• nuclear processes involved in the production of NW,

• basic types of weapons and their construction,

• the effects of the NW use,

• some data of NW testing; and

3. to analyze the reasons behind efforts of various countries to acquire NW showing

• the motivation of the first five NW states,

• the history of writing and passing the NPT,

• the concern about recent spread of NW.

II. History of NW

1. Nuclear physics before World War II

First, in order to start considering this topic, I’d like to define the term of NW. It will help us understand the essence of the topic.

“NUCLEAR WEAPON - is an explosive device that derives its destructive force from nuclear reactions releasing vast quantities of energy from relatively small amounts of matter. Nuclear weapons are considered weapons of mass destruction, their use in a war is disastrous for all mankind, that’s why their application and control should be a major aspect of international policy.” (11)

You see, this topic is extremely serious and important especially nowadays because it affects greatly different spheres of people’s life: political, economical, cultural, social, demographic and others. On the one hand, NW guarantee national security of a country, demonstrates the defense power of states, contribute to the national confidence. On the other hand, NW frighten many people because of its destructive force, their testings pollute and destroy the environment and make everybody to realize possibility of the renewal of Cold War.

(Nuclear bomb models in the main exhibition hall of the Museum of NW in Sarov)

(The Museum of Nuclear Weapons, RFNC-VNIIEF, Sarov, 2005, p.1)

The history of the creation of NW can't be separated from the history of nuclear physics. The 1930-s can be called a revolutionary era in this sphere of science as during some ten or twenty years physicists in different countries made a series of fundamental discoveries which completely changed the possibility of human beings to affect nature. The mankind gained energy of such power that could not only devastate cities and towns but also destroy the Earth as a planet.

The discovery of radioactivity by French physicists Pierre Curie and his Polish wife Maria Sklodowska-Curie in 1898 and the discovery by Ernest Rutherford in 1911 that the nucleus of an atom is made up of protons surrounded by whirring electrons cleared the way for other physicists to make even more prominent discoveries.

Among the countries paying special attention to the research in this sphere were England, France, Germany and Russia. The most outstanding discoveries were made by James Chadwick, Irene and Frederic Joliot-Curie, Leo Szilard, Enrico Fermi, Niels Bohr, Otto Hahn, Fritz Strasmann, Lise Meitner, Otto Robert Frisch, Yuly Khariton, Yakov Zeldovich and others. It should be noted that most of these physicists who had worked in Italy (Enrico Fermi), Austria and Germany (Leo Szilard, Lise Meitner, Otto Robert Frisch, Rudolf Peierls) fled either to Great Britain or the US (Meitner was forced to leave Germany for Sweden) after Mussolini and Hitler came to power and there they continued their experiments and research work. Let’s look at their discoveries and what role they played in the construction of NW.

Thus in 1932, James Chadwick discovered a new elementary particle, the neutron, which made it possible to investigate reactions happening in the nucleus and even to try and measure the binding energy each nucleus had.

In 1934, French physicists Irene and Frederic Joliot-Curie discovered that bombarding stable elements with alpha particles can induce artificial radioactivity; this meant that a self-sustaining chain reaction might be possible. In the same year, Italian physicist Enrico Fermi demonstrated similar results when bombarding uranium with neutrons. “This work led to the discovery of slow neutrons, which led to the discovery of nuclear fission and the production of elements lying beyond what was until then the Periodic Table.” (22)

The year of 1934 is very rich in revolutionary ideas in nuclear physics. Hungarian physicist Leo Szilard proposed the idea of chain reaction via neutron and later he patented the idea of the atomic bomb. So “in a very real sense, Szilard was the father of the atomic bomb academically.” (15)

In 1939, Hahn, Frish and Meitner’s experiments proved that a splitting of the uranium atom was energetically feasible. They named this process with the help of the term “fission” taken from biology. The results were immediately confirmed by other physicists. Russian scientists Yakov Zeldovich and Yuli Khariton made the most accurate calculations of the chain reaction on fission of uranium. And what’s even more important, Niels Bohr, a Dutch physicist, published some theoretical articles where he explained the process of uranium fission by slow neutrons as fission, of only uranium-235 which amounts less than 1% on natural uranium which made physicists look for ways to enrich the material.

2. Creation and development of NW

In the same years as the Nazi army occupied first Czechoslovakia in 1938, and then Poland in 1939, and World War II began, scientists stopped publishing on the topic of fission so that their enemies couldn’t gain any advantages.

During the war research for developing devices of huge power was stopped in some countries like France occupied by the Nazi troops (fortunately, Frederic Joliot-Curie managed to smuggle his working documents and materials to England not to give the Germans any chance to use them for developing new weapons) and Russia which had to concentrate all its resources to resist the Nazi invasion.

As for Germany, its nuclear energy project, also known informally as the Uranium Club, was launched in 1939. But its heads themselves were not very optimistic about feasibility of the project plus the funding couldn’t be efficient during the war, besides at the beginning of 1944, the British Air Forces destroyed the site in Norway where the German main supplies of heavy water were kept; so the Germans didn’t succeed in creating a new weapon.

Since the Allies couldn’t know about the situation in the Nazi Germany for sure, there was concern among scientists that it might create and use in war a device of enormous destructive power. In 1940, Peierls and Frisch working in Britain at the time, reported in their famous Frisch-Peierls memorandum that explained how a uranium fission bomb could become a weapon that could win World War II. The paper estimated the energy released in a nuclear chain reaction and showed how one could devise an atomic bomb from a small amount of fissable uranium-235.

