Institute for Radiation Protection and Nuclear Safety (IRSN)
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Ethnic bias, economic achievement and trust between large ethnic groups: A study in Germany and the U.S
No full textInternational audienceEvidence for ingroup bias is extensive, yet the distinct patterns of discrimination among dominant ethnic groups in the diverse societies of modern industrial nations such as the United States and Germany remain largely unexplored. Incentivized trust games in nationally-representative samples from both countries reveal biases of roughly equal size by non-Hispanic White Americans, Hispanic Americans, and African Americans against each outgroup. In Germany, the majority demonstrates twice as much bias against Turkish minorities compared to Eastern Europeans. Interestingly, both minority groups send similar amounts to ethnic Germans and members of their own groups. We examine the notion that outgroup discrimination by majority group members stems from stereotypes of minorities as economically unsuccessful, employing trust games with high-income counterparts. We find that majority senders’ bias against minority receivers declines when receivers are known to have high incomes, in line with that idea. Interestingly, some minority groups, especially Turkish descendants, display a negative propensity to transfer to rich members of their ingroup in comparison with outgroup members, relative to baseline. While we focus on differences in sending by ethnic pairing, we note that all participants send less to second movers identified as high income, and discuss possible explanations. We estimate that four-fifths of the observed ingroup bias is taste-based rather than due to expected trustworthiness differences. This estimation is robust to identifying the purely altruistic component of trust game sending toward each ethnic group, including one's ow
X-Ray images augmented with simulated virtual flaws for deep learning based defect detections
No full textInternational audienceThis article analyzes the performance of object detection algorithms in detecting flaws in welds inspected by X-ray testing. We propose a learning framework that relies on both experimental acquisitions and simulations to build a training set of images with virtual flaws. This set is then used to fit object detection algorithms aiming at detecting flaws in welds. After training, we analyzed the machine learning performance against real flaws in welds using experimental X-ray testing images that were not included in the training process
Compressibility of a binary bentonite-based mixture with particular emphasis on pellet orientation
No full textInternational audienceBinary mixtures of Wyoming-type bentonite, consisting of 80 % mass high-density pellets and 20 % granular bentonite, are currently considered candidate materials for the French concept of vertical sealing systems for deep and long-term disposal of radioactive wastes. At low emplacement water contents, the hydro-mechanical behaviour is primarily controlled by contact forces between pellets, forming a coarse grain-supported structure over which granular bentonite is poured. These pellets were uniaxially compacted at elevated stresses to reach high dry densities. Subsequent pellet unloading resulted in anisotropic features due to fissuring and delamination, followed by water absorption. This study investigated compressibility changes upon loading under laterally confined conditions of a well-oriented pellet-supported structure, mimicking the setup of the in situ VSEAL 1 experiment at Tournemire (France). Two pellet orientations at the same dry density and coordination number of pellet contacts were examined in a pure pellet skeleton and a mixture to account for potential heterogeneity during pouring. A discrete element method was used to simulate the compression results with pellets represented as a clump with a heterogeneous void ratio distribution due to fissuring. These simulations were instrumental in understanding the important anisotropic deformation properties of pellet-supported structures under two distinct orientations
Step-by-step CFD validation of turbulent particle transport and deposition in industrial bends
No full textInternational audienceNumerical tools are necessary to assess particle transport in ventilation ducts, a topic of many interests for sanitary, safety and security reasons. The objective of this study is to evaluate CFD modelling in industrial rectangular bend ducts. Sensitivity studies are performed at small-scale and the resulting observations are applied at large industrial scale focusing on deposition in bends for which experimental data are obtained on a large-scale facility especially developed for this purpose
Ab Initio Insight into CsHMoO 4 and H 2 MoO 4 Complexes on MoO 3 Surfaces
