Ruthenium-106 has been detected in late September 2017 by several European networks involved in the monitoring of atmospheric radioactive contamination, at levels of a few milliBecquerels per cubic meter of air. IRSN's investigations make it possible to provide information on the possible location of the source of the release as well as the order of magnitude of the quantities released.

As soon as it became aware of the first detections of Ruthenium-106 in the atmosphere in Europe, IRSN mobilized all its means of radiological monitoring of the atmosphere and conducted regular analysis of the filters from its monitoring stations. For the period from September 27 to October 13, 2017, only the stations of Seyne-sur-Mer, Nice and Ajaccio revealed the presence of Ruthenium-106 in trace amounts. Since October 13, 2017, Ruthenium-106 is no longer detected in France.

Measurement results from European stations communicated to the Institute since October 3, 2017, have confirmed the presence of Ruthenium-106 in the atmosphere of the majority of European countries. The results obtained for sampling periods later than October 6, 2017, showed a steady decrease in Ruthenium-106 levels, which is currently no longer detected in Europe.

The concentration levels of Ruthenium-106 in the air that have been recorded in Europe and especially in France are of no consequence for human health and for the environment.

Based on the meteorological conditions provided by Météo France and the measurement results available in European countries, IRSN carried out simulations to locate the release zone, to assess the quantity of ruthenium released, as well as the period and the duration of the release.

The map below summarizes the results obtained and confirms that the most plausible zone of release lies between the Volga and the Urals without it being possible, with the available data, to specify the exact location of the point of release. Indeed, it is in this geographical area that the simulation of a ruthenium release makes it possible to better reproduce the measurements obtained in Europe.

For the most plausible zone of release, the quantity of Ruthenium-106 released estimated by IRSN simulations is very important, between 100 and 300 teraBecquerels. The release, accidental with regard to the quantity released, would have occurred during the last week of September 2017.

Because of the quantities released, the consequences of an accident of this magnitude in France would have required to implement locally measures of protection of the populations on a radius of the order of a few kilometres around the location of the release.

For foodstuffs, the exceeding of maximum permitted levels (1250 Bq/kg for Ruthenium-106 for non-milk products) would be observed over distances of the order of a few tens of kilometres around the location of the release.

The possibility of exceeding maximum permitted levels near the accident site led IRSN to study the scenario of importing foodstuffs from this area. From this analysis, IRSN considers, on the one hand, that the probability of a scenario that would see the importation into France of foodstuffs (especially mushrooms) contaminated by Ruthenium-106 near the source of the release is extremely low and, on the other hand, the potential health risk associated with this scenario is also very low. It does not therefore appear necessary to introduce systematic controls on the contamination of imported foods.

Download IRSN information report from Novembre 9, 2017: Detection of Ruthenium-106 in France and in Europe: Results of IRSN’s investigations

Ruthenium-106 [1] has been detected by several European networks involved in the monitoring of atmospheric radioactive contamination, at levels of a few milliBecquerels per cubic meter of air.

IRSN has therefore undertaken investigations since October 3, 2017 to carry out an in-depth assessment of the measurements of ruthenium levels in the territory and to identify the possible origins of the situation encountered.

In France, IRSN has mobilized all its measurement stations for atmospheric monitoring and undertook the analysis of their filter samples [2]. At this stage, only the filters of the stations of Seyne-sur-Mer (Var) and Nice (Alpes-Maritimes) show the presence of ruthenium-106 at trace levels (respectively 7.4 and 6.8 micro-Bq/m³). The results of measurement of the filters of the other stations of IRSN do not show the presence of this radionuclide. All the measurement results are shown in the table 1 below.

Based on calculations carried out by IRSN, the levels of atmospheric contamination with ruthenium-106 of the order of those observed in Europe are not likely to generate health effects.

By combining levels of contamination observed and numerical simulations performed by IRSN, it appears that the contaminated air masses measured in Europe originate from the southern regions of the Urals. Given the amount of ruthenium-106 that may be at the origin of the air pollution observed in Europe, it appears that measures of protection of the populations could have been necessary in the vicinity of the site of the releases. It should be noted that the detection of ruthenium alone excludes the possibility of an accident on a nuclear power plant, which would result in the presence of other radionuclides. Ruthentium can occur in nuclear fuel cycle installation, in facilities manufacturing radioactive sources or in RTG's (Radioisotope thermoelectric generators) used for the power supply of satellites. Discussions with BfS, the German counterparts of IRSN, show that they reach similar conclusions.

