Engineering aspects of design and integration of ECE diagnostic in ITER

Abstract

Abstract. ITER ECE diagnostic [1] needs not only to meet measurement requirements, but also to withstand various loads, such as electromagnetic, mechanical, neutronic and thermal, and to be protected from stray ECH radiation at 170 GHz and other millimeter wave emission, like Collective Thomson scattering which is planned to operate at 60 GHz. Same or similar loads will be applied to other millimetre-wave diagnostics [2], located both in-vessel and in-port plugs. These loads must be taken into account throughout the design phases of the ECE and other microwave diagnostics to ensure their structural integrity and maintainability. The integration of microwave diagnostics with other ITER systems is another challenging activity which is currently ongoing through port integration and in-vessel integration work. Port Integration has to address the maintenance and the safety aspects of diagnostics, too. Engineering solutions which are being developed to support and to operate ITER ECE diagnostic, whilst complying with safety and maintenance requirements, are discussed in this paper.

Prospects for a dominantly microwave-diagnosed magnetically confined fusion reactor

“…Concerns on limited access led to proposals of adopting a single spherical mirror [22] or Rowland circle optics [23] for microwave imaging. Windows and other in-vessel and in-port components will have to withstand microwave stray radiation [24,25], electromagnetic loads, neutron activation, and meet maintenance, remote handling and safety requirements [26,27]. They will also have to be properly designed to enable diagnostic calibration [28,29].…”

Engineering aspects of microwave diagnostics in ITER

“…Currently, the first mirror is foreseen to be passively cooled, and the hot sources are foreseen to be actively cooled. [3] TheECE frontend is supplied from the factory in modular sub-assemblies. Side view (Fig.2Top) shows someof the key modules, including the two telescope units, calibration sources, shutter mechanisms,vacuum extensions (bearing the vacuum windows), and movement compensation assemblies.…”

“…ITER diagnostic systemswill be installed in total of 8 Equatorial Ports and 10 Upper Ports of vacuum vessel, several lower ports and internally in many vacuum vessel locations.In port diagnostic component that are placed in high radiation environment are expected to operate for a period of at least until next planned maintenance session which is 4 years for port plug [3],the machine equipment on which the diagnostic component is installed this applies for example to in port plug system. In particular, microwave diagnostic will have an important role in ITER operation because they will provide valuable information on electron density and temperature profiles, MHD modes and turbulence properties.…”

Status of the design of the ITER ECE diagnostic

“…This paper reviews the current design of the baseline ECE diagnostic, design challenges that will need to be addressed during the preliminary and final design phases, and possible future upgrades to state-of-the-art ECE instrumentation. Additional information on engineering aspects of the design of the ECE diagnostic and its integration into ITER can be found in the paper by Udintsev et al [5]. Section 2 covers the design of the optical components in the port plug and the calibration sources, Section 3 covers the design of the double vacuum window, polarization splitter boxes and low-loss, broadband transmission line, and Section 4 discusses the instrumentation in the diagnostics hall, including possible upgrades to state-ofthe-art instrumentation.…”