Institute for Radiation Protection and Nuclear Safety (IRSN)
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Le fardeau des maladies attribuables aux polluants de l'air intérieur en Chine entre 2000 et 2017
No full textInternational audienceBackgroundHigh-level exposure to indoor air pollutants (IAPs) and their corresponding adverse health effects have become a public concern in China in the past 10 years. However, neither national nor provincial level burden of disease attributable to multiple IAPs has been reported for China. This is the first study to estimate and rank the annual burden of disease and the financial costs attributable to targeted residential IAPs at the national and provincial level in China from 2000 to 2017.MethodsWe first did a systematic review and meta-analysis of 117 articles from 37 231 articles identified in major databases, and obtained exposure–response relationships for the candidate IAPs. The exposure levels to these IAPs were then collected by another systematic review of 1864 articles selected from 52 351 articles. After the systematic review, ten IAPs with significant and robust exposure–response relationships and sufficient exposure data were finally targeted: PM2·5, nitrogen dioxide, sulphur dioxide, ozone, carbon monoxide, radon, formaldehyde, benzene, toluene, and p-dichlorobenzene. The annual exposure levels in residences were then evaluated in all 31 provinces in mainland China continuously from 2000 to 2017, using the spatiotemporal Gaussian process regression model to analyse indoor originating IAPs, and the infiltration factor method to analyse outdoor originating IAPs. The disability-adjusted life-years (DALYs) attributable to the targeted IAPs were estimated at both national and provincial levels in China, using the population attributable fraction method. Financial costs were estimated by an adapted human capital approach.FindingsFrom 2000 to 2017, annual DALYs attributable to the ten IAPs in mainland China decreased from 4620 (95% CI 4070–5040) to 3700 (3210–4090) per 100 000. Nevertheless, in 2017, IAPs still ranked third among all risk factors, and their DALYs and financial costs accounted for 14·1% (95% CI 12·3–15·6) of total DALYs and 3·45% (3·01–3·82) of the gross domestic product. Specifically, the rank of ten targeted IAPs in order of their contribution to DALYs in 2017 was PM2·5, carbon monoxide, radon, benzene, nitrogen dioxide, ozone, sulphur dioxide, formaldehyde, toluene, and p-dichlorobenzene. The DALYs attributable to IAPs were 9·50% higher than those attributable to outdoor air pollution in 2017. For the leading IAP, PM2·5, the DALYs attributable to indoor origins are 18·3% higher than those of outdoor origins.InterpretationDALYs attributed to IAPs in China have decreased by 20·0% over the past two decades. Even so, they are still much higher than those in the USA and European countries. This study can provide a basis for determining which IAPs to target in various indoor air quality standards and for estimating the health and economic benefits of various indoor air quality control approaches, which will help to reduce the adverse health effects of IAPs in China
The CABRI fast neutrons Hodoscope: CABRI model and signal-to-mass conversion charts
No full textInternational audienceThe CABRI experimental pulse reactor, located at the Cadarache nuclear research center, southern France, is devoted to the study of Reactivity Initiated Accidents (RIA). The hodoscope, installed in the CABRI reactor, is a unique online fuel motion monitoring system, operated by IRSN. This equipment is dedicated to the measurement of the fast neutrons emitted by the tested rod, in real time (with a rate of 1ms), during the power pulse. It is one of the distinctive features of the CABRI reactor facility, which is operated by CEA. To support the experimental task around CABRI reactor, by the experimenters who work on the Hodoscope, a Monte Carlo model, using the MORET code, is used by IRSN. This paper presents the main outcomes obtained during the reactor commissioning tests functioning, using Hodoscope results compared to MORET calculations, which proves the validity of the CABRI MORET model. Furthermore, we show how MORET code is used to build the signal-to-mass conversion charts of the Hodoscope
Protocol for in vitro assessment of human monocyte transendothelial migration using a high-throughput live cell imaging system
No full textInternational audienceIn vitro modeling of the different steps of immune cell recruitment is essential to decipher the role of endothelial cells in this process. Here, we present a protocol for the assessment of human monocyte transendothelial migration using a live-cell imaging system. We describe steps for culture of fluorescent monocytic THP-1 cells and chemotaxis plate preparation with HUVEC monolayers. We then detail real-time analysis using the IncuCyteâ S3 live-cell imaging system, image analysis, and assessment of transendothelial migration rates
3D model of the bronchial epithelial barrier to study repeated exposure to xenobiotics: Application to silver nanoparticles
No full textInternational audienceThere is still a lack of in vitro human models to evaluate the chronic toxicity of drugs and environmental pollutants. Here, we used a 3D model of the human bronchial epithelium to assess repeated exposures to xenobiotics. The Calu-3 human bronchial cell line was exposed to silver nanoparticles (AgNP) 5 times during 12 days, at the air-liquid interface, to mimic single and repeated exposure to inhaled particles. Repeated exposures induced a stronger induction of the metal stress response and a steady oxidative stress over time. A sustained translocation of silver was observed after each exposure without any loss of the epithelial barrier integrity. The proteomic analysis of the mucus revealed changes in the secreted protein profiles associated with the epithelial immune response after repeated exposures only. These results demonstrate that advanced in vitro models are efficient to investigate the adaptive response of human cells submitted to repeated xenobiotic exposures
