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Scientist confirms potential source of Ru-106 as Mayak’s vitrification unit. English version.

H/T Jan Havercamp for article

Translated from Russian on Google from https://trv-science.ru/2017/11/24/otkuda-mog-vzyatsya-ru-106/

Discovered on September 27-29 by French and German experts, the release of ruthenium-106, which occurred, apparently, in the south of the Urals in late September 2017, became the property of the Russian public only at the end of November. And, as usual, we learned about this through publications in the Western media, based on monitoring data from local radiation monitoring services. The scandal that broke out was smoldering since the beginning of October and has flared up just now.

At the end of September in Europe, the level of pollution varied from several microbequerels (μBq) to 5 millibecquerels (MBq) per cubic meter. meter. French experts suggested on the basis of modeling that a radioactive release occurred somewhere on the territory of Russia between the Volga and the Urals, and the amount of ruthenium-106 at the release point was from 100 to 300 terabecquerels (TBq) [1]. German experts believe that the outburst occurred somewhere in the Southern Urals, stipulating, however, that this could happen and somewhere else in the south of Russia [2].

In its turn, Roshydromet, which is subordinate to the Ministry of Natural Resources of the Russian Federation, claims that it timely reported the detection of Ru-106 radioisotope in its weekly monitoring of environmental pollution. For example, in the October 6-13 issue [3], he reported an increase in the level of ruthenium-106 at his posts in the Southern Urals since September 25 (according to the data of the Typhoon of Roshydromet, the contamination was 5.2-7.5.10-2 Bq / m3 [8] ).

According to the same Roshydromet data, on 26-27 September, the Ru-106 decay products were fixed in Tatarstan, on September 27-28 a cloud of pollution moved to Volgograd and Rostov-on-Don. Since September 29, it has already recorded all the countries of Europe
(n.10-3 Bq / m3). On October 2-6, Ru-106 was detected in aerosol samples in St. Petersburg, and at that time the concentration of Ru-106 in Europe decreased to n.10-4 Bq / m3.

Such a rapid spread of the polluted cloud from the South Urals Roshydromet explains the meteorological situation (the link of the two anticyclones), “thanks to which conditions for the active eastward transfer of air masses and pollutants from the territory of the South Urals and South Siberia to the Mediterranean region and then to the north of Europe.”

Now the administration of Roshydromet regrets that it published data on ruthenium-106 without specifying maximum permissible concentration (MPC), which, they say, caused an incorrect and sometimes deliberately unfair interpretation of their data by some media and public organizations. According to the head of Roshydromet Maxim Yakovenko, the concentration of ruthenium-106 never exceeded the MPC [4].

It is worth noting that on October 11 Rossiyskaya Gazeta published a report from Rosatom, according to which there was no ruthenium-106 outflow in Russia, radioactivity at Rosatom’s facilities is within the norm and corresponds to a natural radiation background. Moreover, the newspaper, referring to experts from Rosatom, suggested that the traces of ruthenium-106 do not lead to the south of Russia, but to one of the countries in the east of the European Union, but we will not point a finger at this country. The experts based their conclusions on the fact that aerosol samples showed the presence of ruthenium-106 in Russia only in St. Petersburg, while “the concentration of Ru-106 in the air above Romania was 145 000 μBq / m3, over Italy – 54 300, Ukraine – 40,000, Slovenia – 37,000, Poland – 9,930 μBq / m3 “[5].

It turns out that the information of Rosatom and Roshydromet contradict each other. The head of Roshydromet asserts that as early as October 20, the administration of the Chelyabinsk region administration held a special briefing for the media, which confirmed the presence of ruthenium-106 in samples taken by the Ural Department of the Hydrometeorological Service. Immediately, journalists were told that the concentrations of Ru-106 “are hundreds to thousands of times lower than the permissible average annual volumetric activity and do not pose a threat to the population.” They also stated about some “transit” origin of ruthenium [6].

Preface prepared by Natalia Demina
Where could ruthenium-106 come from?

Boris Zhuikov

DYOR1193-600x400

Boris Zhuikov. Photo by Ignat Nightingale.

What could have happened in reality? By his analysis of the data with the release of ruthenium-106 with TrB-Nauka, he shared his Doct. chem. Sciences, Head. Laboratory of the Institute for Nuclear Research of the Russian Academy of Sciences Boris Zhuikov.

In recent months, Europe and Russia have been agitated by reports of an impending radioactive cloud of ruthenium-106. People ask themselves: what’s the matter, what happened?

