Institute for Radiation Protection and Nuclear Safety (IRSN)
Not a member yet
7928 research outputs found
Sort by
A new milestone for ultra-low 236 U/ 238 U isotope ratio measurements by ICP-MS/MS in environmental samples
No full textInternational audienceThe study presents a breakthrough in measuring ultra-low 236U/238U isotope ratios in environmental samples using the latest generation of ICP-MS/MS (Agilent 8900). Uranium-236 is a key isotope for tracing uranium sources due to the large variations of its ratio with uranium-238, depending on whether it comes from natural background, ore, or global fallout. Detecting 236U is challenging because of its very low abundance, requiring highly sensitive instrumentation.By operating in UO₂⁺ mode and combining the ICP-MS/MS with an advanced desolvation system (APEX Ω) and oxygen in the collision/reaction cell, the team achieved a major improvement: significantly increased sensitivity (4.3×10⁶ cps/ppb) and extremely low hydride formation (7.2×10⁻¹⁰).For the first time, the technique allowed precise measurement of 236U/238U ratios down to 10⁻¹¹, validated with certified reference materials and environmental samples compared to accelerator mass spectrometry (AMS). This milestone opens new possibilities for geochemical, environmental, and nuclear forensic applications
RENEB interlaboratory comparison for biological dosimetry based on dicentric chromosome analysis and cobalt-60 exposures higher than 2.5 Gy
No full textInternational audienceIn previous RENEB interlaboratory comparisons based on the manual scoring of dicentric chromosomes, a tendency for systematic overestimation for doses > 2.5 Gy was found. However, these exercises included only very few doses in the high dose range, and they were heterogeneous in terms of radiation quality and evaluation mode, and comparable only to a limited extent. Here, this presumed deviation was explored by investigating three doses > 2.5 Gy. Blood samples were irradiated (2.56, 3.41 and 4.54 Gy) using a 60Co source and sent to 14 member laboratories of the RENEB network, which performed the dicentric chromosome assay (manual and/or semi-automatic scoring) and reported dose estimates. Most participants provided estimates that agreed very well with the physical reference doses and all provided dose estimates were in the correct clinical category (> 2 Gy). The previously observed tendency for a systematic bias across all laboratories was not confirmed. However, tendencies for systematic underestimation were detected for dose estimations for reference doses given in terms of absorbed dose to blood and for some participants, a laboratory-specific trend of systematic under- or overestimation was observed. The importance of regularly performed quality checks for a broad dose range became obvious to avoid misinterpretation of results
Modélisation de la composition des matières en suspension et des contaminants associés par réseaux de neurones: Applications au Rhône
No full textInternational audienc
Vieillissement des charbons actifs dans le contexte de l’industrie nucléaire
No full textInternational audienceDes charbons actifs (CA) co-imprégnés de triéthylènediamine (TEDA) et d'iodure de potassium (KI) sont utilisés dans les installations nucléaires pour piéger les espèces iodées volatiles (I2 et CH3I). Les performances d’adsorption des CA diminuent au cours du temps en raison des phénomènes de vieillissement (oxydation, empoisonnement). Cependant, des incertitudes subsistent quant aux mécanismes de dégradation mis en jeu. La présente étude vise à étudier l'effet des conditions opératoires sur la cinétique de dégradation tout en donnant des éléments sur les mécanismes de vieillissement
Turbulent entrainment in buoyant releases from horizontal gravity current to vertical planar wall plume
No full textInternational audienceThis paper examines the dynamics of a supercritical, steady, miscible, two-dimensional gravity current flowing along an inclined boundary, with a particular focus on the entrainment, which refers to the mixing between the gravity current and the surrounding fluid. Specifically, the study investigates the combined effects of the Richardson number Ri and slope θ on the entrainment coefficient E. To address these objectives, a theoretical study and large-eddy simulations (LES) were conducted, varying the slope angle from 0 • to 90 • , while maintaining constant injection conditions.The theoretical investigation of gravity currents resulted in the extension of the theoretical model of Ellison and Turner (1959) in the general non-Boussinesq case as well as the identification of two specific angles: the critical angle θ c , beyond which no transition between supercritical to subcritical behaviour is observed, and the supercritical angle θ sc , above which the flow acquires inertia immediately after injection.On the other hand, the