SEOUL — North Korean scientists have learned to produce crucial components of gas centrifuges, undermining years of export controls and sanctions intended to stop the country’s enrichment of uranium for nuclear weapons, according to an analysis by two US arms control experts.
The analysis, made available Monday, comes after experts have reported other signs that North Korea is activating or expanding its nuclear production facilities.
Taken together, they suggest a new effort to master all facets of nuclear production — or perhaps to give the impression of nuclear progress that would drive new offers of talks or economic aid, in the view of some analysts.
The new study focuses on production of advanced centrifuges, a technically difficult feat the United States and others have tried to make harder for North Korea with sanctions and bans on the export of sophisticated parts and metals.
If the North Koreans can make parts, they would essentially invalidate much of the international strategy to force them to denuclearize.
“That means, unfortunately, that we won’t be in a good position to spot them expanding the program through foreign shopping expeditions, and that policies based on export controls, sanctions, and interdiction won’t get much traction, either,” said Joshua Pollack, one of the experts presenting the findings this week.
“The deeper implication, if they are able to expand the program unchecked, is that we’ll never be too confident that we know where all the centrifuges are,’’ he said. “And that in turn could put a verifiable denuclearization deal out of reach.”
Pollack’s findings in collaboration with Scott Kemp, an expert on centrifuge technology at the Massachusetts Institute of Technology, will be presented Wednesday at a conference in Seoul.
Pollack said he and Kemp analyzed such open-source data as scientific journals, news reports, and propaganda from North Korea. They found evidence the country is learning — or has already learned — how to make such crucial centrifuge components and related technologies and materials as uranium hexafluoride, vacuum pumps, frequency inverters, magnetic top bearings, and maraging steel. He said that domestic production appeared to have begun no later than 2009.
North Korea shocked the United States in 2010 when its officials escorted a visiting US nuclear expert, Siegfried S. Hecker of Stanford University, to their main nuclear complex in Yongbyon, north of Pyongyang. They showed him a modern plant that they said housed 2,000 gas centrifuges, a technology that North Korea said it would use to enrich uranium for reactors but that US officials feared was a cover for making highly enriched uranium for atomic bomb fuel. Until then, the North’s sole source of weapons fuel had been plutonium gleaned from the waste of a mothballed nuclear reactor.
In April, at the height of tensions incited by the North’s nuclear test in February, the country declared it would “adjust and alter the use of the existing nuclear facilities” for “bolstering up the nuclear armed force both in quality and quantity.”
This month, the Institute for Science and International Security in Washington cited satellite images to report that North Korea appears to have doubled the size of the building that housed the uranium enrichment plant in Yongbyon in recent months.
Also this month, another monitoring group, the US-Korea Institute at Johns Hopkins University, cited satellite photos showing steam emerging from the Yongbyon reactor, suggesting North Korea was following through on its vow to resume plutonium production.
South Korean officials declined to comment. Kang Jung-min, a nuclear scientist at the Korea Advanced Institute of Science and Technology who said he was familiar with the work by Kemp and Pollack, said he agreed with their analysis.
Since Hecker’s visit to Yongbyon in 2010, he and other experts have said that North Korea was likely to have produced and hidden many more centrifuges elsewhere in the country.
How to ensure North Korea does not lie about its nuclear program was a central dispute behind the collapse of talks aimed at ending the North’s nuclear weapons programs in late 2008.