The usual story. As there is something related to radioactivity, specialists working in this field are silent, and people who have heard something about radioactive isotopes comment on something, but do not really understand.

At one time I had to work with radioactive isotopes of ruthenium, to study their volatility. In general, it’s understandable.
1. How do they get ruthenium-106?

This radionuclide (a half-life of 374 days) is a product of uranium fission and is produced by the operation of nuclear reactors. On cyclotrons it does not get at all, talking about it is stupid.

The yield of ruthenium-106 in fission products is 0.4%, and the other shorter-lived ruthenium radioisotope is ruthenium-103 (half-life 39 days) – 3%. The chemical behavior of both radionuclides is the same, and if the second isotope is not visible (as in this case), this means that ruthenium-106 was separated from the old products of the nuclear reactor, a year and a half or even several years after operating.
2. How could the release of pure ruthenium-106 be obtained?

Pure ruthenium-106 is obtained in small amounts for the manufacture of applicators for the treatment of certain eye diseases. But to explain the appearance of a huge ruthenium cloud by some processing of these medical products is impossible. According to the Institute of Nuclear and Radiation Safety of France (IRSN) [1], the release was 100-300 terabecquerels. This is a huge activity, no applicators are enough. And why recycle them?

Another “duck”: ruthenium appeared as a result of the destruction of the satellite. This is refuted by a member of the Russian Academy of Cosmonautics, former adviser to the head of the RSC Energia AB. Zheleznyakov [7]: on satellites, ruthenium-106 is not used.

So what’s the deal? Why not see other products of uranium fission?

The fact is that ruthenium has a chemical property that is quite rare for metals – it forms an easily volatile compound – ruthenium tetroxide. So when heating nuclear waste in air to a certain temperature, only ruthenium will fly. There are other volatile fission products of uranium, for example iodine-131, but it has already disintegrated (half-life of 8 days); the other isotope iodine-iodine-129 has a very long half-life (16 million years), so its activity is extremely small and against this background is not visible.

Thus, if an aqueous solution of old radioactive waste is evaporated in air or heated in a vitrification furnace, only ruthenium-106 will fly as a tetraoxide. Such long-lived radionuclides, like strontium-90, cesium-137, are not volatile under these conditions and therefore do not stand out when heated. They appear in the air either in the explosion and ejection of solid or liquid matter, or when heated to a much higher temperature – when a nuclear reactor is operating. Existing technologies for processing radioactive waste, of course, provide for the capture of the departed ruthenium with special filters, but apparently in this case the filters did not work.
3. How is ruthenium-106 distributed?

Once in the atmosphere, ruthenium will be deposited on the dust particles already in the form of low-volatile dioxide. Distribution can be quite wide, and the cloud can spread far in accordance with weather conditions. Particle deposition of particles leads to an increased concentration of radioisotope on the surface at individual points. Naturally, more such points will be close to the place where the emission occurred, but the ruthenium precipitation can happen quite far from the accident site. Ruthenium-106 itself emits only beta particles, but its spread is easily traced by the gamma activity of the daughter short-lived decay product – rhodium-106.

The map, with the supposed site of ruthenium-106 emission

Figure 1. Initial distribution of ruthenium-106 activity according to the calculations of the Institute for Nuclear and Radiation Safety of France. Source: http://www.irsn.fr/EN/newsroom/News/Documents/IRSN_Information-Report_Ruthenium-106-in-europe_20171109.pdf

zhuikov_fig1

Fig. 2. The movement of radioactive particles, assumed on the basis of published measurement data. Source: http://www.openrussia.org [9]

zhuikov_fig2-1

4. Where can this happen?

The published maps show (see Figures 1 and 2) that the cloud began its spread from the Ural region. Of the large nuclear facilities there is the production association “Mayak”, the enterprise of the state corporation Rosatom in Ozersk (Chelyabinsk region). Not so far, next to Yekaterinburg, operates the Beloyarsk nuclear power plant – also the enterprise of Rosatom. Most commentators suspect in the incident “Mayak”, because it is there that are engaged in the processing of nuclear waste.

The points with the greatest ruthenium-106 contamination, according to the published bulletin of the Federal Service for Hydrometeorology and Environmental Monitoring of Russia (Rosgidromet) [8], the settlements of Metlino, Argayash, Khudaiberdinsk, and Novogorny are located just in these places, in the Chelyabinsk region. “Mayak” denies involvement in the accident and emissions. This enterprise is a closed, unauthorized access to any of its facilities is strictly prohibited, so it is difficult to verify them.
5. How dangerous is this for the population?