simulations revealed three distinct flow regimes for our source conditions. The first regime, observed at low slopes, exhibits a non-monotonic behavior, characterized by a transition from a supercritical to a subcritical regime. The second regime, related to the critical angle θ c , occurs at intermediate slopes, where the flow remains inertial throughout. In the third regime, related to steeper slopes, the supercritical angle θ sc has been exceeded and the flow immediately gains inertia upon injection. The simulations also enabled an analysis of E, which was found to increase with slope and reach a constant value at θ = 90 • .Moreover, a new entrainment law was developed, incorporating both the effects of the Richardson number and the slope: E = 0.002 cos(θ)/Ri + 0.09 sin 1/2 (θ). This law provides a description of the entrainment behavior across the full range of slope angles. Comparisons between the LES results and the theoretical model demonstrate that the proposed entrainment law offers improved accuracy over existing models for all slope configurations, including the extreme cases of gravity currents (θ = 0 • ) and planar wall plumes (θ = 90 • ).</p
Extreme skew surge estimation combining systematic skew surges and historical record sea levels on the English Channel and North Sea coasts
No full textInternational audienceCoastal planning implies the estimation of extreme sea levels. As the distribution of astronomical high tides can be predicted, most recent publications suggest focusing on the estimation of extreme skew surges. Historical information, record sea levels observed before the beginning of systematic tide gauge recordings, can improve estimations. The corresponding skew surges can be estimated but are not necessarily exhaustive. Indeed, some historical extreme skew surges can remain unnoticed if they are combined with low or moderate tides, or for a variety of reasons. To deal with this exhaustiveness issue, a previous publication proposed an unbiased method for combining systematic period skew surges with historical period extreme sea levels. This method appeared more reliable than previously proposed approaches. The present study aims at presenting a broader evaluation of this method, based on its application to nine sites located on the English Channel and North Sea coasts. The method is also improved to consider several historical periods and various types of historical information. Results confirm the method to be reliable, useful, and relevant. A number of recommendations is also formulated for the selection and use of historical information for sea level frequency analyses
Metabolomics identifies plasma biomarkers of localized radiation injury
No full textInternational audienceA radiological accident may result in the development of a local skin radiation injury (LRI) which may evolve, depending on the dose, from dry desquamation to deep ulceration and necrosis through unpredictable inflammatory waves. Therefore, early diagnosis of victims of LRI is crucial for improving medical care efficiency. This preclinical study aims to identify circulating metabolites as biomarkers associated with LRI using a C57BL/6J mouse model of hind limb irradiation. More precisely, two independent mice cohorts were used to conduct a broad-spectrum profiling study followed by a suspect screening analysis performed on plasma metabolites by mass spectrometry. An integrative analysis was conducted through a multi-block sparse partial least square discriminant analysis (sPLS-DA) to establish multi-scale correlations between specific metabolites levels and biological, physiological (injury severity), and functional parameters (skin perfusion). The identified biomarker signature consists in a 6-metabolite panel including putrescine, uracil, 2,3-dihydroxybenzoate, 3-hydroxybenzoate, L-alanine and pyroglutamate, that can discriminate mice according to radiation dose and injury severity. Our results demonstrate relevant molecular signature associated with LRI in mice and support the use of plasma metabolites as suitable molecular biomarkers for LRI prognosis and diagnosis
Shifting visions of human performance improvement tools − Risks and potential outcomes
No full textInternational audienceThe purpose of human performance improvement (HPI) tools is to guide and control human behaviour in operational settings in order to reduce the risk of errors inherent to operational activities and the conditions under which they are carried out. These tools are increasingly common in high-risk industries, but their systematisation raises several questions. This paper addresses the policies driving the implementation of these practices, their theoretical foundations, and the assumptions upon which these are based. It also reviews strategies used in the rollout and implementation of these practices. Our analysis reveals several potential weaknesses as well as a shift in the way HPI tools are promoted and deployed
