The ‘Krasnoe Sormovo’ explosion: A pre-Chernobyl nuclear disaster

Russia Beyond (Photo: Malte Mueller/Getty Images, Nikolai Moshkov, V.Voitenko/TASS)
The huge ‘Krasnoe Sormovo’ plant experienced a submarine reactor blast, which was kept top-secret for many years.

Chernobyl is the USSR’s most infamous nuclear catastrophe, but some other similar disasters happened in the country even earlier. One of them took place in 1970 at the ‘Krasnoe Sormovo’ plant in Gorky (now Nizhny Novgorod, 400 kilometers north-east of Moscow).

In the Soviet times, ‘Krasnoe Sormovo’ was a restricted-access plant, which was believed to build civic motor ships, barges and tankers. But, in reality, the factory constructed a lot of military watercraft, including nuclear submarines. On Sunday, January 18, 1970, ‘Krasnoe Sormovo’ was working on three of them: the K-320 ‘Skat’ (“Stingray”), K-302 ‘Som’ (“Catfish”) and K-308 ‘Syomga’ (“Salmon”). The specialists had to finish at least one, at whatever cost, by April 22 - the centenary of Vladimir Lenin's birth. :This is why they had been spending their weekends at work and planned to do an important thing that morning: to check if the primary coolant circuit could withstand the operation pressure of 250 atmospheres. The reactor itself didn’t have to be turned on. The shift that had worked the day before had left the plastic plugs on the circuit cover. They had to be changed to metal ones to provide total sealing capacity, but the workers didn’t know about it and started the test anyway.

The workers of ‘Krasnoe Sormovo’, 1930s.

When the pressure built up a little, the weak plastic plugs flew off. It caused an abrupt drop in cooling water pressure inside the circuit and the graphite rods of the reactor began to shift. A nuclear reaction then started and soon reached its maximum strength. The temperature rose and turned some water into radioactive steam. Fifteen minutes later, a strong thermal explosion occurred and made the reactor hatch fly up and punch a hole in the plant section roof. The hatch was found some kilometers away in spring, when the snow finally melted. Some uranium leaked out of the reactor creating a 60 meter tall steam cloud that rose up after the blast. Vitaly Voytenko, who took part in cleanup works, recalled that the air was still and the day was as cold as -40°C (-40°F), so all the dirty steam subsided on the ‘Krasnoe Sormovo’ territory and didn’t spread further.

The entrance to the plant nowadays.

The factory workers, at first, didn’t take the situation seriously: practically nobody knew what had actually happened. Nina Zolina, who worked at the plant as a painter, remembered that her team was told to leave their working place, because a hot water pipe had burst. The military took control over the situation quickly: a nearby base had sent a brigade of dose monitoring technicians headed by Valentin Dneprovsky some hours before the accident. Only they wore chemical protection suits. Dneprovsky himself measured the radioactivity level everywhere in the submarine, despite the risk. Then, six specialists who worked with the ‘Skat’ at the moment of the explosion, were cleaned from the radiation and sent to a Moscow hospital. Three of them died there. Their medical certificates say they had various complications caused by gamma and beta rays.

The Krasnoe Sormovo plant. Submarine, 1938.

People still didn’t know what to do: On Monday, an academician by the name of Anatoly Alexandrov noticed that the affected section door stood open by mistake. Then, the dirtied snow on the territory thawed in just a week, when everybody finally realised it spread radionuclides. On Tuesday, a group of 18 volunteers entered the section to clear the way to the ‘Skat’ and to show other specialists an example. It worked: the following days the number of cleaners rose to 1,000. Everybody worked for 2-4 hours under supervision of the dose monitoring team. The cleaners used simple ways of washing down the radiation: They took mops and pieces of cloth to wash down the radioactive dust. The workers got rid of dirty water by pouring it into the Volga River. At the time, radiation wasn’t researched as well as nowadays. For example, it was believed that alcohol helped to reduce injury from the rays. Voytenko recalled that alcohol was everywhere at the factory and it caused a lot of mess, because people often got terribly drunk and even sometimes died of it.

One of the submarines that was produced at the Krasnoe Sormovo plant.

Despite the disaster, ‘Krasnoe Sormovo’ continued its production and still had to float out a submarine on the centenary of Vladimir Lenin’s birth, so the cleaners had to work quickly so that construction could be finished. It sounds unbelievable, but they managed to fulfil this task and floated out the K-308 submarine by the celebration date. Later, in July, the plant completed the construction of the K-302. The K-320 ‘Skat’, the one that blew up, took much more time: It was thoroughly cleaned, got a new reactor and was finished in 1971. It served the Soviet fleet until April 1990.

Like many Soviet tragedies, the explosion at ‘Krasnoe Sormovo’ immediately became top-secret. All witnesses and cleaners had to sign non-disclosure papers, which were in force until 1995. The newspapers didn’t write anything about the disaster and even the residents of Gorky didn’t know the truth about the disaster. To prevent people from getting radiation from the polluted Volga, the city administration prohibited swimming in the river that year. The authorities said that the waters were dangerous, because of a cholera outbreak that had really started that year in the Georgian SSR and got into the Volga through Astrakhan (1,270 kilometers south-east of Moscow). However, no documents prove that the outbreak actually reached Gorky. And no one knows how many people got doses of radiation ignoring the swimming ban.

The Mustai Karim vessel at the Krasnoe Sormovo plant in Nizhny Novgorod, 2019.

The secrecy affected the cleaners, too. When some of them fell seriously ill, the doctors couldn’t give them the diagnosis of radiation disease. Also, they weren’t officially acknowledged until 1996. When their non-disclosure liability expired, they applied to the Nizhegorodskaya Okrug administration that gave them the official status of regional level cleanup workers. Later, it was decided to commemorate January 18 as ‘Cleanup Worker Day. They started getting paid 2,000 rubles (approx. $27) annually from the ‘Krasnoe Sormovo’ plant. And, by 2021, less than 200 of them are still alive: Many workers died of radiation disease and cancer. Even today, they still don’t have a federal status or any state decorations.

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