An Estimate of North Korean HEU Stockpile for the given Natural Uranium Reserve and Enrichment Capacities

摘要

An estimate of the highly enriched uranium (HEU) stockpile of North Korea is presented based on the available information in literature on their natural uranium reserves and uranium enrichment capabilities. In estimating the HEU stockpile, following uranium enrichment parameters were analyzed by parametrically varying them: separative work unit (SWU range 8,000-10,000 kg-SWU per year), product enrichment (~(235)U from 70 to 95%) and tails enrichment (~(235)U from 0.27 to 0.36%). The SWU capacities assumed here are based on literature reports. Representative results of this parametric study are presented. Production of 40 kg of HEU with 90% ~(235)U enrichment per year is possible for an annual SWU capacity of 8,000 provided a natural uranium feed of 7971 kg per year is available and if the tails ~(235)U enrichment is 0.27%. Instead, if the annual SWU capacity is 10.000 then 50 kg of HEU with 90% ~(235)U enrichment per year can be produced provided a natural uranium feed of 9963 kg per year is available and if the tails ~(235)U enrichment is 0.27%. Literature suggest that a maximum of 60 nuclear weapons is possessed by North Korea as of 2018. out of which 10 of them use plutonium (average 4 to 6 kg plutonium per weapon assumed). Hence, 1,250 kg of HEU should have been produced to make 50 uranium (25 kg HEU per weapon assumed) based nuclear weapons. For this amount of HEU product, the natural uranium feed required will be 249,075 kg for an enrichment capacity of 10,000 Kg-SWU/year. Four million tons of uranium ore is reported as available in North Korea for industrial development. Hence, assuming a 1,000 ppm uranium ore quality the available natural uranium feed is 4,000,000 kg. If one assumes the remaining uranium reserve is utilized for weapons purpose only then North Korea can produce additional HEU stockpile for 750 weapons. Complete details and the results of the parametric study with basis literature information used in making assumptions are presented in the full paper.