Speaker
Yury Krasikov
(Forschungszentrum Jülich GmbH)
Description
The first mirrors of ITER diagnostic systems are the most vulnerable ones since they are directed to the plasma and are subjected to erosion and intensive impurity deposition. In order to prolong the lifetime of the first mirror and to keep its high optical performance and maintainability, single crystalline molybdenum and rhodium have been considered as mirror materials, subject to intensive investigations including R&Ds and mirror cleaning studies.
The paper presents specific design and structural issues of the first mirror considered for the ITER core charge exchange recombination spectroscopy (cCXRS) several years ago [1, 2] where a mirror size reaches ~ 300 mm. Such large mirrors can be assumed as a generic ones for a solid middle mirrors (up to 100 mm in diameter) and for composed large mirrors (diameter > 150 mm) that are potentially made of an assembly of smaller pieces.
The good design for the single crystalline mirror shall provide:
- a reliable structural connection between mirror assembled pieces and a substrate;
- acceptable mirror temperatures and thermal distortions providing the functionality of the optical system;
- cleaning suitability;
- mirror positioning stability within the required limits during operational and dwell time;
- an acceptable level of mechanical and thermo-mechanical stresses;
The mirror design is supported by extensive structural multi-physical analysis. To prove the feasibility of the proposals, a wide spectrum of technological R&D efforts is required.
Co-author
Yury Krasikov
(Forschungszentrum Jülich GmbH, Juelich, Germany)
