Institute for Radiation Protection and Nuclear Safety (IRSN)
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Evaluation des effets des rayonnements ionisants sur les abeilles domestiques (Apis mellifera), de la molécule à la population
No full textInternational audienceRadioactive contamination of the environment is a major ecological challenge, highlighted by the Chernobyl and Fukushima disasters. This reality underlines the importance of deepening our knowledge on the environmental impacts and risks related to irradiation and radioactive contamination. My thesis focuses on the study of the effects of ionizing radiation on the honeybee, Apis mellifera, a choice motivated by the importance of this insect in ecosystems and for society, covering economic, ecological and scientific aspects. The objective is to broaden knowledge on the consequences of ionizing radiation at different levels, from the molecule to the population, in a field that is still poorly documented. This work responds to the priority question of the IRSN Scientific Strategy on the effects of exposure to low doses of radiation. My thesis is based on a dual approach, combining field studies and laboratory experiments. In the field, the study is conducted by monitoring several bee colonies located near the Fukushima nuclear power plant, in areas with a radioactive contamination gradient ranging from 0.15/0.30 µGy/h (controls) to 20/30 µGy/h (heavily contaminated) via 4/6 µGy/h (moderately contaminated) on the ground (monitoring from April to October 2023 then from April to August 2024). In the laboratory, the 2022 and 2023 experiments made it possible to study the combined effects of ionizing radiation (14 µGy/h and 14 mGy/h) and Nosema ceranae, a common intestinal pathogen in bees, in order to study the multistress effect, as well as the impact of radiation on the dynamics of entire colonies (10, 50, 500 and 5000 µGy/h). The first results of the study on the effect of ionizing radiation coupled with Nosema indicate that Nosema reduces food consumption and increases mortality in bees. However, when bees are simultaneously irradiated and infected, these effects are no longer significant, suggesting a possible antagonistic interaction. Concerning biomarkers, few significant physiological differences were observed between control bees and those infected and/or irradiated. In 2024, experiments will focus on reproduction and larval development, with the analysis of the physiological effects of radiation as a common thread. This will include enzymatic assays to assess the response to oxidative stress, metabolic integrity, immune responses and neuronal activity. The aim is to compare results obtained in the field and in the laboratory, in order to assess to what extent laboratory experiments can predict observations made in natural conditions.La contamination radioactive de l'environnement constitue un défi écologique majeur, souligné par les catastrophes de Tchernobyl et Fukushima. Cette réalité souligne l'importance d'approfondir nos connaissances sur les impacts et les risques environnementaux liés à l'irradiation et à la contamination radioactive. Ma thèse se concentre sur l'étude des effets des rayonnements ionisants sur l'abeille domestique, Apis mellifera, un choix motivé par l'importance de cet insecte dans les écosystèmes et pour la société, couvrant des aspects économiques, écologiques et scientifiques. L'objectif est d'élargir les connaissances sur les conséquences des rayonnements ionisants à différents niveaux, de la molécule à la population, dans un domaine encore peu documenté. Ce travail répond à la question prioritaire de la Stratégie Scientifique de l’IRSN sur les effets d'une exposition à de faibles doses de rayonnement. Ma thèse repose sur une approche double, combinant études de terrain et expérimentations en laboratoire. Sur le terrain, l'étude est conduite par le suivi de plusieurs colonies d'abeilles situées à proximité de la centrale nucléaire de Fukushima, dans des zones présentant un gradient de contamination radioactive allant de 0,15/0,30 µGy/h (témoins) à 20/30 µGy/h (fortement contaminés) en passant par 4/6 µGy/h (moyennement contaminés) au sol (suivi d’avril à octobre 2023 puis d’avril à août 2024). Au laboratoire, les expérimentations de 2022 et de 2023 ont permis d’étudier les effets combinés des rayonnements ionisants (14 µGy/h et 14 mGy/h) et de Nosema ceranae, un pathogène intestinal commun chez les abeilles afin d’étudier l’effet multistress, ainsi que l'impact des rayonnements sur la dynamique de colonies entières (10, 50, 500 et 5000 µGy/h). Les premiers résultats de l’étude sur l’effet des rayonnements ionisants couplés à Nosema, indiquent que Nosema réduit la consommation alimentaire et augmente la mortalité chez les abeilles. Toutefois, lorsque les abeilles sont simultanément irradiées et infectées, ces effets ne sont plus significatifs, suggérant une possible interaction antagoniste. Concernant les biomarqueurs, peu de différences physiologiques significatives ont été observées entre les abeilles témoins et celles infectées et/ou irradiées.En 2024, les expérimentations se pencheront sur la reproduction et le développement larvaire, avec pour fil conducteur l'analyse des effets physiologiques des rayonnements. Cela inclura des dosages enzymatiques pour évaluer la réponse au stress oxydatif, l'intégrité métabolique, les réponses immunitaires et l'activité neuronale. L'objectif est de comparer les résultats obtenus sur le terrain et en laboratoire, afin d'évaluer dans quelle mesure les expérimentations en laboratoire peuvent prédire les observations faites en conditions naturelles
