Soviet submarine K - 27 The K - 27 was the only submarine of Project 645 in the Soviet Navy . Project 645 was not assigned a NATO reporting name . That project produced one test model nuclear submarine , which incorporated a pair of experimental VT - 1 nuclear reactors that used a liquid - metal coolant ( Lead - bismuth eutectic ) , placed into the modified hull of a November class submarine ( Project 627A ) . Launch and operations . The keel of the K - 27 was laid down on 15 June 1958 at Severodvinsk Shipyard No . 402 . She was launched on 1 April 1962 , and she went into service as an experimental " attack submarine " on 30 October 1963 . The K - 27 was officially commissioned into the Soviet Northern Fleet on 7 September 1965 . The K - 27 was assigned to the 17th submarine division , headquartered at Gremikha ) . The nuclear reactors of the K - 27 were troublesome from their first criticality , but the " K - 27 " was able to engage in test operations for about five years . On 24 May 1968 , the power output of one of her reactors suddenly dropped sharply ; radioactive gases were released into her engine room ; and the radiation levels throughout the K - 27 increased dangerously – by 1 . 5 grays per hour . This radiation consisted mostly of gamma rays and thermal neutron s , with some alpha radiation and beta radiation in addition – generated by the released radioactive gasses such as radon , gassified radioactive isotopes of iodine , cesium , xenon , and krypton in her reactor compartment . The training of her crew by the Soviet Navy had been inadequate , and these sailors did not recognize that their nuclear reactor had suffered from extensive fuel element failure s . By the time they gave up their attempts to repair her reactor at sea , nine of her crewmen had accumulated fatal radioactive exposures . About one - fifth of her reactor core had experienced inadequate cooling caused by uneven coolant flows . Hot spots in the reactor had ruptured , releasing nuclear fuel and nuclear fission products into the liquid - metal coolant , which circulated them throughout her reactor compartment . The K - 27 was laid up in Gremikha Bay starting on 20 June 1968 . The cooling - off of her reactors and various experimental projects were carried out aboard her through 1973 . These included the successful restarting of her starboard reactor up to the 40 % of maximal power production . Plans were considered to slice off her reactor compartment and then to replace it with a new one containing standard VM - A water - cooled reactors . The rebuilding or replacement of her port nuclear reactor was considered to be too expensive , and also to be inappropriate because more modern nuclear submarine s had already entered service in the Soviet Navy . Scuttled in the Kara Sea . The K - 27 was officially decommissioned on 1 February 1979 and her reactor compartment was filled with a special solidifying mixture of furfuryl alcohol and bitumen during the summer of 1981 to seal the compartment to avoid pollution of the ocean with radioactive products . This work was performed by the Severodvinsk shipyard No . 893 " Zvezdochka " . Then the K - 27 was towed to a special training area in the eastern Kara Sea , and she was scuttled there on 6 September 1982 near the location 72°31 ' 28 " N . , 55°30 ' 09 " E . off the northeastern coast of Novaya Zemlya ( at Stepovoy Bay ) , in a fjord at a depth of just 33 meters ( 108 feet ) . It was necessary for a naval salvage tug to ram the stern of the K - 27 to pierce her aft ballast tank s and sink her , because the K - 27 ' s bow had impacted the seafloor while her stern was still afloat . This scuttling was performed contrary to the International Atomic Energy Agency ' s requirement that nuclear - powered submarines and surface ship s must be scuttled at depths not less than 3 , 000 meters . The last scientific expedition of the " Russian Ministry of Emergencies " to the Kara Sea examined the site of the scuttling in September 2006 . Numerous samples of the seawater , the seafloor , and the sealife were gathered and the analyzed . The final report stated that the radiation levels of the area were stable . Lessons in nuclear submarine construction and safety learned from Projekt 645 were applied in Projects 705 and 705K – that produced the Soviet Alfa class submarine s . These were equipped with similar liquid - metal - cooled reactor s . In September 2012 it was reported that the sub needed to be lifted from its shallow bed in the Kara Sea . The vessel is a " nuclear time bomb " , as the rusting and decaying vessel may be reaching a critical level leading to an " uncontrolled chain reaction " . Although a joint Russian and Norwegian in 2012 did not find alarming levels of radioactivity in the water and soil surrounding the sub , an urgent consideration pertains to the dismantling of the nuclear reactors should the sub be raised . Because the reactors were cooled by liquid metals , the nuclear rods became fused with the coolant when the reactors were stopped and conventional methods cannot be used for disassembling the reactors . However , France ' s Commissariat à l ' énergie atomique et aux énergies alternatives designed and donated special equipment for a dedicated dry - dock ( SD - 10 ) in Gremikha , which was used to dismantle the Alfa - class submarine s that shared this design feature . However , since the last Alfa reactor was dismantled in 2011 , this equipment is at risk .