Institute for Radiation Protection and Nuclear Safety (IRSN)
Not a member yet
7928 research outputs found
Sort by
Les missions de l'équipe HAL-IRSN
No full textInternational audienceDoctorants, chercheurs, responsables, nous sommes à votre service
Découvrir la collection thèse disponible en libre accès sur le portail HAL-IRSN
No full textInternational audienceLe portail institutionnel de l’archive ouverte hal permet d’assurer le libre accès aux productions scientifiques de l’institut que sont les articles scientifiques mais aussi les thèses de doctorats
Calibration curve for radiation dose estimation using FDXR gene expression biodosimetry – premises and pitfalls
No full textInternational audienceRadiation-induced alterations in gene expression show great promise for dose reconstruction and for severity prediction of acute health effects. Among several genes explored as potential biomarkers, FDXR is widely used due to high upregulation in white blood cells following radiation exposure. Nonetheless, the absence of a standardized protocols for gene expression-based biodosimetry is a notable gap that warrants attention to enhance the accuracy, reproducibility and reliability. The objective of this study was to evaluate the sensitivity of transcriptional biodosimetry to differences in protocols used by different laboratories and establish guidelines for the calculation of calibration curve using FDXR expression data.Material and Methods: Two sets of irradiated blood samples generated during RENEB exercise were used. The first included samples irradiated with known doses including: 0, 0.25, 0.5, 1, 2, 3 and 4Gy. The second set consisted of three ‘blind’ samples irradiated with 1.8Gy, 0.4Gy and a sham-irradiated sample. After irradiation, samples were incubated at 37°C over 24h and sent to participating laboratories, where RNA isolation and FDXR expression analysis by qPCR were performed using sets of primers/probes and reference genes specific for each laboratory. Calibration curves based on FDXR expression data were generated using non-linear and linear regression and used for dose estimation of ‘blind’ samples.Results: Dose estimates for sham-irradiated sample (0.020–0.024Gy) and sample irradiated with 0.4Gy (0.369–0.381Gy) showed remarkable consistency across all laboratories, closely approximating the true doses regardless variation in primers/probes and reference genes used. For sample irradiated with 1.8Gy the dose estimates were less precise (1.198–2.011Gy) but remained within an acceptable margin for triage within the context of high dose range.Conclusion: Methodological differences in reference genes and primers/probes used for FDXR expression measurement do not have a significant impact on the dose estimates generated, provided that all reference genes performed as expected and the primers/probes target a similar set of transcript variants. The preferred method for constructing a calibration curve based on FDXR expression data involves employing linear regression to establish a function that describes the relationship between the logarithm of absorbed dose and FDXR ΔCt values. However, one should be careful with using non-irradiated sample data as these cannot be accurately represented on a logarithmic scale. A standard curve generated using this approach can give reliable dose estimations in a dose range from 50 mGy to 4Gy at least
The Wind‐Blown Sand Experiment in the Empty Quarter Desert: Roughness Length and Saltation Characteristics
No full textInternational audienceThe Empty Quarter Desert, one of Earth's major dust sources, frequently experiences dust storms due to wind erosion. Despite its significance as a primary dust source on a global scale, in‐situ observations from this region had not been reported until very recently. In summer 2022, the WInd‐blown Sand Experiment (WISE) Phase‐1 was initiated in the Empty Quarter Desert of the United Arab Emirates, and continued until 7 February 2023. Utilizing a diverse array of instruments, we measured winds, temperature, humidity, radiation fluxes, saltation, and the physical and optical properties of dust aerosols, atmospheric electric fields, and soil characteristics. A total of 38 distinct sand‐saltation events were recorded from September 2022 to February 2023, with activity peaking between 13:00 and 14:00 local time. Key findings include the identification of dominant wind patterns, and the measurement of the average aerodynamic roughness length ( z 0 ) at 0.8 ± 0.6 mm, and the thermal roughness length ( z h ) at 0.3 ± 0.5 mm—the first estimation of z h for this area. In‐situ observations revealed that dust particle concentrations near the surface increased 1.7‐fold on days with saltation compared to days without it. Moreover, we determined a wind‐speed threshold for initiating saltation at 7.70 m s −1 . This comprehensive data set significantly advances our understanding of atmospheric‐soil interactions and sand movement dynamics, providing invaluable insights for ongoing research into desert environments and the global dust cycle