Authorities and experts say that the concentrations of ruthenium-106 found are not dangerous. Many people, remembering the Chernobyl history, they do not believe. Let’s look at it in detail.

Journalists and some environmentalists like to compare the level of pollution with the background value (as they say – the usual meaning). This is completely unjustified. If the background value of someone of a rare substance is close to zero, then a thousand-fold excess of background means little.

It is not at all for the sake of radioactivity, but in the level of radioactivity. It is completely wrong to think that any radioactivity is harmful. Some kind of radioactivity is everywhere and always. At low doses (and only at low doses!), The number of diseases is not at all proportional to the dose of radiation, rather, on the contrary (radiation hormesis). The human body needs this kind of immunity, otherwise it can die, for example, after flashes on the Sun.

There are norms [10], they are rather rigid and made with a large margin. According to these standards, for professionals working with radioactivity and under constant control (persons of category A), the norm of the maximum annual intake of ruthenium-106 is up to 1,100,000 becquerels, in the workplace in the air it can have no more than 440 becquerels per cubic meter .

For people of category B – the whole population – the norms are more stringent – no more than 36 000 becquerels inside the body and 4.4 becquerels per cubic meter on average per year. Radiotoxicity of ruthenium-106 is higher than that of cesium-137, but lower than that of strontium-90.

According to the published data of Roshydromet [8], which has no reason to distrust, the maximum recorded content of ruthenium-106 in air was 0,086 becquerels per cubic meter in Argayash. That is, to get a dose that is the maximum for the population, a person should breathe at least about a million cubic meters of such air, in a professional – 100 million m3. A person inhales usually about a few thousand cubic meters per year … Or you need to carefully ruthenium ruthenium from the most active surface (Metlino) on an area of ​​about 50 m2.

But even a temporary excess of the maximum allowable concentration is not so terrible. After all, otherwise the entire center of Moscow, not to mention Chelyabinsk and Norilsk, has long been needed to be evacuated, since there is regularly a multiple excess of the maximum permissible concentrations of harmful chemicals. And from my point of view this is a much more important problem. But the radioactivity of the people is special – radioactivity can not be seen, sniffed and touched, so it is so scary.

Does this mean that there is absolutely nothing to worry about? Not certainly in that way. Of course, there is no need to talk about any evacuation, even from the dirtiest places. But the loss of radioactivity can be very uneven, and careful monitoring in the contaminated areas is necessary. And, of course, we need to find the reasons for what happened and exclude it in the future.

Boris Zhuikov

  1. www.irsn.fr/EN/newsroom/News/Pages/20171109_Detection-of-Ruthenium-106-in-France-and-in-Europe-Results-of-IRSN-investigations.aspx
  2. www.bfs.de/SharedDocs/Kurzmeldungen/BfS/EN/2017/1003-ruthenium-106.html
  3. www.meteorf.ru/product/infomaterials/91/15078/
  4. www.interfax.ru/russia/588721
  5. rg.ru/2017/10/11/otkuda-v-atmosfere-nad-evropoj-poiavilsia-radioaktivnyj-izotop-rutenij.html
  6. www.rosatom.ru/journalist/smi-about-industry/rosgidromet-ne-skryval-informatsiyu-o-povyshenii-urovnya-ruteniya-106/
  7. ria.ru/incidents/20171121/1509248320.html
  8. www.rpatyphoon.ru/upload/medialibrary/f21/byulleten_rorf_09_2017.pdf
  9. www.openrussia.org/notes/716326
  10. Нормы радиационной безопасности (НРБ-99/2009). Санитарные правила и нормативы (СанПиН 2.6.1.2523-09). Государственное санитарно-эпидемиологическое нормирование Российской Федерации. Москва, 2009.

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November 27, 2017 - Posted by | Uncategorized

2 Comments »

  1. I would rather be satisfied by having an information on such an imporant issue through real translation instead of a google translation. Fyi.

    Comment by pnrizumi | November 28, 2017 | Reply

    • I left a linkto the source and this blog is for scientists/journalist and bloggers who would contact the various scientists who commnent. The translation is good enough for that purpose as a Summary if nothing else but the dose estimates and scientific readings come out reasonably well .. If you have some basic science you can get the details and general point of the paper/report etc.. Regards Shaun

      Comment by arclight2011part2 | November 28, 2017 | Reply


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