Cet article présente une analyse détaillée de la populationautour des sites nucléaires français. Il aborde ensuite la problématiquede l’évacuation massive de populations en cas d’accident, puis donneun aperçu des recherches en cours au laboratoire d’analyse économiquedes risques nucléaires de l’IRSN sur le coût du risque d’accident nucléaire,en particulier celui des territoires contaminés.

A study was done to evaluate the ingestion dose due touranium in drinking water. The area of study is the twin cities ofHyderabad and Secunderabad, India. The uranium concentration inwater samples was analysed by laser-induced fluorimetry. The associatedage-dependent radiation dose was estimated by taking the prescribedwater intake values and dose conversion factors for different agegroups. The concentration of uranium varies from below the detectionlimit (detection limit = 0.20 μg.L–1) to 2.50 ± 0.18μg.L–1, with a geometric mean of 0.67 μg.L–1 intap water, whereas in groundwater the range is 0.60 ± 0.05 to 82± 7.1 μg.L–1 with a geometric mean of 10.07 μg.L–1.The annual ingestion dose by the drinking water pathway due to uraniumin tap water for various age groups was found to vary from 0.23to 6.35 μSv.y–1 with an average of 1.08 μSv.y–1.The ingestion dose due to uranium in tap water is 15 times lowerthan that of groundwater consumption.

An investigation of the latitudinal distribution of concentrationsof 137Cs at 19 stations in the surface water of the SouthernOcean on cross-sections to the South from the Cape of Good Hope(section SR2) and in the Drake Passage (30th cruise "Academic Ioffe",01.12.2009–09.01.2010) was performed. The data obtained reinforcedthe time-dependent exponential decrease in the 137Csconcentrations in the surface water of the Atlantic sector of theSouthern Ocean. Increased 137Cs concentrations were foundin the Drake Passage and in the section SR2 in the vicinity of thePolar Front. The average value of 137Cs concentrationsfor all measurements equals 0.18 Bq.m–3 σ = 0.11.

When the sample activity is measured for various reasonsseveral times, then with each measurement can be associated an individualdecision threshold and limit of detection. Each measurement canbe analyzed through its own decision threshold. The whole measurementscan sometimes present contradictory results, some measurements beinglower than the decision threshold and other higher. The problemthen arises to build a decision threshold and a detection limittaking into account all the individual results, and to decide ifthe radioactivity is finally detected or not. It is interestingto note that it is possible sometimes that the decision thresholdtaking account all results makes it possible to decide that the radioactivityis present whereas the totality of the individual results are negativein terms of individual decision threshold. The purpose of this articleis to show how these thresholds and these coherent limits cumulatedcan be determined in way according to the experimental conditions.In a general way a rigorous method of cumulating makes it possibleto systematically decrease the decision threshold and limit of detectionin terms of activity. This approach has interesting applicationsin gamma spectrometry with multi-emitters, discharge or periodicalenvironmental measurements. On the basis of measurements realizedby the IRSN within the framework of the national monitoring of theenvironment, we will see the potential impact of these methods onthe final assessments.

Accurate dose calculations are very important in radiotherapytreatment planning. The Monte Carlo method has proven to be an accurateand reliable method for simulation of the dose distributions fromelectron beams and can provide theoretically more accurate distributionsthan conventional planning system algorithms (e.g. theGeneralized Gaussian Pencil Beam algorithm) for more complex targetconfigurations. The aim of this work was to assess the parametersand spectrum of a given electron beam (Varian CLINAC 2100 C/D) from experimentaldepth dose distribution and then simulate dose distributions inan experimental arrangement with a 3D polymer gel dosimeter. Thecomparison of data from experimental measurements, Monte Carlo calculationsand the planning system enabled us to verify experimentally thesimulation model and technique as well as the planning system results. Bothsimple and more complex systems (e.g. dose distributions closeto different material interfaces) can be studied. The generationand influence of the “bremsstrahlung” photons in the electron beamswas also analyzed using the simulation technique. The computations,experimental methods used and results obtained are presented anddiscussed.

Interventional cardiology procedures can involve potentiallyhigh doses of radiation to the patients. Stochastic effects of ionisingradiation – radiation-induced cancers in the long term – may occur.We analysed clinical characteristics and dosimetric data in a populationof patients undergoing interventional cardiology. In all, 1 591patients who had undergone coronarography and/or angioplasty inthe course of a year at the Saint-Gatien Clinic in Tours (France)were included. Information on patients’ individual clinical characteristicsand Dose-Area Product values were collected. Organ doses to thelung, oesophagus, bone marrow and breast were mathematically evaluated.The median age of patients was 70 years. Their median cumulativedose-area product value was 48.4 Gy.cm2 for the wholeyear and the median effective dose was 9.7 mSv. The median organdoses were 41 mGy for the lung, 31 mGy for the oesophagus, 10 mGyfor the bone marrow and 4 mGy for the breast. Levels of doses closeto the heart appear to be rather high in the case of repeated interventionalcardiology procedures. Clinical characteristics should be takeninto account when planning epidemiological studies on potential radiation-inducedcancers.

The natural γ-radiation in samples of a variety of marblesimported into Bangladesh for use in building construction was measured,employing γ-ray spectrometry with a HPGe detector. From the measuredγ-ray spectra, activity concentrations were determined for 226Ra(29.31 ± 2.06 to 46.99 ± 2.97 Bq.kg–1), 232Th (42.91± 2.53 to 62.92 ± 3.37 Bq.kg–1) and 40K (824.42± 15.42 to 1071.58 ± 20.14 Bq.kg–1). The measured activityconcentrations for these natural radionuclides were compared withthe reported data of other countries and with the world averageactivity of soil. The radium equivalent activity (Raeq),the hazard indices, the gamma activity concentration index, theindoor absorbed dose rate and the corresponding annual effectivedose were estimated for the potential radiological hazard of themarble. The Raeq values of all marble samples are lowerthan the limit of 370 Bq.kg–1, equivalent to a dose of1.5 mSv.y–1. The average values of the external and internalhazard indices are less than unity. The average indoor absorbeddose rate (121.25 nGy.h–1) is higher than the population-weightedaverage of 84 nGy.h–1, whereas the corresponding annualdose limit falls within an average value of 0.60 mSv, which is anorder of magnitude below the limit specified for building materialsin the literature. The present results indicate that using marblein building construction in Bangladesh does not pose any significant radiologicalhazard.

A workshop dedicated to cancer risks associated withlow-dose internal contamination was organised in March 2011, inParis, in the framework of the DoReMi (Low Dose Research towardsMultidisciplinary Integration) European Network of Excellence. Theaim was to identify the best epidemiological studies that providean opportunity to develop a multidisciplinary approach to improvethe evaluation of the cancer risk associated with internal contamination.This workshop provided an opportunity for in-depth discussions betweenresearchers working in different fields including (but not limitedto) epidemiology, dosimetry, biology and toxicology. Discussionsconfirmed the importance of research on the health effects of internalcontamination. Several existing epidemiological studies providea real possibility to improve the quantification of cancer riskassociated with internal emitters. Areas for future multidisciplinary collaborationswere identified, that should allow feasibility studies to be carriedout in the near future. The goal of this paper is to present anoverview of the presentations and discussions that took place duringthis workshop.