WASHINGTON (AP) -- A recent satellite image appears to show North Korea is restarting a plutonium reactor, in a move that could raise renewed international alarm over its nuclear weapons program, a U.S. research institute said Wednesday.
The 5 megawatt reactor at the Nyongbyon nuclear facility was shuttered in 2007 under the terms of a disarmament agreement. Pyongyang announced plans in April to restart it amid a litany of threats toward the U.S. and South Korea after it faced tougher international censure over its latest nuclear and rocket tests.
North Korea has since toned down its rhetoric and stepped up diplomacy with rival South Korea, but Wednesday's finding by the U.S.-Korea Institute at Johns Hopkins School of Advanced International Studies is sign that the regime of Kim Jong Un is pressing ahead with its nuclear program.
Without access to the secretive facility, it is difficult to say with certainty that the reactor has restarted, but the institute says an Aug. 31 commercial satellite image shows white steam rising from a building next to the reactor. The building houses steam turbines and electric generators that are driven by heat generated by the reactor. The color and volume of the steam is consistent with the electrical generating system being readied to come online, indicating that the reactor is in or nearing operation, the institute says.
The analysis was written by Jeffrey Lewis and Nick Hansen, and provided to The Associated Press ahead of publication on the institute's website, 38 North.
When North Korea announced its plans in April, State Department spokeswoman Victoria Nuland told reporters that restarting the plutonium reactor would be "extremely alarming'' but added: "There's a long way to go between a stated intention and actually being able to pull it off.''
There was no immediate comment from the department Wednesday on the new report. South Korea's National Intelligence Service said it could not confirm the report because it involves confidential intelligence.
Commercial satellite images taken in recent months had indicated preparations for restarting the reactor were progressing rapidly. In June, the institute predicted the reactor could be up and running by the end of August, depending on the availability of fresh fuel rods to power it.
The reactor can be used both to generate electricity and produce fissile material for nuclear weapons, and once it is operating, can produce about 6 kilograms of plutonium a year -- enough for one or two bombs. Experts estimate North Korea already has enough plutonium for between four to eight crude weapons.