“Frisch and Peierls reported to their professor Mark Oliphant who informed in April 1940 a top-secret committee of experts (later known as the MAUD Committee) to investigate the feasibility of an atomic bomb. The memo prompted the MAUD Report which in turn led to the Tube Alloys project.” (17)

Almost at the same time in the US, Leo Szilard urged Albert Einstein, one of the most famous and respected scientists of the day, to write a letter to US President Franklin Delano Roosevelt (August 1939) encouraging him to establish nuclear capability before the Germans. On reading the letter in October 1939, Roosevelt appointed Lyman Briggs to set up and head “The Uranium Committee”. But first the funding was deficient, Lyman Briggs wasn’t optimistic about the research and the progress was small.

Franklin Delano Roosevelt

(http://en.wikipedia.org/wiki/History_of_nuclear_weapons)

Only later at the urging of British scientists, who calculated the fissile properties of uranium-235 and concluded that creation of an atomic bomb was inevitable, the project was paid thorough attention to. General Leslie R. Groves was appointed to direct this top-secret work which was named the Manhattan Project. More than 130,000 people and thirty different research and production sites were involved in the program. The project received a massive investment. For example, one of the secret sites which was erected at Oak Ridge, Tennessee (it separated the nuclear fuel U-235 from U-238 thus creating the fuel for an atomic bomb) employed tens of thousands of employees at its peak.

The best theoretical physicists such as Hans Bethe, John Van Vleck, Edward Teller, Felix Bloch, Emil Konopinski, Robert Serber and others were engaged in the project. They confirmed that a fission bomb was feasible and started exploring different bomb assembly methods. “This international team of scientists and engineers labored around the clock to create the first atomic weapons in Los Alamos Laboratory, known as

Project Y.” (18)

The scientific research was directed by American physicist J. Robert Oppenheimer. As his role in the history of NW is extremely important, we think we should give some short information of this personality.

“The father” of the American atomic bomb – R. Oppenheimer

(http://en.wikipedia.org/wiki/J._Robert_Oppenheimer)

Robert Oppenheimer was born in New York on April 22, 1904 to Jewish parents who had imigrated from Germany in 1888.

From 1922to 1925, he studied at the Harvard University where he got interested in experimental physics. There he learned Sanskrit and read the Bhagavad-Gita in the original language. Later he cited it as one of the most important books that shaped his philosophy of life.

After graduating from Harvard, Oppenheimer decided to go on studying in Europe at Ernest Rutherford's famed Cavendish Laboratory at Cambridge under the eminent but ageing J.J. Thomson. Soon he understood that his interest was not experimental but rather theoretical physics. So he left in 1926 for the University of Gottingen to study under Max Born and there in 1927, he obtained his Ph.D. at the young age of 22.

In September 1927, Oppenheimer returned to America where he worked as senior lecturer at the University of California, Berkeley and the California Institute of Technology, Pasadena.

During the 1930-s, Oppenheimer “did important research in theoretical astronomy (especially as it relates to general relativity and nuclear theory), nuclear physics, spectroscopy, and quantum field theory (including its extension into quantum electrodynamics).”

At the same time he started supporting social reforms and later communist ideas like many other young intellectuals, the more that some of his relatives such as his brother Frank, Frank’s wife Jackie and Oppenheimer’s wife Kitty Oppenheimer were active in the Communist Party.

In 1942 when the Manhattan Project began, General Leslie R. Groves selected Oppenheimer as the project's scientific director. The staff under his head consisted of about 1500 people, the average age being 25.

Soon after the first nuclear explosion near Alamogordo on July 16, 1945 and the atomic bombings of Hiroshima and Nagasaki, Oppenheimer left the directorship of Los Alamos and came back to California.

Like many of his colleagues Oppenheimer felt responsible for making weapons of devastating power and he tried his best to deter a nuclear arms race. In 1946 after the Atomic Energy Commission (AEC) was created, Oppenheimer was appointed as the Chairman of its General Advisory Committee.

In the 1950-s, Oppenheimer became an object of security hearings. Though they didn’t harm him severely apart from public humiliation, after the hearings he started to retreat to a simpler life. He died at his home in Princeton, New Jersey, USA in February 1967, at the age of 62.

All the project research was conducted in extreme secret. Thus, most of the tens of thousands of employees that worked at the Oak Ridge facilities had no idea what they were working on. Very few people in the country knew about the Manhattan project until Potsdam conference in February, 1945. Sometimes, it was even difficult to coordinate the work of different departments. But both Britain and the U.S. agreed not to share the information with their ally, the Soviet Union.

The project research took place at over thirty sites across the United States, Canada, and the United Kingdom, the best minds from all over the world worked on it and the project made great progress in the first three years already. The first nuclear test took place at Trinity Site in the desert north of Alamogordo, New Mexico, on July 16, 1945. “On August 6, 1945, a uranium-based weapon, "Little Boy", was let loose on the Japanese city of Hiroshima. Three days later, a plutonium-based weapon, "Fat Man", was dropped onto the city of Nagasaki. The atomic bombs killed at least one hundred thousand Japanese outright, most of them civilians, with the heat, radiation, and blast effects.”(14) As a result, Japan surrendered on August 15.

And now let’s look at the creation of NW in the USSR. Soviet nuclear physics developed quite successfully in the 1930-s but as the war broke out, almost all the research stopped because of financial and economical deficiency.