At this stage, IRSN does not have information to confirm the end of the releases.

IRSN is continuing its efforts to monitor the level of ruthenium in the territory and its calculations to clarify the origin of the releases and their characteristics.

Notes:

1. Ruthenium 106 is a radionuclide of artificial origin. It is a fission product from the nuclear industry. This radionuclide is also used in the medical field for brachytherapy treatments.
2. In France, IRSN is responsible for monitoring the radioactivity of the atmosphere on a nation-wide scale. Its surveillance network OPERA-Air includes high-volume aerosol samplers (700 to 900 m³ of air per hour) and measurement equipment capable of detecting trace amounts of radioactivity.

Ruthenium-106 has been detected by several European networks involved in the monitoring of atmospheric radioactive contamination, at levels of a few milliBecquerels per cubic meter of air.

Ruthenium-106 is a radionuclide of artificial origin. It is a fission product from the nuclear industry. This radionuclide is also used in the medical field for brachytherapy treatments

So far, IRSN calculations, based on the concentration levels measured in several European countries and on the meteorological conditions of the last few days, seem to indicate that the contamination air could have been generated from southern regions of Ural or located close to those. IRSN is continuing its investigations to try to confirm the origin of this atmospheric pollution.

As a reminder, in France, only the station of Seyne-sur-Mer (Var) shows the presence of ruthenium-106 at trace levels (7.7 micro-Bq/m³). The results of measurement of the filters of the other stations of IRSN do not show the presence of this radionuclide. All the measurement results are shown in the table below.

The ​low levels of atmospheric contamination of ruthenium-106 observed to date by European monitoring networks have no environmental or health consequences. Nevertheless, IRSN maintains a watchful vigilance on this presence of ruthenium in the air.

Ruthenium-106 has been detected by several European networks involved in the monitoring of atmospheric radioactive contamination. Ruthenium-106 is a radionuclide of artificial origin. It is a fission product from the nuclear industry. This radionuclide is also used in the medical field for brachytherapy treatments.

The Austrian Ministry of the Environment published Tuesday October 3rd 2017 a statement indicating that it detected small quantities of ruthenium without consequences for environment and health. The Norwegian Nuclear Safety Authority (NRPA) issued a press release also reporting low levels of ruthenium in the atmosphere.

For its part, the Swiss Federal Office of Public Health (FOPH) gave its first results of measurements indicating "low levels of radioactivity in the air". These measurements "revealed traces of ruthenium-106, a radioactive element with a half-life of 373.6 days, in aerosols taken from Cadenazzo, Ticino, between 25 September and 2 October 2017. The concentration of ruthenium 106 amounts to about 40 micro-Bq/m³, which is 17,000 times lower than the limit of air emissions set for this radionuclide in the Radiation Protection Ordinance."

Since October 3, 2017, IRSN has mobilized all its measurement stations for atmospheric monitoring and undertook the analysis of their filter samples [1].

Analysis of the filters at the Orsay (91) and Grenoble (38) stations gives results of less than 50 micro-Bq/m³. It should be noted that the weather conditions of the last 48 hours did not favor the transfer of air masses from Eastern Europe to Western Europe. On the basis of the weather conditions of the last days, retro-trajectory calculations are under way, to try to determine the origin of this air pollution.

The very low levels of atmospheric contamination of ruthenium-106 observed to date by European monitoring networks have no environmental or health consequences. Nevertheless, IRSN maintains a watchful vigilance on this presence of ruthenium in the air.

Note:

1. In France, IRSN is responsible for monitoring the radioactivity of the atmosphere on a nation-wide scale. Its surveillance network OPERA-Air includes high-volume aerosol samplers (700 to 900 m³ of air per hour) and measurement equipment capable of detecting trace amounts of radioactivity.

​In January and February 2017, radioactive iodine (a radionuclide of anthropogenic origin) at trace levels has been detected in the air in Europe (for more information, read our news of February 13, 2017).

