Institute for Radiation Protection and Nuclear Safety (IRSN)
Not a member yet
7928 research outputs found
Sort by
Apport du projet R2CA concernant la simulation d'accident réacteur APRP visant l'évaluation du nombre de crayons rompus.
No full textPublished in Annals of Nuclear Energy Special issues on the results of the R2CA H2020 EURATOM projectInternational audienceIn the frame of the “Reduction of Radiological Consequences of design basis and extension accidents” European Union’s Horizon 2020 project, a specific effort was focused on the update and the development of methodologies to assess the radiological consequences of loss-of-coolant accidents. Evaluation of the radiological consequences associated to this accident is strongly linked to the prediction of the rod burst ratio and new approaches were investigated through research and development associated to accident simulation software. Complementarily to approaches chaining system thermalhydraulic simulation to fuel performance code, approaches with integral codes ASTEC, DRACCAR and ATHLET-CD were developed respectively by ENEA, IRSN and HZDR. These applications were demonstrated on LOCA simulation for PWR and highlighted the capabilities of the tools. The ASTEC PWR model was extended by ENEA, which proposes a 2D core model with an increased number of representative fuel rods. HZDR and IRSN proposes approaches based on 3D core model which are able to capture distinctive fuel assembly responses and predict the rod burst ratio according to the distribution of rod behaviors within the core. This work highlighted several possible core models to predict the rod burst ratio and which can be used in integral tools abled to couple thermal hydraulics and thermomechanics. Advanced core models simulating the thermomechanical response of several representative rods per fuel assemblies and using 3D thermal hydraulics model are recommended due to the heterogeneities on power distribution, which impacts flow distribution. The need to model RPV in 3D was underlined by ATHLET-CD large break loss-of-coolant demonstrative case, which exhibits non-symmetric core heat-up.In addition, demonstrative cases proposed by ENEA and IRSN compared predictions obtained with the specific burst criteria developed in the frame of R2CA project and more classical one devoted to the core coolability assessment. The strong sensitivity of the rod burst ratio prediction to the burst criteria was highlighted. The need to handle uncertainties within a global methodology for rod burst ratio evaluation was underlined.Finally, throughout the development of loss-of-coolant accident applications with ASTEC, DRACCAR and ATHLET-CD, some prospects of development were identified for the codes and should bring advances for LOCA simulation and RBR predictions.Dans le cadre du projet “Reduction of Radiological Consequences of design basis and extension accidents” réalisé dans le cadre Horizon 2020 de l'Union Européenne, un effort particulier s'est concentré sur l'évolution et le développement de méthodologies dédiées à l'évaluation des conséquences radiologiques des accidents de perte de réfrigérant primaire (APRP). L'évaluation des conséquences radiologique de ce type d'accident est fortement lié au nombre de crayons rompus au cours de l'accident et des nouvelles approches ont été explorées à travers des acitivtés de recherche et développement des logiciels de simulation du comportement accidentel des réacteurs. En complément aux approches chainant un code "crayon combustible" à un code thermohydraulique système, des approches utilisant des outils de simulation intégraux ASTEC, DRACCAR et ATHLET-CD ont été spécifiquement développées respectivement par l'ENEA, l'IRSN et HZDR. Ces approches ont été illustrées sur des cas démonstratifs de simulation APRP à l'échelle réacteur. Le modèle REP d'ASTEC a été étendu par l'ENEA en utilisant un modèle 2D pour le coeur en décrivant un nombre plus important de crayons combustibles. HZDR et l'IRSN ont quant à eux proposés des modèles coeur 3D permettant de décrire la réponse distincte des assemblages combustibles et d'évaluer le nombre de crayons rompus en décrivant des hétérogénéités de réponse des différents crayons composant le coeur. Ce travail a mis en évidence différente possibilité pour décrire le coeur avec des codes intégraux qui couplent les phénomènes thermohydrauliques avec le comportement thermomécanique des crayons. Les modèles les plus avancés décrivant le comportement du coeur en utilisant plusieurs crayons représentatifs par assemblage en prenant en compte les effets thermohydrauliques en 3D sont recommandés notamment pour