Undeclared Russian nuclear accident to blame for 2017 radiation cloud: Study

It was a scene eerily reminiscent of the Chernobyl nuclear accident of 1986, when the news of a suppressed nuclear disaster in Ukraine became evident in Europe only after a Swedish nuclear scientist raised an alarm over an abnormally-high reading of radiation coming from his shoes.

In January, 2017, radiation monitoring institutions detected high levels of iodine-131 across Europe. In October of 2017, multiple European countries reported abnormally-high levels of ruthenium-106 in the air. Both are radioactive isotopes, with Ruthenium-106 only occuring as a result of nuclear fission, ie, atoms being split. It is an isotope that has not been detected in the earth’s atmosphere since the Chernobyl nuclear disaster.

For it to reach so many European nations suggests a fission-related incident. An international radiation monitoring group, the Ring of Five, sounded an alarm.

Russia confirmed the presence of radiation a month later, but did not identify its source. The country’s meteorological agencies did, however, identify the highest concentrations of radiation at a town 30km from the Mayak nuclear power plant, the site of the third-deadliest nuclear accident in human history in 1957. Later that year, Russian state sources, comprising a commission from Rosatom, the Nuclear Safety Institute of the Russian Academy of Science, and other groups, later said that they found no abnormal concentrations of ruthenium-106 at Mayak, and that the radiation in the air could be attributed, “among other things, to the burning in the atmosphere of an artificial satellite or its fragment.”

Now, on July 26, the largest study yet conducted on the incident has confirmed that the source of the radiation came from the Southern Urals region of Russia — which comprises Mayak — and that it was no satellite.

A fissile material storage facility at Mayak | US Army, Public Domain

A team of 70 scientists led by research engineer Olivier Masson looked at 1,100 atmospheric and 200 deposition data points from Eurasia. They reconstructed the spread of the radiation as well as the age of the radioactive material. Two points stand out from their findings: One, that the radioactive material was less than two years old and that it was released from somewhere in the Southern Ural region. Two, that it was probably released during an ‘advanced stage’ of nuclear fuel reprocessing, sometime around the end of September, 2017.

Luckily, the concentrations found were not enough to cause public harm, and Ruthenium-106 has a half life just short of 374 days, which means that half of its radioactive material would decay in little over a year.

The study traced the chronology of ruthenium-106 detections across Europe, identifying only Russia and most likely the Mayak nuclear facility as the possible source for the radioactive plumes (the highest concentrations were found in Romania but the width of the plume suggested it came from outside the country).

During the Cold War, Mayak was among the largest nuclear facilities of the Soviet Union. A chemical explosion at the plant in 1957 released 2,700 trillion becquerels (units of radiation). Dubbed the Kyshtym disaster, it created the 100-km long ‘East Ural Radioactive Trace’. For comparison, the 2017 radioactive cloud registered levels close to just 150 micro-becquerels.

Masson's study discussed a likely explanation for the release — a botched job at reprocessing spent nuclear fuel. In this hypothesis, the Mayak plant was attempting to produce Cerium-144 in order to participate in neutrino research experiments at the Gran Sasso lab in Italy (the world’s largets underground research centre. A hitch during this process could have led to a series of events that would have produced ruthenium-106 in the detected concentrations.

The range and depth of the study was only possible because of its pan-European network, the result of a radioactive monitoring agreement from the Cold War.

A brief history of the Ring of Five: A global radiation monitoring network

In the early 1980s, despite the end of atmospheric nuclear bomb testing by China, scientists in Europe continued to find radioactive particles in the atmosphere. In 1983, a group of North European countries decided to share data with one another whenever even the most-minute levels of radioisotopes were detected in the air. This informal grouping became known as the 'Ring of Five' (RoF). The grouping greatly expanded after the Chernobyl disaster of 1986, adding 20 countries and eventually becoming a global network.

Decades since, the RoF has expanded with laboratories in 22 countries, keeping its old name as it was 'mysterious' and capable of 'evoking interest'. The criteria for joining was that member-states have the ability to detect particles to within a tenth of a micro-becquerels per cubic meter (µBq/m3) — a sub-atomic level of precision for measuring radioactive emissions.

The wilder explanation: A secretive Russian nuclear-powered missile test?

The Tory II-A, an experimental American nuclear-powered missile engine from the 1960s

While an incident at the Mayak plant (which has had over 30 accidents since 1953) is the most likely cause of the cloud at present, a more far-flung explanation would be that of a failed Russian test of an experimental nuclear-powered missile.

In May of 2018, CNBC reported an anonymous source as saying that a new Russian nuclear-powered cruise missile had been tested four times since November 2017, with all four tests resulting in crashes. The Burevestnik was announced in March if 2018 by Vladimir Putin, who said that "no one in the world possesses anything remotely similar so far," claiming that the missile had an ‘unlimited’ range courtesy its internal nuclear reactor.

Iodine-131, the radioactive isotope detected in January of 2017, was an observed by-product of early American tests of a nuclear powered rocket engine in 1965. Trace quantities of ruthenium have also been observed as a result of nuclear detonations. A report published by The Drive compared spikes in iodine-131 readings with the estimated timings of Russian Burevestnik tests. In addition, an American WC-135 was detected over Europe at the time — a special-purpose aircraft used for detecting evidence of a nuclear test. The US later denied that the deployment had anything to do with the spike in iodine concentrations.

The truth of the theory depends on whether the iodine-131 and ruthenium-106 leaks are linked, and whether such missiles are capable of producing such quantities of ruthenium or iodine. Known models of nuclear-powered ramjets emit their isotopes out the sides of the missile, making a nuclear leak a necessary part of their design.

Russia was not the first country to experiment with nuclear-powered nuclear missiles. The American Supersonic Low Altitude Missile (SLAM), a part of 'Project Pluto', was a failed attempt at creating a cruise missile that could travel the world indefinitely, constantly releasing radiation as it went along, serving as an endlessly detonating bomb.

UPDATE: Rosatom has responded to Masson's study, refuting its claims and stating that an independent team of Russian and international regulatory authorities had already reviewed the site and found no evidence of an accident.