Nuclear weapon
Since the atomic bombings of Hiroshima and Nagasaki, nuclear weapons have been detonated over two thousand times for testing and demonstration. Only a few nations possess such weapons or are suspected of seeking them. The only countries known to have detonated nuclear weapons—and acknowledge possessing them—are (chronologically by date of first test) the United States, the Soviet Union (succeeded as a nuclear power by Russia), the United Kingdom, France, China, India, Pakistan, and North Korea. Israel is believed to possess nuclear weapons, though, in a policy of deliberate ambiguity, it does not acknowledge having them. Germany, Italy, Turkey, Belgium and the Netherlands are nuclear weapons sharing states. South Africa is the only country to have independently developed and then renounced and dismantled its nuclear weapons.
Nuclear power by country
Nuclear power plants currently operate in 31 countries. 
Most are in Europe, North America, East Asia and South Asia.
The United States is the largest producer of nuclear power, while France has the largest share of electricity generated by nuclear power.
In 2010, before the Fukushima Daiichi nuclear disaster, it was reported that an average of about 10 nuclear reactors were expected to become operational per year, although according to the World Nuclear Association, of the 17 civilian reactors planned to become operational between 2007 and 2009, only five actually came on stream. 
Global nuclear electricity generation in 2012 was at its lowest level since 1999.
China has the fastest growing nuclear power program with 28 new reactors under construction, and a considerable number of new reactors are also being built in India, Russia and South Korea. 
At the same time, at least 100 older and smaller reactors will "most probably be closed over the next 10–15 years".