Institute for Radiation Protection and Nuclear Safety (IRSN)
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Sexual dimorphism in Cs137 accumulation after chronic low dose exposure in mice
No full textInternational audienceThe presence of 137Cesium (137Cs) in the environment after nuclear accidents at Chernobyl and Fukushima Daiichi raises many health issues for the surrounding populations chronically exposed through the food chain. Unlike previous in vivo studies that focused solely on male exposures, this experimental research aims to assess the dosimetry and biodistribution of low-dose cesium contamination in both male and female C57bl6 mice. This study establishes a model for chronic ingestion of 137Cs, simulating various exposure scenarios. Male and female C57bl6 mice are exposed to concentrations resembling those ingested daily by residents in contaminated areas (20kBq/L), as well as 5- and 10-times higher concentrations to mimic potential cardiovascular damage-inducing levels. We subjected the animals to contaminations lasting either 2 or 6 months. Throughout this period, the animals were closely monitored to determine and quantify the absorbed doses by zooradiametry or measuring the concentration of Cs137 in different organs. After 2 and 6 months exposure to chronic Cs137 in drinking water at 500kBq/L the absorbed dose is 1,6 times less in female mice compared to male mice. 40.02 mGy in female mice and 66.86 mGy in male mice after 2 months exposure. 187.7 mGy in female mice and 309.3 mGy in male mice after 6 months exposure. This dimorphism is also expressed in different organs and is highly expressed in skeletal muscle, heart and kidneys.In this study we demonstrated a sexual dimorphism in cesium accumulation in total body ans across different organs. This disparity is primarily attributed to higher cesium excretion via urine in females
DIGIT: An In Situ Experiment for Studying the Diffusion of Water and Solutes under Thermal Gradient in the Toarcian Clay Rock at the Tournemire Underground Research Laboratory: Part 1Go - Goals, Scoping Calculations, Installation and First Results under Unheated Conditions
No full textInternational audienceThe DIGIT experiment was launched at the Tournemire Underground Research LaboratoryURL with the aim of determining the effects of temperature on the transfer of analogues of mostmobile radionuclides (i.e., 36Cl, 129I and 79Se) in the Toarcian clay rock, the properties of which areclose to host rocks being considered for future deep geological disposal of high-level (HL) radioactivewastes. The experimental principle involves the monitoring of an exchange between a test watertraced with stable halides and deuterium at constant concentration and the porewater of the Toarcianclay rock submitted to various temperatures. This experiment seeks to partially address questionsregarding the potential spread of contaminants during the thermal phase of High Level Waste(HLW) waste packages. Specifically, the in situ experiment aims to evaluate the role of scale effectsand thermodiffusion, a process that combines Fick’s law and the Soret effect, in the transfer ofradionuclides. This paper presents the first steps of the study, including the scoping calculations, theexperimental set-up and the first results obtained during the unheated phase. The study started withthe acquisition of the initial parameters, including the rock thermal properties, the concentrations ofthe four tracers (chloride, bromide, iodide and deuterium) naturally present in the clay porewater andtheir diffusive transport parameters by using four diffusion exchange techniques (phase 0). A modelcoupling heat and mass transfers was then developed using Comsol Multiphysics®, integrating dataacquired so far with existing literature data. A test water with a tracer concentration around 1000times higher than those in the pore water was proposed with a temperature imposed at the testsection wall of 70 ◦C. A large test zone of 50 cm height and 1 m in diameter and installed in a 3 mdeep vertical well located in a sound zone at the URL was then proposed. The installation of theexperiments required the realization of one shaft and of nine peripheral boreholes for the monitoringof temperature, water pressure and deformation. The experiment started with phase 1, involving atraced, unheated water start-up for a period of 5 months. Then, a core sampling was conducted in theemptied well, and the same diffusion exchange techniques were applied. The results of anionic tracerswere compared to simulations based on initial parameters (phase 0), revealing that tracer penetrationat the end of phase 1 exceeded simulated values by approximately 2 cm. This result is interpreted asan increase in the accessible porosity to tracers, possibly due to the excavation damaged zone. Futuresimulations should incorporate these adjusted diffusive transport parameters. Following phase 1, theheating system was activated, applying a temperature of 70 ◦C to the test zone. New data will enablethe comparison of tracer penetration and assess the actual impact of temperature on tracer transfer
Le projet Horizon Euratom ASSAS: le machine-learning peut-il faire des simulateurs d'accident graves rapides et précis une réalité ?
