Le polonium 210 naturel, de période relativement courte (138 jours) et issu de la famille de l'uranium, devrait retenir davantage l'attention en radioprotection car il entraîne des doses chroniques plus élevées que les traces de césium 137 et de plutonium (238, 239 et 240) présentes dans l'environnement. Dans la croûte terrestre, l'uranium est accompagné du radium, du radon et de ses descendants, à des concentrations de l'ordre de 40 000 Bq t-1. Par le jeu de l'exhalaison du radon 222 des sols sur une couche métrique et des retombées du plomb 210 (descendant du radon), la couche superficielle des sols s'enrichit par rapport à la teneur en radium, d'un facteur variant de 2,7 à 8,8 en plomb 210 et en polonium 210 selon des mesures faites dans l'environnement. L'exposition de l'homme au polonium 210 par ingestion est notable. Elle est permanente et 30 à 70 fois plus importante que l'exposition au césium 137 des retombées de Tchernobyl à Helsinki en 1986, qui décroît selon la période radioactive de 30 ans. La toxicité par ingestion du polonium 210 est 500 à 2 000 fois plus élevée que celle du plutonium pour un même nombre de becquerels déposés au sol. Des “ points chauds ” peuvent se former dans certains compartiments de l'environnement : le polonium 210 se concentre particulièrement dans la faune marine, comme le montrent plusieurs campagnes de mesures dans la zone nord-est de l'Atlantique.

This paper presents a comprehensive survey of the tritium content of “reference waters”in real working conditions by French laboratories involved in environmental monitoring.Reference waters are virtually tritium-free waters used to determine blanks for theanalytical system and to check for any contamination. It is therefore crucial to be sureof the low tritium content of these waters as this can limit the sensitivity and accuracyof the measurements. Water from the commercial brand “Abatilles” is widely used in Frenchlaboratories and nine samples were analyzed in this study. Three samples from other deepaquifers were also included. The results all range from 0.004 ± 0.004 Bq/kg to 0.175 ± 0.011 Bq/kg, well below the 0.5Bq/kg advised by the French Safety Authority. The spread of the results can mainly beattributed to contamination through plastic during bottle storage. As expected, twosamples from demineralized tap water showed higher tritium activities (0.3–0.35 Bq/kg).Both waters are suitable as reference water for routine monitoring (DL of about 10 Bq/kg)but should be used with caution for activities in the Bq/kg range.

This article proposes an assessment of the ingestion doses potentially received by peopleliving in the Japanese areas most severely affected by the radioactive deposits due to theFukushima nuclear accident. The assessment distinguishes two consecutive periods: thefirst 2 months (March 15th to May 15th 2011) and the rest of the year 2011, according tothe two main foodstuff contamination periods identified (Renaud et al.,2013). On the basis of the worst-case hypothesis that can reasonably be made, theestimated doses are much lower than they might have been in other circumstances, onaccount of generally moderate levels of contamination for most foods, early evacuation ofthe most severely affected areas and the consumption bans ordered by the Japaneseauthorities. Thus, a single ingestion of 100 g of leafy vegetables in the early days by aone-year-old child living in non-evacuated localities near Iitate and Kawamata could haveled to an equivalent dose to the thyroid of about 25 mSv; and to a thyroid dose of about140 mSv for the rather unrealistic scenario of a daily consumption. Because of the rapiddecrease in the contamination of vegetables and a much weaker contamination of othercrops, and thanks to measures taken by the authorities (prohibition of consumption, use ofcertain fodder, etc.), the ingestion doses potentially received during the remainder ofthe year 2011 are estimated to be below 1 mSv. In the event that sales limits would havebeen ignored, only repeated consumption of mushrooms would have led to doses above thatlevel. Even with the worst-case hypotheses, the doses potentially caused by ingestion aremuch lower than those resulting from outdoor exposure to radioactive deposits:approximately several millisieverts in a year for the population living in thenon-evacuated localities near Iitate and Kawamata.

