Production of reference sources of radioactive aerosols in filters for proficiency testing

International audienceIn the framework of the organization of proficiency testing, filters with deposits of 137Cs and 90Sr+90Y radioactive aerosols have been submitted to laboratories for radionuclide measurement. Procedures for the special preparation and characterization of filters have been developed. The different steps of filter preparation, determination of the deposited radionuclide activity and characterization of the homogeneity of these deposits are presented. This method of filter preparation can also be used in the production of secondary standards, whose properties are more adapted to the needs of laboratories measuring radioactivity in filters than are the solid sources that they typically use. © 2014 Elsevier Ltd

KI and TEDA influences towards the retention of radiotoxic CH3I by activated carbons

International audienceActivated carbons (ACs) are widely used within the ventilation networks of nuclear facilities to trap volatile iodine species. In this paper, the performances of various commercial activated carbons towards the trapping of γ-labelled methyl iodide were evaluated in semipilot scale under different R.H. according to normalized procedures. A combination between the retention performances and the physico-chemical properties as deduced from several techniques was performed to gain insights about the AC influencing parameters on γ-CH3I capture. Different trends were obtained depending on the impregnant nature and the studied conditions. A high sensitivity of KI/ACs towards water vapor was outlined. At R.H. = 40%. The enhancement of water uptake by KI/ACs as deduced from water adsorption experiments, leads to decrease the available microporosity for CH3I physisorption, inducing therefore the reduction of performances as a function of KI content at these conditions. At R.H. = 90%, the adsorption mechanism was found to be governed by isotopic exchange reaction since 90% of the microporosity was occupied by water molecules. Therefore, a slight increase of DF was obtained in these conditions. This sensitivity was found to be of a lesser extent for TEDA/ACs displaying the highest retention performances whatever the studied condition

Stability of metal–organic frameworks under gamma irradiation

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X‐ray study of freshly emitted carbonaceous nano‐aerosols by synchrotron radiation

International audienceYe

Etude par rayonnement synchrotron X d'aerosols carbonés nanostructures fraichement émis

National audienceN

West Nile virus epizootics in the Camargue (France) in 2015 and reinforcement of surveillance and control networks.

West Nile virus (WNV) infection is a non-contagious disease mainly transmitted by the bites of infected mosquitoes from the genus Culex. The virus is maintained in a mosquito-bird-mosquito cycle, and can accidentally be transmitted to mammalian hosts. Among mammalian hosts, equines and humans are the most sensitive to WNV infection and can develop severe meningoencephalitis. As WNV infections are zoonotic and can be severe in humans and equines, West Nile fever is considered to be a public and animal health concern. After a silent period of almost ten years, WNV re-emerged in France at the periphery of the Camargue area during the summer of 2015, underlining the fact that the Camargue area creates favourable conditions for WNV emergence and amplification in France. The French Network for Epidemiological Surveillance of Equine Diseases (Réseau d'Épidémio-Surveillance en Pathologie Équine [RESPE]) facilitated the early detection of WNV cases in horses. In total, 49 horses were found to be infected; among them, 44 presented clinical signs, 41 with meningoencephalitis and three with hyperthermia only. Six horses among the 41 with nervous symptoms died from the disease or were euthanised (a case fatality rate of 14.6%). The authors describe the characteristics of the 2015 WNV epizootics, the early detection of the first WNV equine cases via the RESPE network and the coordination of WNV surveillance in France

X‐ray study of freshly emitted carbonaceous nano‐aerosols by synchrotron radiation

International audienceYe

Etude par rayonnement synchrotron X d'aerosols carbonés nanostructures fraichement émis

National audienceN