Efficiency of porous adsorbents for the selective trapping of I2/CH3I in the presence of a large excess of contaminants
No full textInternational audienceThe nuclear fuel reprocessing industry releases radioactive isotopes into the environmentnotably xenon, krypton and iodine. Among these radionuclides, iodine is highly toxic, mobile andvolatile in the environment. For radioprotection reasons, it is crucial to develop an innovative iodinetrap. As part of the SPECIOSA project, IRSN aims to develop a specific atmospheric samplingdevice for iodine release monitoring into the environment, ensuring the speciation of physicochemical forms (I2 and CH3I). On the one hand, several commercial porous adsorbents (mesoporoussilica, zeolite and activated carbon) were tested for the I2 adsorption in liquid phase. Moreparticularly, silica and zeolites doping with triethylenediamine (TEDA) and copper was achieved toenhance the affinity towards I2 at the expense of CH3I. The obtained adsorption isotherms for I2 inthe liquid phase for these doped materials follow the Langmuir model (Fig.1 A), indicatingtherefore monolayer and homogenous I2 adsorption. Promising performances were also noticedespecially for the TEDA-doped silica material in terms of both adsorption capacities and trappingaffinity. On the other hand, innovative and industrializable MOF formulations are synthesized atUCCS Lille. The obtained powders are shaped by extrusion and spheronization protocols beforefurther tests in gaseous phase (Fig.1 B and C). The extrudates powders were successfully testedwith I2 in the gas phase, showing encouraging performances. The relevant candidates will be testedfor CH3I capture as well as for I2 under more challenging conditions in agreement with the desiredcontext
EURADOS/REMPAN Review on Monitoring and Dosimetry for Radionuclide-contaminated Wounds
No full textInternational audienceThe European Radiation Dosimetry Group (EURADOS) and the WHO's Radiation Emergency Medical Preparedness and Assistance Network (REMPAN) have collaborated to review best practices for managing radionuclide intakes through wounds. Rapid response and decisions on wound decontamination, tissue excision, and chelation therapy are based on measurements of the exposed individual and preliminary dose assessments using reasonable default assumptions. The goal is to minimize exposure, prevent tissue reactions, and reduce the risk of stochastic effects.The management of a contaminated wound is always case-specific, but some general procedures typically apply for a proper evaluation of the contamination case. Medical doctors (surgeons and toxicologists) and internal dosimetrists should work together in the management of the contaminated wound case, with internal dosimetrists providing expert advice to aid clinical decision-making and communication with the patient and his/her family. The ISO standard 20031:2020 provides guidelines on the monitoring and dosimetry for internal exposures due to wound contamination with radionuclides. The Clinical Decision Guide was proposed by the National Council on Radiation Protection and Measurements in its Report 161 to assist physicians in making treatment decisions for individuals with internal radionuclide intakes. Best practices for medical treatment, based on previous experience, are presented here.A joint project was carried out as a collaboration between the European Radiation Dosimetry Group (EURADOS e.V.) 1 and the WHO Radiation Emergency Medical Preparedness and Assistance Network (WHO REMPAN) to review the status of monitoring, dose assessment, and medical management of workers internally contaminated through wounds.Management of a wound contamination case requires reliable knowledge of the exposure scenario, including the time of intake, the radionuclide(s) involved, the physical and chemical form of the radioactive compound, and the location and extent of the contaminated area.A monitoring program should be established soon after the incident identification according to the wound event, to perform direct measurements at the wound site, in vivo whole body/organ measurements and/or in vitro excreta analysis, to determine local activity in the wound, and to estimate systemic contamination.ISO provides guidelines on monitoring and dosimetry for internal exposures due to wound contamination with radionuclides 2 . Available information on wound monitoring will help make decisions on the clinical management of the case, mainly on decontamination, surgical excision, and decorporation therapy.NCRP Report No. 161 3 provides guidance to those who must respond to radionuclide contamination incidents. The objective is an adequate medical management of individuals exposed to and potentially contaminated with radionuclides in such incidents.</p