In April 1942, Soviet physicist Georgii Flerov sent a letter to Joseph Stalin to inform him that nothing was being published in the physics journals by Americans, Britons, or Germans, on nuclear fission since the year of its discovery, 1939, which drove Flerov to the conclusion that the Germans as well as the Allies should be making serious nuclear research. This nonevent was very suspicious. And in his letter, the scientist tried to urge Stalin to start a program. The program began but since the Soviet Union was still involved in the war with Germany on its home front, it couldn’t spend enough resources on the project.

The project started outside Moscow and later moved to the village of Sarov, which then got its code name of Arzamas-16 and disappeared from the maps for forty-five years. Lavrentii Beria, Stalin's former chief of security, was appointed the administrative head of the project while its scientific head was the physicist Igor Kurchatov. Other important figures were Yuli Khariton, Yakov Zeldovich and lead theoretical designer of the Soviet hydrogen bomb, Andrei Sakharov. And again, it’s worth mentioning some information about the Soviet head of the nuclear project while learning the history of NW.

“The father” of the Soviet atom bomb – I. Kurchatov

(http://www.atomicarchive.com/Bios/Kurchatov.shtml)

Igor Vasilyevich Kurchatov was born on January 8, 1903, in Simsky Zavod, Ufa Guberniya (now the city of Sim, Chelyabinsk Oblast).

He graduated from Crimea State University in 1923 where he had studied physics and then went on to study shipbuilding at the Polytechnic Institute in Petrograd. In 1925, he began working on radioactivity problems at the Physic-Technical Institute under Abram Fedorovich Ioffe. In 1932, he received funding for his own nuclear science research team, which built the Soviet Union's first cyclotron.

During World War II he worked on protecting ships from magnetic mines.

In 1943, under Ioffe's recommendation, he was appointed director of the Soviet atomic weapons program. Kurchatov made enormous organization and administrative work as well as scientific leadership. The scientists of his team also used the information from spy Klaus Fuchs. So, the project moved on at great speed.

On August 29, 1949, the first test device named First Lightning (the west named the test Joe-1) was detonated at the Semipalatinsk Test Site.

Kurchatov also headed the work on the Soviet hydrogen bomb program, but later he concentrated on the peaceful use of nuclear technology and advocated against nuclear bomb tests.

Kurchatov died in Moscow on February 7, 1960.

After the United States used its atomic weapons on Hiroshima and Nagasaki, Japan, in 1945, Beria forced the Soviet scientists to duplicate the American process as closely as possible. The project benefited from espionage information gathered from the Manhattan Project, which the Soviets code-named Enormoz. It may have sped up the Soviet project and allowed Khariton, the head of the Arzamas-16 research group developing the bomb to avoid dangerous tests to determine the size of the critical mass. Though we should admit that simultaneously, Soviet physicists successfully conducted research for developing their own bomb making methods.

The first Soviet atomic test named First Lightning in Russia and code-named by the Americans as Joe-1 took place on August 29, 1949 at the Semipalatinsk Test Site in Kazakhstan. The loss of the American monopoly on nuclear weapons marked the beginning of the nuclear arms race.

Both countries, the US and the USSR, began crash programs to develop a far more powerful weapon than those which had already been tested and used. While the first atom bombs were based on the phenomenon of nuclear fission, a more powerful weapon was to be based on igniting a process of nuclear fusion.

Many American scientists were against it as it seemed technically unworkable and morally “too” destructive. Among the promoters of the new weapon was Edward Teller who argued that such a development was inevitable; besides, not moving in that direction could give advantage to the Soviet Union which was likely to create such a weapon itself. And this time he proved to be right.

The first thermonuclear device in Russia was designed by the physicist Andrei Sakharov who was working at the time under Khariton’s administrative and scientific leadership in Arzamas-16. The device nicknamed Joe-4 was tested on August 12, 1953 which created concern within the US government and military especially because this device was a deliverable weapon whereas the US didn’t yet have such one.

So, Truman announced a crash program to develop the hydrogen (fusion) bomb. At that time, the exact mechanism was still not known. Most scientists thought that the "classical" hydrogen bomb, in which the heat of the fission bomb would be used to ignite the fusion material, seemed highly unworkable. But Los Alamos mathematician Stanislaw Ulam showed ”that the fission bomb and the fusion fuel could be in separate parts of the bomb, and that radiation of the fission bomb could first work in a way to compress the fusion material before igniting it”. (15) Teller developed the idea and used the results of the boosted-fission "George" test to confirm the fusion of heavy hydrogen elements before preparing for their first true multi-stage, Teller-Ulam hydrogen bomb test.

The United States tested the first fusion bomb labeled "Mike" on November 1, 1952, on Elugelab Island in the Enewetak Atoll of the Marshall Islands. And on February 28, 1954, the U.S. exploded its first deliverable thermonuclear weapon nicknamed as the "Shrimp" device at Bikini Atoll, Marshall Islands.

The nuclear race went on. On October 30, 1961, on Novaya Zemlya island the Soviet Union detonated the largest, most powerful nuclear weapon ever created which was named the Tsar Bomba. It was a three-stage hydrogen bomb with a yield of about 50 megatons. As it was too powerful, it was never entered into service. It was just demonstration of the Soviet Union’s military power.

The designer of the Russian thermonuclear bomb – Andrei Sakharov

(http://www.atomicarchive.com/Bios/Sakharov.shtml)

Andrei Dmitrievich Sakharov was born in Moscow on May 21, 1921.

