Radioactive iodine at trace levels detected early 2017 in Europe are not related to the incident of October 2016 in a research reactor in Norway
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:
- More information about the incident of October 2016 in the HBWR research reactor on the NRPA website.
- 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.