Operating a full tungsten actively cooled tokamak: overview of WEST first phase of operation

WEST is an MA class superconducting, actively cooled, full tungsten (W) tokamak, designed to operate in long pulses up to 1000 s. In support of ITER operation and DEMO conceptual activities, key missions of WEST are: (i) qualification of high heat flux plasma-facing components in integrating both technological and physics aspects in relevant heat and particle exhaust conditions, particularly for the tungsten monoblocks foreseen in ITER divertor; (ii) integrated steady-state operation at high confinement, with a focus on power exhaust issues. During the phase 1 of operation (2017–2020), a set of actively cooled ITER-grade plasma facing unit prototypes was integrated into the inertially cooled W coated startup lower divertor. Up to 8.8 MW of RF power has been coupled to the plasma and divertor heat flux of up to 6 MW m−2 were reached. Long pulse operation was started, using the upper actively cooled divertor, with a discharge of about 1 min achieved. This paper gives an overview of the results achieved in phase 1. Perspectives for phase 2, operating with the full capability of the device with the complete ITER-grade actively cooled lower divertor, are also described

High reliability high voltage fast switches

International audienceIn France, one joint program between Commissariat à l'Energie Atomique (C.E.A.) for the research part and COGEMA for the industrial application is the development of the Uranium Vapor Laser Isotopic Separation (SILVA). The Power Electronic Laboratory from the C.E.A. in Pierrelatte is in charge of development on power supplies for Copper Vapor Lasers. For this specific application, the association of thousands of small standard components on printed circuit board is a cost-effective and reliable solution. We will explain why this solution is a costeffective and high-performance one for this application. Moreover, we will see that, in our particular case, the serial connection of a large number of components provides a very high reliability without over-cost

Short circuit of a high voltage high current MOSFET MATRIX Switch

International audienceIn France, one joint program between Commissariat à l'Energie Atomique (C.E.A.) for the research part and COGEMA for the industrial application is the development of the Uranium Vapor Laser Isotopic Separation (SILVA). The Power Electronic Laboratory from the C.E.A. in Pierrelatte is in charge of development on power supplies for Copper Vapor Lasers. For this application, the strategy of the laboratory is the association of thousands of small standard components on printed circuit board as a cost-effective high performance and reliable solution. For PCIM, in 1999, [1] we presented a Keynote-paper about the strategy of the laboratory and we gave an overview of some different switches with MOSFETs, IGBTs, Thyristors, Diodes and nanosecond switches with standard MOSFETs. The three first switches are very fast turnon switches for capacitor lines or pulse forming network discharge applications. These three switches are not designed to switch off a high level of current. For high voltage very fast applications, turn-off switches are very difficult because of short circuit. The inductance is low, so it is necessary for the switch to limit the current and to open this short-circuit current. Now, we have a new fast 500 A MOSFETs MATRIX switch for high voltage modulator with a very good short-circuit behavior. We present this new switch :-500 A 10 kV module switch short circuit behavior high voltage fast modulator design some industrial applications

Serial connected active voltage clamping

International audienceThe new post project for uranium enrichment SILVA needs specific power converters. The LETC laboratory of the C.E.A. in Pierrelatte has been studying these since 5 years. The aim of this laboratory consists in developing high voltage solid-state converters using a large number of small standard solidstate components (MOSFETs, IGBTs, thyristors and diodes) connected in series. In these associations, voltage balancement system are not used, but the voltage is limited on each stage in its safety area by clamping protection. This paper describes different voltage clamping systems, active clamping technique and their association in series

Spécificités de l'électronique de puissance pour le photovoltaïque connecté au réseau

EPF 200

Champ électrique pulsé haute tension pour le traitement de l'eau et la conservation des aliments

International audience-Les cellules biologiques sont constituées d'un cytoplasme qui est conducteur électrique, entouré d'une membrane, qui est isolante électriquement. L'application d'un champ électrique pulsé permet de percer la membrane de la cellule de manière réversible ou mortelle. Nous présenterons les applications de cette électroporation dans les domaines du génie génétique, de l'extraction de composés, de l'agroalimentaire et du traitement des eaux, puis nous décrirons les deux technologies de générateurs électriques pulsés pour le traitement des eaux et l'agro-alimentaire développés par Centralp Enertronic, en collaboration avec le CEA et l'ESIM, pour EDF-DER (Département Etude et Recherche) et pour l'Unité de Biochimie-Technologie alimentaire de Montpellier [1]. Un générateur bipolaire basé sur un nouveau commutateur à matrice de transistors MOS supportant le court-circuit en haute tension est décrit