In 1938, he began studying physics at Moscow State University which he graduated from in 1941 in Ashkhabad where he had been evacuated after the beginning of the "Great Patriotic War".

In 1945 he returned to Moscow to study at the Theoretical Department of FIAN (the Physical Institute of the USSR Academy of Sciences), receiving his Ph.D. in 1947. His research was devoted to the problem of controlled nuclear fusion and it led to the creation of the first Soviet hydrogen bomb at Sarov.

The first Soviet device was tested on August 12, 1953.

He went on working at Sarov playing the main role in creation of the first Soviet hydrogen bomb which was tested in 955 and the Tsar Bomba (1961), the most powerful device ever detonated.

Sakharov was against nuclear proliferation and protested against bomb testing. He was awarded the Nobel Peace Prize in 1975, but Soviet government didn’t permit him to travel to Norway to accept the award.

For his active peaceful campaign against the Soviet invasion of Afghanistan and human-rights activities, Sakharov was sentenced to internal exile in Gorki.

In the 1980-s, Sakharov was allowed to return to Moscow. He remained a tireless advocate for political reform and human rights for the rest of his life. He died on December 14, 1989.

The designer of the American thermonuclear bomb – Edward Teller

(http://www.atomicarchive.com/Bios/Teller.shtml)

Edward Teller was born on January 15, 1908, in Budapest, Austria-Hungary.

In 1930, Teller graduated from the University of Karlsruhe where he had studied chemical engineering and received his Ph.D. in physics under Werner Heisenberg at the University of Leipzig. Later, he spent two years at the University of Gottingen, but after Hitler came to power in 1933, he had to leave for England and then worked for a year under Niels Bohr.

In 1935, Teller went to the U.S. to become a Professor of Physics at the George Washington University. There he worked in the fields of quantum, molecular and nuclear physics. In 1941, Teller became a naturalized citizen of the U.S. At that time, he concentrated on the problems of the use of nuclear energy, both fission and fusion.

In 1943, he became a member of the Manhattan Project and headed a group at Los Alamos in the Theoretical Physics division. But his obsession with the hydrogen-bomb caused tensions with other scientists who didn’t believe it possible in the nearest future. So in 1946, Teller left Los Alamos.

After the Soviet Union detonated its own bomb in August 1949, Teller insisted on developing a crash program to build a hydrogen bomb and then headed this work which resulted in testing the first American fusion bomb labeled “Mike” in November 1952.

Teller was always a passionate advocate of a strong defense policy calling for the development of advanced thermonuclear weapons and continued nuclear testing. He died in

Stanford, California, on September 9, 2003.

It’s interesting to note that in the 1990-s Teller came to the Soviet Union and a historical meeting of two “fathers” of nuclear bombs – American Edward Teller and Russian Yuli Khariton - took place on the ground of Sarov, former Arzamas-16. Later, some Soviet physicists from Sarov visited the great scientist in the US. Since then, meetings of American and Russian nuclear physicists have become quite regular.

Soviet physicists with E. Teller in Livermore

(From personal archives of Russian scientist

S. Kulikhov, Dr. of Physics)

Russian and American physicists in Los Alamos

3. Stockpiles of NW

The first nuclear bombs were tested and exploded in 1945 by the US. The Soviet Union toiled to produce and test its own nuclear bomb in 1949. Since the first tests, the states have used developing and testing NW to demonstrate their military power and to dominate the world politics and economics.

The climax of brinksmanship known as the Cuban Missile Crisis came in 1962 when the Soviet Union began stationing Russian nuclear missiles on the island of Cuba and President John Kennedy warned that the US military was prepared "for any eventualities." (14)

Fortunately, the leaders of both superpowers could agree not to use the NW that time. After stepping so close to the brink, both the U.S. and the USSR worked to reduce their nuclear tensions in the years immediately following. They initiated the Treaty on the Non-Proliferation of Nuclear Weapons, also Nuclear Non-Proliferation Treaty (NPT or NNPT) a treaty to limit the spread of nuclear weapons, which has been opened for signature since July 1, 1968.

As far as other countries are concerned, some of them have made great efforts to develop and possess their own NW.

The United Kingdom had been an important part of the Manhattan Project but in 1946, the US broke this partnership and stopped sharing any information with the former ally. So the British government decided to create a British bomb. They modernized an improved version of “Fat Man” and tested it on October 3, 1952. Now GB has submarine missiles of American design with its own warheads.

As for France, its achievements in nuclear research had been quite prominent before World War II but it was stopped during the war. However, in the 1950's they started a civil nuclear research program through which plutonium was produced as a byproduct. Charles de Gaulle’s government made a decision to build a bomb and tested it in 1960.

China donated its atomic bomb in 1964 due to the help of the Soviet Union providing it with various kinds of technical assistance. In October 1966, it tested a nuclear missile and in June 1967 a hydrogen bomb. The current number of weapons is unknown owing to strict secrecy, but it is thought that up to 2000 warheads may have been produced, though far fewer may be available for use.

These five countries are official NWS, also called the “Nuclear Club”.

Unfortunately in the 1970-s, the second nuclear stage began which meant proliferation of nuclear weapons among less powerful countries. This table demonstrates which countries possess or are believed to possess NW.