Since then, IRSN has been regularly called upon by the media and the public regarding this event. Recently, assumptions have been made linking these traces of iodine to an incident that occurred in October 2016 at the HBWR research reactor in Halden, Norway. The information note published today by IRSN presents the circumstances of this incident and the releases of radioactive iodine which it has generated.

Download IRSN information note from April 11, 2017: Information note on iodine releases associated with the October 2016 incident at the HBWR Norwegian research reactor located in Halden

On October 24, 2016, while the HBWR was shut down for maintenance, an incident occurred during handling operations of damaged test fuel assembly. This led to the release of radioactive substances into the reactor building and into the environment.

According to the Norwegian safety authority NRPA [1], releases of iodine into the atmosphere due to this incident accounted for approximately 5% of the annual discharge permit of gaseous releases of the facility for iodine-131 (release of 160 MBq of 131I) and about 1% of the annual discharge permit of gaseous releases of the facility for iodine 132 (release of 27 MBq of 132I) [2].

The information obtained shows that the incident that affected Halden's HBWR reactor at the end of October 2016 led to a limited release of radioactive substances into the environment.

This release concerned the period of October and November 2016; It can therefore not be the source of traces of iodine 131 (with a radioactive period of 8.04 days) detected in several European countries since January 2017.

Although the observed concentrations are very low and well below levels likely to have any effect on human health, research has been conducted to determine the origin of this pollution. The most likely origin would be an industrial radioactive iodine production facility for medical applications, as it has already been the case in similar events that occurred in November 2011 and February 2012. Since the levels were very low, the emission source could not be determined with precision, but it is likely situated in Eastern Europe.

Notes:

1. More information about the incident of October 2016 in the HBWR research reactor on the NRPA website.
2. Nuclear facilities receive authorizations for releases of radioactive substances in the air or in aquatic and marine environments under defined and controlled conditions. These authorizations are issued by the competent authorities after prior assessment of the foreseeable impact on the environment and on human health.

Iodine-131 (131I), a radionuclide of anthropogenic origin, has recently been detected in tiny amounts in the ground-level atmosphere in Europe. The preliminary report states it was first found during week 2 of January 2017 in northern Norway. Iodine-131 was also detected in Finland, Poland, Czech Republic, Germany, France and Spain, until the end of January.

Iodine-131 is a radionuclide with a short half-life (T1/2 = 8.04 day). The detection of this radionuclide is proof of a rather recent release.

Besides the iodine release, the origin of which is still unknown, the poor dispersion conditions due to the thermal stratification [1] of the atmosphere also affected the observed concentration levels, including those of naturally occurring radionuclides such as Lead-210 (210Pb) [2], or fine particles (PM2.5 and PM10) leading to pollution episodes, particularly in the Western part of Europe during week 4 of January.

It must be pointed out that only particulate iodine was reported. When detectable, gaseous iodine is usually dominant and can be estimated to be 3 to 5 times higher than the fraction of particulate iodine.

In France, particulate 131I reached 0.31 µBq/m³ and thus the total (gaseous + particulate fractions) can be estimated at about 1.5 µBq/m³. These levels raise no health concerns.

The data has been shared between members of an informal European network called Ring of Five gathering organizations involved in the radiological surveillance of the atmosphere. In France, IRSN is responsible for monitoring the radioactivity of the atmosphere on a nation-wide scale. Its surveillance network OPERA-Air includes high-volume aerosol samplers (700 to 900 m³ of air per hour) and measurement equipment capable of detecting trace amounts of radioactivity.

Notes:

1. Thermal stratification of the atmosphere that often affects the lower atmospheric layers in winter. The colder air at ground-level compare with altitude stuck or considerably limit atmospheric pollutant dispersion.
2. The 210Pb concentration detected by IRSN peaked at 1600 µBq/m³ in January, four times higher than the usual mean value.

The recommended radon risk prevention approach is simple and focuses on buildings as places of exposure.

ICRP (International Commission on Radiological Protection) issues a new and innovative publication on radon risk management prepared by a working group coordinated by IRSN experts.