Le démantèlement des installations nucléaires : les collectifs acteurs de la réduction de l’incertitude.: Synthèse des travaux du groupe de travail E
No full textExperimental and numerical thermal-hydraulics study of a steam-droplets flow in a venturi-type vertical tube with flow deviation -application to LOCA in PWR reactor
No full textInternational audienceDuring reflooding after a hypothetical loss of coolant accident (LOCA) in a pressurized water reactor (PWR), a flow of steam and dispersed droplets forms and propagates in the assemblies. During the accident, rods can be deformed and ballooned, thus reducing the hydraulic diameter of some sub-channels. In this scenario, the rods' cooling may be affected since the steam will be diverted to less blocked sub-channels. For security reasons, the characterization of heat transfers in these areas is important to know in order to well evaluate the consequences of such an accident (meltdown of the core). This study is dedicated to the estimation of heat and mass transfers in these blocked zone
Contribution to the Modelling of the Structural Behavior of Reinforced Concrete Walls Under ISO Fire Exposure
No full textInternational audienceIn the framework of the international benchmark ‘‘Vulcain tests on 3Walls’’, three full scale ISO fire tests on a reinforced concrete wall, simultaneouslysubjected to a constant uniaxial compressive load, were conducted in CSTB in Paris,France. The duration of these tests exceeded 120 min. In order to assess the capability of available finite elements (FE) models to represent reinforced concrete structuralbehaviour under fire exposure, IRSN, within the scope of the Vulcain benchmark, setup a modelling with help of Mazars isotropic continuum damage mechanical model(Mazars Application de la mécanique de l’endommagement au comportement nonlinéaire et a` la rupture du béton de structure. PhD Thesis, Univ. Paris 6, ENSCachan, France, 1984) ran with the CAST3M software (Verpeaux et al. in Fouet, Ladeve`ze and Ohayon (eds), Calcul des Structures et Intelligence Artificielle, Pluralis,1988), while a user-defined procedure was used to calculate the concrete propertiestaking into account load induced thermal strains (LITS). The effect of LITS according to the model of Anderberg and Thelandersson (Stress and deformation characteristics of concrete at high temperatures: 2 experimental investigation and materialbehavior model, Bulletin 54, Lund Institute of Technology, Lund, 1976) was considered by an explicit term in the strain decomposition. Also, the numerical simulationof three full scale ISO fire tests of Vulcain was carried out with the help of a FEmodel that takes into account the values of the concrete thermomechanical parameters identified. The numerical model is composed of two different parts, one for heattransfer analysis and the other one for structural analysis based on a three-dimensional FE model including concrete and reinforcing steel meshes. It is illustratedthrough this numerical investigation that the proposed model can predict the thermomechanical behaviour of reinforced concrete walls under fire exposure
Engagement opportunities in OECD NEA benchmark development
No full textInternational audienceA myriad of opportunities is available to collaborate via international benchmark exercises and experimental data preservation activities. Many such opportunities abound under the auspices of the Nuclear Science Committee of the Organisation for Economic Co-operation and Development Nuclear Energy Agency (NEA). Key projects and activities of relevance to the development of advanced reactors design include the International Criticality Safety Benchmark Evaluation Project (ICSBEP), the International Reactor Physics Experiment Evaluation Project (IRPhEP), the International Assay Data of Spent Nuclear Fuel Database (SFCOMPO), the Shielding Integral Benchmark and Archive Database (SINBAD), and The International Experimental Thermal HYdraulicS Database (TIETHYS), and various cooperative benchmark exercises. Interested participants are encouraged to contact the leadership and secretariat of the various Technical Working Groups and Working Parties to become more engaged. This paper provides a summary of the current benchmark exercises and experimental databases available for international participation
EURADOS project on the impact of the proposed ICRU operational dose quantities
No full textInternational audienceFollowing the publication of the joint The International Commissions on Radiation Units and Measurements (ICRU) and on Radiological Protection (ICRP) report on new operational quantities for radiation protection, the European Dosimetry Group (EURADOS) have carried out an initial evaluation. The EURADOS report analyses the impact that the new quantities will have on: radiation protection practice; calibration and reference fields; European and national regulation; international standards and, especially, dosemeter and instrument design. The task group included experienced scientists drawn from across the various EURADOS working groups
Detailed description of the flow fields induced by a fire in a mechanically-ventilated compartment obtained using PIV
No full textInternational audienceThis study analyses the performance of non-intrusive PIV (Particle Image Velocimetry) for the study of flows induced during a fire scenario in a mechanically-ventilated enclosure. PIV can be used to obtain detailed measurements for velocity fields in the enclosure and thus offer new experimental data for the understanding of the physical phenomena involved as well as to validate CFD simulation tools. The study is carried out on a reduced scale on an ethanol pool fire positioned in a ventilated enclosure. Several areas of interest are studied such as interaction between the fire plume and the ceiling, the flow under the ceiling and parietal flows. These zones can be analysed to obtain a picture of the global mean flow and associated velocity fields rarely reported in the literature. The influence of the fire heat release rate on the velocity fields is studied and highlights the design parameters