Évaluation des effets des radiations ionisantes chez l'abeille - BEERAD
No full textInternational audienceHuman activities linked to nuclear industry generate ionizing radiation (IR). The risk assessment linked to the radiocontamination of the environment after a nuclear accident is a major ecological issue but is still surrounded by controversial results and conclusions on the real impact of such events on flora and fauna inhabiting the targeted zones. Moreover, the potential underlying mechanisms of the action of IR are poorly known. Therefore, it is important to acquire data on the potential effects of IR on ecosystems both in experimental and realistic conditions.The BEERAD project (ANR-21-CE34-0002, 2022-2025) proposes using the honeybees as a model to study the effects of IR on major physiological functions, and also at individual and population levels. Honeybees are insects of economic, agro-environmental, societal and scientific importance.The objective of this project is to increase the knowledge of effects and mechanisms of action of IR on physiology and populations of honeybees in the context of chronic exposure (i.e., exposure of a significant period of time relative to the lifespan of exposed organisms) and at low dose rates (sublethal ecotoxicity) in realistic conditions, i.e., on the field and in the laboratory.The main objectives are:- To define the exposure conditions both in laboratory and field experiments (in order to compare results obtained via these two approaches) and measure external (micro-dosimeters) and internal dose rates, to give a more precise estimate of the total dose rates absorbed by the bees - To measure the physiological and toxico-pathological effects induced by IR at sub-individual levels (molecule, cell and tissue), particularly with response to an infectious agent- To measure the effects induced by IR at individual and populational levels through the effects on reproduction/development and cognitive process - To compare both types of exposure (laboratory/field), integrate the responses and extrapolate to other living organisms (other bee species, other pollinating insects) through modelling in order to conclude on the level of effects of IR on bees and other pollinating insectsLes activités humaines liées à l'industrie nucléaire génèrent des rayonnements ionisants (IR). L'évaluation des risques liés à la radiocontamination de l'environnement après un accident nucléaire est un enjeu écologique majeur mais reste entourée de résultats et de conclusions controversées sur l'impact réel de tels événements sur la faune et la flore peuplant les zones ciblées. De plus, les mécanismes potentiels sous-jacents à l'action des IR sont mal connus. Il est donc important d'acquérir des données sur les effets potentiels des IR sur les écosystèmes à la fois en conditions expérimentales et réalistes.Le projet BEERAD (ANR-21-CE34-0002, 2022-2025) propose d'utiliser l'abeille domestique comme modèle pour étudier les effets des IR sur les fonctions physiologiques majeures, mais aussi à l'échelle individuelle et populationnelle. Les abeilles domestiques sont des insectes d'importance économique, agro-environnementale, sociétale et scientifique.L'objectif de ce projet est d'accroître la connaissance des effets et des mécanismes d'action des IR sur la physiologie et les populations d'abeilles domestiques dans le contexte d'une exposition chronique (c'est-à-dire une exposition d'une durée significative par rapport à la durée de vie des organismes exposés) et à de faibles doses (écotoxicité sublétale) dans des conditions réalistes, c'est-à-dire sur le terrain et en laboratoire.Les principaux objectifs sont :- Définir les conditions d'exposition aussi bien en laboratoire qu'en expérimentation sur le terrain (afin de comparer les résultats obtenus via ces deux approches) et mesurer les débits de dose externes (micro-dosimètres) et internes, pour donner une estimation plus précise des débits de dose totaux absorbés par les abeilles - Mesurer les effets physiologiques et toxico-pathologiques induits par les IR à des niveaux sous-individuels (molécules, cellules et tissus), notamment en réponse à un agent infectieux- Mesurer les effets induits par les IR à des niveaux individuels et populationnels à travers les effets sur la reproduction/développement et les processus cognitifs- Comparer les deux types d'exposition (laboratoire/terrain), intégrer les réponses et extrapoler à d'autres organismes vivants (autres espèces d'abeilles, autres insectes pollinisateurs) par modélisation afin de conclure sur le niveau d'effets des IR sur les abeilles et autres insectes pollinisateur
Avis de l'Anses relatif au projet « Jourdain » de réutilisation des eaux usées traitées pour l'alimentation d'une retenue d'eau destinée à la production d’eau destinée à la consommation humaine (Vendée)
