Institute for Radiation Protection and Nuclear Safety (IRSN)
Not a member yet
7928 research outputs found
Sort by
Developing adverse outcome pathways to support radioecological risk assessment: challenges and insights
No full textInternational audienceEnvironmental pollution associated with long-term effects, especially in the case of ionizing radiation, poses significant risks to wildlife, necessitating a more nuanced approach to Ecological Risk Assessment (ERA). In radioecology, current methods, as outlined by the International Commission on Radiological Protection, focus primarily on exposure and individual/population-level effects, often both suffering a lack of ecological realism due to the nature of the data used and sidelining a large amount of critical nonindividual effects such as sub-individual ones like genotoxicity. This review aims to address these gaps by suggesting the integration of New Approach Methods (NAMs) and the Adverse Outcome Pathway (AOP) framework in the field of radioecology. New Approach Methods encompass innovative techniques, such as in silico and in vitro methodologies, that can provide predictive insights without relying solely on traditional animal testing. The AOP framework, developed by the Organisation for Economic Co-operation and Development, structures effects data into a sequence of causally linked events, enabling a clearer understanding of how molecular changes lead to adverse ecological outcomes. In the first section of the review, we explore the challenges of applying AOPs within radioecology, including the complexities of modeling realistic exposure scenarios, the temporal dynamics of effects, and the impacts of multiple stressors. The second section highlights the potential and the application of some NAMs within an AOP framework to contribute improving risk assessment methodologies (in the species realism issue and the use of sub-individual data). This part also offers other potential solutions to increase the number of data to be used in ERA as well as their ecological realism, through the use of AOP frameworks with relevant biological scales and ecological endpoints still uninvestigated in such a way. In conclusion, leveraging NAMs and AOPs is very valuable for bridging molecular data and ecological implications, thereby advancing regulatory practices in radioecology and ensuring more comprehensive protection of ecosystems from radiological hazards
Main results of an in-vessel corium thermochemistry benchmark based on MASCA and CORDEB2 experimental data
No full textInternational audienceThis paper is dedicated to an international benchmark on in-vessel corium thermochemistry. Composed of three different steps, it was constructed in the frame of the IAEA Coordinated Research Project on In-Vessel Melt Retention and focuses on the stratification of corium in the lower plenum of a reactor vessel during a severe accident. The experimental data obtained from the MASCA and CORDEB2 programs is utilized to validate and calibrate the models of the various codes employed by the participants. The paper gives an overview of the different models, including their underlying assumptions. The results show that the models are generally in good agreement with the experimental data, but further experimental data is needed for model validation. Besides the need for further work, this paper highlights the fact that integral models (published in the open literature for most of them) are available to account for the first-order phenomena associated with in-vessel corium. Accordingly, this paper may be useful for code developers that would like to upgrade their models in order to take into account transient stratification kinetics, a prerequisite for a state-of-the-art analysis of in-vessel melt retention
Experimental verification to developing safety technology for liquefied hydrogen in the project "STACY"
No full textInternational audienceGlobal efforts are being made to decarbonize the energy sector. Liquefied (cryogenic) hydrogen is suitable for large-scale storage and transportation due to its high storage density, so it is likely to play a fundamental role in the future hydrogen economy. The STACY project, “Towards the Safe Storage and Transport of Cryogenic Hydrogen”, is investigating safety aspects of liquid hydrogen in order to overcome potential safety risks. Research is being conducted into passive autocatalytic recombiners using cutting-edge catalyst technology to enable them to be used in conditions where liquid hydrogen escapes, evaporates and forms a cold (<50 °C) explosive gas mixture with the ambient air.To this end, the crystal structure of the catalyst was designed at the atomic level, an actual catalyst was prototyped, and repeated tests were carried out on a laboratory scale and in a large reaction vessel. Progress has been made in developing catalysts that can oxidize hydrogen even at very low temperatures, high expansion, and low-oxygen environments, are resistant to catalyst poisons, and can prevent spontaneous unintended ignition. The tested catalyst technologies use different carrier materials (alumina and ceria) to control the surface state of precious metals and suppress hydrogen ignition through a multilevel configuration
AOP-helpFinder 3.0: from text mining to network visualization of key event relationships, and knowledge integration from multiple sources
No full textInternational audienceMotivation:The Adverse Outcome Pathways (AOP) framework advances alternative toxicology by prioritizing the mechanisms underlying toxic effects. It organizes existing knowledge in a structured way, tracing the progression from the initial perturbation of a molecular event, caused by various stressors, through key events across different biological levels, ultimately leading to adverse outcomes that affect human health and ecosystems. However, the increasing volume of toxicological data presents a significant challenge for integrating all available knowledge effectively. Results: Text mining techniques, including natural language processing and graph-based approaches, provide powerful methods to analyze and integrate large, heterogeneous data sources. Within this framework, the AOP-helpFinder TM tool, accessible as a web server, was created to identify stressor-event and event-event relationships by automatically screening scientific literature in the PubMed database, facilitating the development of AOPs. The proposed new version introduces enhanced functionality by incorporating additional data sources, automatically annotating events from the literature with toxicological database information in a systems biology context. Users can now visualize results as interactive networks directly on the web server. With these advancements, AOP-helpFinder 3.0 offers a robust solution for integrative and predictive toxicology, as demonstrated in a case study exploring toxicological mechanisms associated with radon exposure