No full textInternational audienceSolid surfaces play a crucial role in many processes, yet their impact in nuclear safety is notwell understood. This study investigates how solid surfaces affect the behavior of radioactivegaseous species, focusing on the interaction of fission product complexes formed under nuclearaccident conditions. Specifically, we examine the condensation and decomposition of Cs-Mocomplexes, CsHMoO4 and H2MoO4, when interacting with MoO3 deposits in a reactor coolingsystem, considering two surface terminations: O and Mo. Using density functional theory(DFT), we calculate Gibbs free energy for these reactions on MoO3 surfaces at temperaturesranging from 300-1800 K. CsHMoO4 condenses below 850 K and dissociates between 300-650K on O-MoO3 and 650-1250 K on Mo-MoO3, forming Cs2MoO4 and MoO3, along with steamrelease. H2MoO4 condenses below 500K and decomposes between 600-800K, but only on Mo-terminated surfaces. These findings improve the accuracy of nuclear simulations, aiding in theprediction of species composition and transport within the reactor cooling system duringaccident
Hydrogen Behavior and Mitigation Measures: State of Knowledge and Database from Nuclear Community
No full textInternational audienceHydrogen has become a key enabler for decarbonization as countries pledge to reach net zero carbon emissions by 2050. With hydrogen infrastructure expanding rapidly beyond its established applications, there is a requirement for robust safety practices, solutions, and regulations. Since the 1980s, considerable efforts have been undertaken by the nuclear community to address hydrogen safety issues because, in severe accidents of water-cooled nuclear reactors, a large amount of hydrogen can be produced from the oxidation of metallic components with steam. As evidenced in the Fukushima accident, hydrogen combustion can cause severe damage to reactor building structures, promoting the release of radioactive fission products to the environment. A great number of largescale experiments have been conducted in the framework of national and international projects to understand the hydrogen dispersion and combustion behaviour under postulated accidental conditions. Empirical engineering models and computer codes have been developed and validated for safety analysis. Hydrogen recombiners, known as Passive Autocatalytic Recombiners (PARs), were developed and have been widely installed in nuclear containments to mitigate hydrogen risk. Complementary actions and strategies were established, as part of severe accident management guidelines, to prevent or limit the consequences of hydrogen explosions. In addition, hydrogen monitoring systems were developed and have been implemented in nuclear power plants. The experience and knowledge gained from the nuclear community on hydrogen safety is valuable and applicable for other industries, involving hydrogen production, transport, storage, and use
Safety and efficacy of pulsed-field ablation for atrial fibrillation in the elderly: A EU-PORIA sub-analysis
No full textInternational audienceBackground: The role of catheter ablation in elderly patients with atrial fibrillation (AF) is unclear. Pulsed field ablation (PFA) demonstrates a favorable clinical profile, however, data on elderly patients are lacking. Aims: We aimed to assess the safety and efficacy of PFA in the elderly, using data from the EU-PORIA registry. Methods: Periprocedural complications and long-term safety and efficacy outcomes of AF ablation using the pentaspline PFA catheter (Farapulse™) were compared between patients older than 80 years old and their younger counterparts, across seven European centers. Results: Among the 1233 patients in the registry, 88 (7.1 %) were older than 80 years. Elderly patients were more often females (51.1 % vs 37.8 %, p = 0.01) with a lower median BMI (26.0, IQR:23.5-29.2 vs 26.9, IQR:24.4-30.4 kg/m 2 , p = 0.02), a higher median CHA 2 DS 2 -VASc score (4, IQR:3-5 vs 2, IQR:1-3, p < 0.001) and a higher incidence of hypertension (73.9 % vs 52.7 %, p < 0.001). In both groups, most patients had paroxysmal AF (58.0 % vs 60.3 %, p = 0.65). Ablation in the elderly was more frequently performed with minimally interrupted anticoagulation (87.5 % vs 59.7 %, p < 0.001). Despite comparable rates of overall complications (5.7 % vs 3.5 %, p = 0.29), elderly patients had a higher incidence of stroke (2.3 % vs 0.3 %, p = 0.04). At 12 months, major adverse clinical events (4.5 % vs. 2.1 %, p = 0.12) and arrhythmia-free survival (70 % vs 74 %, p = 0.69) were comparable in both groups. None of the recurrence-free elderly patients were on antiarrhythmic drugs at the end of follow-up. Conclusion: In this real-world cohort, the efficacy of PFA for AF was similar in elderly and younger patients. Despite comparable complication rates, a higher incidence of stroke was observed in the elderly
The Pyrenean Platform for Observation of the Atmosphere: site, long-term dataset, and science
