A nuclear weapon is an explosive device that derives its destructive force from nuclear fission, nuclear fusion, or a combination of the two. Nuclear weapons are also called atom bombs, nukes, atomic bombs, nuclear warheads, a-bombs, or nuclear bombs.
Nuclear weapons produce enormous and dangerous explosive energy, and their blasts are measured in kilotons and megatons. Nuclear weapons, such as the bomb dropped on Hiroshima, which was 15 kilotons of chemical explosives, produced lethal ionizing radiation in addition to a shock wave and massive amounts of heat. Nuclear weapons also have radioactive fallout, where debris is picked up by winds into the atmosphere and then settles back to Earth days later. Nuclear weapons produce more death, destruction, injury, and sickness than any other single weapon.
The Cold War between the Soviet Union and the United States caused both countries to increase the number of their nuclear weapons. At their peak, the Soviet Union had a total of 33,000 operational warheads and the United States had 32,000. After the Soviet Union disintegrated, thousands of nuclear weapons on both sides were dismantled.
Because of the broad lethality and destruction of these weapons, governments have negotiated arms control agreements such as the Nuclear Nonproliferation Treaty (NPT) of 1996. The NPT’s purpose is to inhibit the spread of nuclear weapons. There are two types of states-parties: nuclear-weapon states (NWS) and non-nuclear weapon states (NNWS). The NWS are the United States, Russia, China, France, and the United Kingdom. Under the treaty, NWS are not allowed to assist NNWS in developing nuclear weapons, and NWS have the inalienable right to research, develop, and use nuclear energy for non-weapon purposes. The treaty also requires states-parties to pursue negotiations in good faith when it relates
North Korea pulled out of the NPT in 2003. North Korea is estimated to have 30 nuclear warheads, none of which are retired.
Today, Russia has the highest number of nuclear weapons estimated at 6,490 warheads. 4,490 of these are active and 2,000 are retired. The United States follows closely behind with 6,185 total nuclear weapons, 3,800 of these are active and 2,385 are retired.