Interband, collective and atomic (p, d) excitations from 2 to 160 eV in Sc, Y, lanthanides and actinides and in some of their compounds by FEELS

Fast electron energy loss spectroscopy (FEELS) is used to obtain the various optical constants over a large energy range in Sc, Sc2O3 , Y, Y2O3, Gd, Gd2O3, Dy, LaF3, GdF3, DyF3, Th, ThF4, U and UF4. For the first time a comprehensive study of the 3p to 6p spectra is performed in the 30-60 eV range, Z varying between 21 and 92. Interesting common features of these resonant p spectra are emphasized and discussed in the light of recent theoretical work. Below 30 eV, strong interband transitions are observed in the wide gap insulators (oxides and fluorides), while the metal spectra are dominated by collective or plasmon excitations. At higher energies, 4d-lanthanide and 5d-actinide spectra are compared with X-UV photoabsorption measurements.L'analyse des spectres de pertes d'énergie des électrons rapides a permis de déterminer dans un domaine d'énergie étendu les diverses constantes optiques des métaux et composés suivants : Sc, Sc2O3, Y, Y 2O3, Gd, Gd2O3, Dy, LaF3, GdF3, DyF3, Th, ThF4, U et UF4. Pour la première fois, une étude d'ensemble des spectres 3p à 6p a été effectuée entre 30 et 60 eV, Z variant de 21 à 92. Des analogies entre ces différents spectres p sont mises en évidence et discutées à la lumière de travaux théoriques récents. En dessous de 30 eV, des transitions interbandes intenses sont observées dans les isolants (sesquioxydes et fluorures), alors que les spectres des métaux sont dominés par des excitations collectives. A plus haute énergie, les spectres 4d des lanthanides et les spectres 5d des actinides sont comparés aux mesures de photoabsorption dans le domaine X-UV

Transient behavior of ASTRID with a gas power conversion system

International audienceThe present article is dedicated to preliminary transient studies carried out for the analysis of the system overall behavior of the ASTRID (Advanced Sodium Technological Reactor for Industrial Demonstration) demonstrator developed in France by CEA and its industrial partners. ASTRID is foreseen to demonstrate the progress made in SFR technology at an industrial scale by qualifying innovative options, some of which still remain open in the areas requiring improvements, especially safety and operability. Among the innovative options, a gas power conversion systems (PCS) is envisaged. In this latter innovative PCS, the working gas is nitrogen whose flow rate delivers power to a turbine driving with the same shaft two compressors (low and high pressure) separated by an intercooler. The other part of the work delivered by the gas is used to drive the alternator that produces electricity. The main objective of such a PCS consists in avoiding physically the possibility of a sodium/water reaction with the secondary circuit but the impact of this PCS on the control of the accidents has also been studied. The main purpose of the studies presented in the paper is to assess the dynamic behavior of ASTRID including a gas PCS with the CATHARE2 code. The first transient presented deals with a loss of off-site power and has been calculated for the gas PCS but also for a classical steam/water PCS for comparison purpose. Then typical transients of gas system have been investigated. Several families of initiating events affecting the PCS are studied: breaches in the ternary circuit, a loss of power supply, a loss of main heat sink and the spurious 1 Corresponding author: [email protected] opening of the turbine bypass valve. Regarding this last transient, sensitivity studies have shown that an adequate design of the turbomachine bypass lines allows a control of the event without shutdown. Moreover, regulating actions following the scram are also investigated in order to take benefit of the PCS in order to remove the decay heat

Fabrication of (u,ce)o2 and (u,am)o2 pellets with controlled porosity from oxide microspheres

International audienc

Fabrication of (U,Ce)O2_2 and (U,Am)O2_2 pellets with controlled porosity from oxide microspheres

International audienc

Implementation of probabilistic assessments to support the ASTRID decay heat removal systems design process

International audienceASTRID, the Advanced Sodium Technological Reactor for Industrial Demonstration, is a GenIV technological demonstrator. Its purpose will be to demonstrate the progress made in the field of Sodium Fast Reactor (SFR) technology on an industrial scale by qualifying innovative options, especially relative to safety and operability. To support the ASTRID design process during the conceptual design phase, probabilistic assessments have been developed since 2012. They are based on the conventional Fault Tree (FT)/Event Tree (ET) approach and on the determination of the minimal decay heat removal (DHR) systems requirement. Limited to a period of one week, without repair of component malfunctions, their goal is to provide probabilistic insights in the assessment of various design choices and to supplement the deterministic approach in the objective of continuous safety improvements throughout the design process. Nevertheless, the conventional FT/ET "static approach", developed for PWRs, appears to be inadequate for SFRs in the objectives of assessing the global risk and contributing to the demonstration of the practical elimination of the situation "loss of DHR function" for longer periods of time. Since DHR systems have to operate during long mission times, PSA modelling must consider the repair possibility, adapt the systems requirement to decay heat evolution and take into account all available systems at any time. Therefore, different dynamic probabilistic approaches are developed in a prospective way to comply with the safety demonstration. A first calculation will be performed by the end of the decade to support the demonstration of practical elimination of the DHR function of ASTRID

Qantitative Approach In Dynamic Parathyroid Scintigraphy And FCH PET For Evaluation Of Parathyroid Vs. Thyroid Anomalies

Annual Congress of the European-Association-of-Nuclear-Medicine, Oct 15-19, 2016, Barcelona, Spai

Qantitative Approach In Dynamic Parathyroid Scintigraphy And FCH PET For Evaluation Of Parathyroid Vs. Thyroid Anomalies

Annual Congress of the European-Association-of-Nuclear-Medicine, Oct 15-19, 2016, Barcelona, Spai