The North Koreans weren't supposed to be building nukes at all. In the early 1990s, the U.S. suspected Pyongyang was striving to join the atomic club by using plutonium extracted from a Soviet-built nuclear reactor (the CIA at the time said it believed Pyongyang could have one or two bombs). Under a 1994 agreement with the West, North Korea agreed to shut the reactor down in exchange for an ongoing supply of free fuel oil from the U.S. and two tamper-proof reactors for electrical power generation to be built by Japan and South Korea.
But Pyongyang's revelation that it hasn't stuck by the accord suggests it has been pursuing a two-track strategy to get the bomb. Instead of plutonium, the fissile material for atomic weapons can also be enriched uranium. (That's how the bomb dropped on Hiroshima was made.) In a report to Capitol Hill staffers in the U.S. last week, the CIA said Pyongyang in 2001 started seeking materials to build a production plant to turn out enriched uranium in large quantities. If the facility comes online in two or three years, as the spy agency suggests it could, North Korea could have enough weapons-grade uranium for two or more bombs a year, according to the CIA.
Earlier this month, the U.S. suspended oil shipments until Pyongyang agrees to dismantle its nuclear program. So far, there's no sign the North Koreans are willing to play along. In fact, with the 1994 deal as good as dead, some experts warned Pyongyang could retaliate by taking its original reactor program out of mothballs and finishing work on two others. In its report last week, the CIA warned North Korea could in "several years" be churning out up to 281 kg of plutonium a year—enough for dozens of new nukes. No doubt Radio Pyongyang will keep us informed.