No full textCitation suggérée : Anses. (2024). Avis relatif aux relatif aux projets de décret et d'arrêté relatifs à l'utilisation d'eaux non potables pour certains usages domestiques. (saisine 2023-SA-0037). MaisonsAlfort : Anses, 66 p.L’augmentation de la fréquence et de la durée des vagues de chaleur et des sécheresses, en lien avec les changements climatiques1 et la croissance démographique et ses conséquences en termes d’urbanisation, d’industrialisation et de besoins d’irrigation pour la production agricole, affecte le cycle de l’eau et la disponibilité des ressources en eau douce sur terre. Cette raréfaction des ressources en eau est considérée comme un risque majeur par le groupe d’experts intergouvernemental sur l’évolution du climat (GIEC). En France, la fréquence plus élevée des épisodes de sécheresse et des vagues de chaleur impose des mesures de restriction d’eau, avec un risque croissant de multiplication des conflits d’usage. Parmi les solutions proposées pour pallier cette problématique du manque d’eau, le recours aux eaux impropres à la consommation humaine (nommées également « eaux non potables » et « eaux non conventionnelles ») est encouragé au niveau communautaire et national.Au niveau communautaire, plusieurs directives ou règlements encouragent et encadrent une utilisation durable des ressources en eaux, notamment :- l’article 12 de la directive 91/271/CEE du Conseil du 21 mai 1991 relative au traitement des eaux urbaines résiduaires mentionne que les eaux usées traitées (EUT) peuvent être réutilisées chaque fois que cela se révèle approprié ;- la directive 2000/60/CE du Parlement européen et du Conseil du 23 octobre 2000 établissant un cadre pour une politique communautaire dans le domaine de l'eau, promeut une utilisation durable des ressources en eaux et contribue à atténuer les effets des inondations et des sécheresses ;- le règlement (UE) 2020/741 du Parlement européen et du Conseil du 25 mai 2020, relatif aux exigences minimales applicables à la réutilisation des EUT, rappelle que cette réutilisation vise à contribuer aux objectifs de développement durable de l’Union européenne, en particulier l’objectif 6 sur la disponibilité et la gestion durable de l’eau et de l’assainissement pour tous, et l’objectif 12 sur la consommation et la production durable. Si ce règlement s’applique à la réutilisation des eaux urbaines résiduaires traitées à des fins d’irrigation agricole, il précise, au considérant 29, que « le présent règlement ne devrait pas empêcher les États-membres d’autoriser l’utilisation d’eau de récupération à d’autres fins, y compris à des fins industrielles, environnementales et de services collectifs, dans la mesure jugée nécessaire en fonction des circonstances et des besoins au niveau national, à condition qu’un niveau élevé de protection de l’environnement et de la santé humaine et animale soit garanti ». (extrait) [Saisines liées n° 2014-SA-0177 et 2015-SA-0146
Microvolume analysis of 226Ra by inductively coupled plasma mass spectrometry: Environmental applications to high-resolution profile of wetland soil pore waters
No full textInternational audienceBackground: The release to the environment of natural radionuclides like 226Ra due to human activities have raised concerns about human and ecosystem exposure. 226Ra’s resemblance to calcium and involvement in biological processes accentuate the importance of understanding its geochemical behavior and migration pathways. Soil and sediment pore waters provide valuable information but have proved to be challenging to analyze, requiring to push the limits of current sample preparation and detection methods often not scaled for low concentrated microvolumes of samples. A more efficient and accurate analytical method is therefore needed to get reliable data to support hydro-geochemical modeling.Results: We describe here a novel comprehensive approach for accurate 226Ra quantification in pore waters of a wetland located downstream of the former Rophin uranium mine. In order to highlight the migration of 226Ra between the different soil layers, microvolumes of soil pore waters were in situ sampled up to 50 cm depth employing Diffusive Equilibrium in Thin-Films (DET) probes. The workflow included spiking DET extracts with an in-house 228Ra tracer, specific solid-phase extraction with 50 mg of AnaLig Ra-01® resin, and elution fraction calcination. This process eliminated interferences and simplify the analysis matrix. Quantification relied on isotope dilution after measurement by ICP-MS hyphenated to a desolvator module and to a microsampler (150 µL injection). The resulting 1 cm-high-resolution profile revealed unusual 226Ra enrichment with depth, signs of Ra mobility from the solid contamination source. These elements are essential for assessing 226Ra distribution coefficients across soil horizons and subsequent wetland remobilization considerations.Significance and novelty: This first methodological advance for 226Ra constitutes a significant step to understand 226Ra behavior i.e., to quantify its activity level, fluxes inside of wetland soils or at the interface overlying waters/sediments. Its potential extension to studies involving other elements underscores its broader applicability in environmental research. The findings contribute to evidence-based decision-making for environmental protection and management, aiding in the preservation of ecological integrity and human health
