ASN Report 2018

Radon exhalation potential in metropolitan France (source: IRSN) 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) and the ventilation of the rooms. So-called “domestic” exposure to radon (radon in dwellings) has been estimated by IRSN through measurement campaigns which were then followed by statistical analyses (see irsn.fr ) . The average radon activity value measured in France is 63 Bq/m 3 , with about half the results being below 50 Bq/m 3 , 9% above 200 Bq/m 3  and 2.3% above 400 Bq/m 3 . These measurements have allowed the French départements to be classified according to the radon exhalation potential of the ground (see map below). In 2011, 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 (BRGM). Based on this, a finer classification, by locality, was published by Interministerial Order of 27 June 2018. Ultimately, the new obligation placed on dosimetry laboratories to communicate the dosimeter results to IRSN should enhance knowledge of radon exposure in France (see the 3rd National Plan 2016-2019 for Radon Risk Management , published in January 2017 and 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. Considering the average time spent inside the home (which itself attenuates the ionic component of cosmic radiation), the average individual effective dose in a locality at sea level in France is 0.27 mSv per year, whereas it could exceed 1.1 mSv per year in a mountain locality situated at an elevation of about 2,800 metres. The average annual effective dose per individual in France is 0.32 mSv. It is lower than the global average value of 0.38 mSv per year published by UNSCEAR. On account of the increased exposure to cosmic radiation due to extensive periods spent at high altitude, flight personnel must be subject to dosimetric monitoring (see point 3.1.3). —  Bounds of 31 priority départements for radon monitoring ■  Areas of the potential for radon exhalation ASN report on the state of nuclear safety and radiation protection in France in 2018  95 01 – NUCLEAR ACTIVITIES: IONISING RADIATION AND HEALTH AND ENVIRONMENTAL RISKS 01