Nuclear weapons - the facts

There are over 27,000 nuclear weapons in the world. Thousands are deployed on land, at sea and in the air, posing the constant threat of nuclear war and radioactive contamination.

The weapons
An atomic explosion is a chain reaction in which atoms are split. This releases colossal amounts of energy, and particles that collide with more and more atoms causing an exponentially growing chain reaction. This process is called fission. The most powerful fission explosion is achieved by using enriched uranium and plutonium atoms, which are unstable and radioactive.

  • Atomic bombs (also known as A-bombs or fission bombs) produce their explosive energy purely through nuclear fission reaction.

  • Hydrogen bombs (also known as H-bombs, thermonuclear bombs or fusion bombs) produce energy through nuclear fusion reactions, and can be over a thousand times more powerful than fission bombs. In a similar process to the sun, they work by using fission energy to compress and heat fusion fuel.1

  • The destructive power of a nuclear explosion is measured in kilotonnes (which are equivalent to thousands of tonnes of TNT) and megatonnes (equivalent to millions of tonnes).2


W87 thermonuclear weapon

What they do
Nuclear weapons are far more destructive than conventional bombs. Their explosions kill indiscriminately on a massive scale, and their radioactive fallout can continue causing fatal illness for years to come.

  • The 15 kilotonne bomb dropped on Hiroshima in 1945 destroyed 13 square kilometres of the Japanese city. The heart of the explosion reached several million degrees centigrade. Everybody within half a mile of the centre of the blast was killed and 92 per cent of the city’s structures were destroyed or damaged. Around 75,000 people were killed immediately but many more died from radiation poisoning. By the end of 1950, the death toll was 200,000.2

  • The Nagasaki bomb three days later killed 40,000 immediately, rising to 140,000 by 1950. Even today, more babies are born dead or deformed in these areas.2

  • Current nuclear weapons are much more powerful than those dropped on Japan. Just 50 could kill 200 million people3 – or the combined populations of Britain, Canada, Australia, Aotearoa/NZ and Germany.


Testing them

  • There have been at least 2,053 nuclear test explosions in the atmosphere, underwater and underground. The bombs had a combined explosive yield equivalent to 40,000 Hiroshima bombs, and resulted in 50 times more radioactive contamination than the 1986 Chernobyl nuclear accident.4

  • Exposure to the radioactivity produced by atmospheric tests will eventually cause the death of about 1.5 million people.4

  • The largest nuclear weapon ever tested was the Soviet Union’s ‘Tsar Bomba’ in 1961, with an explosive yield of 50 megatonnes (the bomb dropped on Hiroshima was a ‘mere’ 15 kilotonnes).


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Nuclear map5
Nine countries have nuclear weapons and it is estimated that 35-40 have the knowledge to acquire them.6

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Who’s complicit?

  • Apart from the 9 nuclear weapon countries, there are 26 ‘umbrella states’ who have accepted a ‘security guarantee’ under the US nuclear shield, and who lend infrastructure to the nuclear war machine.5

  • Belgium, Germany, Holland, Italy and Turkey have several hundred US nukes on their soil as part of their membership of NATO.8

  • There are uranium mines in 24 countries supplying the ‘fissile’ materials to make warheads. The biggest are in Canada, Australia, Namibia, Niger, Russia, South Africa and the US.4

  • Uranium mining is the most ecologically damaging phase of nuclear weapons production. Uranium miners suffer increased rates of lung cancer, and waste from the mines retains 85 per cent of the original ore’s radioactivity.

Who’s kicked the habit?

  • During apartheid South Africa secretly developed, and then dismantled, a small number of nuclear warheads.

  • Belarus, Kazakhstan and Ukraine inherited nuclear weapons following the Soviet Union’s 1991 collapse, but returned them to Russia.

  • Libya, Argentina, Brazil, South Korea and Taiwan have shelved nuclear weapon programmes.

  • Iraq had an active programme before the 1991 Gulf War, but was forced to dismantle it under UN supervision.

Who’s nuke free?

  • A Nuclear Weapon Free Zone (NWFZ) is a region in which countries commit themselves not to manufacture, acquire, test or possess nuclear weapons.

  • Latin America in 1967, the South Pacific in 1985, and Southeast Asia in 1995 have all forsworn the bomb.

  • African countries have agreed to prohibit nukes on their continent, but the 1996 Treaty of Pelindaba has not entered into force. Nor has a Central Asian Zone treaty, signed in 2006 by five countries from the former Soviet Union.9

Who generates nuclear power?

  • 31 countries are operating 440 nuclear power reactors for the generation of electricity.10

  • Countries with a civil nuclear programme have the technical know-how and capability to produce weapons-grade plutonium.4

  • Iran is pursuing a uranium enrichment programme that could enable it to develop nuclear weapons in the next few years.11


What they cost

  • In the 21st century around $40 billion a year, or 10 per cent of the annual US military budget, is spent on nuclear weapons.12 This is roughly the same cost as universal access to basic education, healthcare, adequate food, clean water and safe sewers for the world’s population.13

  • The top secret Manhattan Project, through which the US developed the first nuclear weapons in 1945, cost $20 billion14 – about 7 per cent of the cost of the entire war.15

  • The US spent $5.8 trillion on nuclear weapons between the early 1940s and 1996.14

  • Trident, the UK’s nuclear weapons system, costs up to $4 billion a year to run, and plans to replace it will cost $154 billion.16


The eco-cost of one bomb

The radioactive waste created in the manufacture of an average nuclear bomb includes 2,000 tons of uranium mining waste, 4 tons of depleted uranium and 50 cubic meters of ‘low-level’ waste. ‘Clean up’ following nuclear weapons production and testing in the US will cost more than $300 billion through to the year 2070.17

  1.; How Stuff Works,
  2. Kate Hudson, CND – Now More Than Ever, The Story of a Peace Movement, Vision Paperbacks, 2005.
  3. ICAN, ‘Nuclear Weapons Today’,
  4. Frank Barnaby, How to build a nuclear bomb, 2003, Granta.
  5. ICAN Nuclear Map,
  6. Mohamed ElBaradei, ‘Preserving the Non-Proliferation Treaty’, 2005,
  7. Bradford Disarmament Research Centre,
  8. Nuclear Information Project, ‘US Nuclear Weapons in Europe’,
  9. Arms Control Association, ‘Nuclear Weapon Free Zones’,
  10. International Atomic Energy Association,
  11. Arms Control Association, ‘Nuclear Weapons – who has what?’,
  12. Natural Resources Defense Council, ‘Nuclear Insecurity – A Critique of the Bush Administration’s Nuclear Weapons Policies’, 2004,
  13. 1998 UNDP Human Development Report,
  14. Brookings Institution, ‘The US Nuclear Weapons Cost Study Project’, 1998,
  15. The American War Library,
  16. Campaign for Nuclear Disarmament, ‘The cost of British nuclear weapons’,
  17. ‘The Environment and the Nuclear Age’, Women’s International League for Peace and Freedom,