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Nuclear Energy
Published in Ivan G. Draganić, Zorica D. Draganić, Jean-Pierre Adloff, Radiation and Radioactivity on Earth and Beyond, 2020
Ivan G. Draganić, Zorica D. Draganić, Jean-Pierre Adloff
The immediate effects of a nuclear explosion are those of blast, heat and radiation. In addition, fission products appear as fallout. Energetic radiation in the form of γ -rays and neutrons represents about 5 percent of the total energy released by a fission bomb of a few kilotons, and up to 30 percent in the case of a neutron bomb.
Nuclear Terrorism
Published in Robert A. Burke, Counter-Terrorism for Emergency Responders, 2017
Fission is a nuclear reaction that occurs when a heavier unstable nucleus divides or splits into two or more lighter nuclei. Splitting of the nucleus occurs when a free neutron enters the nucleus of a fissionable atom. This makes the nucleus of the atom unstable because of the extra neutron. Because of this imbalance, the nucleus then splits into two or more lighter nuclei. When this occurs, very large amounts of energy can be released along with more free neutrons. Newly released electrons then enter the nucleus of other atoms, causing more splitting, more released energy, and more free neutrons. Fission is the process that produces the nuclear chain reaction that results in a nuclear explosion. A chain reaction initiates its own repetition. Elements used to produce a nuclear explosion by fission are the isotopes of uranium-235 or plutonium-239, which experience fission much more easily than other isotopes of the same elements. Nuclear explosions are a chain reaction of numerous fissions taking place among the isotopes of uranium-235 or plutonium-239. Collectively, these fissions can produce enormous amounts of energy. Each time a nucleus is split, energy is released, resulting in many more fissions taking place feeding upon each other to produce the awesome power of a nuclear explosion. In order for fission reactions to take place, there must be an appropriate amount of fissionable material (i.e., uranium-235 or plutonium-239) in the appropriate configuration so that free neutrons will be produced, which can cause equal or increased numbers of fissions. The amount of material needed to sustain the chemical reaction is termed as the critical mass. Nuclear fission can produce 2 million times more energy than a chemical reaction. However, there still must be an enormous number of fissions to produce a significant amount of energy release. The process of fusion in general may be thought of as the opposite of fission. Instead of splitting the nucleus, two light nuclei come together to form a heavier nucleus. In order for fusion to take place, there must be enough energy to force the nuclei together and overcome the electrostatic forces of repulsion. Two forces are necessary in order for fusion to take place. First of all, there must be high temperatures to accelerate the nuclei, and, second, there must be high-pressure density to increase the probability of interaction between the nuclei. Interestingly, the only way for the types of temperature and pressure to be generated for a fusion reaction is to create a fission reaction first. Therefore, weapons containing a fusion element must also contain a fission element. The energy from the fusion–fission reaction is generated in approximately equal amounts from each process.
The ‘conceit of controllability’: nuclear diplomacy, Japan’s plutonium reprocessing ambitions and US proliferation fears, 1974-1978
Published in History and Technology, 2021
By this point, however, the international environment related to nuclear power and proliferation had undergone a marked shift. In May 1974 India performed what it called a peaceful nuclear explosion, but what was in fact a weapons test. That it had been able to divert material from its civilian nuclear power program to do so led to a renewed global focus on nonproliferation and on tightening safeguards.44 Japan was placed on notice by the United States and by Canada, its principal suppliers, that future imports of uranium would be put in increasing jeopardy the longer it delayed NPT ratification.45 Taken with the generous safeguards agreement with the IAEA, the threat to supplies of uranium secured the support of the nuclear power industry for ratification of the NPT.46 The Ministry of Foreign Affairs underscored these factors in a point by point rebuttal of arguments against ratification. This placed particular emphasis on the importance of continued access to nuclear fuel and how the preliminary agreement reached with the IAEA on safeguards was in Japan’s interests.47 By this time then, rather than the NPT being seen as limiting Japan’s freedom of action, ratification was increasingly seen as necessary in order for Japan to retain and expand its leading position in terms of nuclear power technology. This was all the more important given how the oil crisis of 1973 showed how exposed Japan was to the vagaries of international energy markets.48
Aligning missions: nuclear technical assistance, the IAEA, and national ambitions in Pakistan
Published in History and Technology, 2020
Pakistan wanted reactors, and it pursued a path that fit its needs as a poor country. The use of natural uranium was at the time being promoted by numerous scientists around the world, especially in Canada. The reactors were less efficient than those using enriched uranium, but they had the advantage of not requiring expensive and complicated facilities for uranium enrichment – or worse, relying on the US or Europeans for a supply of fuel. The natural uranium pathway would make headlines in 1974 when India used it to produce its first nuclear explosion. But in 1971, it still had an untarnished reputation as an attractive option for an impoverished nation seeking to provide electricity for its people. Such ideas were on display at the Fourth International Conference on the Peaceful Uses of Atomic Energy, in September 1971 in Geneva. Overseeing this conference, as scientific secretary, was Munir Ahmed Khan, who gave a presentation on the potential of small and medium power reactors. By this time, Khan already had tried to convince his government that Pakistan should build a bomb rather than stick to peaceful applications, but had been rebuffed.34