No full textInternational audienceInterfacing reference severe accident (SA) codes with commercial nuclear simulators can help spread SA knowledge to a larger audience and build more accurate plant models. However, this requires improving the performance of calculation codes. The Horizon Euratom ASSAS project (Artificial intelligence for the Simulation of Severe AccidentS) addresses this issue and evaluates, among other strategies, the possible added-value of machine-learning (ML) to speed-up calculations. Efficient programming will be applied to ASTEC (Accident Source Term Evaluation Code, developed by IRSN), with negligible impact on accuracy. This might be sufficient to achieve a real time execution of ASTEC if combined with simplifications of some physical models and of the nodalization used in the input decks. Nevertheless, such modifications are hard to implement, and high acceleration factors are out of reach for complex legacy multiphysics codes like ASTEC. ML could be a game-changer to reach significantly higher acceleration factors. The first step is the definition of the parts of the SA code that can be replaced by a data-driven surrogate model. Global models, replacing the code integrally, can be more efficient and do not require access to the source code. They will be tested on ASTEC for the ex-vessel phase of the accident. On the other hand, they are expected to be data-greedy since they need to capture a large diversity of physical phenomena. Therefore, ASSAS also explores hybrid approaches, for which surrogate models will replace only selected functions of ASTEC and will be interfaced with other modules. The specifications of the basic-principles simulator to be developed during ASSAS must be selected at the beginning of the project, to ensure the consistency between the plant model and the training data for ML models. Exercise scenarios have been chosen to determine the systems to be modelled, their scope and the data to be displayed on the Human-Machine Interface.The present paper aims at providing a description of the ASSAS project and its goals. The adopted strategy and the related challenges will be discussed
Experimental and numerical study of an elevated pool fire scenario in a confined and mechanically ventilated compartment
No full textInternational audienceThe present work deals with an experimental and numerical investigation of an elevated pool fire scenarioin a confined and forced ventilated compartment. Although often encountered in industrial installations or incommon buildings, this type of configuration is rarely studied in the literature. This study is supported by a setof two large-scale fire experiments performed in the framework of the OECD-PRISME3 project and numericalsimulations (RANS and LES methods) carried out with the CALIF3S-Isis software. The objective is to improvethe physical understanding of the phenomena that are experimentally highlighted and to assess the capabilitiesof Computational Fluid Dynamics (CFD) on this type of configuration. First, the comparison between the twolarge-scale fire tests (one elevated and its equivalent on the ground) exhibits a strong modification of thefuel mass loss rate associated with a change in the thermal and species stratifications. Then, a preliminarysimulation using a predictive approach commonly used and efficient for the case of a ground fire scenarioshows by contrast its limitations when applied to the case of the elevated fire. Therefore, in addition to theessential step consisting in the validation of the code with a prescribed approach on this type of elevated fire,the simulations also reveal a specific phenomenology (smoke filling, strong vitiation, oxygen-pumping, .. .).Finally, taking into account these particularities allows in fine, for the studied case, the improvement of theprediction of the mass loss rate of the fire
microRNA blood signature for localized radiation injury
No full textInternational audienceA radiological accident, whether from industrial, medical, or malicious origin, may result in localized exposure to high doses of ionizing radiations, leading to the development of local radiation injury (LRI), that may evolve toward deep ulceration and necrosis of the skin and underlying tissues. Early diagnosis is therefore crucial to facilitate identification and management of LRI victims. Circulating microRNAs (miRNA) have been studied as potential diagnostic biomarkers of several diseases including hematological defects following whole-body irradiation (WBI). This study aims to identify a blood miRNA signature associated with LRI in a preclinical C57BL/6J mouse model of hindlimb irradiation using