On présente un bref exposé des activités de métrologie de la dose du Laboratoire National Henri Becquerel (LNE-LNHB), laboratoire national de métrologie pour les rayonnements ionisants. Les résultats des principaux travaux effectués ces dernières années dans ce domaine sont exposés, en particulier les développements se rapportant aux calculs par simulation Monte Carlo, aux instruments étalons (calorimètres, chambres d’ionisation) et aux références dosimétriques pour la radiothérapie, le radiodiagnostic et la radioprotection.

The EC 3rd and 4th framework programs have produced several models and Decision Support System (DSS) in order to assess the radioactive contamination of terrestrial ecosystems. However a critical evaluation of such systems had not been undertaken. The EVANET-TERRA network has been established in order to perform such a task. A comprehensive methodology have been adopted; the uncertainty and sensitivity analysis have been performed in order to establish the differences between conceptual and constructed model, while the model-scenario comparison has been used to determine how the predictions fit empirical data. A synthesis of the current state-of-the-art regarding terrestrial radioecological models has been produced and recommendations have been made for further research needs.

Our aim was to measure the effects of irradiation treatments on soil communities from three different soils. Undisturbed soil cores from three temperate sites (deciduous and coniferous woodland and grassland) were irradiated to give cumulative doses from 0-160 Gy. Cores were incubated at 15$^{\circ}$C and three cores from each treatment sampled after <1, 3 and 8 d. Soil fungi and heterotrophic bacteria were enumerated and the activity and functional diversity of soil microbial communities assessed in terms of their potential to utilise a range of C-sources. Although no significant treatment effects were observed in the numbers of cultivable fungi or fast growing heterotrophic bacteria, the numbers of cultivable Pseudomonas spp. declined in all three soils after irradiation at 80 and 160 Gy. Microbial communities from the coniferous forest soil also showed a dramatic decrease in the metabolic activity and number of substrates utilised by after irradiation at 160 Gy. Gamma irradiation had a greater affect on microbial communities in the two organic forest soils as compared to the mineral grassland soil, this could be related to variations in the physico-chemical shielding properties and in the indigenous communities in terms of radio-resistant species.

Tritium concentrations of groundwater samples from the Environmental Monitoring Program at IPEN (Institute of Nuclear and Energetic Researches), São Paulo, Brazil, covering the years 2000 to 2003, were determined by liquid scintillation counting and the results laid in the range of 20 Bq$\cdot$L-1 to 91 Bq$\cdot$L-1. The effective committed dose for general public considering the highest concentration value is 1.3 μSv$\cdot$y-1, which is below the ICRP dose limit of 1mSv$\cdot$y-1. Tritium concentration of radioactive liquid effluents samples from the IEA-R1 research reactor storage tank showed values from 3.6×103 Bq$\cdot$L-1 to 6.2×103 Bq$\cdot$L-1, approximately 1000 times below the Brazilian daily discharge limit of 3.7×106 Bq$\cdot$L-1.

La directive européenne 2006/25/CE, relative à l’exposition des travailleurs auxrayonnements optiques, prévoit l’évaluation des risques au poste de travail par la mesureet/ou le calcul. L’objectif de cette étude était de permettre à des organismes de contrôlede mettre en œuvre la directive en mettant à leur disposition une méthodologie simpled’évaluation des risques in situ, compatible avec leurs moyens. Cette étude a doncconsisté à faire un état du marché, acquérir quelques appareils de mesure de coûtraisonnable (radiomètres et spectroradiomètres) et ensuite évaluer leurs performances. Lesrésultats des mesures effectuées sur 5 lampes de spectres divers, à l’aide de cesappareils, ont été comparés à ceux donnés par un spectroradiomètre de laboratoire priscomme référence. De cette étude il est ressorti qu’aucun d’eux ne permet de mesurer avecune précision acceptable le rayonnement émis par des sources de différentes natures surl’ensemble du domaine spectral compris entre 180 et 3 000 nm. Les radiomètres ne sont pasadaptés à la mesure de sources émettant sur un domaine spectral étroit. Lesspectroradiomètres à simple monochromateur ou à barrettes CCD linéaires présentent quant àeux des erreurs importantes attribuables à la lumière parasite (stray light). Cependant,l’approche d’une méthode de correction de cette lumière parasite a montré qu’il étaitpossible d’améliorer la précision de ces appareils.