The new text, which replaces a document dating from 1993, incorporates developments in scientific knowledge and experience acquired by various countries and organizations in managing radon exposure.

The recommended radon risk prevention approach is simple and focuses on buildings as places of exposure, regardless of their purpose or of the characteristics of their occupants. This avoids having to distinguish between smokers and non-smokers or to propose specific criteria for children for the purpose of risk management.

Yet it is integrated, and ambitious in its goals, aiming to reduce individual and collective exposure levels to below the reference level of 10 mSv/year, or a maximum of 300 Bq/m-3 in indoor radon concentration (above which it is not appropriate to go or stay).

Recommendation suggests applying the optimization principle as part of an action plan based on exposure prevention in the case of new buildings, and on exposure mitigation in the case of existing buildings, while involving stakeholders in the process. Such an action plan would typically be set up by competent national authorities, taking into account the specificities of the country’s situation with respect to radon exposure risks.

More information: Recommendation on radon risk management issued by ICRP

The publication by Reuters on August 5, 2013 of a news report about the situation at the Fukushima Daiichi nuclear power plant (read) has revived questions concerning the management of the contaminated water on the site of Fukushima-Daiichi.

For IRSN, there was no sudden aggravation of the situation in recent days, but statements by the authority present at the site reminding the operator TEPCO of the need to put in place as quickly as possible corrective actions regarding the diffuse contamination of the Pacific Ocean.

Volumes of contaminated water at the site are estimated at several hundreds of thousands of cubic meter. The natural phenomena that led to the accident that affected TEPCO’s Fukushima Daiichi nuclear power plant on March 11, 2011 also led to flooding of the site leading to an accumulation of water in the basements of the power plant buildings. Furthermore, since the accident, the water used to cool the damaged cores of the reactors has been flowing into the basements of the buildings from where it is pumped in order to be re-used, after treatment, to cool the reactors.

However, the galleries below the plant are not completely sealed; there is a suspicion of contamination of groundwater. Tepco is trying to strengthen the leak tightness of the ground by injection of sealing products and by creating a first barrier between the facilities and the ocean (expected to be completed by mid-2014).

For more information on the situation, download the information notes by IRSN:

Fukushima Daiichi nuclear accident: Management of contaminated water from the damaged reactors (PDF)

Fukushima Daiichi nuclear accident: Contamination of the ground between the damaged reactors and the Pacific Ocean  (PDF)

In an information notice published in French on November 15 2011, IRSN reported that it had detected traces of iodine-131 in the form of airborne particles. The traces were detected in a number of samples taken by aerosol monitoring stations in the IRSN OPERA-Air network.

The results of sampling measurements taken over the first ten days of November were around a few microbecquerels per cubic meter of air (µBq/m³). These values are close to the detection limits of the most effective measuring methods.

Although iodine-131 is not normally found in the air throughout the country, its presence did not give any cause for concern for the population's health or the environment.

It was detected in France following similar detection reports in various countries in central and northern Europe. As the reasons for this radioactive pollution were unknown, IRSN performed trajectory calculations to try to locate the origin of the air masses transporting the iodine-131.

Meanwhile, the International Atomic Energy Agency (IAEA) issued a press release on November 17, indicating that it had received information from the Hungarian Atomic Energy Authority (HAEA) that «… the source of the iodine-131 detected in Europe was most probably a release to the atmosphere from the Institute of Isotopes Ltd., Budapest ». The institute produces radioisotopes for healthcare, industrial, and research applications. According to the HAEA, the release is thought to have begun on September 8, 2011, with a period of increased intensity on October 12-14. The authority stated, however, that the quantity of iodine-131 released over the period was below the institute's authorized annual radioactive release limit. The cause of the release has yet to be determined and is still under investigation.

The information notice of November 30, 2011, provides an update of measurement results in France, together with IRSN's trajectory analysis of the air masses that explain the iodine-131 traces observed in Europe. Based on currently available technical data, IRSN also estimated the radiological impact of this radioactive release in the near field, in other words in the Budapest region.

More information

Download the information notice of November 30, 2011: No health risk related to airborne traces of iodine-131 from Hungary

Download the information notice of November 15, 2011: Detection in France of traces of iodine-131 in the air coming from radioactive releases in a foreign country