Review of chemical models and applications in Geant4‐DNA: Report from the ESA BioRad III Project
No full textInternational audienceA chemistry module has been implemented in Geant4‐DNA since Geant4 version 10.1 to simulate the radiolysis of water after irradiation. It has been used in a number of applications, including the calculation of G‐values and early DNA damage, allowing the comparison with experimental data. Since the first version, numerous modifications have been made to the module to improve the computational efficiency and extend the simulation to homogeneous kinetics in bulk solution. With these new developments, new applications have been proposed and released as Geant4 examples, showing how to use chemical processes and models. This work reviews the models implemented and application developments for modeling water radiolysis in Geant4‐DNA as reported in the ESA BioRad III Project
Premières mesures des flux de dépôts humides de chlore 36 (Cl) à proximité de l'usine de retraitement nucléaire Orano La Hague en France
No full textInternational audienceChlorine 36 (Cl) is a radionuclide of natural and anthropogenic origin, mainly used as a tracer in geochemical studies. Owing to analytical constraints and its low environmental levels, knowledge of Cl behavior in the environment is still very limited. In this study, we use environmental measurements to report for the first time the wet deposition fluxes of Cl downwind an anthropogenic source, the Orano nuclear reprocessing plant, which chronically emits Cl into the environment. Measurements of Cl in rainwater samples at our study site were 1–2 orders of magnitude above the environmental background. The isotope ratios Cl/Cl of the samples and the Cl content in the rainwater averaged 2.3x10 at.at and 1.7x10 at.l respectively. A decrease in these levels was observed 20 km away from the study site, outside the plant's gas plume, indicating that the marking of Cl on the study site is related to the plant discharges. Over the sampling period, wet deposition fluxes at the study site averaged 3.4x10 at ms, with significant values measured when precipitations scavenge the plant's gas plume down onto our study site. Analysis of these fluxes also revealed the presence of a significant rainout phenomenon in the study area. These results provide new data on the wet deposition flux of Cl and will thus enable better assessment of impact studies in a context of decommissioning or accidents involving nuclear power plants.Le chlore 36 (Cl) est un radionucléide d'origine naturelle et anthropique, principalement utilisé comme traceur dans les études géochimiques. En raison de contraintes analytiques et de ses faibles niveaux environnementaux, les connaissances sur le comportement du Cl dans l'environnement sont encore très limitées. Dans cette étude, nous utilisons des mesures environnementales pour rapporter pour la première fois les flux de dépôts humides de Cl sous le vent d'une source anthropogénique, l'usine de retraitement nucléaire Orano, qui émet chroniquement du Cl dans l'environnement. Les mesures de Cl dans les échantillons d'eau de pluie sur notre site d'étude étaient supérieures de 1 à 2 ordres de grandeur au bruit de fond environnemental. Les rapports isotopiques Cl/Cl des échantillons et la teneur en Cl de l'eau de pluie étaient en moyenne de 2,3x10 at.at et de 1,7x10 at.l respectivement. Une diminution de ces niveaux a été observée à 20 km du site d'étude, en dehors du panache gazeux de l'usine, ce qui indique que le marquage du Cl sur le site d'étude est lié aux rejets de l'usine. Sur la période d'échantillonnage, les flux de dépôts humides sur le site d'étude ont été en moyenne de 3,4x10 at ms, avec des valeurs significatives mesurées lorsque les précipitations lessivent le panache gazeux de l'usine vers notre site d'étude. L'analyse de ces flux a également révélé la présence d'un phénomène de rainout important dans la zone d'étude. Ces résultats fournissent de nouvelles données sur le flux de dépôt humide de Cl et permettront ainsi de mieux évaluer les études d'impact dans un contexte de démantèlement ou d'accidents impliquant des centrales nucléaires
Characterizing the main sources of radiocesium using 135Cs/137Cs ratio
No full textInternational audienceSeveral decades after the releases, man-made 137Cs still occurs in both the terrestrial and aquatic environments. Such a persistance is not only due to the radioactive period of this radionuclide (halflife = 30.08 y), but also to its strong retention by the clay minerals which makes radiocesium ubiquoulsy present in both the soils and the sediments. While the isotopic signatures of the actinides (e.g., uranium and plutonium) have been used successfully to distinguish the contributions of various sources of nuclides, radiocesium isotopic fingerprint has not yet been applied routinely for source identification. In the current work it is assumed that each anthropogenic source of 137Cs ischaracterized by a specific 135Cs/137Cs ratio and thereby this latter can be used in the frame of theenvironmental