We used CR-39 detectors to evaluate radon activity concentrations in several habitationsof Bamako. The calibration factor of the dosimeters was determined experimentally withknown radon activity concentrations inside a radon chamber, and was also simulated withMCNPX. The experimental and simulated calibration factors are, respectively,kexp = 0.119 ± 0.017 and ksim= 0.126 ± 0.007 tr.cm-2.d-1.Bq-1.m3. Indoorradon activity concentrations in Bamako were found to vary from 70 ± 18 to 154 ± 35Bq.m-3. No significant differences were observed in the mean radon activityconcentrations compared with five other African countries. Taking into account anoccupancy factor of 0.8 and an equilibrium factor of 0.4 for radon indoors, the effectivedose rate ranges from 1.77 to 2.35 mSv.y-1. In all cases the radon activityconcentrations measured were below the action limits recommended by the InternationalCommission on Radiological Protection (ICRP) Statement on Radon.

Peu d’études sur le thème des recommandations de radioprotection que doivent suivre les patients hors du secteur d’hospitalisation après traitement du cancer différencié de la thyroïde par de l’iode-131, sont basées sur une détermination expérimentale de la période effective. Le but de ce travail a été de calculer des valeurs de durées pendant lesquelles le patient doit respecter des recommandations à l’aide d’une mesure du débit de dose à 30 cm le dernier jour avant qu’il quitte le secteur d’hospitalisation. Les mesures du débit de dose ont été réalisées tous les jours au niveau de l’abdomen et du cou pendant la durée d’hospitalisation. Ces points sont ajustés par un modèle mono-exponentiel ou bi-exponentiel pour déterminer la période effective. Nous modélisons 7 situations d’exposition des personnes proches. Nous montrons que dans les conditions réalistes de diffusion le rapport des débits de dose en fonction de la distance suit une loi en l’inverse de la distance de mesure. La période effective est de 16 ± 6 h quelle que soit la localisation de la mesure. Cela nous conduit à un calcul de respect de recommandations n’excédant pas 2 jours après 3 jours d’hospitalisation. Un abaque simple est donné pour permettre le calcul des durées de recommandations en fonction du débit de dose mesuré à la sortie. Ce protocole de mesure est mise en oeuvre dans notre institution et donne entière satisfaction tant du point de vue de l’information au patient que du respect de l’irradiation minimale des proches suivant le principe ALARA.

Because plants significantly affect radionuclides (RN) cycling and further dispersion into the biosphere, it is important to understand the biological factors influencing RN plant uptake, accumulation and redistribution. In this respect, mycorrhizal fungi are of particular interest. The effects of ecto-mycorrhizal (ECM) and arbuscular mycorrhizal (AM) fungi on the transport of uranium (U) or radiocaesium (Cs) were investigated both under pot and in vitro culture conditions. Results obtained in vitro demonstrated that AM hyphae can take up and translocate U and Cs towards roots, while this uptake and translocation were not perceptible using pot culture systems with soil. These contrasting results could be due to different experimental conditions, including the K level in the external solution and the bio-availability of Cs. The in vitro studies also indicated that root colonisation by AM fungi might limit U and Cs root transport. Under pot culture conditions, they appeared to significantly reduce root to shoot translocation of U. Under the same conditions, ECM transport of Cs was demonstrated, and appeared to be dependent on fungal species. A better estimation of the potential use of mycorrhizal fungi for the phytoremediation of RN-contaminated areas is now available and will be further discussed.

ITER will be the first fusion reactor producing much more energy than that necessary to establish and heat the plasma. This nuclear energy is mainly exported from the plasma by neutrons and deposited in the plasma facing components, generating nuclear activation. One of the elements used in the fusion reaction is tritium, a radioactive isotope of hydrogen. Although some feedback may be used from in service fusion machines, such as JET in England, the ITER radiological protection issues need to be assessed as early as possible. The protection against radiological hazards is, as usual shielding, waiting for radioactive decay, limitation of airborne contaminants, reduction of exposure time, etc. This has been done in the present design and has followed a first step of ALARA studies. Radiation fields have been calculated and work effort estimated leading to the evaluation of a collective yearly dose of 356 p mSv, below the project dose target which is 500 p mSv. A second step of occupational radiological exposure studies should allow refining further the dose estimate as well as the ALARA optimization.

