ASN Report 2020

2.1.2 Radon Some geological areas have a high radon exhalation potential due to the geological characteristics of the ground (granitic bedrock, for example). The concentration measured inside homes also depends on the tightness of the building (foundations), the ventilation of the rooms and the life style of the occupants. So-called “domestic” exposure to radon (radon in dwellings) has been estimated by the IRSN through measurement campaigns which were then followed by statistical analyses (see irsn.fr ) . The average value of the radon activities measured in France has thus been estimated at 68 Bq/m 3 . These measurements have allowed the French département s to be classified according to the radon exhalation potential of the ground. In 2011, the IRSN published a map of France considering the radon exhalation potential of the ground, based on data from the French Geological and Mining Research Office. Based on this, a more fine-grained classification, by municipality, was published through the Ministerial Order of 27 June 2018 (see search engine by municipality and mapping accessible on asn.fr and irsn.fr ) . As from 2021, the new obligation placed on radon detector analysis laboratories to communicate the dosimeter results to the IRSN will enhance knowledge of radon exposure in France (see the 3rd National Plan 2016-2019 for Radon Risk Management, accessible on asn.fr ). 2.1.3 Cosmic radiation The cosmic radiation from ionic and neutronic components is also accompanied by electromagnetic radiation. At sea level, the dose rate resulting from electromagnetic radiation is estimated at 32 nSv/h and that resulting from the neutronic component at 3.6 nSv/h. Radon potential zones in metropolitan France defined by the Order of 27 June 2018 Zones with low radon potential Zones with low radon potential but in which specif ic geological factors can facilitate radon transfer to buildings Zones with signif icant radon potential Radon potential zones def ined according to the radon exhalation fluxes from the ground: (Source: IRSN) ASN Report on the state of nuclear safety and radiation protection in France in 2020 107 01 – NUCLEAR ACTIVITIES: IONISING RADIATION AND HEALTH AND ENVIRONMENTAL RISKS 01