List of NW states

Types	States
NPT nuclear weapon states	The USA, Russia, GB, France, China
Non- NTP nuclear weapon states	India, Pakistan, North Korea
States believed to have NW	Iran, Syria
States that used to have NW	Belarus, Kazakhstan, the Ukraine

(Made by Denis Kalyapin)

India tested its first atomic bomb which was named Smiling Buddha in 1974. Pakistan successfully tested its fission devices at the same year.

South Africa also had a program to develop uranium-based nuclear weapons, but dismantled its nuclear weapon program in the 1990s.

Israel is widely believed to possess some hundred nuclear warheads.

North Korea announced in 2003 that it also had several nuclear explosives and in 2006 it conducted a nuclear test.

Such former Soviet bloc countries as Belarus, Ukraine, and Kazakhstan used to have nuclear weapons but they returned their warheads to Russia by 1996.

There is mounting concern in many nations about Iran's refusal to halt its nuclear power program.

Some other countries also develop their nuclear programs.

All this arouses global fears of nuclear war and requires new steps in non-proliferation process.

III. Physical processes of creation and use of NW

1. Nuclear processes

While considering issues of NW it’s necessary to understand the essence of the processes involved in the production of nuclear weapons. In the first half of the 20th century, scientists made a breakthrough in nuclear physics which allowed the mankind to get control over incredibly enormous amounts of energy. This could be derived from nuclear fission or nuclear fusion reactions. What are they like?

The atomic fireball at the "Trinity" nuclear test

(http://en.wikipedia.org/wiki/History_of_nuclear_weapons)

Nuclear fusion reaction

Two light nuclei can fuse together if they come very close to each. But it takes enormous energy to push them close enough to have an effect. So, the nuclear fusion process can only take place at very high temperatures and densities. When the nuclei get close enough strong force overcomes their electromagnetic repulsion and turns them into a new nucleus. This process takes place with the release of a very large amount of energy.

“Different stars like the sun are powered by the fusion of four protons into a helium nucleus, two neutrinos and two positrons. The uncontrolled fusion of hydrogen into helium calls thermonuclear runaway.” (16)

The problem for the man is how to find the most economically viable method of using energy from a controlled fusion reaction.

Nuclear fission reaction

“Nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts, often producing free neutrons and lighter nuclei, which may eventually produce photons (in the form of gamma rays).” (16)

It’s known that nuclear fission produces energy for nuclear power and to drive the explosion of nuclear weapons. “Both uses are made possible because certain substances called nuclear fuels undergo fission when struck by free neutrons and in turn generate neutrons when they break apart. This makes possible a self-sustaining chain reaction that releases energy at a controlled rate in a nuclear reactor or at a very rapid uncontrolled rate in a nuclear weapon. “(16)

2. Types of NW

There are two basic types of NW.

The first NW type produces its explosive energy through nuclear fission reactions alone. Such fission weapons are called atomic bombs (A-bombs), though their energy comes specifically from the atom nucleus also.

In fission weapons, the fissile material mass - enriched plutonium or uranium - is assembled into a supercritical mass. A supercritical mass is the amount of material needed to start an exponentially growing nuclear chain reaction. This can be done either by shooting one piece of sub-critical material into another (this process is used in a gun-type bomb), or by compressing a sub-critical sphere of material using chemical explosives to increase many times its original density (this process is used in an implosion bomb). The latter approach is considered more sophisticated than the former, and only the latter approach is used if plutonium is the fissile material.

The most difficult in creating nuclear weapon of any design is to ensure that a significant fraction of the fuel is consumed before the weapon destroys itself. The amount of energy is released by the fission bombs that can range between the equivalents of less than a ton of TNT upwards to around 500,000 tons of TNT.

The mushroom cloud of the atomic bombing of Nagasaki, Japan in 1945 (A-bomb)

(http://en.wikipedia.org/wiki/Nuclear_weapon)

The second basic type of nuclear weapons produces a large amount of its energy through nuclear fusion reactions. “Such fusion weapons are generally referred to as thermonuclear weapons or more colloquially as hydrogen bombs (H-bombs), as they rely on the fusion reactions between deuterium and tritium.” (13)

Thermonuclear bombs work by using the energy of a fission bomb in order to compress and heat fusion fuel. When the fission bomb is detonated, X-rays and gamma emitted first compress the fusion fuel. Then it heats it to thermonuclear temperatures. The fusion reaction following the process creates enormous numbers of fast neutrons, which then can induce fission. These steps are called “stages” and if you manage to chain together numerous stages with increasing amounts of fusion fuel, thermonuclear weapons can be made to an almost arbitrary yield. The largest ever detonated bomb (the “Tsar Bomba” in the SU) released an energy equivalent to over 50 million tons of TNT.

The "Mike" shot in 1952 (H-bomb)

(http://en.wikipedia.org/wiki/History_of_nuclear_weapons)

Only six countries - the USA, Russia, GB, China, France and India - have conducted thermonuclear weapon tests. (Whether India has detonated a "true," multi-staged thermonuclear weapon is controversial).

There are other types of nuclear weapons. For example, “a boosted fission weapon is a fission bomb which increases its explosive yield through a small amount of fusion reactions”. (13) However it is not a fusion bomb. In the boosted bomb, the neutrons produced by the fusion reactions serve primarily to increase the efficiency of the fission bomb.

Some weapons are designed for special purposes. Thus, a neutron bomb is a thermonuclear weapon that yields a relatively small explosion but a relatively large amount of neutron radiation. Such a bomb can cause massive casualties as it leaves infrastructure mostly intact and creates a minimal amount of fallout.

