The Krasnoe Sormovo explosion: a nuclear disaster before Chernobyl

The huge “Krasnoe Sormovo” factory suffered an underwater reactor explosion, which was kept secret for many years.

Chernobyl is the USSR’s most infamous nuclear disaster, but other similar disasters have occurred in the country even earlier. One of them took place in 1970 at the “Krasnoe Sormovo” factory in Gorky (now Nizhny Novgorod, 400 kilometers northeast of Moscow).

In Soviet times, “Krasnoe Sormovo” was a restricted-access factory, which was supposed to build motorboats, barges and civilian oil tankers. But, in reality, the factory built a lot of military craft, including nuclear submarines. On Sunday January 18, 1970, ‘Krasnoe Sormovo’ was working on three of them: the K-320 ‘Skat’ (“Stingray”), the K-302 ‘Som’ (“Catfish”) and the K-308 ‘Syomga ‘ (“Salmon”). The specialists had to finish at least one, no matter what, before April 22 – the centenary of the birth of Vladimir Lenin. : That’s why they spent their weekends at work and planned to do one important thing that morning: check if the primary cooling circuit could withstand the operating pressure of 250 atmospheres. The reactor itself did not need to be turned on. The team that had worked the day before had left the plastic caps on the circuit cover. They had to be replaced with metals to provide full sealing capability, but the workers didn’t know that and started testing anyway.

Workers of 'Krasnoe Sormovo', 1930s.

Workers of ‘Krasnoe Sormovo’, 1930s.

Nizhny Novgorod State Historical and Architectural Museum-Reserve

When the pressure increased a bit, the fragile plastic plugs flew off causing the cooling water pressure inside the circuit to drop sharply and the reactor graphite rods began to collapse. to move. A nuclear reaction then began and quickly reached its maximum strength. The temperature rose and turned some of the water into radioactive vapor. Fifteen minutes later, a strong thermal explosion occurred that blew the reactor hatch and drilled a hole in the roof of the plant section. The hatch was found a few miles away in the spring when the snow finally melted. Uranium escaped from the reactor, creating a 60-meter-high cloud of vapor that rose after the explosion. Vitaly Voytenko, who took part in the clean-up work, recalled that the air was calm and the day was as cold as -40C (-40F), so all the dirty steam calmed down in the territory of ‘Krasnoe Sormovo ‘and did not spread further.

The entrance to the factory nowadays.

The entrance to the factory nowadays.

Mikhail Solunin / TASS

The factory workers at first didn’t take the situation seriously: hardly anyone knew what really happened. Nina Zolina, who worked at the factory as a painter, recalled that her team had been ordered to leave their workplace because a hot water pipe had burst. The soldiers quickly took control of the situation: a neighboring base had sent a brigade of dose control technicians led by Valentin Dneprovsky a few hours before the accident. Only they wore chemical protective suits. Dneprovsky himself measured the level of radioactivity all over the submarine, despite the risk. Then, six specialists who were working with the “Skat” at the time of the explosion were cleaned of radiation and sent to a hospital in Moscow. Three of them died there. Their medical certificates indicate that they have had various complications from gamma and beta rays.

The plans of Krasnoe Sormovo.  Submarine, 1938.

The plans of Krasnoe Sormovo. Submarine, 1938.

N. Lufchan / Archive of audiovisual documentation of the Nizhny Novgorod region

People still did not know what to do: on Monday, an academician named Anatoly Alexandrov noticed that the door to the affected section was opened by mistake. Then, the dirty snow on the land thawed in just a week, when everyone finally realized that it was spreading radionuclides. On Tuesday, a group of 18 volunteers entered the section to pave the way for ‘Skat’ and set an example for other specialists. It worked: the following days the number of cleaners increased to 1000. Everyone worked 2-4 hours under the supervision of the dose control team. Cleaners used simple means to remove radiation: they took mops and pieces of cloth to remove radioactive dust. The workers got rid of the dirty water by pouring it into the Volga. Back then, radiation was not as studied as it is today. For example, alcohol was believed to help reduce radiation injuries. Voytenko recalled that alcohol was everywhere in the factory and caused a lot of damage, as people often got terribly intoxicated and sometimes even died from it.

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

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

Nikolai Moshkov / TASS

Despite the disaster, ‘Krasnoe Sormovo’ continued production and still had to float a submarine on the centenary of the birth of Vladimir Lenin, so the cleaners had to work quickly so that the construction could be completed. It sounds incredible, but they managed to accomplish this task and floated the K-308 submarine on the date of the celebration. Later, in July, the factory completed construction of the K-302. The K-320 ‘Skat’, the one that exploded, took much longer: it was thoroughly cleaned, received a new reactor, and was completed in 1971. It served the Soviet fleet until April 1990.

Like many Soviet tragedies, the explosion of ‘Krasnoe Sormovo’ immediately became top secret. All witnesses and cleaners had to sign nondisclosure papers, which were in effect until 1995. The newspapers did not write anything about the disaster, and even the people of Gorky did not know the truth about the disaster. To prevent people from receiving radiation from the polluted Volga, the city administration banned swimming in the river that year. Authorities said the waters were unsafe, due to a cholera epidemic that had really started that year in the Georgian SSR and spread to the Volga through Astrakhan (1,270 kilometers southeast of Moscow ). However, there is no document to prove that the epidemic actually reached Gorky. And no one knows how many people received radiation doses by ignoring the swim ban.

The Mustai Karim ship at the Krasnoe Sormovo factory in Nizhny Novgorod, 2019.

The Mustai Karim ship at the Krasnoe Sormovo factory in Nizhny Novgorod, 2019.

Mikhail Solunin

Secrecy also affects the cleaners. When some of them became seriously ill, doctors could not give them the diagnosis of radiation sickness. Moreover, they were not officially recognized until 1996. When their responsibility for non-disclosure expired, they applied to the Nizhegorodskaya Okrug administration which granted them the official status of cleaning agents in the country. regional level. Later, it was decided to commemorate January 18 as “Cleaning Workers Day”. They began to be paid 2,000 rubles (about $ 27) per year at the ‘Krasnoe Sormovo’ factory. And, by 2021, fewer than 200 of them are still alive: many workers have died from radiation sickness and cancer. Even today, they still do not have federal status or state decoration.

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