August 15, 2022
A nuclear weapon is an unconventional weapon which uses the energy released by the fission of heavy atomic nuclei (uranium, plutonium in the case of A-bombs), or by a combination of this phenomenon with that of the fusion of light nuclei (hydrogen in the case of H-bombs). The energy released by the explosion is expressed by its equivalent in TNT. The nuclear weapon was used operationally only by the United States during the bombings of the Japanese cities of Hiroshima and Nagasaki during the Second World War, resulting in between one hundred thousand and two hundred and twenty thousand deaths. Its destructive effects are mainly due to the blast, as with conventional explosives, but also to burns and fires caused by its high temperature, and to the effect of radiation. Because of these destructive capacities unmatched by those of conventional weapons, nuclear weapons became, from the end of the years following their use against Japan, a weapon of deterrence aimed at discouraging any attack against the vital interests of a nation out of fear for the aggressor to suffer in return massive destruction which would far exceed the expected benefits. Different nuclear deterrence strategies are developed during the Cold War, during which up to 70,000 nuclear warheads will be accumulated by the United States, the Soviet Union, China, the United Kingdom and France, the five states also permanent members of the UN Security Council. Since the end of the Cold War, stockpiles of nuclear weapons have been greatly reduced to about 14,000 nuclear warheads at the end of 2017. In contrast, despite the 1968 Nuclear Non-Proliferation Treaty, India, Pakistan, Israel and North Korea have developed nuclear weapons, bringing the number of states possessing them to nine.