The detonation of a nuclear weapon is followed by a blast of neutron radiation. Surrounding a nuclear weapon with suitable materials such as gold or cobalt creates a weapon known as a salted bomb. This device can produce exceptionally large quantities of radioactive contamination. “Most variety in nuclear weapon design is in different yields of nuclear weapons for different types of purposes, and in manipulating design elements to attempt to make weapons extremely small.” (13)

3. Effects of nuclear weapons

All the effects produced by the explosion of NW can be divided into immediate, or direct, and delayed, or indirect, destructive effects. Direct effects cause significant destruction within seconds or minutes of a nuclear detonation; these are blast, thermal radiation, and prompt ionizing radiation. The delayed effects, such as radioactive fallout and other environmental effects, cause damage over an extended period ranging from hours to years.

NW explosions release enormous amounts of energy which “can be divided into four basic groups:

Blast - 40-50% of total energy

Thermal radiation - 30-50% of total energy

Ionizing radiation – 5% of total energy

Residual radiation – 5- 10% of total energy” (28)

Direct effects

Blast effect

The heat from the fireball causes a high-pressure wave to develop and move outward producing the blast effect. The front of the blast wave, the shock front, travels rapidly away from the fireball like a moving wall of highly compressed air.

The air immediately behind the shock front is accelerated to high velocities and creates a powerful wind. These winds in turn create dynamic pressure against the objects facing the blast. Shock waves cause a virtually instantaneous jump in pressure at the shock front. The combination of the pressure jump (called the overpressure) and the dynamic pressure causes blast damage.

Most of the material damage caused by a nuclear air burst is caused by a combination of the high static overpressures and the blast winds which can reach several hundred kilometers per hour. The long compression of the blast wave weakens structures, which are then torn apart by the blast winds.

The effects of the blast wave on a typical wood framed house

(http://en.wikipedia.org/wiki/Effects_of_nuclear_explosions)

Thermal radiation

Nuclear weapons emit large amounts of electromagnetic radiation as visible, infrared, and ultraviolet light. The chief hazards are burns and eye injuries. On clear days, these injuries can occur well beyond blast ranges. The light is so powerful that it can start fires that spread rapidly in the debris left by a blast.

Thermal radiation damage depends very strongly on weather conditions. Clouds or smoke in the air can considerably reduce effective damage ranges versus clear air conditions.

Burns visible on a woman in Hiroshima during the blast

(http://en.wikipedia.org/wiki/Effects_of_nuclear_explosions)

Ionizing radiation

Initial nuclear radiation which is about 5% of the energy released in a nuclear air burst is defined as the radiation that arrives during the first minute after an explosion, and is mostly gamma rays and neutron radiation.

The level of initial nuclear radiation decreases rapidly with distance from the fireball. Though people close to ground zero may receive lethal doses of radiation, they are concurrently being killed by the blast wave and thermal pulse. In typical nuclear weapons, only a relatively small proportion of deaths and injuries result from initial radiation.

Indirect (long-term) effects

The residual radiation from a nuclear explosion is mostly from the radioactive fallout. This radiation comes from the weapon debris, fission products, and, in the case of a ground burst, radiated soil.

There are over 300 different fission products that may result from a fission reaction. Many of these are radioactive with widely differing half-lives. Some are very short, i.e., fractions of a second, while a few are long enough that the materials can be a hazard for months or years.

Most of the particles decay rapidly. Even so, beyond the blast radius of the exploding weapons there would be areas (hot spots) the survivors could not enter because of radioactive contamination from long-lived radioactive isotopes like strontium 90 or cesium 137. For the survivors of a nuclear war, this lingering radiation hazard could represent a grave threat for as long as 1 to 5 years after the attack.

4. Nuclear weapons tests

“Nuclear weapons tests (NT) are the experiments carried out to determine the effectiveness, yield and explosive capability of NW.” (27) All NWS conduct them to get information about how the weapons work, as well as how the weapons behave under various conditions and how structures behave when subjected to nuclear explosions. Additionally, NT has often been used as an indicator of scientific and military strength, and many tests have been overtly political in their intention; most nuclear weapons states publicly declared their nuclear status by means of a nuclear test.

“The first atomic test was detonated by the USA at the Trinity site on July 16, 1945, with a yield approximately equivalent to 20 kilotons. The first hydrogen bomb, codenamed "Mike", was tested at the Eniwetok atoll in the Marshall Islands on November 1, 1952, also by the US. The largest nuclear weapon ever tested was the "Tsar Bomba" of the USSR at Novaya Zemlya on October 30, 1961, with an estimated yield of around 50 megatons.” (27)

Nuclear test explosions

Countries	Number of tests
United States	1,054
Soviet Union	715
France	210
United Kingdom	45
China	45
India	6
Pakistan	6
North Korea	1
All in all	Over 2,000

(Made by Denis Kalyapin)

Nuclear tests can be atmospheric, underground, exoatmospheric and underwater.

All of them are extreme hazards for the mankind. The first and only war atomic bombs use in Hiroshima and Nagasaki killed tens of thousands of Japanese civilians. The main causes of death and disablement immediately after the bombings were thermal burns and the failure of structures from the blast effect. Many more died of cancer tens of years after the bombings.

Nuclear tests also cause numerous casualties, mainly because of long-term effects, such as nuclear fallout contaminating large territories. The most significant long term risk is cancer induction and birth defects. All this makes people protest against nuclear testing.

