More than half a century ago, the Krasnoye Sormovo plant manufactured submarines, including nuclear ones. This was known to residents of Nizhny Novgorod, but little known in other cities.
On a winter day, January 18, 1970, a day off, the whole country is resting, but at the Krasnoye Sormovo shipyard in the city of Gorky (now Nizhny Novgorod) work does not stop for a minute. After all, the submarine must be ready for the 100th anniversary of the leader – Vladimir Lenin. a radiation accident occurred. This accident occurred during the construction of the nuclear submarine of project 670 “Skat” with the tactical number K-320. In parallel with this submarine, in two neighboring workshops, the construction of submarines of the K-302 “Som” and K-308 “Syomga” projects was being completed.
That Sunday, the reactor’s primary circuit needed to be tested. It was necessary to find out whether the submarine’s nuclear engine was capable of operating at the extremely high pressure of 250 atmospheres, so that it could withstand such conditions in reality. The parts needed to produce the submarines were delivered to the plant from various cities. At 09:25 in the morning, there were only 156 people in the workshop. There were 12 fitters on the boat who worked in the reactor area, and three more fitters were nearby. The entire testing methodology was extremely complex and had been honed on previous vessels; all employees were highly qualified specialists who had undergone strict selection and verification by the secret services. The probability of an error was practically zero.
The reactor was loaded with radioactive uranium fuel. As part of the tests, the rods were not inserted into the reactor zone and metal plugs were used instead. However, an error at the reactor assembly stage was that some of the plugs were forgotten to be replaced with metal ones and plastic ones were left. No one present knew about this error.
At 09:30, a catastrophic emergency occurred. Due to technical failures, the reactor started up earlier than planned and began operating at full capacity. The plastic plugs could not withstand the water pressure and flew out, which led to contact between the water and the uranium rods and an irreversible reaction. The water pressure immediately exceeded critical values, causing a hydraulic explosion. High pressure tore the compensation grids and tore off a 1.5-meter-diameter section of the reactor casing, which broke through the ceiling and flew a considerable distance. It was found only several months later, after the snow melted. At the same second, due to the explosion, water and steam contaminated with radioactive particles rose to a height of 60 meters. The reaction lasted about 15 seconds, but the emergency system did not have time to work. The reactor was damaged and shut down, however, the fitters who were closest to the reactor received a large dose of radiation.
Several people who survived the event are still alive and talking about it. The participants in the accident never had the same status as, for example, the liquidators of the Chernobyl disaster. This accident remained “an accident that cannot be talked about.” Perhaps because these were secret military facilities.