North Korea has continued to produce bomb fuel while in denuclearisation talks with the United States and may have produced enough in the past year to add as many as seven nuclear weapons to its arsenal, according to a study released just weeks before a planned second summit between the North Korean leader and U.S. President Donald Trump.
However, the country’s freeze in nuclear and missile testing since 2017 mean that its weapons programme probably poses less of a threat than it did at the end of that year, the report by Stanford University’s Center for International Security and Cooperation found.
Siegfried Hecker, a former director of the U.S. Los Alamos weapons laboratory in New Mexico who is now at Stanford and was one of the report’s authors, said that analysis of satellite imagery showed North Korea’s production of bomb fuel continued in 2018.
He said spent fuel generated from operation of the 5 megawatt reactor at its main nuclear plant at Yongbyon from 2016 to 2018 appeared to have been reprocessed starting in May and would have produced an estimated 5 kg to 8 kg of weapons-grade plutonium. This, combined with production of perhaps 150 kg of highly enriched uranium, may have allowed North Korea to increase the number of weapons in its arsenal by between five and seven.
Halt in testing
The Stanford report said that while North Korea was likely to have continued work on warhead miniaturisation and to ensure they can stand up to delivery via intercontinental ballistic missiles, the halt in testing greatly limited its ability to make such improvements.
“They have continued the machinery to turn out plutonium and highly enriched uranium,” Mr. Hecker said, “but it also depends on weaponisation — the design, build and test and then the delivery. “When they ended missile testing, those things rolled backwards. So when I look at the whole spectrum, to me North Korea ... is less dangerous today than it was at the end of 2017...”
The Stanford experts said it was their assessment that “North Korea cannot deliver a nuclear warhead with any measure of confidence to the U.S. mainland,” although Mr. Hecker said its nuclear weapons were a real threat to Japan and South Korea.