I’d just like to give a small example of great concern about nuclear testing and its political results from the Atom magazine of Sarov. The author Olaf Njolstad writes that at the end of the 50-s - the beginning of the 60-s Norway was often subject to the nuclear fallout as the result of the Soviet nuclear weapons tests carried out on Novaya Zemlya (the Soviet Union), an island in Barents Sea not far from the country. “The amount of radioactive isotopes such as strontium-90 (Sr⁹⁰) and iodine (I¹³) found in milk, sea water, reindeer moss, animal bones and venison in Norway turned out to be several times higher the maximum level permitted for the civilian population” (8 – p. 41) whereas doctors admitted considerable growth of children’s thyroid cancer in the areas close to the border on the Soviet Union. “In order to keep the situation under control, the FFI (Norwegian Defense Research Establishment) was charged with working out an effective control and prevention system, RAVAKO-North. Also, a special American-Norwegian reconnaissance site (ELINT) was constructed near the border which could register and measure all the tests conducted by the USSR.”(8) In spite of numerous Norwegian protests, the USSR continued nuclear testing which caused tension in the relations between the two countries for a long period.

In 1963, all nuclear and many non-nuclear states signed the “Limited Test Ban Treaty”, pledging to refrain from testing NW in the atmosphere, underwater, or in outer space. The treaty permitted underground nuclear testing. France continued atmospheric testing until 1974, while China continued up until 1980. The last underground test by the US was in 1992, the SU in 1990, GB in 1991, and both France and China continued testing until 1996. After adopting the Comprehensive Test Ban Treaty in 1996, all of these states have pledged to discontinue all nuclear testing. Non-signatories India and Pakistan last tested nuclear weapons in 1998. First North Korea tested its first fission device but it resulted as a fizzle.

IV. Motivation to acquire NW

«Nuclear era» is the concept meaning destructive force. It describes the period in the history of mankind which began in August 1945 with the bombings of Hiroshima and Nagasaki. The half-century history of nuclear weapons creation and application has shown its terrible impact on all living creatures on the Earth and has demonstrated impossibility for anyone to survive in a nuclear war. In spite of the fact that the Cold War is finished, nuclear danger is not reduced. It is necessary to mention that quite many nuclear accidents still happen now and then and their consequences are difficult to predict. Still, a number of countries possess or toil to acquire NW. What are the reasons and motivations behind their efforts?

1. The first five NWS

The mankind realized the opportunity to gain sources of enormous energy before World War II and it’s natural that the enemy countries should toil to create a new weapon which could allow them to win the war. The efforts, the pace of development and the secrecy of the first NW construction projects in the US and the Soviet Union are quite understandable.

But after the war, the winner countries wanted to keep dominating positions in the world policy and economics and NW was the best “argument” in this competition. So, the nuclear arms race began. The United States used its nuclear bomb against civic population of Japan in 1945 and tested its first hydrogen bomb in 1952. The Soviet Union conducted its first tests in 1949 (A-bomb) and in 1953 (H-bomb).

The US wasn’t inclined to share the results of its NW research program with its former European allies. That’s why the UK and France developed their own programs to acquire NW. Their main motivation was “to have an independent deterrent against the USSR” as well as “to retain great power status”. (31) The UK tested its bomb which was drawn to a great extent on the information gained by the British physicists while working on the Manhattan Project during the war. As for France, its nuclear bomb based on its own research was tested in 1969.

Another great developing state, China, wanted to have a deterrent against both the United Stated and the USSR and in 1964 (due to the previous scientific and technological assistance from the Soviet Union), it also tested a nuclear bomb.

2. Nuclear Non-Proliferation Treaty

The spread of NW was becoming more and more threatening.

Many politicians and scientists understood how dangerous it was to preserve and spread NW. Even soon after the war they had begun promoting nuclear non-proliferation. Take the American Acheson-Lilienthal Report of 1946 and the Baruch Plan of 1946 which was derived from the report. The USSR suggested total ban on NW construction and use as well as immediate destruction of all NW stockpiles. Both variants were unacceptable for either partner.

The contradictions between the USSR and the US were so great that the efforts couldn’t succeed until July 1968 when the U.N. General Assembly endorsed the Nuclear Nonproliferation Treaty (NPT). The same month, it opened for signature in Washington, DC, London and Moscow and immediately was signed by the US, the USSR, the UK and 60 more countries. The NPT entered into force in March 1970.

“Since the mid-1970s, the primary focus of nonproliferation efforts has been to maintain, and even increase, international control over the fissile material and specialized technologies necessary to build such devices because these are the most difficult and expensive parts of a nuclear weapons program”. (29)

Some countries like Australia, Sweden and Egypt had developed their NW research programs but stopped them before 1970 as they hadn’t had enough financial, industrial and scientific resources to maintain them. Others, such as Argentina, Brazil, Rumania, South Africa and some others, closed their programs after 1970, on the one hand, for the same reasons, on the other hand, because while following the NPT they could get scientific and technological assistance to develop various nuclear civilian programs.

“At present, 189 countries are States Parties to the Treaty on the Nonproliferation of Nuclear Weapons, more commonly known as the Nuclear Nonproliferation Treaty or NPT. These include the five Nuclear Weapons States (NWS) recognized by the NPT: the People's Republic of China, France, Russian Federation, the UK, and the USA”. (29)

3. New declared nuclear powers

Great concern is about the fact that the NPT can’t stop spreading NW in the world. Some developing countries want to acquire NW not only as a deterrent against their enemies maintaining their national security but also to become great regional power.

