A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or from a combination of fission and fusion reactions (thermonuclear bomb).
Both bomb types release large quantities of energy from relatively small amounts of matter.
dating the jjang from - Updating international nuclear law
These are identifiable in our development breakdown above, though Belarus and Poland have been moved up one category as of early 2012, and Saudi Arabia in mid 2012.
However, by September 2012 the picture was less positive for the leading 14 countries, and the IAEA expected only seven newcomer countries to launch nuclear programs in the near term.
Radiation particularly associated with nuclear medicine and the use of nuclear energy, along with X-rays, is 'ionizing' radiation, which means that the radiation has sufficient energy to interact with matter, especially the human body, and produce ions, it can eject an electron from an atom.
X-rays from a high-voltage discharge were discovered in 1895, and radioactivity from the decay of particular isotopes was discovered in 1896.
Research into the development of nuclear weapons was undertaken during World War II by the United States (in cooperation with the United Kingdom and Canada), Germany, Japan, and the USSR.
The United States was the first and is the only country to have used a nuclear weapon in war, when it used two bombs against Japan in August 1945.However, in the longer term, the trend to urbanisation in less-developed countries will greatly increase the demand for electricity, and especially that supplied by base-load plants such as nuclear.The pattern of energy demand in these countries will become more like that of Europe, North America and Japan.Nuclear power is planned in over 20 countries which do not currently have it, and under some level of consideration in over 20 more (in a few, consideration is not necessarily at government level).In the following list, links are provided for those countries that are covered by specific country papers where the nuclear power prospects are more fully dealt with: Despite the large number of these emerging countries, they are not expected to contribute very much to the expansion of nuclear capacity in the foreseeable future – the main growth will come in countries where the technology is already well established.However, of the 65 interested countries, 31 are not currently  planning to build reactors, and 17 of those 31 have grids of less than 5 GW, “too small to accommodate most of the reactor designs on offer.” The report added that technology options may also be limited for countries whose grids are between 5 GW and 10 GW.