In late 1945, mere months after atomic bombs from the United States decimated Hiroshima and Nagasaki, the Soviet Union sent 70,000 inmates from labor camps to the banks of the Techa River in order to construct a sprawling plutonium-production complex in the southern Ural mountains. The military-industrial community was to be operated by Russia’s Mayak Chemical Combine, and it would be called Chelyabinsk-40.
Chelyabinsk-40 was absent from all official maps for over forty years before the Soviet government would even acknowledge its existence. Nevertheless, the small city would create a corona of contamination nearly as bad as Chernobyl.
By June 1948, after 31 months of construction, the first of the Chelyabinsk-40 reactors was brought online. Soon bricks of common uranium-238 were being bombarded with neutrons, resulting in loaves of weapons-grade plutonium. In their haste to begin production, Soviet engineers skipped proper waste-handling procedures and most of the byproducts were dealt with by diluting them in water being dumped into the Techa River. The watered-down waste was a mixture of “hot” elements, including long-lived products such as Strontium-90 and Cesium-137, each with a half-life of approximately thirty years.
In 1951, after about three years of operations at Chelyabinsk-40, Soviet scientists conducted a survey of the Techa River to determine whether radioactive contamination was becoming a problem. In the village of Metlino, just over four miles downriver from the plutonium plant, radiation was found to be 5 Röntgens per hour rather than the typical gamma radiation of about 0.21 Röntgens per year.
Such elevated levels were rather distressing since the river was the primary source of water for the 1,200 residents there. Extensive contamination was found in 38 other villages along the Techa, jeopardizing the health of about 28,000 people. Also, almost 100,000 other residents were being exposed to elevated, but not deadly doses of gamma radiation, from the river and floodplain.
The Soviet government relocated about 7,500 villagers from the most heavily contaminated areas, fenced off the floodplain, and dug wells to provide an alternate water source for the remaining villages. Engineers were brought in to erect earthen dams along the Techa to prevent radioactive sediments from migrating further downstream. The Soviet scientists at Chelyabinsk-40 also revised their waste disposal strategy and constructed a set of “intermediate storage tanks” where waste water could bleed off radioactivity. After lingering in these vats for a few months, the diluted dregs were periodically piped to the new long-term storage location: a ten-foot-deep, 110 acre lake called Karachay. These measures seemed to work... for a time.
By the mid 1950s the workers at the plutonium production plant began experience symptoms of chronic radiation syndrome. The facility itself was also beginning to encounter complications.The row of waste vats sat in a concrete canal a few kilometers outside the main complex, submerged in a constant flow of water to carry away the heat generated by radioactive decay. Soon the technicians discovered that the hot isotopes in the waste water tended to cause a bit of evaporation inside the tanks, resulting in more buoyancy than had been anticipated. This upward pressure put stress on the inlet pipes, eventually compromising the seals and allowing raw radioactive waste to seep into the canal’s coolant water. To make matters worse, several of the tanks’ heat exchanges failed.
The workers were aware of these faults, but the radiation in the cooling trench halted any repairs. A flurry of calculations indicated that most of the waste water in the tanks would remain in a stable liquid state even without the additional cooling, so technicians continued to operate the plutonium plant in spite of these problems. Their evaporation calculations were incorrect, however, and the water inside the defective tanks gradually boiled away, leaving behind a radioactive sludge of nitrates and acetates.
The concentrated radioactive slurry continued to increase in temperature within the defective containers. On September 29th 1957, one tank overheated and the explosive salt deposits in the bottom of the vat detonated. The blast ignited the contents of the other tanks, and the thick concrete lid which covered the cooling trench was hurled eighty feet away. Seventy tons of highly radioactive products were ejected into the air.
This explosion allowed a mile-high column of radionuclides to be carried across the landscape. The gamma-emitting dust cloud spread hazardous isotopes of cesium and strontium over 9,000 square miles, affecting some 270,000 Soviet citizens and their food supplies. Over twenty megacuries (MCi) of radioactivity were released, almost half of that expelled by the Chernobyl incident.
In the days that followed, residents of the Chelyabinsk Province became hysterical with fear with the incidence of unknown ‘mysterious’ diseases breaking out. Victims were seen with skin ‘sloughing off’ their faces, hands and other exposed parts of their bodies. Ten days later, the government ordered the evacuation of many villages where sicknesses had appeared.
The facilities at Chelyabinsk-40 were swiftly decontaminated and soon plutonium production was underway again. The intermediate storage system had been partially compromised by the accident, but the factory was still able to release its constant flow of radioactive waste into Lake Karachay. The lake lacked any surface outlets, so engineers believed the waste could not escape.
Ten years later, in 1967, a severe drought struck the Chelyabinsk Province. Over several months the water in Lake Karachay dwindled considerably, leaving the lake about half-empty and exposing radioactive sediment in the lake basin. This released fifteen years’ worth of radionuclides, peppering 900 square miles of land was with Strontium-90, Cesium-137, and other unhealthy elements. Almost half a million residents were in the path, many of whom had been affected by the last disaster.
The Mayak Chemical Combine conceded that the lake was an inadequate long-term storage system and ordered that Karachay be slowly sealed in with concrete.
In 1990, government officials finally acknowledged the existence of the secret city of Chelyabinsk-40. They also acknowledged its radiological disasters. At that time Lake Karachay remained as the principal waste-dumping site for for the plutonium plant, but the effort to fill the lake with concrete had halved its surface area.
Thirty-nine years of waste had left the lake saturated with isotopes, including an estimated 120 megacuries of long-lived radiation. The Chernobyl incident released100 megacuries of radiation into the environment. Specialists visited Lake Karachay in 1990 to measure the radiation at the point where the effluent entered the water, and their Geiger counters read about 600 Röntgens per hour–enough to provide a lethal dose in one hour.
Today, there are huge tracts of Chelyabinsk land still uninhabitable due river contamination, the 1957 blast, and the 1967 drought. The surface of Lake Karachay is now made up of more concrete than water, but it is still leaking. Recent surveys have detected gamma-emitting elements in nearby rivers, indicating that undesirable isotopes in the water table. Estimates suggest that approximately a billion gallons of groundwater have already been contaminated with 5 megacuries of radionuclides.
The Mayak Chemical Combine is now credited by the Worldwatch Institute as the creator of the “most polluted spot” in history.
