In 1957, there was a serious nuclear accident in Ozyorsk, Russia at the Mayak nuclear fuel reprocessing plant. Ozyosk was one of the "closed cities" that the Soviet Union built to carry out for highly classified research and industry. Ozyorsk was not on any public maps so the disaster has been referred to under the name of the nearest town that was on public maps, Kyshtym.
In a rush to catch up with the United States in nuclear weapons development, the Soviets built the Mayak reprocessing plant between 1945 and 1948 without great concern for safety or the environment. The six reactors on the site discharged irradiated cooling water directly into Lake Kyzyltash and high-level radioactive waste was dumped into a nearby river.
In 1953, they built storage for liquid nuclear waste underground. Steel tanks were mounted on concrete bases and a cooling system was created to deal with heat generated by continuing radioactive decay in the waste. The monitoring systems which were created were not sufficient to deal problems arising from the cooling systems and the contents of the tanks.
In September of 1957, the cooling system failed in one of the tanks and was never repaired. The tank contained about eighty tons of liquid waste. The temperature in the tank continued to rise and the liquid waste was dried out through evaporation. The ammonium nitrate and acetates in the dried waste eventually exploded with a force equivalent to one hundred tons of TNT, blowing the one hundred and sixty ton concrete lid off the tank. Up to fifty microcuries of radiation were released into the atmosphere.
Over the next twelve hours, the radioactive plume spread to two hundred miles northeast over the east Ural region of western Russia. Three hundred square miles of the landscape were contaminated with cesium-137 and strontium-90. This contaminated area has been given the name of the East-Ural Radioactive Trace. Over the next two years ten thousand people in twenty two villages were evacuated. Early evacuations took place without explanations to the people being moved.
Because of the secrecy surround the Soviet nuclear program, only vague reports of a the release of radioactivity over Russia from a terrible accident appeared in April of 1958. In 1968, the Soviet Union created the East-Ural Nature Reserve and forbid any unauthorized access to the Reserve in order to conceal the effects of the accident. Eventually, it was revealed that supposed laboratory experiments on the effects of radiation on plants and animals published in Soviet scientific journals were actually reports on the impact of the accident on the environment. Finally, in 1976, Zhores Medvedev revealed what had really happened at Ozyosk. IN 1979, a Freedom of Information Act request filed with the CIA revealed that the CIA had learned about the accident in 1957 but had withheld the information in order to protect the new US nuclear industry. The Soviets finally declassified their records on the disaster in 1990.
Ultimately, it is estimated that over eight thousand people died because of the accident at Ozyosk. The disaster is rated as a six on the International Nuclear Event Scale.