Le personnel du milieu médical représente la majorité (70%) des travailleurs exposés aux rayonnement ionisants. Leur exposition est très variable selon les pratiques et les domaines concernés.Nous nous sommes intéressés dans ce travail à l'exposition externe en abordant successivement les concepts du passge de la dose à l'équivalent de dose, les principaux dosimètres (actifs etpassifs) disponibles, l'origine de l'exposition et enfin, l'exposition individuelle au travers de la dosimétrie réglementaire et de quelques études de dosimétrie opérationnelle. Actuellement lesinformations issues de la dosimétrie réglementaire sont rassurantes puisque 93% des travailleurs sont exposés à des niveaux inférieurs au niveau d'enregistrement des films dosimètres (0,2 mSv) et 98% à moins de 5 mSv/an. Cependant des études en médecine nucléaire et surtout en radiologie interventionnelle montrent la nécessité d'un rappel constant des bonnes pratiques deradioprotection, le besoin de relais entre la personne compétente et les services concernés et leur intérêt pour la mise en oeuvre d'une démarche d'optimisation.

During an accidental release of tritium, mechanisms of hydrogen transferfrom air to man are very numerous, dependent on multiple climate,physiological and biological parameters, and the kinetic is highlyvariable from one environmental compartment to another. To evaluatethe impact of an acute tritium release requires either an overallassessment of the state of the environment during the release and thefollowing hours from a number of restricted data, or the establishmentof a significant data bank, a complex model and a system of dataacquisition in real time whose potential for daily purposes is veryhypothetical. To facilitate the first approach, this paper discussesthe key elements of the mechanisms to guide the choice of parametersfor a rapid assessment of the situation, and to clarify the typesof measurements to carry out and their interpretation.

Alpha spectrometry is the most commonly used analytical tool for the determination of Pu, Am, Pa, U and Th long live radionuclides. Thermal ionization mass spectrometry (TIMS) and acceleration mass spectrometry (AMS) are also still considered as primary methods for the determination of their isotope ratios. Spectrometers with plasma ion sources now offer another efficient alternative method with the development of sector field inductively coupled plasma mass spectrometry (SF ICP-MS). This paper summarizes the development work performed and results obtained using this technique for the analysis of such radionuclides. Isotopic ratios and ultra trace levels of man made radionuclides like 239, 240, 241 plutonium but also naturally occurring species like 231 protactinium, 234, 235, 238 uranium and 230, 232 thorium were determined in different field samples and reference materials using a micro concentric nebulizer as an introduction system for the mass spectrometer. Prior to the mass spectrometric measurements these elements were isolated from major elements by different selective precipitations. In further steps, they were purified by anion exchange. Results of isotope ratios including plutonium ones are also discussed.

The aim of the study was to measure the carbon 14 activity at natural level in air samples using classical methods of radiochemistry and beta counting. Three different methods have been tested in order to minimise the detection limit. In the three methods, the first step consists in trapping the atmospheric carbon 14 into NaOH (1N) using a bubbling chamber. The atmospheric carbon dioxide reacts with NaOH to form Na2CO3. In the first method the Na2CO3 solution is mixed with a liquid scintillate and is directly analysed by liquid scintillation counting (LSC). The detection limit is approximately 0.3 Bq.m-3 of air samples. The second method consists in evaporating the carbonate solution and then counting the solid residue with a proportional gas circulation counter. The detection limit obtained is equivalent to the first method (0.36 Bq.m-3 of air samples). In the third method, Na2CO3 is precipitated into CaCO3 in presence of CaCl2. CaCO3 is then analysed by LSC. This method appears to be the most appropriate, the detection limit is 0.04 Bq.m-3 of air samples.