décrire les hétérogénéités de puissance et les effets de déviation de l'écoulement. Le besoin de décrire la cuve en 3D a été souligné par la simulation démonstrative d'un APRP Grosse brèche avec ATHLET-CD qui a mis en évidence un échauffement du coeur non axisymétrique.En complément, sur les cas démonstratifs proposés par l'ENEA et l'IRSN, les critères d'éclatement développés dans le cadre du projet R2CA ont été comparés avec les critères classiquement utilisés pour la démonstration de refroidissabilité du coeur en APRP. Une sensibilité importante de la fraction de crayon rompu a été identifiée. Cette sensibilité motive le besoin d'inclure dans la méthodologie l'évaluation et la propagation des incertitudes associées aux données d'entrée et aux modèles physiques.Finallement, au travers du développement d'application APRP REP avec ASTEC, DRACCAR et ATHLET-CD, les limites des outils de simulation et des perspectives d'amélioration ont été identifiées. Celles-ci pourraient apporter des avancées significatives pour la simulation des APRP et l'évaluation de la fraction de crayon rompu (RBR)
Direct determination of 237Np in nuclear effluent by ICP-MS/MS
No full textInternational audienceA new method for the rapid quantification of neptunium 237 in nuclear effluent was developed. This method is based on the direct measurement of neptunium 237 by ICP-MS/MS in mass-shift mode as NpO and using 20% CO2 as a reaction gas. These measurement conditions allowed the best signal-to-noise ratio at m/z 253 (237Np16O) to be obtained by the efficient elimination of the interferences due to the abundance sensitivity of uranium 238 and hydrides of uranium 235 and uranium 236 while minimizing the elemental fractionation between neptunium and plutonium. Moreover, plutonium 242 can be used as a tracer for neptunium 237 isotopic dilution-based quantification. After an optimization of the measurement parameters, excellent figures of merit were obtained. Indeed, this protocol allows an accurate direct measurement of neptunium 237 in various nuclear effluent samples containing up to 2 μg L−1 (2.4 Bq L−1) of uranium 236 and up to 20 mg L−1 (250 Bq L−1) of uranium 238 with excellent accuracy and uncertainties lower than 15%, for samples containing 10−5 to 10−1 μg L−1 (10−3 to 13 Bq L−1), and a limit of detection for 237Np as low as 4 pg L−1 (10−4 Bq L−1)
EURADOS Intercomparison of age-dependent thyroid phantoms for thyroid monitoring in nuclear or radiological emergencies
No full textInternational audienceDirect in-vivo measurement of radioiodine in the thyroid by gamma spectrometry is usually thepreferred method for assessing intake of 131I. To obtain reliable values of the committed doses relatedto these accidental intakes, detector systems have to be properly calibrated, using age-dependentthyroid phantoms for simulating the internal contamination for individuals of different age groups.In-vivo monitoring laboratories all over the world usually use adult thyroid phantoms for calibratingpurposes, however, only a few of them have age-dependent thyroid phantoms. For improving andharmonizing the calibration procedures for in-vivo thyroid monitoring, particularly for children incase of radiological or nuclear emergencies, members of the EURADOS WG7 “Internal Dosimetry”have organized and carried out an intercomparison exercise aimed at comparing different agedependentthyroid phantoms. Intercomparison measurements were conducted at the Whole BodyCounter Laboratory (WBC) of CIEMAT. This paper presents the design and development of thecampaign as well as a summary of the most relevant results obtained and conclusions
Citizen science in environmental health research: A comparison with conventional approaches and creation of a guidance tool issued from the LILAS initiative
No full textInternational audienceContext: Public interest for citizen science (CS) in environmental health is growing. The goals of environmental health research projects are diverse, as are the methods used to reach these goals. Opportunities for greater implication of the civil society and related challenges differ at each step of such projects. These methodological aspects need to be widely shared and understood by all stakeholders. The LILAS initiative (acronym for "application of citizen science approaches such as LIving LAbS to research on environmental exposures and chronic risks") aimed to 1) favor a mutual understanding of the main issues and research methods in environmental health, of their stakes for different actors, but also of the requirements, strengths and limitations of these methods and to 2) identify expected benefits and points of