30 years before Chornobyl, a nuclear accident occurred in the USSR: why the data about it was hidden

The Chornobyl accident remains the largest and most famous nuclear disaster of the Soviet era. But it was not the only one - on September 29, 1957, an explosion occurred at the Mayak chemical plant located in the closed Russian city of Chelyabinsk-40 (now Ozersk), which led to a radiation leak.

The catastrophe was named the Kyshtym disaster after the nearest open settlement, Kyshtym. OBOZ.UA tells about its history and consequences. The Soviet authorities concealed information about the explosion until 1989.

The city where the accident occurred is located in the Urals. And the plant with the neutral name "Mayak" actually produced nuclear bombs. The nuclear waste incident released 20 million curies of radiation into the atmosphere, and nearly 300,000 people were exposed. According to various estimates, the contaminated area amounted to 15-20 thousand square kilometers and was named the East Ural Radioactive Trail. According to the International Nuclear Event Scale, the incident was classified as a sixth category. Only the Chornobyl and Fukushima disasters received the highest seventh level.

The reactor, which produced weapons-grade plutonium, had been operating here since June 1948. In August 1949, it was used to test a nuclear bomb at the Semipalatinsk test site. The Soviet government acted quickly and without much regard for safety.

At first, the waste from the Mayak plant was dumped into the local river Techa. Because of this, residents of 39 villages located downstream began to get cancer, give birth to children with developmental disabilities, and die earlier. When the authorities learned about this, they decided to start putting the production waste into concrete containers, nicknamed "cans," for storage. They were dug into the ground, covered with a concrete lid about a meter thick and weighing 160 tons, and covered with soil for two meters.

In March 1957, the workers noticed that one of these "cans", which contained high-level waste, began to heat up and smoke. Its volume was about 80 cubic meters. In September, the can exploded, destroying all protective structures.

The area of radiation contamination resulting from the Kyshtym accident included the territory of several enterprises of the Mayak plant, a military camp, a fire station, a prison colony, and an area of 23,000 square kilometers with a population of 270,000 people. The damage was done to 217 settlements in three regions: Chelyabinsk, Sverdlovsk and Tyumen. As a result, it was decided to completely resettle 23 villages that suffered the most. Hundreds of thousands of military personnel and civilians were involved in the aftermath of the explosion. Almost all of them were exposed to radiation.

Nevertheless, the plant, whose territory remained almost unaffected, continued to operate. The company continued to produce plutonium and its isotopes. It also processed nuclear fuel. Mayak is still operating and still polluting the environment.

According to environmentalists and activists, accidents still occur here today. However, they continue to be carefully concealed from the public. It is known that in 2017, the plant emitted ruthenium, the trace of which reached as far as France. However, Rosatom and the management of the Mayak plant deny any involvement in this event.

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