On September 3 , 2017 , North Korea conducted a sixth nuclear test just few hours after photographs of North Korean leader Kim Jong-un inspecting a device resembling a thermonuclear weapon warhead were released . Initial estimates in first few days were between 70 and 160 kilotons and were raised over a week later to range of 250 to over 300 kilotons . Jane 's Information Group estimated , based mainly on visual analysis of propaganda pictures , that the bomb might weigh between 250 and 360 kilograms ( ~ 550 – 790 lbs . )
a sixth nuclear test
2017 North Korean nuclear test
History of the Teller–Ulam design