B. Beaumont

Concept development for the ITER equatorial port visible/infrared wide angle viewing systema)

The ITER equatorial port visible∕infrared wide angle viewing system concept is developed from the measurement requirements. The proposed solution situates 4 viewing systems in the equatorial ports 3, 9, 12, and 17 with 4 views each (looking at the upper target, the inner divertor, and tangentially left and right). This gives sufficient coverage. The spatial resolution of the divertor system is 2 times higher than the other views. For compensation of vacuum-vessel movements, an optical hinge concept is proposed. Compactness and low neutron streaming is achieved by orienting port plug doglegs horizontally. Calibration methods, risks, and R&D topics are outlined.

R&D activities on RF contacts for the ITER ion cyclotron resonance heating launcher

Abstract Embedded RF contacts are integrated within the ITER ICRH launcher to allow assembling, sliding and to lower the thermo-mechanical stress. They have to withstand a peak RF current up to 2.5xa0kA at 55xa0MHz in steady-state conditions, in the vacuum environment of the machine. The contacts have to sustain a temperature up to 250xa0°C during several days in baking operations and have to be reliable during the whole life of the launcher without degradation. The RF contacts are critical components for the launcher performance and intensive R&D is therefore required, since no RF contacts have so far been qualified at these specifications. In order to test and validate the anticipated RF contacts in operational conditions, CEA has prepared a test platform consisting of a steady-state vacuum pumped RF resonator. In collaboration with ITER Organization and the CYCLE consortium (CYclotron CLuster for Europe), an R&D program has been conducted to develop RF contacts that meet the ITER ICRH launcher specifications. A design proposed by CYCLE consortium, using brazed lamellas supported by a spring to improve thermal exchange efficiency while guaranteeing high contact force, was tested successfully in the T-resonator up to 1.7xa0kA during 1200xa0s, but failed for larger current values due to a degradation of the contacts. Details concerning the manufacturing of the brazed contacts on its titanium holder, the RF tests results performed on the resonator and the non-destructive tests analysis of the contacts are given in this paper.

Ion Cyclotron Power Source System For ITER

Abstract The ITER ion cyclotron heating and current drive system is designed to deliver 20 MW to a broad range of plasma scenarios, during very long pulses (∼500 s in inductive, up to 1 h in noninductive, plasma scenarios). The associated radio-frequency (rf) source system has to be compliant with all operation modes foreseen in ITER operation. India is responsible for delivering the rf source package to ITER, which includes one prototype rf source followed by eight bulk production units. This lecture presents the ITER rf source system, design considerations, and status of the research and development program to identify and resolve the major technological challenges involved.

Design of a mechanically actuated RF grounding system for the ITER ICRH antenna

Abstract In the ITER equatorial ports containing ICRH antennas, parasitic electrical resonances can be excited in the nominal 20xa0mm clearance gap between the port walls and the plug contained within it. RF calculations have established that these resonances can be effectively mitigated by a series of suitably located electrically conducting contacts between the port and plug. These contacts must allow installation and removal of the antenna but must also make reliable electrical contact during antenna operation. In addition, the contacts must be compliant enough to survive deflection of the port during seismic and disruption events without transmitting large forces to the vacuum vessel. The distance to be spanned is subject to significant uncertainty, due to the large manufacturing tolerances of the surrounding components, and this also must be considered during the design process. This paper outlines progress made in the design of the grounding system, as well as detailing a number of concepts which have been investigated and abandoned, leading up to the current reference design. The current reference design is a simple and robust mechanical solution consisting of sprung Copper-plated Inconel flaps which use part of the range of the shimming system included in the antenna design as the actuation mechanism. This paper also details practical testing of a number of aspects of the design, including building and testing a prototype to validate mechanical and thermal analyses.

ITER ICRF system: R&D progress and technical choices

This paper describes the ITER ICRF system main requirements and the latest developments for its different parts which are to be procured by the ITER Parties. The built in margins will allow reaching the requirements on a large parameter range, or delivering more power in a restricted range.

Status of the ITER ion cyclotron heating and current drive system

The paper reports on latest developments for the ITER Ion Cyclotron Heating and Current Drive system: imminent acceptance tests of a prototype power supply at full power; successful factory acceptance of candidate RF amplifier tubes which will be tested on dedicated facilities; further design integration and experimental validation of transmission line components under 6MW hour-long pulses. The antenna Faraday shield thermal design has been validated above requirements by cyclic high heat flux tests. R&D on ceramic brazing is under way for the RF vacuum windows. The antenna port plug RF design is stable but major evolution of the mechanical design is in preparation to achieve compliance with the load specification, warrant manufacturability and incorporate late interface change requests. The antenna power coupling capability predictions have been strengthened by showing that, if the plasma scrape-off layer turns out to be steep and the edge density low, the reference burning plasma can realistically be di...

ITER project and RF systems

ITER is an international project supported by seven partners: China, Europe, India, Japan, Korea, Russian Federation and USA. Formally established in 2006, construction has started in France, more precisely in Provence. General progress of the project is presented followed by a focus on the RF systems which will provide 40 MW into the plasma, based on systems around 50 MHz and 170 GHz. These systems are using high power grid tubes, gyrotrons, and the latest power supplies technology to feed kilometres of transmission lines connected to specific antennas located at a few centimeters from the hot burning plasma.