attention related to stronger degrees of participation as part of environmental health research projects.Methods: The LILAS initiative gathered institutional researchers, academics and civil society representatives interested in environmental exposures. Five meetings allowed to collectively identify different types of environmental health research studies and reflect about the benefits, limitations, and methodological issues related to the introduction of growing citizen participation as part of such studies. An analytic table matrix summarizing these aspects was co-created and filled by participants, as a tool devoted to help stakeholders with the definition of future CS research projects in environmental health.Results: For different fields of research (e.g.: studies for assessment of environmental exposures, interventions on these exposures, quantitative risk assessment, epidemiological studies), the matrix lists expected benefits for various stakeholders, the fundamental principles of research methods and related practical constraints, but also advantages and limitations related to the use of CS or conventional research approaches.Conclusion: The LILAS initiative allowed to develop a tool which provides consolidated grounds for the co-creation of research projects on environmental exposures involving CS
PyDrag, A User-Friendly Approach to Dragon Deterministic Code
No full textInternational audienceDRAGON is a deterministic code for neutron transport and, more generally, for nuclear reactor simulation. It is completely open-source from the processing of nuclear data evaluations to the simulation of full cores, and therefore without equivalent in the open world. It is powerful, fast and versatile. However, this flexibility comes at a price: it is an expert code, and its use requires constant learning of the underlying methods. The proposed PyDrag software is a complementary tool, facilitating its use to cover a rather common need: the simulation of pressurized water reactors. Its simplicity derives from the use of the Python language and also a pursuit of the highest minimalism in the interface offered to the user: a simple case can be described in less than 30 lines, based on information directly available in typical industrial or scientific documentation. Potential users are in fields related to nuclear reactor physics, encouraging interdisciplinarity: nuclear data, fuel cycle and reactor physics experts and analysts (fuel, thermal-hydraulics), etc. Like DRAGON, PyDrag is open source and available today
A systematic approach for the adequacy analysis of a set of experimental databases: application in the framework of the ATRIUM activity
No full textInternational audienceIn the Best-Estimate Plus Uncertainty (BEPU) framework, the use of best-estimate code requires to go through a Verification, Validation and Uncertainty Quantification process (VVUQ). The relevance of the experimental data in relation to the physical phenomena of interest in the VVUQ process is crucial. Adequacy analysis of selected experimental databases addresses this problem. The outcomes of the analysis can be used to select a subset of relevant experimental data, to encourage designing new experiments or to drop some experiments from a database because of their substantial lack of adequacy. The development of a specific transparent and reproducible approach to analyze the relevance of experimental data for VVUQ still remains open and is the topic of this contribution.In this paper, the concept of adequacy initially introduced in the OECD/NEA SAPIUM (Systematic APproach for model Input Uncertainty quantification Methodology) project is formalized. It is defined through two key properties, called representativeness and completeness, that allows considering the multifactorial dimension of the adequacy problem. A new systematic approach is then proposed to analyze the adequacy of a set of experimental databases. It relies on the introduction of two sets of criteria to characterize representativeness and completeness and on the use of multi-criteria decision analysis method to perform the analysis. Finally, the approach is applied in the framework of the new OECD/NEA ATRIUM project which includes a set of practical IUQ exercises in thermal-hydraulics to test the SAPIUM guideline in determining input uncertainties and forward propagating them on an application case . It allows evaluating the adequacy of eight experimental databases coming from the Super Moby-dick, Sozzi-Sutherland and Marviken experiments and identifying the most adequate ones
Etude de la cancérogénèse rénale sur des modèles animaux génétiquement modifiés