different 10-MV X-ray doses that lead to injuries of different severities. To this end, we first performed broad-spectrum plasma miRNA profiling, followed by a targeted validation step, on two independent animal cohorts. Using a multivariate sparse partial least square discriminant analysis, we identified a panel of eight circulating miRNAs able to segregate mice according to LRI severity. Interestingly, these miRNAs were previously associated with WBI (miR-150-5p, miR-342-3p, miR-146a-5p), inflammation (miR-18a-5p, miR-148b-3p, miR-532-5p) and skin diseases (miR-139-5p, miR-195-5p). Our results suggest the use of circulating miRNAs as suitable molecular biomarkers for LRI prognosis and diagnosis
Rapport sismologique, Séisme de La Laigne (Charente-Maritime), 16 juin 2023, magnitude 5,3 Mlv (BCSF-Rénass), intensité communale maximale VII
No full textL’épicentre du séisme du 16 juin de 18 h 38 (locale) est localisé en Charente-Maritime (Pays d’Aunis) à proximité des communes de La Laigne (3 km SSE) et Cram-Chaban (2 km SSE). La magnitude locale calculée par le BCSF-Rénass est de 5,3, pour une profondeur comprise entre 2 et 5 km. Tous les mécanismes de rupture (mécanismes au foyer) indiquent un mouvement latéral sur une faille d’orientation est-ouest ou nord-sud (préférentielle d’après la localisation des répliques). Parmi les structures géologiques connues dans la région, les failles principales sont plutôt orientées NO-SE, tandis que d’autres orientations (E-O ou NNO-SSE) se trouvent, en minorité, sur des failles secondaires.Le séisme a été précédé par au moins deux précurseurs à 14 h 58 (locale) d’une magnitude ML comprise entre 2,0 (Rénass) et un deuxième de faible magnitude uniquement visible sur la station de Chizé une quinzaine de secondes avant le choc principal de 18 h 38 (locale). Le choc principal a été ensuite suivi par plusieurs répliques dont la plus forte est survenue le 17 juin à 4 h 27 locale avec une magnitude ML de 4,3 (Rénass). Des nombreuses répliques de magnitudes plus faibles ont été enregistrées dans les semaines qui ont suivi le séisme principal, ressenties pour certaines d’entre elles par les habitants les plus proches de La Laigne et Cram-Chaban.L’intensité maximale de ce séisme a été estimée à VII (dégâts) pour la commune de La Laigne et à VI - VII pour la commune de Cram-Chaban. 30 autres communes ont connu une intensité macrosismique supérieure à V.La distinction des effets cumulés des différentes secousses (16, 17 juin principalement) sur les bâtiments a été particulièrement difficile, voire impossible à réaliser.54 départements français ont été affectés par cette vibration sismique jusqu’à une distance épicentrale maximale de 637 km (Mulhouse).Cette étude a permis d’estimer 875 points d’intensités communales. Des effets dus au séisme ont été signalés dans 1511 communes supplémentaires, notamment grâce aux témoignages individuels internet complémentaires. Aucun dommage de degré 5 n’a été observé. Les dommages les plus importants sont de degré 4 (ouverture partielle de murs) et ont principalement affecté des granges en structure de pierres (vulnérabilité A – EMS-98), majoritairement localisées dans les communes de La Laigne et Cram-Chaban. Les dommages les plus nombreux de degré 2 à 3 sont localisés dans un périmètre de 20 à 25 km autour de l’épicentre. Certains administrés ont signalé à des distances importantes (au-delà de 50 km) des dommages de degré 1, pour la plupart confondus avec des dommages déjà présents avant le séisme selon nos vérifications par l’outil Google Street View ou par l’expertise des images fournies. De nombreux bâtiments en construction de pierres comportaient des fissures préalables qui ont cependant pu être agrandies par les différentes secousses dans les jours suivant le choc principal.Les églises ou édifices historiques marqués auparavant par des fragilités structurelles, ont été affectés parfois de dommages significatifs entraînant, par l’instabilité de certains éléments, quelques fermetures au public.L’ensemble de la population localisée dans les 20 premiers kilomètres a été fortement éprouvée par cette secousse brutale et inhabituelle semblable à une explosion. La panique et quelques traumatismes psychologiques de certains habitants ont été observés lors de notre mission de terrain (description de pleurs et de panique), notamment par les dommages aux bâtiments générés ou la chute d’objets parfois en grand nombre et le déplacement ou la chute de mobiliers légers à lourds mal fixés
An inventory of territorial approaches to the management of domestic radon risks in France: Difficulties, key successes and ways forward
