Cet article présente une analyse détaillée de la population autour des sites nucléaires français. Il aborde ensuite la problématique de l’évacuation massive de populations en cas d’accident, puis donne un aperçu des recherches en cours au laboratoire d’analyse économique des 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 to uranium in drinking water. The area of study is the twin cities of Hyderabad and Secunderabad, India. The uranium concentration in water samples was analysed by laser-induced fluorimetry. The associated age-dependent radiation dose was estimated by taking the prescribed water intake values and dose conversion factors for different age groups. The concentration of uranium varies from below the detection limit (detection limit = 0.20 μg.L–1) to 2.50 ± 0.18 μg.L–1, with a geometric mean of 0.67 μg.L–1 in tap 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 uranium in tap water for various age groups was found to vary from 0.23 to 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 lower than that of groundwater consumption.

An investigation of the latitudinal distribution of concentrations of 137Cs at 19 stations in the surface water of the Southern Ocean 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 reinforced the time-dependent exponential decrease in the 137Cs concentrations in the surface water of the Atlantic sector of the Southern Ocean. Increased 137Cs concentrations were found in the Drake Passage and in the section SR2 in the vicinity of the Polar Front. The average value of 137Cs concentrations for all measurements equals 0.18 Bq.m–3 σ = 0.11.

When the sample activity is measured for various reasons several times, then with each measurement can be associated an individual decision threshold and limit of detection. Each measurement can be analyzed through its own decision threshold. The whole measurements can sometimes present contradictory results, some measurements being lower than the decision threshold and other higher. The problem then arises to build a decision threshold and a detection limit taking into account all the individual results, and to decide if the radioactivity is finally detected or not. It is interesting to note that it is possible sometimes that the decision threshold taking account all results makes it possible to decide that the radioactivity is present whereas the totality of the individual results are negative in terms of individual decision threshold. The purpose of this article is to show how these thresholds and these coherent limits cumulated can be determined in way according to the experimental conditions. In a general way a rigorous method of cumulating makes it possible to systematically decrease the decision threshold and limit of detection in terms of activity. This approach has interesting applications in gamma spectrometry with multi-emitters, discharge or periodical environmental measurements. On the basis of measurements realized by the IRSN within the framework of the national monitoring of the environment, we will see the potential impact of these methods on the final assessments.

Accurate dose calculations are very important in radiotherapy treatment planning. The Monte Carlo method has proven to be an accurate and reliable method for simulation of the dose distributions from electron beams and can provide theoretically more accurate distributions than conventional planning system algorithms (e.g. the Generalized Gaussian Pencil Beam algorithm) for more complex target configurations. The aim of this work was to assess the parameters and spectrum of a given electron beam (Varian CLINAC 2100 C/D) from experimental depth dose distribution and then simulate dose distributions in an experimental arrangement with a 3D polymer gel dosimeter. The comparison of data from experimental measurements, Monte Carlo calculations and the planning system enabled us to verify experimentally the simulation model and technique as well as the planning system results. Both simple and more complex systems (e.g. dose distributions close to different material interfaces) can be studied. The generation and influence of the “bremsstrahlung” photons in the electron beams was also analyzed using the simulation technique. The computations, experimental methods used and results obtained are presented and discussed.

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

The natural γ-radiation in samples of a variety of marbles imported into Bangladesh for use in building construction was measured, employing γ-ray spectrometry with a HPGe detector. From the measured γ-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 activity concentrations for these natural radionuclides were compared with the reported data of other countries and with the world average activity of soil. The radium equivalent activity (Raeq), the hazard indices, the gamma activity concentration index, the indoor absorbed dose rate and the corresponding annual effective dose were estimated for the potential radiological hazard of the marble. The Raeq values of all marble samples are lower than the limit of 370 Bq.kg–1, equivalent to a dose of 1.5 mSv.y–1. The average values of the external and internal hazard indices are less than unity. The average indoor absorbed dose rate (121.25 nGy.h–1) is higher than the population-weighted average of 84 nGy.h–1, whereas the corresponding annual dose limit falls within an average value of 0.60 mSv, which is an order of magnitude below the limit specified for building materials in the literature. The present results indicate that using marble in building construction in Bangladesh does not pose any significant radiological hazard.

A workshop dedicated to cancer risks associated with low-dose internal contamination was organised in March 2011, in Paris, in the framework of the DoReMi (Low Dose Research towards Multidisciplinary Integration) European Network of Excellence. The aim was to identify the best epidemiological studies that provide an opportunity to develop a multidisciplinary approach to improve the evaluation of the cancer risk associated with internal contamination. This workshop provided an opportunity for in-depth discussions between researchers working in different fields including (but not limited to) epidemiology, dosimetry, biology and toxicology. Discussions confirmed the importance of research on the health effects of internal contamination. Several existing epidemiological studies provide a real possibility to improve the quantification of cancer risk associated with internal emitters. Areas for future multidisciplinary collaborations were identified, that should allow feasibility studies to be carried out in the near future. The goal of this paper is to present an overview of the presentations and discussions that took place during this workshop.