Occupational Exposure to Radon in French Treatment Spa Facilities

Titre du congrès :9th European ALARA Network Workshop on "Occupational Exposure to Natural Radiation" Ville du congrès :Augsbourg Date du congrès :18/10/2005

From the earliest times, the human being is exposed to ionising radiation from various natural sources. Radon, natural radioactive gas, takes an important part in this exposure. Recent international recommendations have included exposure to natural radiations as one of the sources to monitor in certain occupationally exposed groups. Among those mentioned are workers in thermal spas who may be exposed to high radiation doses due to high radon concentrations in indoor air through degassing from thermal water. The European Union set limits on radon concentrations in its 1996 OJEC directive and these have been incorporated into French national legislation. The implementation of the French regulation on radiation protection in thermal spas required the determination of a particular measurement methodology due to specific indoor environments (wide variation in the indoor radon concentration over time, warm and moist atmosphere). Two ways are proposed depending on the type of exposed people: public or workers. The first one is an improved version of the French AFNOR standard (NF M60-771) describing the protocol for radon mapping in buildings in order to detect radon concentrations higher than the French reference levels. The second way deals with both accurate radon concentration measurement during working hours and workstations' analysis