Dose assessments due to discharges of radionuclides from nuclear facilities near La Hague (France)
C. Rommens, A. Merle-Szeremeta, C. Drombry-Ringeard and A. Sugier
IRPA-10: 10. international congress of the International Radiation Protection Association Hiroshima (Japan) 14-19 May 2000, P-4b-231
One aim of the Nord-Cotentin study is to provide informations to help the authorities in the instruction of discharge authorisation for the reprocessing plant of COGEMA-La Hague. The study was carried out by a working group supported by IRSN (Groupe Radioecologie Nord-Cotentin 1998), whose participants are the operators, the authorities, some international experts and members of environmental associations. The working group identified the situations which are likely to lead to the highest exposure, named <>. Two types of scenarii were defined: 1. <>: likely specific behaviours of the local population but for which the occurrence is difficult to quantify for example: staying one hour close to the marine discharge pipe or eating a crustacean captured at the extremity of the pipe. The dose were assessed for one occurrence. 2. <>: overall way of life of groups of population for example the fishermen or the farmers. Yearly doses were computed. These scenarii can be compared to the <> of the operator. For each scenario, relevant behaviours or way of life were discussed on the basis of local data. Locations leading to highest exposure were chosen. Contamination of the environment predicted by transfer models was validated by environmental measurements as often as possible. Effective dose for each scenario was assessed for the most critical year. The doses were compared with the average dose received by a member of the public living near the La Hague site (between 0,2 muSv and 18 muSv per year for the period 1966-1996). Doses associated with the <> were similar to the average yearly exposure, but for the maximum scenario, associated with the consumption of crustaceans captured at the extremity of the discharge pipe (about 300 muSv for one occurrence in 1985). Doses associated with <> have been maximum in the past due to marine releases (about 250 muSv in 1985). Groupe Radioecologie Nord Cotentin. Rapport detaille d'etape n deg2, France, Paris, 1998.