No full textInternational audienceThe number of cases of kidney cancer has been steadily increasing for over 30 years. In 2023 in France, kidney cancer was the 4th most common cancer in men, and the 8th in women. Kidney cancer is mostly asymptomatic in the early stages; it is often diagnosed incidentally during routine clinical examinations and therefore sometimes at an advanced stage.In order to improve its diagnosis or the development of new therapies. The new in-vitro and in-vivo models developed over the last 15 years make it possible to respond more precisely to the needs in experimental or applied research because they more faithfully reproduce the different RCC (Renal Cell Carcinoma) observed in humans both at the morphological and functional levels. GMO models are recognized by the regulatory authorities and they make it possible, for example, to study the toxic potential of a product or to evaluate the therapeutic effect of a treatment.Existing in vivo models of renal cancer use different strategies: xenograft of human tumor cell lines at the level of the renal capsule or by transplantation, induction by chemical agents such as ferric nitrilotriacetate (Fe-NTA), genetically modified animals (GEM) allow to increase the frequency of development of renal tumors. Depending on the GEM model, the promoters used, the tumor and non-tumor lesions, the kinetics of lesion development and the survival of the animals differ
L'IA pour l'analyse des aérosols radioactifs
No full textInternational audienceIn nuclear facilities, the mandatory monitoring of airborne contamination is carried out by dedicated instruments that collect aerosols on a filter, measure the deposited radioactivity and trigger an alarm when a predetermined activity threshold is exceeded. This measurement, and hence the alarms, are highly influenced by variations in aerosol size and concentration. In order to overcome this difficulty, we are interested in using artificial intelligence to obtain information on aerosol granulometry and the presence of artificial alpha emitters, based on a spectrum. The ultimate aim is to reduce the false alarm rate.Dans les installations nucléaires, la surveillance obligatoire de la contamination aéroportée est opérée par des instruments dédiés qui collectent les aérosols sur un filtre, mesurent la radioactivité déposée et déclenchent une alarme lorsqu'un seuil prédéterminé en activité est dépassé. Cette mesure et donc les alarmes sont très influencées par les variations en taille et concentration des aérosols. Afin de contourner cette difficulté, nous nous intéressons à l'apport de l'intelligence artificielle pour obtenir de l'information sur la granulométrie des aérosols et sur la présence d'émetteurs alpha artificiels, à partir d'un spectre. L'objectif final est de réduire le taux de fausses alarmes
Minimum reporting standards should be expected for preclinical radiobiology irradiators and dosimetry in the published literature
No full textCorrection to: Minimum reporting standards should be expected for preclinical radiobiology irradiators and dosimetry in the published literature (International Journal of Radiation Biology, (2024), 100, 1, (1-6), 10.1080/09553002.2023.2250848)International audiencePreclinical researchers have long acknowledged the critical need for accurate dosimetry in the conduct of radiation-exposure studies involving living systems. Although radiation dosimetry is required to be National Institute for Standards and Technology (NIST)-traceable for human irradiation protocols, there were previously only limited requirements stipulating accurate radiation exposures for preclinical radiation studies funded by the National Institutes of Health (NIH). In one of the earliest identified publications (1956) that addressed radiation dosimetry in murine studies, Hurst et al. (Hurst et al. 1956) discussed their calculations surrounding estimating neutron responses, and “distribution of of absorbed energy versus LET”. In 2009, Zoetelief et al. (Zoetelief et al. 2001) outlined European efforts to harmonize X-ray dosimetry studies in radiation biology, which resulted in the establishment of a protocol to improve dosimetry oversight and allow for better comparison of results across different institutions. It is, however, unclear if these early efforts substantially changed the approach of biologists to ensuring accurate and reproducible dosimetry in their radiation research. The lack of consideration of dosimetry in in vitro and in vivo work was further explored in 2011 during the “Radiation Dose is More than a Number” workshop convened by NIST, and co-sponsored by the National