No full textInternational audienceDuring a decade, the French Institute of Radiation Protection and Nuclear Safety (IRSN) has been involved in 2 territorial multi-partner approaches for the management of domestic radon risk. Their feedback showed the relevance and the innovative nature of the projects implemented to develop radon-awareness among the population, to encourage radon measurement and implementation of remediation work. The projects also show the importance of stimulating the commitment and the growing competence on radon of building professionals. Nevertheless, despite these positive feedbacks, the recurring issue remains the difficulty for the inhabitants to go beyond the measurement step.It appeared therefore necessary to obtain a global view of the territorial approaches carried out in France. In June 2020, IRSN started to inventory the approaches undertaken at the territorial level (in which IRSN was not involved directly), to describe them, identify their difficulties, solutions and key success, ultimately aiming at promoting the sharing of regional experiences at a national level. Interviews were conducted in 11 regions with a wide range of stakeholders: regional/territorial public bodies (e.g. health, environment, ecological transition), NGOs and municipalities. The lack of building professionals has been confirmed as being the main difficulty for inhabitants; not only to undertake remediation action but also to provide building expertise thatis a key step to identify these remediation actions. These deficits have led some territories to even stop their action on radon and others to adapt, notably by searching for new actors to ensure the “relay” of building expertise. Additional investigations on this topic have been conducted with support of CEPN (Nuclear Protection Evaluation Centre) to analyze the experiences of these new actors “in relay” and assess the possibility and conditions of the transferability of these approaches in other territories.This paper firstly presents the results of the inventory of domestic radon management approaches in France, highlighting their difficulties as well as their success factors, and then underlying the experience of several territories to find new ways to overcome the absence of building expertise professionals and discuss their transferability, arguably by setting up interregional networks
Augmented Quantization: a General Approach to Mixture Models
No full textInternational audienceThe investigation of mixture models is a key to understand and visualize the distribution of multivariate data. Most mixture models approaches are based on likelihoods, and are not adapted to distribution with finite support or without a well-defined density function. This study proposes the Augmented Quantization method, which is a reformulation of the classical quantization problem but which uses the p-Wasserstein distance. This metric can be computed in very general distribution spaces, in particular with varying supports. The clustering interpretation of quantization is revisited in a more general framework. The performance of Augmented Quantization is first demonstrated through analytical toy problems. Subsequently, it is applied to a practical case study involving river flooding, wherein mixtures of Dirac and Uniform distributions are built in the input space, enabling the identification of the most influential variables
Reconstruction of the radiological component of the exposome in the CONSTANCES cohort: first step of the CORALE project
No full textInternational audienceIntroduction: The aim of the CORALE project is to integrate for the first time, year by year, the exposures to ionising radiation (IR) received by individuals since birth and to study their associations with chronic diseases, in the French population-based CONSTANCES cohort. The present work focuses on reconstructing the IR doses to organs at several stages of life.Methods: A questionnaire was sent to 76,693 volunteers from the CONSTANCES cohort. Some environmental exposures are reconstructed by linking residential histories since birth with radioactivity maps (radon, terrestrial gamma and cosmic rays, and artificial sources) and other through a questionnaire (e.g. on their dwelling – type, floor; on their diet – unfiltered tap water, local mushroom and seafood consumption; on their flights). Occupational exposures will be reconstructed based on a national registry dedicated to IR exposure at work. Medical exposures to IRs will be identified through the National Health Data System from 2007 onwards and by a questionnaire for the pre-2007 period. Results: So far 28,730 participants replied to the questionnaire. In terms