Fission bomb

    

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    A fission bomb, known also as the atomic bomb or the atom bomb, is a fission reactor designed to release as much energy as possible in a very short time before the reactor is destroyed by the huge amount of energy. If the reactor is destroyed too soon then the chain reaction is interrupted and the nuclear explosion will not take place. Development of nuclear weapons was the motivation behind early research into nuclear fission: the Manhattan Project of the U.S. military during World War II carried out most of the early scientific work on fission chain reactions, culminating in the Trinity test bomb and the Little Boy and Fat Man bombs that were exploded over the cities Hiroshima, and Nagasaki, Japan in August 1945. 

    Even the first fission bombs were thousands of times more explosive than a comparable mass of chemical explosive. For example, Little Boy weighted about 4 tons out of which 60 kg was the nuclear fuel, and was 3.4 m long and had an explosion equivalent to 15 kilotons of TNT. As technology evolved, nuclear bombs (or warheads) became more powerful and smaller. For example a modern nuclear warhead weighting less than 1/8th of Little Boy can have the energy of 475 kilotons of TNT. 

    The physics behind fission theory is the same in nuclear reactors and in nuclear bombs. The difference is in how they are constructed. It is impossible for a nuclear reactor to be converted into causing a nuclear explosion as a nuclear bomb would. 

    The strategic importance of nuclear weapons is a major reason why the technology of nuclear fission is politically sensitive. Although, the engineering process is not very complicated, the problem occurs when trying to obtain nuclear fissionable fuel. This process is not available to all countries, only to the most advanced and capable (politically and financially) of producing such types of fuel.  

    Enriched uranium represents the nuclear fuel. The problem is that in natural uranium contains only 0.7 % U235 of it's entire weight. During the Manhattan Project enriched uranium was given the codename oralloy, a shortened version of Oak Ridge alloy, after the location of the plants where the uranium was enriched. The term oralloy is still occasionally used to refer to enriched uranium. There are about 2,000 tonnes of highly enriched uranium in the world, produced mostly for nuclear weapons, naval propulsion, and smaller quantities for research reactors. All enrichment methods are expensive, elaborate and time consuming and in order to conduct such an operation higher understanding of the phenomena taking place is required.