SYLVIA - a software to study ventilation network, fire, and airborne contamination
No full textInternational audienceSYLVIA is a mature software package developed by IRSN used internally by IRSN to carry out fire safety studies. SYLVIA is currently the only software available which seamlessly couples using an implicit method the operation of a complete ventilation network and the effects of one or more fires in the premises of this network. Outside IRSN, this software is mainly used to simulate the operation of ventilation networks in existing installations in order to study incidental scenarios or interventions. The aim of this paper is to present the SYLVIA software and its objectives. It covers ventilation network modelling, fire modelling, and heat and mass exchange modelling. From the user's point of view, a description of the scenario options and the GUIs available is also given. Finally, an application example based on a validation case is presented
A thermogravimetric comparative study of the high temperature steam oxidation of bare and pre-oxidized Zircaloy-4, M5Framatome and Optimized ZIRLO™
No full textInternational audienceFor Loss of Coolant Accident (LOCA) analysis, high-temperature oxidation kinetics in steam of Zircaloy-4 and the two Nb-bearing alloys used in French Pressurized Water Reactors (PWRs), M5Framatome1 and Optimized ZIRLO™2, have been studied using Thermo-Gravimetric Analysis (TGA) technique in the temperature range of 900–1200 °C. A specific test procedure allowing the use of a high steam flow rate and good steam supply to the whole specimen surface, as well as fast heating of the specimen, has been developed. Clean kinetic data, not affected by steam starvation, were obtained on the bare, as-received alloys. For as-received claddings, oxidation kinetics are comparable and close to parabolic for the three alloys at 1100 °C and above. Below 1100 °C, a significant deviation from the parabolic kinetic regime was observed, and M5 Framatome oxidizes slower than Zircaloy-4 and Optimized ZIRLO. Thanks to the fast-heating protocol, the influence of pre-oxidation, simulating corrosion in normal reactor operation, could be investigated, avoiding evolution of the pre-oxidation scale during a slow, long heating phase. Pre-oxidized Zircaloy-4 and M5 Framatome were investigated. A strong protective effect is observed below 1200 °C, while at 1200 °C, the pre-oxidation layer appears to be much less protective, possibly due to the monoclinic to tetragonal zirconia phase transformation
Evaluations of radionuclide activity releases into environment during loss of coolant accidents using the ASTEC code in pressurized water reactors within design basis and design extension conditions
No full textInternational audienceThe work described in this paper was carried out within the R2CA (Reduction of Radiological Consequences of design basis and extension Accidents) project, funded in HORIZON 2020 and coordinated by IRSN (France). An increase of the level of Nuclear Power Plant (NPP) safety by consolidated and more realistic evaluations of the Radiological Consequences (RC) of Design Basis Accidents (DBA) and a strengthening of the assessments of the NPP safety levels by considering accidental situations more severe than those integrated in plant designs (i.e belonging to Design Extension Conditions domain) were the two main motivations behind this project.More specifically, the project aims at consolidating and/or refining the assessments of the radiological consequences of explicit accidental scenarios within Design Basis Accidents (DBA) and Design Extension Conditions (DEC-A conditions without significant fuel degradation) in Light Water Reactors (LWR) through the improvements of existing code predictability; the upgrading of calculation chains and methodologies; the development/refinements of models. Within the Work Package 2 of the project, coordinated by TRACTEBEL and dedicated to calculation methodologies, existing methodologies or calculation chains and simulation tools have been applied to run a first batch of calculations dealing with different reactor types: PWR (Pressurized Water Reactor), BWR (Boiling Water Reactor), VVER (Water-Water Power Reactor) and EPR (European Pressurized Reactor). Loss Of Coolant (LOCA) and Steam Generator Tube Rupture (SGTR) accidents have been selected for the exercise and bounding scenarios of the DBA and DEC-A domains have been analysed. The results of this first set of calculations will be used as a reference to quantify the gains obtained by the updated methodologies/simulation tools developed within the project.This paper describes the results of the first batch of calculations, performed with the ASTEC integral code, simulating LOCA scenarios (DBA and DEC-A categories) in a PWR 900 MWe with a focus on the predicted number of failed fuel rods and Source Term (ST) in the environment governing the RC. Limitations of the used approach are outlined, as well as the needs for further upgrading the calculation chains are proposed in the light of the improvement that was planned within the project in Work Package 3 (WP3: LOCA – Loss of Cooling Accidents), coordinated by IRSN and dedicated to the improvement of code models dealing with LOCA scenarios
