T. Gassmann

THE EC H&CD TRANSMISSION LINE FOR ITER

Abstract The transmission line (TL) subsystem associated with the ITER electron cyclotron heating and current drive system has reached the conceptual design maturity. At this stage the responsibility of finalizing the design has been transferred from the ITER Organization to the U.S. Domestic Agency. The purpose of the TL is to transmit the microwaves generated by the 170-GHz gyrotrons installed in the radio-frequency building to the launchers located in one equatorial and four upper tokamak ports. Each TL consists of evacuated HE11 waveguides, direct-current breaks, power monitors, mitre bends, polarizers, switches, loads, and pumping sections and will have a typical length that ranges from 100 to 160 m. Overall transmission efficiency could be as high as 92% depending on the specific path between a given gyrotron and launcher. All components are required to be 2-MW compatible, and their layout and organization have been optimized for simplifying the maintenance accessibility and monitoring the primary tritium barrier integrity. Two different TL layouts are at the moment under study, to accommodate the two alternative options for the European sources: four 2-MW units or eight 1-MW units. In this paper the actual design is presented and the technical requirements are discussed.

The targeted heating and current drive applications for the ITER electron cyclotron system

A 24 MW Electron Cyclotron (EC) system operating at 170 GHz and 3600 s pulse length is to be installed on ITER. The EC plant shall deliver 20 MW of this power to the plasma for Heating and Current Drive (H&CD) applications. The EC system is designed for plasma initiation, central heating, current drive, current profile tailoring, and Magneto-hydrodynamic control (in particular, sawteeth and Neo-classical Tearing Mode) in the flat-top phase of the plasma. A preliminary design review was performed in 2012, which identified a need for extended application of the EC system to the plasma ramp-up, flattop, and ramp down phases of ITER plasma pulse. The various functionalities are prioritized based on those applications, which can be uniquely addressed with the EC system in contrast to other H&CD systems. An initial attempt has been developed at prioritizing the allocated H&CD applications for the three scenarios envisioned: ELMy H-mode (15 MA), Hybrid (∼12 MA), and Advanced (∼9 MA) scenarios. This leads to the ...

Status of the ITER IC H&CD System

The ITER Ion Cyclotron Heating and Current Drive system will deliver 20 MW of radio frequency power to the plasma in quasi continuous operation during the different phases of the experimental programme. The system also has to perform conditioning of the tokamak first wall at low power between main plasma discharges. This broad range of requirements imposes a high flexibility and a high availability. The paper highlights the physics and design requirements on the IC system, the main features of its subsystems, the predicted performance, and the current procurement and installation schedule.

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.

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...

Design status of ITER IC H&CD plant system control

A functional approach has been used to define functions & responsibility sharing of each Local Control Unit (LCU) and Ion Cyclotron Heating and Current Drive (IC H&CD) Plant System Control (IC-PSC). The resulting functional architecture of the IC H&CD control system is detailed in this paper. The paper highlights functional study of management of fast radio-frequency (RF) arc protection across the IC H&CD subsystems. Lastly, a possible hardware architecture compliant with the functional one is described.