No full textInternational audienceThe Pyrenean Platform for Observation of the Atmosphere (P2OA) is a coupled plain–mountain instrumented platform in southwestern France. It is composed of two physical sites: the “Pic du Midi” mountaintop observatory (2877 m a.s.l.) and the “Centre de Recherches Atmosphériques” (600 m a.s.l). Both sites are complementarily instrumented for the monitoring of climate-relevant variables and the study of meteorological processes in a mountainous region. The scientific topics covered by P2OA include surface–atmosphere interactions in heterogeneous landscapes and complex terrain, the physics and chemistry of atmospheric trace species at a large scale, the influence of local- and regional-scale emissions and transport on the atmospheric composition, and transient luminous events above thunderstorms.With a large number of instruments and a high hosting capacity, P2OA contributes to atmospheric sciences through (i) building long-term series of atmospheric observations, (ii) hosting experimental field campaigns and instrumental tests, and (iii) educational training in atmospheric observation techniques.In this context, P2OA is part of the French component of the Aerosol, Clouds and Trace Gases Research Infrastructure (ACTRIS-Fr) and also contributes to the Integrated Carbon Observation System (ICOS) research infrastructure and to several European or international networks.Here, we present the complete instrumentation of P2OA and the associated datasets, give a meteorological characterization of the platform, and illustrate the potential of P2OA and its dataset with past or ongoing studies and projects
Contrasting platinum trajectories in three major French rivers using dated sediment cores (1910–2021): From geochemical baseline to emerging source signals
No full text(IF 8.2; Q1)International audiencePlatinum (Pt) is a Technology Critical Element (TCE) which, since the 1990s, has been mainly used in the industry in catalytic converters for automobile emission control. Previous studies have shown Pt contamination of road-side sediments and surface sediments in urban rivers and lakes but few of them have addressed temporal variations. The present work presents historical Pt concentration trends in 137Cs-dated sediment cores from floodplains or secondary channels at the outlets of three major French watersheds (Loire, Rhone, and Seine Rivers) covering the past ∼110 years, i.e., from the 1910s to 2021. Platinum baseline levels in the sediment were estimated for the Loire River (0.76 ± 0.22 μg kg−1 for the period ∼1910-∼1955) and the Rhone River (1.64 ± 0.41 μg kg−1), and historical Pt variations seem to reflect variations in hydrodynamics and grain size composition. Since the early 2000s, Pt concentrations in the Loire and the Rhone River sediments tend to increase (>2.5 μg kg−1) and were attributed to the use of car catalytic converters, an emerging technology since the 1990s using >50 % of European Pt demand. High and variable historical Pt concentrations (up to 14.6 μg kg−1) in the Seine River sediments may reflect legacy Pt sources due to former anthropogenic activities in this watershed, such as the use of Pt-based catalysts for petroleum refinery since the end of the 1940s, coal handling and precious metals refining, probably concealing the likely presence of an emerging traffic-related Pt signal. This first comparison of historical Pt concentration trends in sediments from contrasting watersheds allows to distinguish signals originating from different natural and anthropogenic sources (background level, historical sources, road traffic)
Gamma irradiation-induced offspring masculinization is associated with epigenetic changes in female zebrafish
No full textInternational audienceSex ratio variation is a key topic in ecology, because of its direct effects on population dynamics and thus, on animal conservation strategies. Among factors affecting sex ratio, types of sex determination systems have a central role, since some species could have a sex determined by genetic factors, environmental factors or a mix of those two. Yet, most studies on the factors affecting sex determination have focused on temperature or endocrinedisrupting chemicals (EDCs), and much less is known regarding other factors. Exposure to gamma irradiation was found to trigger offspring masculinization in zebrafish. Here we aimed at deciphering the potential mechanisms involved, by focusing on stress (i.e. cortisol) and epigenetic regulation of key genes involved in sex differentiation in fish. Cortisol levels in exposed and control (F0) zebrafish females' gonads were similar. However, irradiation increased the DNA methylation level of foxl2a and cyp19a1a in females of the F0 and F1 generation, respectively, while no effects were detected in testis. Overall, our results suggest that parental exposure could alter offspring sex ratio, at least in part by inducing methylation changes in ovaries