North Korea appears torestart plutonium reactor

New satellite photographs showing steam emerging from a newly reconstructed nuclear reactor in North Korea suggest that the country may be making good on its promise to resume the production of plutonium for its small nuclear arsenal, six years after it reached an agreement with the Bush administration to dismantle the facility.

The discovery of the activity at the Yongbyon complex, the centerpiece of North Korea’s nuclear program, was reported by the U.S.-Korea Institute, at Johns Hopkins University, which follows the North’s nuclear program closely.

If the source of the steam proves to be the restarting of the reactor, it would enable the North, after a year or more, to begin to add to its arsenal of plutonium weapons. It would also underscore the failure of efforts by four American presidents to stop the North Korean program; so far, the North has conducted three nuclear tests, including two during the Obama administration.

The possible restart of the reactor comes just months after one of the worst crises in years on the divided peninsula, as the North conducted a third nuclear test, then lashed out with threats of nuclear attacks after additional international sanctions were imposed.

In recent weeks the North Koreans have appeared more conciliatory, including expressing a willingness to return to negotiations with the United States, China, Russia, South Korea and Japan, though they have not clarified if they would be willing to agree to the ultimate goal of nuclear disarmament. The United States and its allies, however, have stood firm, saying they would resume the talks on the nuclear program only if the North agreed to eventually give up its arsenal.

Analysts said the re-emergence of steam at the plant — whether real or a contrivance — could well be designed by the North to try to force the United States and its allies into the talks in the hopes of winning economic aid by creating the fear that North Korea is preparing to add to its weapons stockpile.

But the move could have the opposite effect. President Obama has been deeply reluctant to take steps that would reward North Korea for halting activities it had already agreed to stop. His former secretary of defense, Robert M. Gates, once famously said that the United States was “tired of buying the same horse twice.” So far there have been no new offers to the North Koreans, and with attention focused on Syria and the Arab Spring uprisings, the administration has been reluctant to spend much political capital on a country that seems unlikely to give up its arsenal.

David Albright, the president of the Institute for Science and International Security, a Washington research group that tracks the North Korean nuclear program, said he had also studied satellite images of the complex and concluded that the venting steam suggested that the reactor had indeed begun working again.

“It implies that the reactor is restarted, but that needs to be confirmed,” he said in an interview. “You want to get confirmation because you never know” with the North Koreans. “They can surprise you,” he added, “but I can’t think of any alternative explanations.”

Mr. Albright added that the reactor would have to operate for two or three years in order to make plutonium in its core. Additional time, he said, would then be needed for the spent fuel to cool and the plutonium to be separated out from highly radioactive byproducts, known as reprocessing.

In all, Mr. Albright said, it might take the North Koreans three to four years to complete the manufacturing process, at which point they would have enough added plutonium to make anywhere from two to five more nuclear weapons. American intelligence officials say the country already has enough plutonium for six to a dozen bombs.

A South Korean government intelligence official on Thursday said that the government needed more time to figure out if the reactor had been restarted. “After all, the country we’re trying to figure out is North Korea,” said the official who spoke on the condition of anonymity citing the policy of his office.

But he quickly added that both Washington and Seoul have increased monitoring of Yongbyon since North Korea declared during a time of heightened tensions this year that it would put all its nuclear facilities — including the mothballed reactor — to use in expanding its nuclear weapons stockpile.

North Korea also has a uranium enrichment program, but that started after the plutonium program and it is unclear whether the North has produced enough uranium for a weapon.

The original agreement to halt operations at the nuclear reactor was hailed at the time as a breakthrough, especially when the North showed the destruction of part of the plant on television in 2008.

In return, the State Department removed North Korea from its list of state sponsors of terrorism. But that agreement began to fall apart within a year after it was signed, when the North Koreans evicted inspectors and began to rebuild parts of the reactor complex that they had dismantled.

The latest news comes as North Korea has significantly toned down its warlike rhetoric, restoring military hot lines with the South cut off several months ago, and agreeing to restart a jointly run industrial complex shut amid the threats and counterthreats following this year’s nuclear test. It also agreed to restart a program of reuniting Korean families separated by the Korean War.

But analysts said such mixed signals were not unusual, with the country’s young leader, Kim Jong-un, following a pattern set by his father.

“North Korea’s latest ‘peace offensive’ is almost preordained,” said Lee Sung-yoon, a North Korea specialist at the Fletcher School of Law and Diplomacy at Tufts University, calling it part of North Korea’s timeworn tactic of raising tensions to remind its adversaries that it is a menace that needs placating, then pushing for economic and diplomatic concessions.

“Through its latest ‘conciliatory’ gestures, it seeks in the short term to bolster Kim Jong-un’s credentials as a ‘statesman,’ ” Mr. Lee said. “In the long term, Pyongyang seeks to advance its strategic interests of improving its ballistic missiles and nuclear arsenal.”

Lee Byong-chul, a senior fellow at the Institute for Peace and Cooperation in Seoul, said the attempts to negotiate might be driven by economic difficulties, some of them brought on by the international sanctions. “They are desperate for cash,” Mr. Lee said.