Determining the porosity and water impregnation in irradiated graphite

International audienceImpurities in nuclear graphite can become neutron-activated during operation, generating radionuclides and leading to modifications in the microstructure of the graphite due to fast neutrons. The long-term disposal of nuclear graphite waste requires collecting data on the behaviour of long-lived radionuclides in disposal conditions (water-saturated). The release of radionuclides in solution depends on a number of physicochemical processes such as water ingress into the graphite structure (radionuclides sites), as well as the solubilisation and transport of radionuclides in solution through the graphite pores. Analysis of the impregnation (impregnation speed, impregnation rate) of water in the porous graphite environment represents one of the main parameters that will greatly influence the physicochemical processes controlling the release of radionuclides in solution. For this reason, the impregnation of irradiated samples from the G2 and St Laurent A2 (SLA2) gas-cooled graphite-moderated reactors was studied, as was the distribution of the porosity. Results show that the geometric density of the samples decreases after irradiation, which is expressed as an increase in the total porosity or more precisely in the open porosity. This means that irradiated graphite is mainly a macroporous solid. Nuclear graphite becomes a more hydrophobic material with its open porosity filled by water in just a few days. This is due to the presence of functional groups on the pore surface

Infección de vacas gestantes con una cepa neurotrópica de herpesvirus bovino-1

El Herpesvirus Bovino-1 (HVB-1) es uno de los principales agentes abortigénicos virales del ganado bovino. La aplicación de vacunas preparadas con virus atenuado puede inducir aborto. En América del Sur sólo se emplean vacunas preparadas con virus inactivado, por lo que los abortos atribuidos a HVB-1 se deben a infecciones naturales. Se han descripto tradicionalmente 3 tipos de HVB-1: respiratorio (HVB-1.1.), genital (HVB-1.2, clasificado en 2a y 2b), y neurotrópico (HVB-1.3 , clasificado en 3a y 3b), que se distinguen mediante el uso de anticuerpos monoclonales, análisis de los perfiles de proteínas y ácidos nucleicos virales, aunque la relación signos clínicos-tipo viral no es unívoca. No se ha establecido aún si los 3 suptipos de HVB-1 o sólo algunos de ellos poseen capacidad abortigénica. En este trabajo presentamos los resultados de la inoculación de vacas gestantes en distintos estadios de preñez con la cepa encefalitogénica argentina A-663 (subtipo 1.3b). La infección no indujo aborto, aunque los 5 animales inoculados presentaron signos clínicos (no neurológicos), seroconvirtieron, y secretaron virus correspondiente al subtipo viral inoculado.Palabras claves: Herpevirus Bovino-1, Virus Neurotrópico, Aborto.AbstractBovine Herpesvirus-1 (BHV-1) is the most important viral cause of bovine abortion. Modified live vaccines against this virus are abortigenic, since all BHV-1 vaccines used in South America are inactivated, then abortions attributable to BHV-1 are induced by field strains. BHV-1 isolates belong to one of three subtypes: respiratory (BHV-1.1), genital (BHV-1.2, classified in 2a and 2b), and neurotropic (BHV-1.3, classified in 3a and 3b), which can be distinguished by monoclonal antibodies reactivity, proteins patterns and nucleic asid restriction maps. It is not known whether all three subtypes are abortigenic,or only one or two of them. This paper presents the results of the inoculation of 5 pregnant cows between 17-34 weeks of gestación with the Argentine strain A-663 (subtype 1.3b). One cow was seropositive for BHV-1. The animals showed symptoms of mild disease (non neurological), seroconverted and shed subtype 1.3b virus in their nasal or ocular secretions. No abortions were observed.Key words: Bovine Herpesvirus-1-, Abortion, Neurotropic virus

Infección de vacas gestantes con una cepa neurotrópica de herpesvirus bovino-1

El Herpesvirus Bovino-1 (HVB-1) es uno de los principales agentes abortigénicos virales del ganado bovino. La aplicación de vacunas preparadas con virus atenuado puede inducir aborto. En América del Sur sólo se emplean vacunas preparadas con virus inactivado, por lo que los abortos atribuidos a HVB-1 se deben a infecciones naturales. Se han descripto tradicionalmente 3 tipos de HVB-1: respiratorio (HVB-1.1.), genital (HVB-1.2, clasificado en 2a y 2b), y neurotrópico (HVB-1.3 , clasificado en 3a y 3b), que se distinguen mediante el uso de anticuerpos monoclonales, análisis de los perfiles de proteínas y ácidos nucleicos virales, aunque la relación signos clínicos-tipo viral no es unívoca. No se ha establecido aún si los 3 suptipos de HVB-1 o sólo algunos de ellos poseen capacidad abortigénica. En este trabajo presentamos los resultados de la inoculación de vacas gestantes en distintos estadios de preñez con la cepa encefalitogénica argentina A-663 (subtipo 1.3b). La infección no indujo aborto, aunque los 5 animales inoculados presentaron signos clínicos (no neurológicos), seroconvirtieron, y secretaron virus correspondiente al subtipo viral inoculado.Palabras claves: Herpevirus Bovino-1, Virus Neurotrópico, Aborto.AbstractBovine Herpesvirus-1 (BHV-1) is the most important viral cause of bovine abortion. Modified live vaccines against this virus are abortigenic, since all BHV-1 vaccines used in South America are inactivated, then abortions attributable to BHV-1 are induced by field strains. BHV-1 isolates belong to one of three subtypes: respiratory (BHV-1.1), genital (BHV-1.2, classified in 2a and 2b), and neurotropic (BHV-1.3, classified in 3a and 3b), which can be distinguished by monoclonal antibodies reactivity, proteins patterns and nucleic asid restriction maps. It is not known whether all three subtypes are abortigenic,or only one or two of them. This paper presents the results of the inoculation of 5 pregnant cows between 17-34 weeks of gestación with the Argentine strain A-663 (subtype 1.3b). One cow was seropositive for BHV-1. The animals showed symptoms of mild disease (non neurological), seroconverted and shed subtype 1.3b virus in their nasal or ocular secretions. No abortions were observed.Key words: Bovine Herpesvirus-1-, Abortion, Neurotropic virus

Les défaillances d'interaction dans les accidents impliquant un deux-roues motorisé. Rapport scientifique Tâche 1 (R1)

Rapport de rechercheCe projet a pour ambition d'identifier les différentes facettes de l'insécurité des DRM : du point de vue de l'usager DRM, du point de vue des autres usagers et du point de vue de l'infrastructure routière. Il s'appuie sur trois approches complémentaires : L'analyse des accidents de deux-roues à partir de données EDA (Etudes Détaillées d'Accidents) et d'exploitations de procédures (Procès-Verbaux) ; L'analyse comportementale des situations de conduite en deux-roues en interaction avec les autres usagers ; L'analyse des représentations réciproques des usagers de deux-roues et des autres usagers.ANR / Predit / Projet "2RM" 2006-2008 : Accidentologie, Usage et Représentation des Deux-Roues Motorisés. Partenariat : INRETS-MA, LAB-GIE PSA/Renaul