A Look at North Korean Nuke Capabilities

North Korea announced Monday that it had tested an atomic weapon, a claim that if true would make it the latest member of the elite club of nuclear powers.

HOW MANY BOMBS: Estimates of the amount of radioactive material the North possesses vary widely, enough for possibly between four and 13 weapons, and are unverifiable.

The count compares with a U.S. arsenal of more than 5,000 strategic warheads, more than 1,000 operational tactical weapons -- meant for the battlefield and less powerful than the strategic arms -- and approximately 3,000 reserve strategic and tactical warheads.

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DELIVERY: A top concern is the possibility of North Korea mounting bombs atop missiles aimed at Seoul, Tokyo or even parts of the United States.

The communist nation shocked the world in 1998 by firing a long-range ballistic missile over Japan into the Pacific Ocean. But the country isn’t believed to have a nuclear weapons design that would be small and light enough to be mounted atop a missile.

In July, North Korea test-launched seven missiles, but a long-range rocket believed capable of reaching American shores exploded shortly after liftoff.

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HOW STRONG: There were conflicting reports on the strength of the blast. A state-run South Korean geological institute said the force of the test was equivalent to 550 tons of TNT. That is relatively small compared to the bomb the United States dropped on Hiroshima, which was equivalent to 15,000 tons of TNT.

But Russia’s defense minister said it was far more powerful, equivalent to 5,000 to 15,000 tons of TNT.

In 1996, France detonated a bomb beneath Fangataufa Atoll about 750 miles southeast of Tahiti that had a yield of about 120,000 tons of TNT.

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HISTORY: North Korea is believed to have been accumulating plutonium for a bomb since the mid-1980s. It froze the program in 1994 as part of an agreement with the United States. Since the breakdown of that agreement in late 2002, North Korea is believed to have ramped up production.

Some experts estimate that at least 80 percent of the country’s stockpile of 44 to 116 pounds of refined plutonium was processed since the end of the freeze in 2002.

Without another agreement, North Korea is forecast to boost its stockpile to 160 pounds by 2008 -- enough to build between eight and 17 bombs.

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Source: Washington-based Institute for Science and International Security.