Soviet submarine K-8

K-8 was a November class submarine of the Soviet Northern Fleet that sank in the Bay of Biscay with its nuclear weapons on board on April 12, 1970. A fire on April 8 had disabled the submarine and it was being towed in rough seas. 52 crewmen were killed attempting the salvage the boat when it sank.

1960 Loss of coolant
On 13 October 1960, while operating in the Barents Sea, K-8 suffered a ruptured steam generator tube, causing a loss-of-coolant accident. While the crew jury-rigged a system to supply emergency cooling water to the reactor, preventing a reactor core meltdown, large amounts of radioactive gas leaked out which contaminated the entire vessel. The gas radiation levels could not be determined because instrumentation could not measure such large scales. Three of the crew suffered visible radiation injuries, and many crewmen were exposed to doses of up to 1.8 – 2 Sv (180 – 200 rem).

1970 Bay of Biscay fire
During the large-scale "Ocean-70" naval exercise, K-8 suffered fires in two compartments simultaneously on 8 April 1970. Due to short circuits that took place in III and VII compartments simultaneously at a depth of 120 m, a fire spread through the air-conditioning system. Both nuclear reactors were shut down.

The captain ordered his entire crew to abandon ship but was countermanded once a towing vessel arrived. 52 crewmen, including the commander, Captain 2nd Rank Vsevolod Borisovich Bessonov, re-boarded the surfaced submarine that was to be towed. This was the first loss of a Soviet nuclear-powered submarine, which sank in rough seas as it was being towed in the Bay of Biscay of the North Atlantic Ocean. All hands on board died due to CO2 poisoning and the flooding of the surfaced submarine during 80 hours of damage control in stormy conditions. 73 crewmen survived. K-8 sank with four nuclear torpedoes out of total 24 on board to a depth of 4,680 m approximately 490 km northwest of Spain.