The Rhône watershed extends over almost one hundred thousands square kilometers, i.e. one fifth of the metropolitan French territory. The Rhône is the major River entering the Western Mediterranean Sea as it generates the main source of sediments and freshwater (50%) to the sea, with an average water discharge of 1700 m3 s-1. The River input affects primary production significantly in the north-western Mediterranean area and plays a leading role on the marine ecosystem functioning in the whole Gulf of Lion. Almost twenty nuclear reactors are situated along the Rhône valley, representing Europe’s biggest concentration of nuclear power plants. Down flow all these installations the spent fuel reprocessing plant of Marcoule released over many years most of the liquid radioactive wastes including plutonium isotopes in the Rhône river. Artificial radionuclides also originate from the weathering of the catchment basin labeled by both the global and the Chernobyl accident atmospheric fallout. These radioactive inputs have led to a permanent contamination of the Rhône river waters. Long-term chronological series of artificial radionuclide activities within the waters at the lower reaches of the Rhône river were acquired from 1979 to 2002. These data give evidence for various radioecological responses of the aquatic system over years. Based on these observations several major radioecological sensitivity factors for river waters are identified.

Widespread contamination occurred in the building in which radiation waste was handled. An occurrence of internal contamination of workers was also suspected. Therefore, workers were measured in vivo and bioassay was performed too. Estimation of committed effective dose had to be based on results of excretion analysis as irremovable surface contamination occurred on the skin and hair of workers, thus influencing results of in vivo measurements. The results of bioassay of 7 workers are presented. Intakes and committed effective doses were calculated from excretion data using IMBA Professional Plus software. The best fits for the most of workers were obtained when combination of acute and chronic intakes was used. Acute intakes varied from 135 Bq to 1300 Bq, chronic intakes from 0.03 Bq/d to 0.3 Bq/d. Committed effective doses from 3 to 36 mSv were estimated for individual workers.

Depuis le tragique accident du réacteur n° 4, les unités 1, 2 et 3 de la centrale de Tchernobyl (ChNPP) ont été successivement arrêtées. Or, depuis l’indépendance de l’Ukraine en 1991, la Russie n’assure plus le traitement du combustible irradié ukrainien. L’Ukraine, avec l’aide de la Communauté internationale, a donc envisagé une solution d’attente. En juillet 1999, à l’issue d’un appel d’offres international, le ministère ukrainien, EnergoAtom, retient un consortium de trois entreprises françaises, Framatome, Vinci Construction et Bouygues Travaux Publics, est retenu pour la construction d’un centre de stockage intermédiaire de longue durée du combustible usé des unités 1, 2 et 3, l’« Intérim Storage Facility-2 » (ISF-2). La construction démarre en mars 2000. La spécificité de ce chantier de génie civil est son déroulement dans la zone d’exclusion, au voisinage immédiat de la centrale accidentée. Les exigences de sécurité radiologique liées à l’implantation d’un tel chantier dans un environnement contaminé font l’objet de la présente synthèse. Après une description succincte du projet, de son environnement et des dispositions de sécurité radiologique, l’article présente les particularités du chantier. Le contexte local de culture de sûreté, différent de celui existant en Europe, a pu parfois générer de l’incompréhension ou des malentendus entre les acteurs occidentaux et ukrainiens et créer quelques difficultés. Afin de développer une prise de conscience du risque radiologique, l’ensemble du personnel expatrié et ukrainien a reçu une formation pendant toute la durée du chantier. Grâce aux importants moyens engagés et aux actions de prévention, de formation et de contrôle, le chantier s’est déroulé sans problème majeur. L’expérience ainsi acquise peut indubitablement apporter un enseignement profitable pour des situations semblables.

A low cost in-situ gamma-ray spectrometric method for rapid assessment of radiation exposure, identification of radionuclides and detection of changes in environmental radioactivity has been employed in the determination of the natural gamma radiation dose levels in six major cities of the southeastern region of Nigeria. The soil radioactivity concentrations of the primordial radionuclides; 40K, 238U and 232Th were determined and have been related to the γ-dose rates in the cities. The activity concentration of 40K across the region ranged between 0.021 and 0.200 kBq kg–1; 238U was between 0.001 and 0.066 kBq kg–1 while that of 232Th ranged between 0.015 and 0.103 kBq kg–1. The total γ-absorbed dose rates in air in the region ranged between 0.016 and 0.090 μGy h–1 with a mean of 0.039 ± 0.018 μGy h–1. The mean of the annual outdoor effective dose due to the terrestrial gamma radiation for the region was calculated as 50 μSv y–1 representing 66% of the world average value.

Un nouveau dosimètre passif basé sur la technologie OSL vient d’être introduit sur le marché français. Dans cet article sont décrits : la technologie et le matériau sur lequel s’appuie ce nouveau détecteur, le dosimètre lui-même.