Satellite photos show North Korea is “nearing completion” of a small nuclear reactor that can produce plutonium for atomic weapons and presents the risk of a nuclear accident, analysts say.
The experimental light water reactor could be started up as early as this year and be fully operational in 2014, according to scholars at the U.S.-Korea Institute at Johns Hopkins University.
Built at the Yongbyon nuclear complex about 55 miles north of Pyongyang, it could produce small amounts of plutonium, but the dangers of an accident probably outweigh concerns about nuclear proliferation, analysts said Thursday.
North Korea is thought to have enough plutonium for up to eight nuclear bombs and has conducted three underground atomic tests. But it is not known how successful these tests have been or how much progress has been made toward miniaturizing an atomic weapon so it can fit onto a missile warhead.
In an analysis of commercial satellite imagery, the U.S.-Korea Institute’s Jeffrey Lewis and Nick Hansen said external construction of the reactor building and underground pipes that will carry water to cool the reactor core are complete.
“It’s probably a safe assumption that it’s all there,” Mr. Lewis said of the interior construction, which cannot be seen from the satellite photos.
North Korea says the reactor is designed to produce electricity for peaceful purposes, but skeptical scholars point out that it will produce relatively small amounts of power and that the spent fuel from a light water reactor can be reprocessed into plutonium.
North Koreans have built a switching station, which could carry electricity generated by the plant to the country’s grid, Mr. Lewis said.
“They’ve gone to the effort of making it look as much like a civilian reactor as they can,” he said.
“It could be, as they say, a prestige power project,” he said.
Mr. Lewis said a testing and fueling period will be required once the reactor is complete and before it can begin operating. If it goes smoothly, that should take nine to 12 months, he said, but may well take longer as North Korea has no experience at this kind of project.
“It’s a very specialized activity, and they’ve never done it before,” he said of the design and engineering challenges involved.
That “raises serious concerns” about an accident at the reactor, which could release radioactive water or gases, he added. For instance, the reactor’s fuel elements must be built to stay together while going through slow radioactive breakdown.
“If defective fuel is inserted into the core, the cladding may fail to maintain physical integrity and release fission products possibly into the pressure vessel and containment building, forcing a shutdown,” Mr. Lewis notes in his analysis.
“For this reactor, I’m more worried about safety than about proliferation,” he said, noting that North Korea announced this year that it would restart a second reactor as soon as possible.
This second gas graphite reactor was designed specifically to produce plutonium, he said.
“It makes more and better plutonium,” he said.
It could produce enough for one or two bombs a year, according to estimates.
North Koreans are connecting the cooling system of the new reactor to the old gas graphite reactor, which was disabled and its cooling tower demolished in 2007 as part of an energy-for-disarmament deal on which Pyongyang later reneged.
By some estimates, the gas graphite reactor could be brought back online within as little as six months.
Mr. Lewis said the North Koreans had stolen a lead in preparing to reopen the old reactor by building the cooling system for the new one.
“They were hiding in plain sight,” he said. “Publicly, the building work on the cooling system for the new reactor [which has been public knowledge since work started in 2010] was not interpreted as a move toward reopening the old reactor.
“Maybe the intelligence community figured this out,” he said.
“But it never came out in public, and North Korea was able to do this work without the enormous international condemnation” that work on the gas graphite reactor would have provoked.