Prohibiting the spread of nuclear weapons presents an enormous challenge.
Explore the past, present, and future threats that nuclear weapons pose.
Treaty on the Nonproliferation of Nuclear Weapons
Learn about the history of this landmark treaty.
Discover how South Africa, North Korea, and Japan have approached nuclear decision-making.
Understand the science behind nuclear power.
(about 55 pounds) of highly enriched uranium or 8 kilograms (about 18 pounds) of plutonium is needed to make an elementary nuclear weapons.
Source: Belfer Center and IAEA
31 countries and areas operate a total of 449 nuclear reactors for generating power. Top countries:
United States: 99
The Nuclear World
Find out why few countries develop nuclear weapons.
Tools of Nonproliferation
Know how international leaders try to limit the spread of nuclear weapons.
How Nuclear Proliferation Affects You
Source: Lee Jae-Won/Reuters
What Would Happen in the Minutes and Hours After North Korea Nuked the United States
A step-by-step account of a hypothetical North Korean nuclear attack—and how the United States and others might respond.
Source: Shannon Stapleton/Reuters
Why America Can’t Spot Dirty Bombs
The U.S. government would struggle to detect a terrorist attack using radiation and to communicate and respond effectively, according to an evaluation by the Department of Homeland Security itself.
Source: Vincent Kessler/Reuters
The World’s First Permanent Nuclear-Waste Repository
Finland is close to finishing construction of a storage site, but the real challenge will be keeping it protected for hundreds of millennia.
Source: Yuri Gripas/Reuters
Top Commander Says Banning Nukes Would Make Wars Worse
The general in charge of U.S. nuclear forces argues that nuclear weapons keep wars—and their death tolls—smaller than they would otherwise be.
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A Sharper Choice on North Korea: Engaging China for a Stable Northeast Asia
Photo: Korean Central News Agency via Reuters
On the Iran Nuclear Agreement and its Consequences
Photo: Leonhard Foeger/Reuters
The Unsung Success of Nuclear Nonproliferation
Photo: Kevin Lamarque/Reuters