of lifestyles linked to environmental exposure, 60.5% of respondents ate shellfish and 37.6% ate local mushrooms and 79.1% have flown at least once in their lives. Regarding medical exposure prior to 2007, 30.6% of respondents reported having had at least one scanner and 16.8% an X-ray with contrast agent. Among women, 43.1% reported having had at least one mammogram. Dose estimates to 6 organs (brain, thyroid, lung, breast, colon, and prostate) are currently being derived.Discussion: The survey remains open, allowing responses from other participants to be recorded. These data are essential to the CORALE study, allowing for the most exhaustive reconstruction of IR as possible throughout life, and will be precious for epidemiological analyses
Le réseau REFRAIN : une expertise indispensable, à votre disposition, pour des chronologies 14C fiables
No full texthttps://calenda.org/1005649National audienceThe Francophone Network for Radiocarbon and Other Cosmogenic Isotopes: Analysis and Interpretation (REFRAIN) was established following the 21st International Radiocarbon Conference, held in 2012 in Paris by French teams working in the field of 14C geochronology. This major event inspired these groups to continue their synergy and meet regularly, leading to the creation of REFRAIN and its annual meeting. This event has become a cornerstone in structuring the Francophone 14C community and serves as a privileged platform for exchanges between 14C geochronology and other scientific disciplines. REFRAIN is more than just a discussion forum; it provides comprehensive support for 14C geochronology, benefiting the archaeological community in general and preventive archaeology in particular. The geochronologists of REFRAIN can guide users towards 14C geochronology laboratories whose reliability and quality are recognized by the international community. The network offers valuable assistance in advising on sample selection based on specific research questions and in warning against potential pitfalls related to fossilization and/or preservation conditions. Their expertise also extends to the statistical analysis of data. Furthermore, some members are experienced in science communication and can contribute to training sessions, events, and webinars. The laboratories within the network open their doors for visits, providing opportunities to strengthen exchanges and gain a deeper understanding of this ever-evolving scientific discipline. Contrary to popular belief, 14C geochronology is not a static field; rather, it is continuously advancing. This poster presents the REFRAIN network, its activities, and key contacts to help you integrate this expertise into your projects.Le Réseau Francophone pour le Radiocarbone et autres cosmogéniques : Analyse et InterprétatioN (REFRAIN) a vu le jour à l’issue de la 21ème International Radiocarbon Conference, organisée en 2012, à Paris, par les équipes françaises œuvrant dans le domaine de la géochronologie 14C. Cette grande aventure a suscité chez ces groupes, l’envie de prolonger la synergie et de se retrouver régulièrement, ce qui a conduit à la naissance de REFRAIN et de sa journée annuelle. Celle-ci est devenue un pilier de la structuration de la communauté francophone du 14C et un lieu privilégié d’échanges entre la géochronologie 14C et d’autres disciplines scientifiques. Ce réseau ne se limite pas à un simple forum, il offre un accompagnement complet vers la géochronologie 14C dont peuvent bénéficier les communautés de l’archéologie en général et de l’archéologie préventive en particulier. Les géochronologues de REFRAIN peuvent orienter vers les laboratoires de géochronologie 14C dont le sérieux et la qualité sont reconnus par la communauté internationale. Le réseau fournit un appui précieux pour conseiller sur la sélection des échantillons selon votre questionnement scientifique et mettre en garde contre les écueils potentiels inhérents aux conditions de fossilisation et/ou de conservation des échantillons possibles. Leur expertise s’étend également à l’analyse statistique des données. En outre, certains membres sont aguerris à la communication et peuvent intervenir lors de vos réflexions, que ce soit pour des formations, des animations, des webinaires. Enfin, les laboratoires du réseau vous ouvrent leurs portes pour des visites, une opportunité pour renforcer les échanges et de mieux comprendre une discipline scientifique en constante évolution. Contrairement aux idées reçues, la géochronologie 14C n’est pas figée, mais au contraire, progresse sans cesse. Ce poster présente le réseau, ses activités et les principaux contacts pour intégrer cette expertise dans vos projets