nuclear weapon

Table of Contents

Introduction & Top Questions
Principles of atomic (fission) weapons
- The fission process
- Critical mass and the fissile core
- Gun assembly, implosion, and boosting
Principles of thermonuclear (fusion) weapons
- The fusion process
- Basic two-stage design
- Enhanced designs
The effects of nuclear weapons
- Blast
- Thermal radiation
- Initial radiation
- Residual radiation and fallout
- Electromagnetic pulse
The first atomic bombs
- Discovery of nuclear fission
- Producing a controlled chain reaction
- Founding the Manhattan Project
- Selecting a weapon design
- Racing to build the bombs
- The weapons are used
The first hydrogen bombs
- Origins of the “Super”
- Policy differences, technical problems
- The Teller-Ulam configuration
- The weapons are tested
- Further refinements
The spread of nuclear weapons
- The Axis powers
- The United Kingdom
  - Atomic weapons
  - Thermonuclear weapons
  - The British deterrent force
- The Soviet Union
  - Atomic weapons
  - Thermonuclear weapons
- France
- China
- India
- Pakistan
- Israel
- South Africa
- North Korea
- Other countries
  - Taiwan
  - Argentina and Brazil
  - Libya
  - Iraq
  - Iran

References & Edit History Quick Facts & Related Topics

Images & Videos

A test of a U.S. hydrogen bomb in the Marshall Islands

World War II: total destruction of Hiroshima, Japan

M65 atomic cannon

Nuclear submarine

Nuclear fission and fusion

Teller-Ulam bomb design

For Students

World War II: total destruction of Hiroshima, Japan

nuclear weapon summary

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nuclear weapon: Facts & Related Content

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News •

US Warns Iran 'Too Close for Comfort' to Nuclear Weapons • May 16, 2025, 6:57 AM ET (Newsweek)

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US Simulates ICBM Attack by Nuclear-Armed North Korea • Apr. 28, 2025, 9:50 PM ET (Newsweek)

Facts

Also Known As	thermonuclear weapon • atomic weapon

Photos and Videos

A test of a U.S. hydrogen bomb in the Marshall Islands

World War II: total destruction of Hiroshima, Japan

M65 atomic cannon

Nuclear submarine

Nuclear fission and fusion

Teller-Ulam bomb design

View footage of the first test of a hydrogen bomb carried out by the United States in the Marshall Islands

Watch U.S. B-29 Superfortress Enola Gay decimate Hiroshima with a nuclear bomb in the Pacific War

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Topics

doomsday machine nuclear electromagnetic pulse tactical nuclear weapons intermediate-range nuclear weapons Atomic Annie intermediate nuclear force atomic bomb thermonuclear bomb neutron bomb gun-assembly fission bomb mine grenade ammunition Greek fire napalm nuclear strategy nuclear football

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Key People

Raja Ramanna

Indian nuclear physicist

Atal Bihari Vajpayee

Atal Bihari Vajpayee

prime minister of India

A.P.J. Abdul Kalam

A.P.J. Abdul Kalam

president of India

Yuly Borisovich Khariton

Russian physicist

Lord Noel-Baker.

Philip John Noel-Baker, Baron Noel-Baker

British statesman

David Lange

prime minister of New Zealand

Alva Myrdal.

Alva Reimer Myrdal

Swedish diplomat

Bertrand Russell

Bertrand Russell

British logician and philosopher

Teller, Edward

Edward Teller

Hungarian-born American physicist

Abdul Qadeer Khan

Abdul Qadeer Khan

Pakistani scientist

Freeman Dyson

Freeman Dyson

American physicist

List

Figure 13: A Maxim machine gun, belt-fed and water-cooled, operated by German infantrymen, World War I.

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