Benchmark of Coupling Codes (ALOHA, TOPLHA, and GRILL3D) with ITER Lower Hybrid Antenna

In order to assist the design of the future ITER Lower Hybrid launcher, coupling codes ALOHA, from CEA Cadarache, TOPLHA, from Politecnico di Torino, and GRILL3D (Dr.Mikhail Irzak, A.F.Ioffe Physico-Technical Institute, St. Petersburg, Russia), from ENEA Frascati, have been compared with the initial (3 modules with 8 active waveguides per module) and updated (6 modules with 4 active waveguides per module) Passive-Active Multijunction (PAM) Lower Hybrid antennas. Both ALOHA and GRILL3D formulate the problem in terms of rectangular waveguides modes, while TOPLHA is based on boundary-value problem with the adoption of a triangular cell-mesh to represent the relevant waveguides surfaces. Several plasma profiles, with varying edge density and density increase, have been adopted to provide a complete description of the simulated launcher in terms of reflection coefficient, computed at the beginning of each LH module, and of power spectra. Good agreement can be observed among codes for all the simulated profiles

RF Modeling of the ITER Lower Hybrid Antenna

In the frame of the EFDA task HCD-08-03-01, a 5 GHz Lower Hybrid system being able to deliver 20 MW CW on ITER and sustains the expected high heat flux has been reviewed. The design of the key RF elements of the antenna such as the Passive-Active Multijunction (PAM), TE10-TE30 mode converter, 3 dB splitter and RF window has been updated. Overall dimensions have been updated from the 2005 design in collaboration with ITER organization. ITER mechanical constraints, such as the port plug size or the rear flange have been taken into account since the initial RF design. The main parallel index has been chosen to be n//=2.0 with a flexibility of [1.8-2.2] in order to maximize the current drive efficiency. In parallel to the RF design, the coupling to the plasma has been studied with the ALOHA and TOPLHA codes and results are in good agreement. The antenna is made of 48 identical modules, 12 on the toroidal direction and 4 on the poloidal direction. Each module is terminated by a RF window located inside the frame and connected to a poloidal 3 dB splitter which feeds 2 TE10-TE30 mode converters. Each of these mode converters divides the power into 3 poloidal rows corresponding to the input of a 4 active waveguides multijunction. An optimization of the multijunction and the mode converter has been made in order to reduce VSWR and total length in order to satisfy the ITER frame constraints. 5 GHz CW RF windows capable of sustaining 500 kW are one of the most challenging RF devices of this antenna, since the ceramic which separates the tokamak vacuum from the pressurized transmission line must handle and evacuate high RF power density flux. Different designs have been proposed based on pill-box geometry and actively water cooled. Efficient designs ensuring low theoretical return loss and acceptable dielectric RF losses for beryllium oxide (BeO) window has been found. All the devices which have been separately studied have been integrated together, allowing a RF characterization of the whole antenna and further optimization for neutron shielding

Bends in Oversized Rectangular Waveguide for the ITER Relevant LHCD System

The present work has been developed within the frame of the EFDA task “HCD-08-03-01: LH4IT, EU contribution to the ITER LHCD Development Plan” The use of rectangular oversized waveguides in the Main Transmission Lines (MTLs) of the Lower Hybrid Current Drive (LHCD) system of ITER, requires to investigate the problem of bends. The high number of involved waveguides (from 24 to 48) must be also taken into account. Thus, it has to consider not only the best choice in terms of curved framework, but also the proper allocation of all the waveguides. In this context, the principal specifications that characterize the design of the bends are: a) to minimize the reflection of the fundamental TE10 mode; b) to maximize the transmission of the fundamental TE10 mode; c) to minimize the coupling between the TE10 mode and other spurious modes that propagate at 5 GHz. This paper presents an overview about the bend options, and it compares the performances of several frameworks analyzed by using the Finite Element Method (FEM) commercial software, HFSS®. First of all, simple circular trajectory curves with different angulations, are considered. Then, the so called Mitre Bends alternatives are deeply analyzed. These curves are studied by several authors in the mono-modal configuration, with different techniques but the propagation in an oversized environment is a topic not much attended in literature. The only design parameter of the simple circular trajectory bend is the bending radius, so that the design is not flexible; the Mitre Bend structure is at least more flexible than the previous one and it is of great interest to study this type of bend to check the possible advantages. Finally an innovative modified Mitre Bend solution based on a cascade of trapezoidal elements is proposed