Coronary inflammation and cardiovascular risk in breast cancer after radiotherapy
No full textInternational audienceRadiotherapy (RT) is known to reduce the rate of disease recurrence following breast-conserving surgery in patients with breast cancer, but also entails irradiation of the heart, which can lead to cardiotoxicity and vascular injury, specifically through sustained inflammation.1 During the last decades, RT advancements have been made in limiting the heart dose and the link between RT and long-term cardiovascular risk is less clear, with some older studies highlighting a dose-dependent increase in the subsequent rate of ischaemic heart disease,2 while more recent studies showed no evidence for increased cardiac mortality among women treated with RT.3 We sought to explore the evolution of coronary inflammation and residual inflammatory risk 2 years after RT in women with breast cancer
IVMR modelling with transient effects during molten pool formation and stabilization – Outcomes from models’ comparison performed in the IAEA CRP J46002
No full textArticle published as part of the Special Issue “ERMSAR 2024 – 11th European Review Meeting on Severe Accident Research”.International audienceIn 2020, the International Atomic Energy Agency (IAEA) has started the 4-year Coordinated Research Project (CRP) on In-Vessel Melt Retention (IVMR) with the main objective to harmonize the international understanding of the scientific and technological bases underpinning crucial parts of the safety demonstration of this Severe Accident (SA) management strategy. This strategy consists in maintaining the degraded reactor core (corium) within the vessel by ensuring its cooling thanks to cavity flooding and power extraction through the vessel wall. In the scope of this CRP, analytical benchmarks were performed focusing on different reactor designs. Among them, a generic 1000MWe PWR design benchmark was set up with a different objective compared to those dedicated to a given scenario and reactor. Its main purpose was to allow detailed comparison of models implemented in capable codes (either integral SA code or dedicated code) based on prescribed and simplified configurations. This paper presents the work done and achievements obtained within this benchmark. Different cases, corresponding to different corium configurations and boundary conditions, were developed with increasing complexity. In total, eight benchmarks are studied covering molten pool formation from solid particles, progressive corium relocation to the lower plenum, progressive molten steel incorporation, vessel wall ablation and possible stratification inversion. Together, they form an efficient and useful tool to better understand IVMR results and code capabilities or limitations. State of codes performance and remaining issues are discussed, focusing mainly on configurations involving progressive molten material arrival in the lower plenum
Geochemical analysis of overbank fine sediments of the Upper Rhine (Rhinau island, France): Evidence of metal (Pb, Zn, Cu & Sn) enrichments over the last century
No full textInternational audienceA geochemical analysis of a well-dated 1.2 m-thick sedimentary sequence collected on the Rhinau island at ~60km south of Strasbourg (France) has been performed in order to reconstruct the evolution of metal contents inoverbank fine sediments of the Upper Rhine over the last 150 years. Data indicate that most of the geochemicalvariations in major elements as well as in trace elements along the sedimentary profile can be related to variationsin the sediment mineralogical composition during deposition. Only Cu, Pb, Zn, and Sn highlight enrichmentin the sediments, interpreted as resulting from human releases into the fluvial hydrosystem. Enrichmentquantification is made by using diagrams of variation of element X normalized to silica as a function of Al2O3/SiO2. The results point out that each metal has its own enrichment pattern. The enrichment significances andorigins are discussed by comparing them with the knowledge of historical contaminant release and/or depositionin the Upper Rhine hydrosystem. Sn enrichment is thus linked to Sn releases by textile industries downstream ofBasel, whose activity peaked in ~1940/1950 CE before gradually declining. Pb enrichment, which started to decline in the mid-1980s and disappeared in the 2000s, is explained by the reduction and then cessation in the early 2000s of the two main sources of Pb pollution to the Rhine hydrosystem, namely (i) atmospheric fallout linked to the combustion of leaded gasoline and (ii) Pb flux associated to the Alsacian Potassium Mining rejects into the Rhine river. Cu and Zn enrichments are explained by diverse sources (e.g. agriculture, industries and wastewater treatment plants), whose emissions have reduced over the last decades but can still occur to a significant extent. Overall these results confirm potential and usefulness of our multi-method approach for assessing the effectiveness of public policies to reduce the impact of metal releases into continental hydrosystems, as well as their response time
Godiva-IV leakage dose characterization
No full textInternational audienceAs new nuclear accident dosimetrists are being trained by their respective institutions, there was a need for nuclear accident dosimeter (NAD) ntercomparison exercises. This required a reference neutron and photon dose for nuclear accident dosimetrists to test their dosimeters and analysis. The U.S. Department of Energy (DOE) Nuclear Criticality Safety Program (NCSP) supported an experimental campaign to characterize the Godiva-IV leakage dose in 2014 to support future exercises. A Passive Bonner Sphere Spectrometer (PBSS) was deployed by Atomic Weapons Establishment (AWE) to measure the neutron spectrum. CaF thermoluminescent dosimeters (TLDs) were used to measure the photon doses. The results were documented in a report at that time but this paper reanalyzed and updated those results with other measurements in the interim. This work established updated reference neutron and photon doses as a function of radial distance from the center of Godiva-IV, which will be used for future NAD intercomparison exercises
