The Institute for Science and International Security (ISIS), which is a non-profit, non-partisan institution dedicated to informing the public about science and policy issues affecting international security, said in a report entitled “Plutonium, Tritium, and Highly Enriched Uranium Production at the Yongbyon Nuclear Site” that North Korea might have produced an additional four to six nuclear weapons for over 18 months, since the end of 2014.
It turns out that North Korea has been increasing its stockpile of fissile material through uranium enrichment. ISIS estimates that North Korea now possesses 13 to 21 nuclear weapons. Prior to this, ISIS estimated North Korea’s nuclear arsenal to be between 10 and 16 weapons as of the end of 2014.
ISIS presumes that North Korea has produced enough additional nuclear explosive materials for roughly another nine nuclear weapons since the end of 2014 and 70% of the materials were successfully used to make nuclear weapons. ISIS also says that due to North Korea’s fourth nuclear test in January, one weapon was subtracted to bring the North’s total to 13-21 nuclear weapons as of now.
ISIS explains that the initial estimate did not take into account any contribution from the second centrifuge plant in the facility, and that North Korea’s nuclear arsenal may be larger than previously thought.
38 North, a website devoted to analysis of North Korea, reported that suspicious activity was noted at the Yongbyon Nuclear Facility in Pyeonganbuk-do, North Korea, two months ago. Experts said there were emanations of exhaust smoke from the Yongbyon nuclear facilities and they were possible signs of reprocessing spent nuclear fuel, and perdicted that more significant activity couldd take place in the future.