Weapon of mass destruction
The only country to have used a nuclear weapon in war is the United States, which dropped two atomic bombs on the Japanese cities of Hiroshima and Nagasaki during World War II. There are eight countries that have declared they possess nuclear weapons and are known to have tested a nuclear weapon, only five of which are members of the NPT. The eight are China, France, India, North Korea, Pakistan, Russia, the United Kingdom, and the United States.
Nuclear power
As of April 2012 there were thirty one countries that have civil nuclear power plants, of which nine have nuclear weapons, with the vast majority of these nuclear weapons states having first produced weapons, before commercial fission electricity stations.
Moreover, the re-purposing of civilian nuclear industries for military purposes would be a breach of the Non-proliferation treaty, of which 190 countries adhere to.