High-resolution geophysical data unravel the post-Variscan structural history of the NW Cotentin inner shelf (Central English Channel)
No full textInternational audienceThe Cotentin Peninsula (CP) is one of the only area in Europe which contains records of a > 2.5 Ga-lasted geological history including three orogenic events (Archaean, Cadomian and Variscan) followed by a polyphase basin/inversion evolution during Meso-Cenozoic times. The CP area sensu lato is thus a suitable place for discussing how the structural configuration of the basement might have influenced the development of part of the southern shelf margin of the Central English Channel, even if sediments and post-Variscan tectonic records are limited at this place. This issue is addressed through an onshore/offshore structural approach combining newly-acquired high resolution bathymetric data and reflection seismic profiles, further constrained by lateral correlations onshore. The resulting Land-Sea Digital Elevation Model and corresponding geological map reveal a number of fault-bounded blocks involving a relatively thin package of Jurassic to Plio-Quaternary sequences, locally involved in slightly compressional deformations. These specific sedimentary and tectonic features typically characterize the southern shelf margin of the Central English Channel. They are discussed in terms of basin development and inversion processes in relation with basement structures and then integrated in the English Channel basin framework. Special attention is paid to three major structural features, i.e. the La Hague Offshore Fault, the La Hague Deep Fault network and the La Hague Deep, which emphasize, respectively, the role of structural inheritance and erosion/incision/deposition events during the post-Variscan tectono-sedimentary history of the southern elevated shoulder of the Central English Channel
Dosimetry with the TruView gel on a 0.35 T MR-Linac: A feasibility study
No full textInternational audienceThe purpose of this work is to assess the feasibility of performing dosimetry with the TruView (ModusQA, London, Ontario, Canada) MTB Fricke gel by MRI reading on a low field MR-Linac (0.35 T). Radiochromic TruView gels were manufactured at IRSN. A 4 echoes time (TE) single-shot fast spin echo sequence (HASTE) was used for 2D images acquisitions. Raw MRI images were denoised (MP-PCA) and transversal relaxation rates (R2) maps were extracted using a homemade Matlab routine. Temperature influences on R2 as well as gel homogeneity were investigated. A dosimetric evaluation of the TruView gel was conducted implying four gels made from the same batch, with three of them dedicated to calibration, and the fourth one received a simple dosimetric plan. Results showed the TruView gel to be sensitive to temperature drift. A protocol was thus developed to ensure thermal stability with the use of a dedicated temperature-controlled water bath. An inhomogeneity that manifests as a R2 increase near the air/gel interface was found to cause a 4% amplitude deviation in R2 along unirradiated gels. Air sealing drastically reduced the inhomogeneity. Dose versus R2 calibration was established. TruView gel sensitivity was found to be low (0.0093 Gy−1 s−1). 1D and 2D comparison to planned dose distribution displayed overall agreement with global gamma index (5%/3 mm) evaluation with an 87 % passing rate. Main discrepancies in the low and gradient dose regions were attributable to the calibration range and diffusion effects. This study demonstrated the feasibility of using the TruView gel for dosimetric evaluation on a low field MR-Linac. The protocol developed needs to be extended to a full 3D evaluation to enable patient QA and may require modifications to the gel formulation to increase its overall sensitivity and ensure limited dependence on temperature drift
Global characterization of a laser-generated neutron source
No full textInternational audienceLaser-driven neutron sources are routinely produced by the interaction of laser-accelerated protons with a converter. They present complementary characteristics to those of conventional accelerator-based neutron sources (e.g. short pulse durations, enabling novel applications like radiography). We present here results from an experiment aimed at performing a global characterization of the neutrons produced using the Titan laser at the Jupiter Laser Facility (Livermore, USA), where protons were accelerated from 23µm thick plastic targets and directed onto a LiF converter to produce neutrons. For this purpose, several diagnostics were used to measure these neutron emissions, such as CR-39, activation foils, time-of-flight detectors and direct measurement of 7Be residual activity in the LiF converters. The use of these different, independently operating diagnostics enables comparison of the various measurements performed to provide a robust characterization. These measurements led to a neutron yield of 2.0x10 9 neutrons per shot with a modest angular dependence, close to that simulated