[Science] Gigantic, mysterious radiation leak traced to facility in Russia – AI

A nuclear fuel processing facility in Russia looks to have been been the source of the leakITAR-TASS News Agency / Alamy Stock Photo By Ruby Prosser ScullyThe source of a gigantic, mysterious leak of radioactive material that swept across Europe in 2017 has been traced to a Russian nuclear facility, which appears to have been preparing materials for experiments in Italy. The leak released up to 100 times the amount of radiation into the atmosphere that Fukushima disaster did. Italian scientists were the first to raise the alarm on 2 October, when they noticed a burst of the radioactive ruthenium-106 in the atmosphere. This was quickly corroborated by other monitoring laboratories across Europe. Georg Steinhauser at Leibniz University Hannover in Germany says he was “stunned” when he first noticed the event. Routine surveillance records several radiation leaks each year, mostly of extremely low levels of radionuclides used in medicine. But this event was different. “The ruthenium-106 was one of a kind. We had never measured anything like this before,” says Steinhauser. Even so, the radiation level was not high enough to impact human health in Europe, though exposure closer to the site of release would have been far worse. Advertisement Read more: HBO’s Chernobyl drama highlights the human cost of nuclear catastrophe The Institute of Radioprotection and Nuclear Security in Paris soon concluded that the most probable source of the leak was between the Volga river and Ural mountains in Russia. This is where the Russia’s Mayak facility is located. The site, which includes a plant that processes spent nuclear fuel, suffered the world’s third most serious nuclear accident in 1957. At the time of the 2017 leak, Russian officials denied the possibility of the Mayak facility being the source, saying there was no radioactive ruthenium traces in the surrounding soil. Instead, they suggested the source may have been a radionuclide battery from a satellite burning up during reentry into the atmosphere. Steinhauser and his colleagues decided to investigate more thoroughly by forensically analysing 1300 measurements from hundreds of monitoring stations across Europe. They found that radiation levels in the atmosphere were between 30 and 100 times higher than those measured after Fukushima. “This was indeed quite alarming,” says Steinhauser. Eliminate the impossible The team excluded Romania as the source of the accident, despite the country’s high radiation levels. Each station in the country detected the radioactive plume simultaneously, which indicated the source was far enough away for it to have grown to the width of Romania. They also excluded a satellite as the cause because space organisations did not report any missing at the time. The pattern of radiation through the atmosphere did not match the spread of radiation from a satellite’s reentry either. Combining these findings with information on air movements and concentration levels from monitoring data, the team found clear evidence that the release happened in the Southern Urals, which is where the Mayak nuclear facility is. The leak was unusual because the release was limited to radioactive ruthenium. “If there is a reactor accident, one would expect the release of radioactive isotopes of many different elements,” says Steinhauser. Exactly why such a specific element was released remained a mystery until Steinhauser learned that an Italian nuclear research facility had ordered a consignment of cerium-144 from Mayak before the incident. “There are several indications that the release of ruthenium-106 was linked to this order,” says Steinhauser. Journal reference: Proceedings of the National Academy of Sciences , DOI: 10.1073/pnas.1907571116