| Title | Evolution of the natural radioactivity within the Soultz geothermal installation |
|---|---|
| Authors | Cuenot, Scheiber, Moeckes, Guéry, Bruzac, Sontot, Meneust, Maquet, Orsat, Vidal |
| Year | 2013 |
| Conference | European Geothermal Conference |
| Keywords | natural radioactivity, Soultz-sous-Forêts, EGS, radioprotection. |
| Abstract | After the first studies on natural radioactivity done during the 2005 hydraulic circulation test at the Soultz-sous-Forêts power plant, the ASN (French National Agency for Nuclear Safety) recommended to follow precisely the evolution of natural radioactivity within the geothermal installation. The first goal of these studies is to ensure the protection of workers against potential radiations. Seven measurement campaigns have been carried out since 2009 to observe and characterize the natural radioactivity evolution during hydraulic circulation tests, both on GPK2 and GPK1 surface installation. For all measurements campaigns, the results show a general increase of the dose rates with the circulation time and volume. The highest values were found mostly on the reinjection line, where the temperature is lower (~70°C). This indicates a correlation between the observed radioactivity and the scaling processes inside the installation: some newly formed minerals are able to trap radionuclides. Finally, all these studies allowed us to take several measures for workers and public radioprotection. A restricted zone has been defined around the installation and adapted equipments must be worn by workers, when they have to operate on surface facilities, especially when dismantling pipes or cleaning heat exchangers and filters. Moreover, a proper plan has been established for the disposal of radioactive waste, consisting mainly of residues from filters: they have to be removed from the site, following the French regulation. |