On the Necessity of Adopting Irradiation Protocols Recommended by the Compatibility in Irradiation Research Protocols Expert Roundtable (CIRPER) in Published Research and Why It Matters to Health Physicists
No full textInternational audienceThe National Nuclear Security Administration (NNSA) seeks to assist and support all partners in the fields of radiobiology, health physics, radiation physics, and related areas to transition from cesium-137 chloride-based technologies, which can potentially be used in an act of terrorism, to x-ray technologies. The absence of information on experimental procedures, equipment, and irradiation parameters directly and negatively impacts the reproducibility and translatability of a sizable portion of radiation biology studies. It also discourages researchers from adopting new tools that eliminate the risks of a radiological dispersal device.Ongoing discussions on reproducibility have not had a significant impact on publishing practices. The lack of agreement on minimum standards for disclosure of irradiation parameters results in the need to repeat costly studies, yielding uncertainty in observed effects and producing difficulty in validating characterized animal models. The lack of standard reporting measures also contributes to the confusion and reluctance that researchers may experience when considering whether they should transition to alternatives to gamma irradiation. This reluctance is despite the many advantages these alternatives provide, including technological innovations such as guided imaging that mirror clinical applications (which cesium-137 irradiators simply cannot accommodate), significantly decreased regulatory burdens, and eliminating potential terror threats, among others. Forty-one percent of researchers that transitioned to x-ray irradiators surveyed by Brookhaven National Laboratories (BNL) reported that the advantages of x-ray irradiators allowed them to pursue new lines of research.Both BNL’s recent Alternative Technologies Meta Study (Stern et al. 2022) and the work of Draeger et al. (2020), on which it builds, reaffirm that many radiation biology studies lack information on experimental procedures, equipment, and physics parameters that would allow other researchers to compare and reproduce the outcomes of the studies. These literature reviews demonstrate that, although source specifications (e.g., model, energy, and spectra) are well reported, experimental methodologies and irradiation protocols are not. For example, there are significant information gaps in reporting dosimetry, geometry, filtration, and experimental error of uncertainty. Thus, replication of reported values across studies and users is problematic. For studies where the critical biological endpoints measured have a narrow range (±5% or less), knowing the parameters that control the dosimetry is critical. However, most published studies do not provide enough information on experimental results to reproduce the study or experiment.Two recent initiatives have attempted to bring about consensus on minimum standards for disclosure of irradiation methods and protocols. The AAPM empowered Task Group No. 319 to work on creating guidelines for accurate dosimetry in radiation biology experiments, and its findings are eagerly awaited. A second initiative, the Compatibility in Irradiation Research Protocols Expert Roundtable (CIRPER), began in October 2022 on the margins of the Radiation Research Society’s annual conference. Sponsored by the NNSA through its Office of Radiological Security and BNL, the roundtable invited radiation biologists, medical physicists, health physicists, federal grant managers, and device manufacturers to agree on a standardized set of parameters that radiation biologists working with x-ray cabinet irradiators should include when publishing their work. Such inclusion of parameters would allow other researchers to determine their work’s comparability to similar studies using different irradiation modalities, as well as facilitate reproducibility of their experimental results.Over two days of discussion, CIRPER participants agreed that, at a minimum, the methods sections of radiation biology papers must reference irradiation protocols, providing details on device specifications, dosimetry, experimental setup, and calibration. The CIRPER Recommended Methodological Disclosure Requirements are listed in Table 1. Summarizing the minimum recommended methodological information following Table 1 would provide for consistent, efficient, and standardized submissions to peer-reviewed research journals and federal funding agencies
Diffusivity in metallic beryllium: The case of the H, C, N and O species
No full textInternational audienceThe insertion and diffusivity of interstitial species in metallic beryllium are discussed in this work using a multi-scale methodology, coupling first-principles calculations and a multi-site approach. Emphasis is placed on the main interstitial species, i.e., H, C, N and O atoms. The results show that the most stable site is strongly dependent on the nature of the interstitial atom. Indeed, carbon is most stable in octahedral sites and hydrogen tetrahedral sites, while oxygen and nitrogen are most stable in basal tetrahedral sites. From the stable insertion sites and symmetrical saddle points identified, a number of migration pathways were mapped. The diffusion pathways were then completed using nudged elastic band (NEB) calculations. The diffusivity of the atoms shows an isotropic behavior as expected for carbon, which shows a strong anisotropic behavior with faster diffusivity along the basal plane. These theoretical results are in agreement with known experimental data, especially for hydrogen diffusion. The discrepancy between theory and experiment is corrected by the vacancy trapping effect. Finally, this paper theoretically determines the Arrhenius parameters of each diffusing species, in particular carbon and oxygen, for which no data were available