Countercurrent reactor design and flowsheet for iodine-sulfur thermochemical water splitting process

A conceptual design is presented for the I/S process for the production of hydrogen using a high-temperature nuclear heat source to split water. The process includes a countercurrent reactor being developed by CEA within the framework of an international collaboration (I-NERI project) with DOE at General Atomics (San Diego, CA). A ProsimPlus? model of the flowsheet indicates 600 kJ high-temperature heat and 69 kJ electric power are consumed per mole of H₂ product (with an assumed pressure of 120 bars). The net thermal efficiency would be 38% (HHV basis) if electric power is available at a conversion efficiency of 45%.     

The effect of bovine whey proteins on the ability of poliovirus and Coxsackie virus to infect Vero cell cultures

The antiviral activity of esterified whey proteins (IC₅₀=20–40 μg mL⁻¹) observed against poliovirus type-1 and Coxsackie virus B6 infecting Vero cells depended on five factors (in order of importance): concentration of esterified proteins, multiplicity of infection, duration of incubation, timing of esterified proteins addition after infection, and extent of esterification of proteins. Renewal of cell growth medium after 24 h of incubation with new medium containing the same amount of esterified proteins enhanced the anti Coxsackie virus effect. Difference between start of infection of the reporter Vero cells and the time of addition of esterified proteins significantly decreased their antiviral efficacies. The poliovirus titer reduced gradually in response to the increase of the concentrations of esterified proteins. The relative amounts of viral RNA were less affected by the esterified proteins concentration than was the virus infectious titer, indicating that inhibitory proteins may slow down viral multiplication, yielding reduced amounts of viral RNA.     

Low and intermediate level waste management in EDF PWRs

This paper aims to explain how Electricité de France as owner and plant operator of nuclear power stations generating wastes has improved its management to meet its obligations which are the protection of man and preservation of the environment. Beyond the technical aspects (reducing liquid effluents and sorting waste at source for example) which have led to a significant decrease of radioactive waste volumes, continued success depends on planned management initiatives. These include computerized waste management and will be completed finally by setting up centralized treatment methods such as fusion and incineration. To provide packages in accordance with French specifications for final near-surface disposal, EDF has applied the same quality approach to radioactive waste management as that used for other operating actions. Management decisions taken mainly coordinate around two axes, namely "Accountability" and "organisation".     

Acoustic, piezoelectric, and dielectric nonlinearities of AlN in coupled resonator filters for high RF power levels

Coupled resonator filters (CRFs) are the new generation of BAW filters recently designed for the front-end modules of mobile transmission systems. Looking for designers' requirements, CRF devices have been characterized and modeled. The model based on equivalent circuits relies on material constants such as stiffness and electro-coupling coefficients, and works only for linear-mode propagation. Because of their positions between antennas and power amplifiers, they often work under high RF power, inducing nonlinear response in the AlN piezoelectric layer. In this work, we analyze for the first time the nonlinear behavior of AlN material particularly for coupled BAW resonators. To characterize the nonlinear effects in CRFs, we measure the 1-dB gain compression point (P1dB) and the intercept point (IP(3)). Then, we develop a nonlinear model of CRFs using harmonic balance (HB) simulation in commercially available software. The HB environment allows fitting simulations to measurements in terms of P(1dB) and IP(3). We find that a high RF power induces nonlinear changes in the material constants' real parts: elastic stiffness c(33) (4.9%), piezoelectric e(33) (17.4%), and permittivity ?(33) (5.2%). These nonlinear variations of material constants describe the nonlinear behavior of CRF devices using the same deposit process for AlN material.     

Selective Oligomerization of Glycerol Over Mesoporous Catalysts

In the general context of the development of the use of agricultural products for nonfood applications, particularly in the field of glycerol valorization (coproduct of triglyceride hydrolysis and methanolysis processes), the selective etherification of glycerol to di- and triglycerol was studied. Part of this study consisted in the synthesis and the modification, by different techniques, of cesium containing mesoporous solids of the MCM-41 type in order to make them active, selective and stable catalysts for the target reaction. The catalytic results obtained show that the impregnation method gives the highest activity. Concerning the selectivity of the modified mesoporous catalysts, the best values to (di- + tri-) glycerol (>90%) are obtained over solids prepared by the impregnating or the grafting methods. The cesium-impregnated catalysts can be reused without loss of selectivity. In the presence of lanthanum- or magnesium-containing catalysts, the glycerol dehydration to acrolein is important, whereas this unwanted product is not formed when cesium is used as promoter. Moreover, when compared to homogeneous catalysts, the mesoporous solids induce a different regioselectivity. Finally, as far as the catalyst leaching and stability is concerned, the best results are obtained with the grafted solids, which retain their structure and their specific area after the promoter addition or incorporation. Such property is not observed over impregnated catalysts.     

Influence of δ phase precipitation on the stress corrosion cracking resistance of alloy 718 in PWR primary water

The negative influence of δ phase on the intergranular stress corrosion cracking (IGSCC) resistance of alloy 718 is commonly taken for granted. In addition, δ phase formed at low temperature (about 1023 K) do not present the same characteristics than the one formed at higher temperatures (from 1173 to 1273 K). The aim of the present study is then to understand how δ phase precipitation could enhance crack initiation in alloy 718, whatever the form of δ phase is. For that purpose, several heat treatments leading to δ phase precipitation were realized on two alloy 718 heats, one sensitive to IGSCC and the second not. Specific slow strain rate tensile tests carried out on thin tensile specimens in simulated PWR primary medium at 633 K conclusively prove that δ phase has no effect on the intrinsic sensitivity to intergranular crack initiation of tested heats.     

Réalisation de filtres multidiélectriques sur un substrat biréfringent,déformable et de faible épaisseur (mylar)

La répartition spectrale d'un filtre interférentiel à bande étroite est fixée par le type d'empilement et le choix des diélectriques.Nous étudions une technique qui permet de changer le pouvoir de transmission d'un filtre terminé, en faisant varier l'épaisseur optique du substrat. Ce substrat, qui fait partie intégrante du filtre, est élastique et biréfringent. Cette variation peut être obtenue soit par déformation élastique du substrat qui entraîne une modification de l'épaisseur mécanique, soit par utilisation d'un polariseur qui permet de changer la valeur de l'indice utilisé.     

DIVA: Recognition of typical situations for turbine generator diagnosis

DIVA is an expert system for turbine generator diagnosis. Its aim is to help a plant operator interpret vibration evolution to diagnose developing faults. Interpretation of vibration evolution is primarily a recognition process which is achieved by a particular model of heuristic classification. DIVA tries to recognize the observed situation among a hierarchy of typical situations.The purpose of this paper is to present the model we used for heuristic classification, based on prototypes. Prototypes represent typical problem situations and may also be seen as experts with special knowledge of what to do in such situations. We argue that this model presents significant advantages to deal with complex problems such as vibration surveillance.     

Calcul d'energie de fautes d'empilement dans le dioxyde d'uranium

Energy computations of some (100), (110) and (111), planar defects were performed using an ionic bond model for stoichiometric uranium dioxyde. The repulsive contribution to the fault was estimated in two different ways, i.e. using the Born-Mayer classical treatment, or potentials derived from shell model calculations. The stability of the various defect configurations has been studied; on the basis of our numerical values, we may conclude that dislocation dissociation is unlikely in stoichiometric uranium dioxyde.