WASHINGTON North Korea may be just one to two months away from following through on its threat to restart a plutonium reactor that can produce fissile material for nuclear bombs, a U.S. research institute said Monday.
But the North's ability to put the five-megawatt reactor back to work will depend on the availability of fresh fuel rods to power it, and the institute says that remains uncertain.
The U.S.-Korea Institute at Johns Hopkins School of Advanced International Studies is basing its conclusions on analysis of commercial satellite images, the latest taken May 22.
North Korea announced it plans to restart the reactor at Nyongbyon in early April, 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. The reactor was shuttered in 2007 under the terms of a disarmament agreement.
The threats have subsided in recent weeks, and under pressure from ally China, North Korea has said it is willing to restart international negotiations but has not recommitted to a previous goal of abandoning atomic weapons. It's among the issues expected to be taken up by President Barack Obama and China's leader Xi Jinping when they hold a summit in California late this week.
"North Korea may not be testing long-range missiles or nuclear weapons right now but its WMD program is moving ahead," said former State Department official Joel Wit, who is editor of the institute's web site, 38 North. The abbreviation WMD stands for weapons of mass destruction.
"The purpose of restarting the five megawatt reactor is crystal clear: the production of more plutonium for more bombs," Wit said.
An analysis being published Monday by 38 North says a new system to provide cooling for the reactor appears almost finished, and two underground water tanks are now in place next to a building that would hold spent fuel. External activity suggests that work is continuing inside the reactor building.
North Korea is believed to have a supply of fuel rods, but many of them may need adapting for use in the reactor, making it uncertain whether the North is indeed in a position to restart the reactor.
Once the reactor is up and running, it is capable of producing six kilograms of plutonium a year enough for one or two bombs.
Analysts now put the North's arsenal at four to eight plutonium bombs. They also suspect it is making fuel for uranium bombs, but they don't know how much.
The North has conducted three underground nuclear tests since 2006. It is believed to be developing a nuclear-tipped missile that could target the United States, although it could still be years away from having that capability.