La dosimétrie neutronique des personnels à l'aide de dispositifs électroniques est étudiée depuis quelques années. Ces dispositifs offrent un avantage majeur : l'obtention d'une réponse en temps réel. Après une étude de faisabilité d'un système à double diode, fondé sur l'utilisation de la méthode différentielle, le capteur (convertisseur de polyéthylène (CH2)n avec une implantation d'ions 10B et diode silicium) a été expérimenté dans divers champs de neutrons et modélisé afin de confirmer et compléter les mesures. La contribution des photons γ de ces champs de neutrons est la principale perturbation pour la détermination de la réponse aux neutrons. La sensibilité aux neutrons Sn est de 1 impulsion cm-2 µSv-1 pour les thermiques et sur la gamme d'énergie 1,5 - 5 MeV avec un seuil énergétique à 125 keV pour les particules secondaires détectées. Lorsque les équivalents de dose γ et neutron (équivalent de dose ambient H* (10)) deviennent du même ordre de grandeur, la perte de sensibilité Sn est d'autant plus grande que la composante du spectre neutronique en dessous de 500 keV est plus importante par rapport à celle au-dessus de cette énergie. La sensibilité aux photons γ (Sγ) est de l'ordre de 300 impulsions cm-2 µSv-1 avec un seuil de coupure à 130 keV. La modélisation du capteur a été effectuée avec un code Monte-Carlo (EGS4) pour les photons γ et un programme développé au laboratoire (PNEDIOD) pour les neutrons. Une structure adéquate utilisant tous les paramètres optimisés issus de la modélisation améliorerait la discrimination (n-γ) en divisant la sensibilité Sγ par 15. Le seuil de détection énergétique de notre système pour les neutrons serait alors inférieur à 200 keV.

The study investigates accumulation of radionuclides in 5 species of berry shrubs in forests of the Yenisei River basin (the Krasnoyarskii Krai, Russia). Activity concentrations of 60Co, 90Sr, 137Cs, 238U and transuranic elements in aboveground organs of the shrubs have been determined and their transfer factors calculated. Analysis of the calculated TFs shows that shrubs concentrate 90Sr more effectively than other study elements (TF = 0.25–1.9). The highest concentration of 137Cs is recorded in the berries and leaves of Ribes nigrumand Rubus idaeus. For these species, the range of 137Cs TFs (0.006–0.027) overlaps with the range of 238U TFs (0.004-0.018). For the aboveground parts of Ribes nigrum, TFs for transuranic radionuclides (0.01–0.056) are similar to or higher than the TFs for 238U and 137Cs.

In Northern Europe the use of tree biomass for production of energy is mostly based on thinning of forests, harvest residues, stumps from final cutting, bark of commercial roundwood, and organic waste of pulp industry. Results based on field experiments allow estimations of 137Cs activity removed from forests in wood fuel, and also the activity returned in ash used as a fertiliser. After one fertilisation treatment in three types of coniferous forests the activity concentration of 137Cs in wood fuel and ash was reduced to a fraction of 0.3 to 08 of activities in products from unfertilised forests. The improved tree growth and lowering activity concentrations of 137Cs in trees and understorey after fertilisation refer to reduction of human radiation exposure in Chernobyl-affected areas in the long term. Thereby radiation doses to workers handling the ash and members of the public using forests will gradually decrease faster than through radioactive decay only. A documented and traceable ash recycling history of forests is important for all users of forests.

