New high power CW test facilities for ITER ICRH components testing

To decrease the power density and associated high voltages, a distributed antenna system is proposed as ICRH system for the DEMO reactor. Among the different solutions, a layout made from a set of travelling wave array (TWA) sections is considered as the most promising [1, 2]. It optimizes coupling to the plasma, is load resilient and avoids large values for the VSWR in the feeding lines. The total radiated power scales as the number of independently fed sections such that high reliability can be expected. The TWA concept for ICRH is innovative and very different from the traditional IC antennas. A test on WEST should provide a proof of principle of the validity of the TWA approach together with a comparison with the existing WEST IC antennas. The chosen geometry of the TWA section is compatible with one unit of the complete set designed for a future reactor [3]. The paper describes the progress made in the preparation of a test on WEST along with the extrapolation for a future reactor like DEMO. A comparative modeling with the present antennas is also discussed and a preliminary RAMI analysis is introduced showing the promising positive impact of the TWA design on the RAMI scores.

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“…A test of the RF strap configuration at high power is also under preparation. It will exploit the TITAN facility located in CEA-Cadarache [10].…”

Section: Discussionmentioning

confidence: 99%

Traveling wave array for DEMO with proof of principle on WEST

Ragona

Messiaen²,

Bernard

et al. 2019

Fusion Engineering and Design

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“…All the inner and outer conductors of the resonator are actively water cooled by a cold water loop (4 bar/20°C). The resonator, located in the TITAN facility [25], can also be connected to a hot water loop compatible with ITER specifications (up to 44 bar/250°C). The water cooling temperature during RF operations in the ITER IC antenna is estimated to be 90°C at the contact location.…”

Section: Figure 1 General Description Of the Rf Resonatormentioning

confidence: 99%

Radiofrequency and mechanical tests of silver coated CuCrZr contacts for the ITER ion cyclotron antenna

Hillairet

Chen

Lombard

et al. 2018

Fusion Engineering and Design

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The ITER Ion Cyclotron Resonance Heating (ICRH) system is designed to couple to the plasma 20 MW of RF power from two antennas in the 40-55 MHz frequency range during long pulses of up to 3600 s and under various plasma conditions with Edge Localized Modes. Radio-Frequency (RF) contacts are integrated within the ITER ICRH launcher in order to ensure the RF current continuity and ease the mechanical assembly by allowing the free thermal expansion of the Removable Vacuum Transmission Line coaxial conductors during RF operations or during 250°C baking phases. A material study has been carried out to determine which materials and associated coatings are relevant for RF contacts application in ITER. In parallel, RF tests have been performed with a new prototype of Multi-Contact® LA-CUT/0,25/0 contacts made of silver-coated CuCrZr louvers. During these tests on a RF vacuum resonator, currents between 1.2 kA and 1.3 kA peak have been reached a few tens of times in steady-state conditions without any visible damage on the louvers. A final 62 MHz pulse ending in a 300 s flat top at 1.9 kA resulted in severe damage to the contact. In addition, a test bed which performs sliding test cycles has been built in order to reproduce the wear of the contact prototype after 30 000 sliding cycles on a 3 mm stroke at 175°C under vacuum. The silver coating of the louvers is removed after approximately a hundred cycles whilst, to the contrary, damage to the CuCrZr louvers is relatively low.

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“…Once the antenna will be fully assembled, a full leak test on the dedicated TITAN test bed [7], [8] will be performed.…”

Section: Leak Test Procedures Used For the West Icrh Antennamentioning

confidence: 99%