The aim of this study was to compare the indicator properties of Fucus vesiculosus and Ascophyllum nodosum. Activity concentrations of 137Cs, 40K, 7Be, 228Ra, 99Tc, 90Sr and $^{239,240}$Pu were measured in plants of the two species collected monthly in 2002 from one location at the southeastern coast of Norway. For 40K, 137Cs, 90Sr, 7Be and 228Ra the activity concentrations were significantly higher in Fucus vesiculosus than in Ascophyllum nodosum, whereas the opposite was the case for 99Tc. For 137Cs, 90Sr, 7Be and 228Ra the temporal variations in activity concentrations showed similar pattern for the two species, whereas for 99Tc the temporal pattern was different for the two species. The observed temporal variations in activity concentrations of 137Cs (both species) and 90Sr (only Fucus vesiculosus) correlate with expected variations in seawater concentrations. For 137Cs salinity, light conditions, temperature and growth rates seem to work in the same direction as the variations in seawater concentrations. A lack of correlation between salinity and 99Tc concentrations in the algae indicates a slower dynamic in uptake and/or secretion for technetium. The observed differences between the two species may partly be explained by the difference in growth rate and life length between the two species.

ASTRAL est acronyme d'“ Assistance Technique en Radioprotection Post-accidentelle ”. Si un rejet important de radionucléides dans l'environnement se produisait, il faudrait rapidementévaluer la concentration des radionucléides dans les milieux et les produits alimentaires, en déduire l'exposition potentielle aux rayonnements des populations concernées, prévoir l'évolution de lasituation et proposer différents scénarios de gestion des zones contaminées. A ces fins, il a été décidé il y trois ans environ de créer un logiciel utilisable par un ensemble relativement larged'agents gréant les centres de crise, réalisant des études prévisionnelles, ou s'occupant habituellement du contrôle de l'impact des rejets de routine. Le point de départ des estimations est ledépôt sur le sol des radionucléides. La phase de dispersion atmosphérique et les conséquences de l'exposition au nuage et aux radionucléides à vie courte ne sont pas traitées ici. Les calculseffectués concernent à la fois l'évolution dans le temps des concentrations des radionucléides dans les sols et les éléments de la chaîne alimentaire, ainsi que l'évaluation des doses efficacesdues à l'exposition externe et interne. Ces grandeurs sont comparées aux limites et niveaux d'intervention en vigueur. Différentes simulations de la gestion des zones contaminées peuvent êtreconduites par application de contre-mesures. Ainsi, le logiciel ASTRAL peut être utilisé comme un élément d'aide à la décision.


There has been recent interest in the transport and fate of 36Cl in the environment. The IUR task force on Radioecology and Waste has identified the need for further uptake data. Reported here are the results of a 6-month study of the uptake in ryegrass of 36Cl in five lysimeters. Lysimeters were deployed in a greenhouse from November 2007 to May 2008. Except for an initial watering, exterior reservoirs connected to the base of the lysimeters maintained the water tables at a constant level with a solution containing 36Cl in a chloride form. A destructive analysis of the lysimeters showed that between 75 and 80% of 36Cl added to the system during the course of the experiments was taken up into the plant tissue. The quantities of 36Cl found in weekly soil tests and a simple mass balance provide supporting evidence for the significant bioavailability of 36Cl in a chloride form.

Locations of gamma dose rate sensors have often been chosen by administrative or geometrical criteria. Nowadays computational capacity allows for a more realistic basis. We use simulations of potential radioactive plumes based on weather data of one year to investigate the threats to regions without own nuclear power plants and to find good numbers and locations of sensors to detect such plumes. We optimise sensor locations by minimising a cost function that can take into account numbers of undetected plumes, their dose to the region in general, or on the population. Besides we assess the effect of administrative constraints, be it that sensors have to cover administrative units, or that optimisation is done for sub-regions separately. Finally we evaluate the robustness of the approach if less or other plumes are used. The main findings are that sensors at boundaries are often best, but also typical paths of plumes may be important, and that administrative constraints may necessitate much more sensors. The small numbers of sensors actually deployed in these regions seem sufficient. However, the latter may be an artefact of the low number of plumes we considered. Altogether, combined with other considerations, this approach can contribute to better decisions about gamma dose rate sensor locations.