Thus, India and Pakistan that have never been members of the NPT tested their nuclear bombs in 1974 and 1998. North Korea used to be a member of NPT but announced a withdrawal in 2003 and tested its bomb in 2006. (Though most specialists agree that the test was only partially successful with the yield less than a kiloton).

4. States alleged to have or develop NW

Still more countries haven’t announced their tests but are suspected of either possessing NW or developing NW programs. These are Israel, Iran and Syria. What’s even more dangerous is that radical politicians of some NW states are likely to use them not only as a deterrent or an evidence of their power but also as a means of political blackmail and pressure.

V. Conclusion

In the first half of the 20^th century, some fundamental discoveries in nuclear physics gave people a gift that enabled them either to improve their lives to an incredible extent or to completely destroy themselves using energy of fantastic force. Unfortunately, at first this energy was used not for peaceful purposes but for creation of weapons of mass destruction. The results of NW use and testing demonstrated its devastating effects on people, the environment and the planet itself.

Soon after the creation of the first nuclear bomb, both scientists and politicians realized how dangerous it could be and started working out measures to put an end to NW proliferation. However, its spread can’t be stopped so far.

It’s evident that new generations of leaders should find ways to improve the situation and to prevent people from making things of their own destruction.

VI. Reference materials

1. Exams Dictionary. Pearson Education Limited. Harlow. 2006
2. Dictionary of American English. Pearson Education Limited. Harlow. 2002
3. V.P. Maksakovsky. Geography. text-book for secondary schools. Moscow. Prosvesheniye. 2007.
4. G.F. Bystritsky. Foundations of Energy. Text-book for schools. Moscow. Infra-M. 2007
5. G.M. Pshakin. N.I. Geraskin and others. Nuclear Non-proliferation. Moscow Engineer Physicist Institute. 2006
6. V.A.Orlov and N.N. Sokov. Nuclear Non-Proliferation. Political Research Centre. Moscow. 2002
7. R.M. Timerbayev. Russia and Nuclear Non-proliferation. Moscow. Nauka. 1999
8. O. Njolstad. Norwegian response to the Soviet nuclear atmospheric testing as well as to the testing the “super” bomb on October 30. 1961. ”Atom” journal. p. 41-46. № 16. 2001. Russian Federal Nuclear Centre – VNIIEF. Sarov
9. T.I.Gorbachyova and others. Scientific Leader. Krasny Oktyabr. Sarov. 2004
10. The Museum of Nuclear Weapons. Russian Federal Nuclear Centre –VNIIEF. Sarov. 2005
11. “Weaponry encyclopedia”. 22 Dec. 2008. http://mega.km.ru/
12. “Weapon of mass destruction” 19 Jan. 2009.

http://en.wikipedia.org/wiki/Weapons_of_mass_destruction

13. “Nuclear weapon”. 29 Jan. 2009. http://en.wikipedia.org/wiki/Nuclear_weapon
14. “History of nuclear weapons”. 22 Jan. 2009.

http://en.wikipedia.org/wiki/History_of_nuclear_weapons

15. “Nuclear physics”. 02 Feb. 2009. http://en.wikipedia.org/wiki/Nuclear_physics
16. “Nuclear fission”. 02 Feb. 2009. http://en.wikipedia.org/wiki/Nuclear_fission
17. “Tube Alloys”. 05 Feb. 2009. http://en.wikipedia.org/wiki/Tube_Alloys
18. “Manhattan Project”. Los Alamos Historical Society. 05 Feb. 2009.

http://www.losalamoshistory.org/manhattan.htm

19. “Little Boy”. 05 Feb. 2009. http://en.wikipedia.org/wiki/Little_Boy
20. “Fat Man”. 05 Feb. 2009. http://en.wikipedia.org/wiki/Fat_Man
21. http://www.atomicarchive.com
22. “Enrico Fermi (1901 – 1954)”. 09 Feb. 2009. http://www.atomicarchive.com/Bios/Fermi.shtml
23. “J. Robert Oppenheimer”. 09 Feb. 2009. http://en.wikipedia.org/wiki/J._Robert_Oppenheimer
24. “Igor Kurchatov (1903 – 1960)”. 09 Feb. 2009.

http://www.atomicarchive.com/Bios/Kurchatov.shtml

25. “Edward Teller (1908 – 2003)”. 09. Feb. 2009 http://www.atomicarchive.com/Bios/Teller.shtml
26. “Andrei Sakharov (1921 – 1989)”. 09 Feb. 2009.

http://www.atomicarchive.com/Bios/Sakharov.shtml

27. “Nuclear testing”. 06 Feb. 2009. http://en.wikipedia.org/wiki/Nuclear_testing
28. “Effects of nuclear explosions”.05 Feb. 2009.

http://en.wikipedia.org/wiki/Effects_of_nuclear_explosions

29. “Nuclear proliferation”. 10 Feb. 2009.

http://en.wikipedia.org/wiki/Nuclear_proliferation

30. “Nuclear Non-Proliferation Treaty”. 30 Jan. 2009.

http://en.wikipedia.org/wiki/Nuclear_Non-Proliferation_Treaty

31. “List of states with nuclear weapons”. 31 Jan. 2009.

http://en.wikipedia.org/wiki/List_of_states_with_nuclear_weapons

32. “Nuclear bombs and health”. 06 Feb. 2009.

http://en.wikipedia.org/wiki/Nuclear_bombs_and_health