By Jamie Crawford
North Korea may be increasing its ability to enrich uranium at its Yongbyon nuclear complex, according to an analysis of recent satellite imagery.
The Institute for Science and International Security report concluded that North Korea appears to have greatly expanded a building in the fuel fabrication complex that is used for gas centrifuges in the uranium enrichment process at the reactor facility.
The development amounts to a doubling in size of the complex from its original construction.
Construction on the building expansion appears to have preceded an announcement by the North Korean government earlier this year that it planned on restart all the nuclear facilities at the previously mothballed site.
"This announcement may have been partially intended as an oblique effort to reveal this new construction; one missed publicly at the time," wrote David Albright and Robert Avagyan, the authors of the report.
The imagery reveals an internal floor plan divided into three sections according to the report. In addition to two smaller rooms, the larger area appears to be a cascade hall where new centrifuges would be placed, Albright and Avagyan said.
While North Korea said the Yongbyon plant contained about 2,000 centrifuges in 2010, Albright and Avagyan said the new building could possibly accommodate up to 4,000, which would allow an increase in the nuclear fuel processing cycle.
Given the opaque nature of the North Korean government, it is impossible to know whether its assertion that it is only processing low-enriched uranium (LEU), compared to a more highly enriched fuel needed for nuclear weapons, is true.
"The extent of North Korea's centrifuge enrichment infrastructure is not fully known, and it is possible that some LEU produced in this facility could have been further enriched at a secret centrifuge site to produce weapon-grade uranium," Albright and Avagyan wrote. "A significant question remains whether North Korea has made weapon-grade uranium, and if so, how much it has made."
While North Korea detonated plutonium-based atomic devices in 2006 and 2009, enriched uranium is generally considered a more effective material for making weapons. The country revealed it had a duel uranium enrichment program in 2010. It is unknown if North Korea's most recent nuclear test in February was plutonium or uranium based.
A doubling of capacity at the site would mean that annual weapons grade production would double to 68 kilograms the report said, while noting that some of that output could be used to make LEU for the experimental light water reactor at Yongbyon.
"A more realistic estimate is that doubling the capacity would allow for an increase in the production of enough weapon-grade uranium for up to two nuclear weapons per year," Albright and Avagyan said.
Analysts who follow North Korea said the developments are potentially worrying due to the unknown nature of the uranium program in North Korea.
Joseph Cirincione, who studies global nuclear proliferation for the Ploughshares Fund, said current estimates show the North has four to eight nuclear weapons from their plutonium program.
If the centrifuges to enrich uranium were proven to work "they could generate dozens of new bombs in the next 10 years," he said.
But Cirincione cautioned the latest construction, while possibly a true addition to its enrichment facilities, could also be more of an effort to put “on a new roof" in order to get incentives from the United States to back away from its nuclear ambitions.
"This underlines the need to restart negotiations [with North Korea] in order to get the intelligence to understand the scope of their program, and to find ways to stop it," Cirincione said.
The latest report came on the heels of two other findings over the uncertain nature of North Korea's long-range missile programs.
Satellite imagery released last month showed North Korea moving ahead with efforts to improve and possibly modernize its missile program through a series of engine tests.
But an analysis of separate images a few weeks later suggested the North appeared to have stopped work on a long-range missile launch site.