Occupational exposure to Radon in French treatment spa facilities Roselyne AMÉON Institute for Radiological Protection and Nuclear Safety (IRSN) European ALARA Network 9 th Workshop

European ALARA Network 9 th Workshop – Augsburg - Germany Introduction European recommendations Workers in thermal spas have been incorporated into French national legislation Regulation on Workers protection Regulation on Public protection have included exposure to natural radiation as one of the sources to monitor in certain occupationally exposed groups Hydrotherapy

European ALARA Network 9 th Workshop – Augsburg - Germany Public protection Decree relating to public protection Worker protection Decree relating to worker protection 25 th may 2005 Order relating to work activities including NORM Order (not published) relating to Rn exposure (underground workplaces) public buildings 31 departments measurements in conformity with AFNOR standards approved organisations 2 action levels 400 et 1000 Bq.m th july 2004 Order relating to Rn risk management 15 th july 2003 Order relating to Rn competence action level 400 Bq.m -3 action level 1 mSv.y -1 Spa facilities French regulation on radiation protection Spa facilities Public + workers concerned workers concerned

SOURCES of RADIATION EXPOSURE in SPA FACILITIES

European ALARA Network 9 th Workshop – Augsburg - Germany Sources of radiation exposure in spa facilities Ingestion of radioactive thermal water (patients) Inhalation of Rn and its short lived decay products Ambient Gamma Radiation

European ALARA Network 9 th Workshop – Augsburg - Germany Inhalation of Rn and its short lived decay products (1) Soil underneath Buildings materials Rn sources in buildings Thermal Water spa

European ALARA Network 9 th Workshop – Augsburg - Germany Inhalation of Rn and its short lived decay products (2) Rn sources in spa buildings Soil underneath (texture and radioactive characteristics) Rn entry Radioactive thermal water Rn contents Degree of use Water supply mode Type of treatment 10 – Bq.l -1 non existent after treatment maximum during treatment directly from point of emergence indirectly via storage reservoirs driving forces (stack and wind effect) characteristics of soil/indoor interfaces accelerated release of Rn

European ALARA Network 9 th Workshop – Augsburg - Germany Injection of compressed air Vaporization of water Movements of patients

European ALARA Network 9 th Workshop – Augsburg - Germany Inhalation of Rn and its short lived decay products (3) Rn sources in spa buildings Mechanical ventilation systems run continuously run only during treatment application Ventilation stop when facility is not in operation (closed period) treatments with specific atmospheres incompatible with any ventilation Soil underneath Radioactive thermal water Rn sources in spa buildings Soil underneath Radioactive thermal water Lack of ventilation old spa facilities

European ALARA Network 9 th Workshop – Augsburg - Germany Inhalation of Rn and its short lived decay products (4) Mechanical VSNo mechanical VS

European ALARA Network 9 th Workshop – Augsburg - Germany Sources of radiation exposure in spa facilities Inhalation of Rn and its short lived decay products Ambient Gamma Radiation Inhalation of Rn and its short lived decay products Rn decay products present in indoor air Deposits of radionuclides in the water circuit Thermal activity (indoor Rn concentration) Air renewal rate Level of humidity Water radionuclides content Frequency of cleaning (pipes, tanks, …) 200 nSv.h -1

METROLOGICAL and METHODOLOGICAL ASPECTS

European ALARA Network 9 th Workshop – Augsburg - Germany Metrological aspects Long term average indoor Rn concentration integrating Rn measurements with passive devices Measuring instruments suitable for application in warm/humid places Variability of equilibrium factor F SSNTD, Electret Rn exposure in building Rn exposure in spa building 0,1 – 0,6 Problems with bare  -track detectors

European ALARA Network 9 th Workshop – Augsburg - Germany AFNOR STANDARD NF M Measurement of environnemental radioactivity : Air Radon-222 in buildings Methodologies for mapping and additional investigations Methodology – Rn public exposure with amendments to take into account the peculiarities of thermal facilities

European ALARA Network 9 th Workshop – Augsburg - Germany Determination of Homogeneous Zone Type Implantation Number Exposure Results Soil/indoor interface Ventilation Thermal gradient Use of water Supply mode Type of treatment + Passive detectorClosed SSNTDs Occupied HZ 1 per 200 m 2 in each occupied ZH – at least 2 per building At least 2 months between 15 th sept. and 30 th april Average Rn concentration per HZ or the highest value compared with action levels dispensatory period (except summer period) All occupied levels Measuring devices

European ALARA Network 9 th Workshop – Augsburg - Germany Methodology – spa workers exposure Due to temporal variability of Rn concentration Underestimation of A v (Rn) during period of using water (no ventilation) Overestimation of A v (Rn) when Rn accumulates during night time (ventilation during treatment) Conventional integrating Rn measurements Spa workers exposed Medical staff (doctors, bath attendants,…) Maintenance staff Cleaning staff Administrative staff ???

European ALARA Network 9 th Workshop – Augsburg - Germany Methodology – spa workers exposure Action level of 1 mSv.y -1 Personal Rn dosimeters (  -track detectors) – 3 months period Action level of 400 Bq.m -3 Personal RnDP dosimeters – 1 month period Measurement of Rn at monitoring sites Measurement of Rn decay products +  at monitoring sites French rules not yet well defined

European ALARA Network 9 th Workshop – Augsburg - Germany Conclusions What kind of methodology has to be used ? Main sources of exposure : inhalation of Rn +  radiation People exposure to natural sources of RI in French spa facilities must be managed in respect of both regulations (public and workers) Public exposed Action level of 400 Bq.m -3 2 different action levels (400 Bq.m mSv.y -1 ) Who is exposed ? French regulation for Public protection Workers exposed 2 regulations (Public + Workers) Methodology linked to AFNOR standard 2 different methodologies (Rn or Rn decay products)

European ALARA Network 9 th Workshop – Augsburg - Germany

French thermal spa

European ALARA Network 9 th Workshop – Augsburg - Germany E 1 E 3 E 2 Points of Emergence Steam rooms – thermal gallery Inhalation rooms Direct supply Treatment place Warm water tap Treatment place Cold water tap Storage reservoir Heat exchanger Indirect supply Thermal water supply circuit 80 % of loss

European ALARA Network 9 th Workshop – Augsburg - Germany Rn Atlas of France Average Rn concentrations measured in dwellings Concentrations Bq/m departments ranked as priority