Radiation accident at the Krasnoye Sormovo plant — the unauthorized startup of the nuclear reactor of an atomic submarine under construction, which occurred on January 18, 1970, in the assembly shop of the Krasnoye Sormovo shipbuilding plant in the city of Gorky (now Nizhny Novgorod). The accident resulted in radioactive contamination of the shop and the irradiation of hundreds of workers; four of them died. For more than twenty-five years, information about the disaster remained classified.[1][2]

Background and circumstances

The Krasnoye Sormovo plant was officially listed as a civilian shipbuilding enterprise, yet since 1930 it had been producing combat submarines. The first diesel submarine, the Komsomolets, left the slipway in 1930; the first nuclear submarine of Project 670 was launched in 1967. Over several decades the plant built more than 300 combat submarines, including 26 nuclear-powered ones.[1]

In January 1970, the nuclear submarine of Project 670 "Skat" (Skate), with tactical number K-320 (length 95 m, width 10 m, designed crew of 100), was in the assembly shop. In neighboring shops, construction of the sister boats K-302 "Som" (Catfish) and K-308 "Syomga" (Salmon) was nearing completion. Work was proceeding at an accelerated pace: the submarine was supposed to be ready by April 22, 1970 — for the centennial of Lenin.[3][2]

Course of the accident

On January 18, 1970, a Sunday, hydraulic tests of the reactor's primary circuit at a pressure of 250 atmospheres were being carried out in the shop. At 9:25 there were 156 people in the shop; 12 fitters were working aboard the submarine, three of whom — Nikolay Lisov, Vyacheslav Gorokhov, and Nikolay Pomozov — were directly in the reactor area, and three more were in its immediate vicinity.[3][2]

The reactor had been loaded with uranium fuel. Instead of the standard metal plugs, plastic ones had been left in several places during assembly. At 9:30, owing to violations of the technical procedures, the reactor started up without authorization: under the pressure of the water the plastic plugs blew out, the water came into contact with the uranium rods, and an uncontrolled nuclear process began. A hydraulic explosion followed: the compensating grids were torn off, and a fragment of the reactor circuit casing 1.5 m in diameter punched through the shop's roof and flew several hundred meters — it was found only in the spring, when the snow melted. A column of radioactive steam and water rose to a height of about 60 meters. The reaction lasted roughly 15 seconds; the automatic protection system did not have time to activate.[3][2]

Casualties and cleanup

The fitters Lisov, Gorokhov, and Pomozov, who were in the reactor area, received lethal doses of radiation and died within a month at Moscow's Tushino Hospital — the same institution to which victims of the Chernobyl nuclear power plant accident would be taken 16 years later. Watch-service fitter Ivan Korkin died three months later.[3]

From the first minutes, more than a thousand plant workers took part in the cleanup of the accident, along with staff of the Afrikantov Design Bureau and several other Gorky enterprises.[1] The damaged reactor and the ash from contaminated objects and protective clothing burned in furnaces were buried in a radiation burial site. Despite the accident, the submarine K-320 was delivered on schedule.[1]

Secrecy and recognition

Information about the accident remained classified until the collapse of the USSR — about 25 years.[1] Residents of Gorky knew nothing about the construction of nuclear submarines at the plant or about the disaster that had occurred. Participants in the cleanup never received an official status comparable to that of the Chernobyl liquidators.[2]

In November 2017, the Legislative Assembly of Nizhny Novgorod Region established January 18 as the Day of the Liquidator of the Consequences of the Nuclear Accident at the Production Association "Krasnoye Sormovo Plant." This day was first observed on January 18, 2018.[1]

Sources

  1. napp52.ru — Today Is the Day of the Liquidator of the Consequences of the Radiation Accident at the Krasnoye Sormovo Plant — NAPP
  2. ufa1.ru — Everything About the Radiation Accident at the Krasnoye Sormovo Plant in Nizhny Novgorod in 1970: How the Soviet Authorities Concealed a Nuclear Catastrophe — January 18, 2021 — UFA1.ru
  3. pikabu.ru — The Radiation Accident at the Krasnoye Sormovo Plant (1970) — 04/25/25 07:43 — Pikabu