Institute of Allergy and Infectious Diseases (NIAID), and the National Cancer Institute (NCI). The report that followed (Desrosiers et al. 2013) made nine recommendations that ranged from coordinating with radiation physicists during the experimental design phase and including more setup and dosimetry details in publications, to establishing working groups to develop protocols, and implementing formal dosimetry intercomparison programs. In an attempt to address the latter suggestion, and ensure rigor and reproducibility in their funded research portfolio consistent with NIH grants policy , the NIAID Radiation and Nuclear Countermeasures Program (RNCP) released a request for proposals (NIAID-NIH-RFP-NIHAI201800020 ) in 2019, seeking to make a single contract award for “RNCP-Wide Dosimetry Guidance & Monitoring of Sources and Irradiation Protocols”. This funding opportunity requested that offerors develop a consistent means of dosimetry comparison and reproducibility, as well as provide the administrative foundation necessary to facilitate and coordinate dosimetry activities in partnership with the NIAID. Respondents were asked to provide services, facilities, expertise, and capabilities to develop a centralized dosimetry harmonization effort that fits the resources and circumstances of projects across the funded RNCP portfolio. The contract award was made in 2020 to the University of Wisconsin (Principal Investigator Larry DeWerd), who established a harmonization protocol to encompass all the irradiators in use across the RNCP-funded portfolio of grants, contracts, and inter-agency agreements. In 2019, the RNCP also became concerned with the specifics of establishing and reporting neutron dosimetry and convened a “Neutron Radiobiology and Dosimetry Workshop” with presentations from 17 subject matter experts, planned in collaboration with the Department of Defense (DoD), Defense Threat Reduction Agency (DTRA), and the National Aeronautics and Space Administration (NASA). The meeting report that was published in 2021 (Stricklin et al. 2021) explored historical neutron exposure research and highlighted the need for harmonized reporting of exposure and experimental parameters. The authors concluded that efforts should be made to update computer coding for neutron dosimetry estimates, government policies needed to be re-visited in terms of expected radiation energy spectrums, and funding agencies must make key investments in consideration of neutron dosimetry, to improve science and ensure radiation emergency preparedness. All of these early attempts to ensure the use of accurate dosimetry in research laboratories culminated in the current effort to take the next step and require that sufficient information be included in published manuscripts, such that reviewers and editors can be assured that the irradiations were carried out correctly, and readers can have the necessary information to replicate published experiments
Strategic Research Plans for Environmental Radiation Protection Research
No full textInternational audienceThe MEENAS webinar on April 18, 2024, featured a presentation by the European Radioecology ALLIANCE, led by Rodolphe Gilbin and colleagues, on strategic research plans for environmental radiation protection. The presentation highlighted the ALLIANCE’s long-standing mission since its founding in 2009 to coordinate research, address long-term priorities in radioecology, and ensure the field's sustainability. Central to the discussion was the Strategic Research Agenda (SRA), updated in 2019 and published in 2021, which identifies key challenges for advancing radioecology. These include improving the prediction of human and wildlife exposure, understanding ecological consequences under real-world conditions, and integrating risk assessments for human and environmental protection. The presentation also detailed the Joint Roadmap for Radiation Protection, developed collaboratively to address societal needs and optimize radiation protection practices. The ALLIANCE emphasized the importance of fostering education and training to maintain a skilled workforce, as well as the development of shared infrastructures like observatory sites at Chernobyl and Fukushima. Looking ahead, the focus is on adapting to new societal and technological contexts, such as artificial intelligence, novel nuclear technologies, and the integration of environmental health considerations into broader frameworks like the UN Sustainable Development Goals. This presentation underscored the ALLIANCE’s commitment to advancing scientific knowledge and addressing societal challenges in radiation protection