So he cloned it, the result being a five-megawatt electric, gas-cooled, graphite-moderated nuclear reactor at Yongbyon, 90km north of the capital Pyongyang.

North Korean officials said the five-megawatt experimental reactor, which still holds the core originally installed in 1986, had a number of rods damaged.

In response, Dr. ElBaradei noted that the five-megawatt reactor was a research reactor, calling it "irrelevant" to North Korea's ability to produce electricity.

North Korea took a step toward expanding its bomb material when it shut down the five-megawatt reactor at Yongbyon in mid-April.

Today, South Korean officials said North Korea had begun taking steps to reactivate a five-megawatt nuclear reactor that had been mothballed under the agreement.

North Korea has often claimed that the five-megawatt reactor was built with indigenous technology.

In 1989, it shut down its five-megawatt reactor at Yongbyon for three months.

The five-megawatt reactor at Yongbyon, the country's tightly guarded nuclear complex, was probably shut in early April, intelligence analysts said, based on satellite photos.

The five-megawatt reactor that was restarted can produce slightly more plutonium in a year than would be necessary for one bomb, according to some estimates.

The atomic energy agency, which had been administering the controls, estimates that the North Koreans will have the five-megawatt reactor operational by the end of February.