In the present paper, we estimated backscattering factors for the TLD and active personaldosimeters using 662 keV gamma-ray photons on a PMMA surface, which are, for the TLD,1.12; Dosicard, 1.116; DRD, 0.99; and Saphydose, 1.073, and on a water slab phantomsurface; for the TLD, 1.115; Dosicard, 1.112; DRD, 1; and Saphydose, 1.059. Thebackscattering factor contribution for the Saphydose is nearly half that of the TLD andDosicard, whereas it is zero for the DRD. The DRD underestimates Hp(10)by 10.3–11.6%, whereas for the Saphydose it is 3.4–5% compared with the TLD or Dosicard.The response of the DRD to Hp(10) is nearly independent of the phantom,whereas the TLD, Dosicard and Saphydose require phantoms for calibration for personalmonitoring. It is observed that the PMMA phantom contributes slightly higherbackscattering compared with the water slab phantom. The backscattering factor of theselected dosimeters is comparable with ICRU tissue already reported.

There is much current interest in managing and manipulating radionuclide transfer from soils to plants, either for `safe' crops or for phytoextraction of radionuclide contaminated soils. Potentially there is biodiversity in plant uptake that might aid these efforts. We have established the effects of phylogeny (evolutionary history) on the uptake of numerous heavy metal and nutrient elements. Here, using the same Residual Maximum Likelihood techniques, we report phylogenetic effects on radionuclide uptake by plants derived from databases of several hundred species of plants we have collated over recent years. There are differences of at least two orders of magnitude in the concentration to which plants take up isotopes of Cs, Sr, Cl, Ru, S, and I. When analysed using hierarchical Analysis of Variance coded using a recent molecular phylogeny of flowering plants it is clear that for no radionuclide is all the variation inter-specific. Rather, for all radionuclides some of the inter-taxa variation is associated with higher taxonomic levels. In general, therefore, groups of plants with high and low uptake of radionuclides, and that might be useful for managing or manipulating radionuclide uptake, can be delineated. Here we discuss some of these groups and how they might be useful.

Les études épidémiologiques concernant des personnes exposées aux rayonnementsionisants restent à la base des estimations de risque de cancer radioinduitchez l'homme. La principale étude ayant servi à l'élaboration des normesde radioprotection est celle des survivants d'Hiroshima et Nagasaki. Lesmalades traités par radiothérapie ou ayant subi des radiographies dans un butdiagnostique, ainsi que des groupes de travailleurs exposés professionnellementfournissent également nombre d'informations sur le risque de radiocarcinogenèse.Ces études épidémiologiques permettent d'affirmer avec certitude l'existenced'un risque pour certains cancers après irradiation à fortes doses, souvent délivréesà fort débit de dose. Par contre, aucune conclusion n'est possible pour lesfaibles doses et faibles débits de dose. On est donc obligé d'extrapoler auxfaibles doses et faibles débits les risques connus pour les fortes doses enutilisant divers modèles mathématiques pour la relation entre la dose et l'effetobservé. Une autre difficulté vient de la grande période de latence des cancersradio-induits, ce qui explique que tous les cancers en excès n'aient pas encoreété observés dans les populations irradiées étudiées. Là encore, on a recours àdes modèles mathématiques pour projeter sur la vie entière le risque de cancersexcédentaires. Les estimations de risque de radiocancers sont, par conséquent,entachées de nombreuses incertitudes, puisqu'elles varient en fonction dumodèle utilisé. D'autres incertitudes proviennent des données de base, en particulierde la dosimetrie, et se majorent lorsqu'il s'agit de transposer les risquesd'une population à une autre.L'UNSCEAR, en 1988, a proposé de nouvelles estimations pour le risque dedécès excédentaires par cancers sur la vie entière qui serait compris entre 4 et11 % par gray ; ces valeurs représentent une réévaluation des précédentesestimations d'un facteur 1,6 à 4,4, et sont en grande partie la conséquence del'utilisation de modèles de projection différents. D'autre part, elles s'appuientuniquement sur les observations des survivants d'Hiroshima et Nagasaki, alorsque les études de malades fournissent un risque moindre. Enfin, l'UNSCEAR nedéfinit pas précisément le facteur de réduction utilisable pour passer des fortesdoses et forts débits de dose aux faibles doses et faibles débits qui restecompris entre 2 et 10. En raison des nombreuses incertitudes persistantes, il nesemble pas justifié de modifier actuellement les normes de radioprotection.

