50 Megaton Tsar Bomba Declassified • Ivan RDS-220 Hydrogen Bomb

Subscribe to Nuclear Vault 22:40 Countdown and detonation Credit: Rosatom State Atomic Energy Corporation The Soviet RDS-220 hydrogen bomb (code name Ivan or Vanya), also known as Tsar Bomba (Russian: Царь-бо́мба, tr. Tsar’-bómba, IPA: [t͡sarʲ ˈbombə], lit. ’Tsar bomb’), was the most powerful nuclear weapon ever created and tested. Tested on 30 October 1961 as an experimental verification of calculation principles and multi-stage thermonuclear weapon designs, it also remains the most powerful human-made explosive ever detonated. The bomb was detonated 4000 m above the Sukhoy Nos (“Dry Nose“) cape of Severny Island, Novaya Zemlya, 15 km (9.3 mi) from Mityushikha Bay, north of Matochkin Strait. The detonation was secret but was detected by US Intelligence agencies. The US apparently had an instrumented KC-135R aircraft (Operation SpeedLight) in the area of the test – close enough to have been scorched by the blast. The bhangmeter results and other data suggested the bomb yielded about 58 megatons of TNT [Mt] (240 PJ), and that was the accepted yield in technical literature until 1991 when Soviet scientists revealed that their instruments indicated a yield of 50 Mt (210 PJ). As they had the instrumental data and access to the test site, their yield figure has been accepted as more accurate. In theory, the bomb would have had a yield in excess of 100 Mt (420 PJ) if it had included a uranium-238 fusion tamper but, because only one bomb was built to completion, that capability has never been demonstrated. The remaining bomb casings are located at the Russian Atomic Weapon Museum in Sarov and the Museum of Nuclear Weapons, All-Russian Research Institute of Technical Physics, at Snezhinsk. Thumbnail: Castle Bravo #TsarBomba #HydrogenBomb