"North Korea ended the eight-year freeze on its nuclear program in late 2002, expelling international inspectors and restarting plutonium production facilities. Before then, the CIA estimated that North Korea might have enough plutonium (Pu) for 1 or 2 weapons. Since then, North Korea may have reprocessed the 8000 spent fuel rods previously under seal at Yongbyon, yielding enough Pu for 6 or 8 weapons. In 2005, North Korea announced it had nuclear weapons and was building more. It restarted construction on two larger reactors, and shut down its small reactor, possibly to extract plutonium. In July 2005, North Korea rejoined the Six Party talks after a 13-month hiatus. Two unknowns in estimating the size of North Korea's arsenal are the status of its uranium enrichment efforts and whether Pakistani scientist A.Q. Khan gave North Korea a weapons design, as he did to Libya. This report will be updated as needed."
CRS Report for Congress, RS21391