The International Atomic Energy Agency has, under its Statute, specifically defined functions relating to radiation safety, in particular, responsibilities for the development of standards of safety and provision for their application. These functions are fulfilled through the development of a wide range of standards, including those on preparedness and response to nuclear accidents or radiological emergencies. It also devotes considerable effort to assisting countries in applying those standards. In addition, the Agency has responsibilities placed on it by virtue of a number of Conventions, two of which are relevant to nuclear accidents or radiological emergencies: the Convention on Early Notification of a Nuclear Accident (Early Notification Convention) and the Convention on Assistance in the Case of a Nuclear Accident or Radiological Emergency (Assistance Convention). Under the Assistance Convention, assistance may include medical response. This paper provides an overview of the Agency's work regarding emergency preparedness and response, with specific reference to a number of recent events. It also discusses new initiatives regarding the safety and security of radiation sources, which have, as a principal objective, the reduction of the risk of such events.

Des zones anatomiques superficielles exposées au rayonnement gamma d'une source d'iridium 192 ont été suivies in vivo par imagerie de résonance magnétique. Une étude de cas a été effectuée sur trois miniporcs irradiés à des doses de 96, 32 et 64 Gy à la peau, sur la région dorsale entre les vertèbres T7 et L4. Les acquisitions réalisées sur un système à 1,5 tesla montrent que les images pondérées en temps de relaxation spin-spin (T2) font apparaître une diminution du signal pendant les deux premières semaines suivant l'irradiation. Les variations observées, analogues dans la peau, le tissu adipeux et le muscle sous-cutané, sont plus fortes dans la peau. Cette observation indique que l'imagerie de résonance magnétique, qui peut être un moyen de diagnostic précoce des brûlures radiologiques en profondeur, peut également renseigner de façon spécifique et précoce sur le comportement du tissu cutané.

The new technologies were developed for spent nuclear fuel (SNF) condition operative monitoring and search for the lost objects with SNF at the sea bottom using Kr-85. The new paradigm of sea radioecology based on extensive research was proposed. The investigations include a preliminary experimental study of kinetics of fission products (Kr-85 and Cs-137) release from SNF, a subsequent expedition to the Arctic, as well as modeling radionuclides transfer in a near-bottom layer by means of fractal formalism using hydrological data on the expedition area [1,2]. Series of original experimental studies on Kr-85 and Cs-137 release from SNF during corrosion in sea water were conducted in 2002–2010. Time dependence of fission products (FP) release was measured in laboratory under conditions typical of a near-bottom water layer in the Novaya Zemlya Basin. Another important result was received during the expedition to the Arctic in the fall of 2000. The H-3 anomaly was recognized in the surface layer of the Kara Sea in the Novaya Zemlya Basin (228 ± 9.1 TU vs.10–15 TU in the Arctic on average!). This anomaly is located 100 miles south from the dumped reactor of atomic icebreaker “Lenin”. So it can be caused by SNF from the reactors of icebreaker “Lenin” or nuclear submarine K-140.

The objective of this study is the implementation of a method combining extraction chromatography and liquid scintillation counting (LSC) technique to the determination of 90Sr in milk samples. The strontium separation is performed using the commercially available Sr-resin (Eichrom) and the beta counting is carried out using a liquid scintillation detector system (Tri-Carb 3170 TR/SL, Packard). Firstly, the trials are performed with 300 mL of milk and 0.7 g of resin. Validation trials are carried out using spiked milk samples with different 90Sr activities and the accuracy of the methodology is also been tested with an IAEA 152 reference milk sample. The results obtained had shown good accuracy of expected value. The minimum detectable activity (MDA) obtained for a confidence level of 95% and 60 minutes of sample counting time was 0.20 Bq L-1. In order to improve the detection limits for 90Sr, 1 liter of milk and 3 g of resin were used and the MDA value in these conditions was improved to 0.012 Bq L-1. The method was applied to the determination of the 90Sr concentrations in milk samples from different regions of Portugal.