monitoring programs or the studies of the transfer in the environment.Thus the present work aims at determining the cesium isotopes ratios in some environmental samples representative of the main sources of 137Cs. The determination of the signatures of the main sources is of primary importance since they constitute the end-members of the mixing equationused to determine the proportion of each source.Before any environmental analysis, a selective radiochemical protocol to separate Cs fraction from the environmental samples (such as soils and sediments) and an innovative ICP-MS/MS method for the 135Cs/137Cs ratio measurement have been developed. Then radiocesium isotopes emmited in the atmosphere by the former nuclear weapons tests and the Chernobyl accident were characterized in the soils and the sediments taken in the central part of the Pyrenees (135Cs/137Cs = 4.29 decay corrected to 2022) and in the south of the Alps (135Cs/137Cs = 0.66) respectively, assuming a long range transport of radioactive contaminations in the atmosphere before deposition with rain/snow on the both studied areas. An attempt is also made to characterizea third source, namely radiocesium isotopes routinely released by the nuclear industry by analysing sediments and aquatic vegetals taken in the Rhine river which hosts four nuclear power plants, even if two of them are now shut-down
Editorial: Advances in the environmental distribution of less studied elements
No full textEditorialInternational audienceThis Research Topic focused on the advancements in our understanding of theenvironmental processes governing the transport and fate of several elements within naturalbiogeochemical cycles. The target elements were a group characterized by potentialenvironmental impacts, including emerging contaminants (e.g., critical elements) andradionuclides
Radiolysis of bituminized radioactive waste: a comprehensive review
No full textInternational audienceIn the realm of radioactive waste management, the impact of radiolysis on bitumen and bituminized radioactive waste also called bituminized waste product (BWP) is considered one of the most significant factors influencing structural changes and the generation of radiolysis gas bubbles. This review provides a comprehensive overview of several studies that have explored the intricate interaction between radiation and various types of bitumen, to gain a better understanding of how such waste ages when exposed to radiation. While these studies provide insights into the diverse effects of radiolysis on bitumen, they also highlight numerous unanswered questions. The absence of gas bubbles does not necessarily indicate an absence of gas production, leaving further research to be undertaken. The complexities of bitumen radiolysis offer multiple avenues for future investigation, aiming to enhance our understanding and provide comprehensive solutions for bituminous radioactive waste management. Among the studied types of bitumen, blown R85/40 bitumen and straight-run distilled bitumen with a penetration grade of 70/100 stands out due to their widespread use in immobilizing co-precipitated radioactive sludges. These bituminous matrices play an essential role in understanding the broader implications of radiolysis within the context of bituminous waste management. This review underscores the significance of further research into radiolysis and bitumen ageing, emphasizing the need for a more in-depth exploration of these complex phenomena and their implications for the long-term safety and efficacy of repositories and disposal facilities
Rheological investigation of bitumen, used for radioactive waste conditioning, with ultrasonic waves
No full textInternational audienceIn the context of bituminized radioactive waste storage and disposal, nucleation monitoring at room temperature and radiolysis bubbles migration at elevated temperature is crucial particularly in fire scenarios where bubble may impact thermal properties. Traditional methods are limited by the opacity of bitumen. To gain a deeper insight into bitumen rheology and ultrasonic wave propagation, we conducted a pilot study using ultrasonic testing cells spanning temperatures from 10°C to 60°C. Ultrasonic velocities and attenuations were measured at around 500 kHz in a 70/100 grade bitumen. Rheological information was deduced with the Time-Temperature Superposition principle and a behaviour model was proposed to describe bitumen across a wide frequency range. Notably, our study reveals a transition point around 50°C to 60°C, where bitumen’s liquid behaviour becomes dominant. The shear-thinning characteristics gradually give way to a more Newtonian response. Using the proposed model, ultrasonic attenuation and viscosity were estimated at 110°C. Acceptable ultrasonic frequencies for monitoring the nucleation and migration of radiolysis bubbles are discussed for future investigations. These findings have significant implications for safety measures and a deeper understanding of bitumen response within the realm of radioactive waste management