On the frame of a broad project devoted to the evaluation of the occupational and environmental radiological impact of several NORM industries located at the South-West Spain, a study determining the U-series radionuclides levels in air particulate matter has been accomplished inside a phosphate rock processing plant dedicated to phosphoric acid production. U-series radionuclides concentrations in aerosols collected inside this plant have been determined and compared with those obtained in aerosols collected from a reference monitoring station not affected by NORM industries or other anthropogenic inputs. Additionally, based on the observed increments in the volumetric concentrations of the radionuclides from the U-series in the plant, the increase in the occupational doses due to inhalation for their workers has been estimated. Even under conservative assumptions, the dose enhancements are clearly below 1 mSv/year, the annual limit for the public.

The deposition from Chernobyl in spring 1986 was most unevenly distributed in Finland and elevated the 137Cs contents of fishes in Finnish lakes significantly. High activity concentrations of 137Cs still occur in fish from certain lakes in the areas of the highest deposition. Activity concentrations of 137Cs in perch varied from 20 to 7 800 and those in lake water from 4 to 330 Bq/m3 in 1998 and 2002. Concentration factors (Bq/kg in perch / Bq/kg in lake water) ranged from 1 300 to 30 000 in the lakes studied. Ecological halftimes of 137Cs in perch in certain lakes, monitored regularly since 1986, and representing different types in terms of environmental transfer, were estimated as examples. The longest halftimes of 137Cs in perch were approximately 8 years and the shortest approximately 3 years determined for the time period of 1988-2002. Except for estimation of radiation doses to people eating fish, data on changes of activity concentrations in various parts of the aquatic system are also needed when estimating radiation doses to fish and other biota. Slow recovery of the habitat and feed from 137Cs results in higher exposure of biota than in case of rapid activity decrease.

Un bilan résumé des connaissances sur le radiocobalt dans le milieu terrestre est présenté. La chimie du cobalt dans les sols est étroitement liée à celle du fer et du manganèse. Il présente une meilleure solubilité en milieu acide. On estime que 5 à 10 % du cobalt total du sol sont hydrosolubles ou facilement extractibles, et que la majeure partie du cobalt est, soit faiblement adsorbée sur les argiles, soit complexée avec les acides humiques. L'intensité de l'absorption racinaire du cobalt par les végétaux est conditionnée principalement par le pH du sol, par la présence d'éléments tels le fer, l'aluminium ou le calcium et, dans une moindre mesure, par la texture du sol et sa teneur en matière organique. Les résultats concernant le transfert foliaire sont peu nombreux. Pour une contamination foliaire unique, l'intensité du transfert varie en fonction du stade végétatif de la plante au moment de la contamination. Comme pour d'autres radioéléments, le transfert résultant d'un apport sur les organes aériens est plus pénalisant que le transfert d'origine racinaire, pour un dépôt équivalent. Les transformations alimentaires permettent d'abaisser de près de 50 % l'activité résiduelle des aliments, par comparaison avec les végétaux récoltés bruts.

In the radiobiological studies of aquatic organisms, fish eggs are a favorite subject for experimental work because of easy availability of embryos and the possibility of observing the development of embryos within eggs. Data from Russian/FSU publications concerning the effects of ionizing radiation on the survival and development of fish eggs were compiled within the framework of the EC Project EPIC “Environmental Protection from Ionizing Contaminants in the Arctic" (2000-2003). Comparative analysis was performed for effects on roe of two representative fish species: cold-water fish salmon (Salmo salar), and pike (Esox lucius), which is widespread predatory fish from the temperate climatic zone.