The effects of low-dose γ-irradiation on the crustacean Daphnia magna have been analyzed. Given that the LD50 for this species is approximately 100 Gy, one-day-old daphnids were exposed to 10, 100 and 1000 mGy of acute γ-rays. The survival of irradiated animals was evaluated over the maximum lifespan of 90 days. Increased mortality among irradiated at doses of 100 and 1000 mGy daphnids was found. Our data also showed that the observed decrease in survival of irradiated animals was attributed to their early aging, thus providing an important evidence for the effects of low-dose irradiation on early senescence. Overall, the results of our studies have shown that low-dose irradiation can result in a significant reduction in life span of exposed daphnids. As the majority of irradiated Daphnia showed reduced viability regardless the dose, our data therefore imply the presence of a threshold of dose of low-LET exposure capable of impairing the viability of this species. We have also found that parental irradiation significantly affected the survival of first-generation offspring, the magnitude of which cannot be attributed to the segregation of radiation-induced deleterious mutations. Potential implications of the results of our studies for the risk assessment of low-dose exposure have been discussed.

Knowledge of excretion rates of naturally occurring 210Po in non-exposed people is a prerequisite for assessment of potential internal contamination with polonium. Significant differences in published data on excretion rate of 210Po in urine have been long known. In this paper we study the differences of excretion rates of 210Po in urine of non-exposed population in detail. All available studies of this field published by the middle of 2008 (according to INIS abstracts) have been evaluated.

Les variations passées du carbone-14 atmosphérique peuvent être reconstruites sur les derniers 50 000 ans par l'étude des différences entre âges carbone-14 et âges calendaires. Liées en premier lieu à la modulation géomagnétique du taux de production du 14C par le rayonnement cosmique et aux variations d'origine climatique du stock de 14C océanique, ces variations ont atteint un facteur 2 au début du paléolithique supérieur. Des variations de même amplitude ont été provoquées par les essais nucléaires militaires des années 50 et 60. La contribution cumulée de l'industrie nucléaire depuis ses débuts jusqu'à nos jours est de l'ordre d'un centième des quantités relâchées dans l'environnement par les retombées des explosions nucléaires atmosphériques. Représentant annuellement 14 % du taux de production naturel de 14C, cette contribution au rapport isotopique 14C/12C est actuellement contrebalancée par l'effet de dilution du 14C par les émissions de CO2 fossile (effet Suess).

One of the most serious problems occurring during coal extraction in Upper Silesia in Poland is caused by waters with high salinity which also often contain high concentrations of natural radionuclides, mainly 226Ra and 228Ra. Similar phenomenon is also observed in oil and gas industry. On the Norwegian continental shelf, substantial amounts of produced waters containing elevated levels of 226Ra and 228Ra are discharged to the sea. All of these facts outlined elsewhere in the reports serious resulted in contamination of wide areas surrounding mines and other related industries. Research studies conducted so far have provided a lot of data concerning the scale of this phenomenon. But nowadays, all of them should be reconsidered in the light of newest recommendation of the state of-the-art radiation protection. Namely, such waste deposited directly into the environment creates significant risk to the non-human biota that currently must be assessed as well. On the other hand, such scenario of exposure to ionising radiation creates a good opportunity to observe potential effects of low and protracted doses to the living organisms occurring on contaminated areas, especially plants.

Aim of the work was analysis of the modern and rapid data acquisition methods for agricultural countermeasures, feedstuff restrictions and clean-up of large contaminated areas (104–105 km2) after accident in a nuclear power reactor. Acquiring and generating agricultural reliable data especially based on satellite technology and analysis of landscape contamination (computer code vs. in situ measurements, airborne and/or terrestrial mapping of contamination) are discussed.