Soviet submarine K-27

The keel of K-27 was laid down on 15 June 1958 at Severodvinsk Shipyard No. 402.[1] It was launched on 1 April 1962, and went into service as an experimental "attack submarine" on 30 October 1963.[1] K-27 was officially commissioned into the Soviet Northern Fleet on 7 September 1965. K-27 was assigned to the 17th submarine division, headquartered at Gremikha.[1]

The nuclear reactors of 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 K-27 increased dangerously – by 1.5 grays per hour. This radiation consisted mostly of gamma rays and thermal neutrons, with some alpha radiation and beta radiation in addition – generated by the released radioactive gases such as xenon and krypton in her reactor compartment.

The training of the crew by the Soviet Navy had been inadequate, and these sailors did not recognize that their nuclear reactor had suffered from extensive fuel element failures. By the time they gave up their attempts to repair the reactor at sea, nine of the crewmen had accumulated fatal radioactive exposures.[4]

About one-fifth of the 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.

K-27 was laid up in Gremikha Bay starting on 20 June 1968. The cooling-off of the reactors and various experimental projects were carried out aboard the submarine through 1973. These included the successful restarting of the starboard reactor up to 40% of maximal power production. Plans were considered to slice off the reactor compartment and replace it with a new one containing standard VM-A water-cooled reactors. The rebuilding or replacement of the nuclear reactor was considered to be too expensive, and also to be inappropriate because more modern nuclear submarines had already entered service in the Soviet Navy.[3][5]

K-27 was officially decommissioned on 1 February 1979,[1] 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".[5]

Then K-27 was towed to a special training area in the eastern Kara Sea, and it was scuttled there on 6 September 1982 near the location 72°31'28"N., 55°30'09"E.[6] off the northeastern coast of Novaya Zemlya (at Stepovoy Bay), in a fjord at a depth of just 33 m (108 ft). It was necessary for a naval salvage tug to ram the stern of K-27 to pierce her aft ballast tanks and sink it, because K-27's bow had impacted the seafloor while her stern was still afloat. This scuttling was performed contrary[7] to the International Atomic Energy Agency's requirement that nuclear-powered submarines and surface ships must be scuttled at depths not less than 3,000 m (9,800 ft).

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 then analyzed. The final report stated that the radiation levels of the area were stable.[8]

Lessons in nuclear submarine construction and safety learned from Project 645 were applied in Projects 705 and 705K – that produced the Soviet Alfa-class submarines. These were equipped with similar liquid-metal-cooled reactors.

• List of sunken nuclear submarines