South Koreans watch a report on North Korea's TV announcement that it had successfully conducted a hydrogen bomb test. North Korea's neighbors have condemned the nuclear test, which is still being verified. Jeon Heon-Kyun/EPA/Landov hide caption

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Inside a nondescript building at Los Alamos National Laboratory known as TA-66, nuclear weapons inspectors are carefully trained in the detection of plutonium. Courtesy of Los Alamos National Laboratory hide caption

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How Do You Find Plutonium? Go To Nuclear Inspector School
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The U.N. Security Council endorsed the historic Iran nuclear deal on Monday. Now, world leaders — notably in the U.S. and Iran — must garner enough support for the agreement at home. Seth Wenig/AP hide caption

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Parrying Doubts In Two Capitals, Leaders Sell The Iran Nuclear Deal
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Interview: Israeli Prime Minister Bejamin Netanyahu On Iran Nuclear Deal
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Iran Nuclear Deal Leaves Plenty Of Room For Disagreement
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Obama Sees Long Legacy For Iran Deal; GOP's 2016 Candidates Want It Gone
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Secretary of State John Kerry (left), and Russian Foreign Minister Sergey Lavrov (right) wait for the start of a meeting at the Beau Rivage Palace Hotelin Lausanne, Switzerland, on Sunday to discuss a nuclear deal on Iran. Brendan Smialowski/AP hide caption

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Lt. Raj Bansal and Capt. Joseph Shannon (right) approach Foxtrot-01, a remote nuclear missile base in Nebraska. Geoffrey Brumfiel/NPR hide caption

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Welcome To The Nuclear Command Bunker
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A worker rides a bicycle in front of the Bushehr nuclear power plant in Iran in 2010. Iran and six world powers are meeting in Vienna this week with the goal of reaching a comprehensive deal on Iran's nuclear program before a July 20 deadline. Majid Asgaripour/Mehr News Agency/AP hide caption

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The second atomic bomb test at Bikini Atoll on July 25, 1946. The Marshall Islands, where Bikini is located, is suing the U.S. for what it calls a violation of the Nuclear Non-Proliferation Treaty. Anonymous/AP hide caption

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An Aug. 31 image from DigitalGlobe shows the 5-megawatt reactor at North Korea's Yongbyon facility. South Korean officials say they have confirmed that the nuclear reactor has been restarted. DigitalGlobe/ScapeWare3d/via Getty Images hide caption

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Nuclear bomb tests like this one, conducted at the Nevada Test Site in 1957, are helping scientists understand how the human body works. Photo courtesy of National Nuclear Security Administration / Nevada Site Office hide caption

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