The country's nuclear development began in the 1950s and has since grown into a source of deep concern for the international community. Pyongyang has developed a nuclear fuel cycle capability and has both plutonium and enriched uranium programs capable of producing weapons-grade material. At the heart of the nuclear program is the Yongbyon nuclear reactor and reprocessing plant.
The frequency of missile and nuclear tests has increased under Kim Jong-Un. The North’s latest nuclear test is believed to be many times more powerful than the previous test in September 2016. The seismological observatory NORSAR at Kjeller, Norway, has estimated the explosive yield to be 120 kilotons. In comparison, the explosive yield of the nuclear bomb dropped on Hiroshima on 6 August 1945 was estimated at 15 kilotons.