First plasma exposure of a pre-damaged ITER-like plasma facing unit in the WEST tokamak: procedure for the PFU preparation and lessons learnt

Abstract The evaluation of the impact of plasma-facing components (PFCs) damage on subsequent plasma operation is an important issue for ITER. During the first phase of operation of WEST, a few ITER like divertor plasma-facing units (PFUs) have been installed on the lower divertor. One PFU was pre-damaged under electron beam gun thermal loading, before its installation in WEST, and the subsequent evolution of the damage was studied after the WEST plasma exposure. This paper presents the procedure followed to get the pre-damaged PFU. It consists in the characterization of the response of tungsten samples representative of WEST PFU under high heat flux (HHF) loading, the selection of damage (namely small cracks, crack network, crack network and W melt droplets). Finally, according to the WEST plasma loading conditions, the blocks with damage within the PFU and the position of the pre-damaged PFU on the WEST lower divertor are attributed. The first results obtained after an initial plasma exposure in WEST lead to assess, as expected with regard to the heat loading conditions, that no major surface aspect modification was found. This result emphasized the possibility to implement as pre-damage some small local droplets of melted tungsten in a high heat loaded zone for a future WEST experimental campaign.

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Design and Analysis of High Heat Flux Plasma-Facing Components for NSTX Upgrade

IEEE Transactions on Plasma Science ◽

10.1109/tps.2020.3046229 ◽

2021 ◽

pp. 1-7

Author(s):

Andrei Khodak ◽

Douglas Loesser ◽

Michael Messineo ◽

Arthur Brooks ◽

Michael Jaworski ◽

...

Keyword(s):

Heat Flux ◽

High Heat ◽

High Heat Flux ◽

Plasma Facing Components

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High Heat Flux Testing of TiC-Doped Isotropic Graphite for Plasma Facing Components

Advanced Materials Research - New Materials for Extreme Environments ◽

10.4028/3-908454-01-8.288 ◽

2008 ◽

pp. 288-292

Author(s):

I. López-Galilea ◽

G. Pintsuk ◽

C. García-Rosales ◽

Jochen Linke

Keyword(s):

Heat Flux ◽

High Heat ◽

High Heat Flux ◽

Plasma Facing Components ◽

Isotropic Graphite

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Empirical Optimization of High Density Plate-Fin Heat Sink for Constant Pumping Power in Low Profile Cooling Application

Advances in Electronic Packaging, Parts A, B, and C ◽

10.1115/ipack2005-73106 ◽

2005 ◽

Author(s):

Kazuaki Yazawa ◽

Tatsuro Yoshida ◽

Shinji Nakagawa ◽

Masaru Ishizuka

Keyword(s):

Fluid Dynamic ◽

Dynamic Performance ◽

High Heat ◽

Heat Sinks ◽

High Heat Flux ◽

Pumping Power ◽

Low Profile ◽

Data Points ◽

Narrow Space ◽

The Impact

Since the VLSI processors are increasing power in accordance with exponential law, cooling solutions for such as personal computers have been evolving for over a decade. Recent heat sinks are designed with high dense fins and low profile to adapt to a high heat flux source within a slim enclosure. To achieve such compact cooling solution, thin fin and small gap is desirable. In addition, the pumping power is also limited by the allowable narrow space for fans. Thus it is important to minimize the thermal resistance for given pumping power that we define the optimum. Due to the lack of literatures on topic of low profile and high dense fins experiments, an apparatus was specially built to measure the thermal and fluid dynamic performance at the same time. Since such a high dense fin arrangement requires extra space on the sides by manufacturing reasons, the impact of bypass flow needs to be considered. The experiments are carefully carried out and the results are precisely compared with numerical analysis. The numerical model aiming to find the optimum for given pumping power is discussed with extrapolating the data points. This report is concluded with the best configuration of plate fins of low profile heat sinks for a given fan performance.

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Vapor shield protection of plasma facing components under incident high heat flux

Journal of Nuclear Materials ◽

10.1016/s0022-3115(06)80106-6 ◽

1992 ◽

Vol 196-198 ◽

pp. 596-601 ◽

Cited By ~ 12

Author(s):

J. Gilligan ◽

M. Bourham ◽

O. Hankins ◽

W. Eddy ◽

J. Hurley ◽

...

Keyword(s):

Heat Flux ◽

High Heat ◽

High Heat Flux ◽

Plasma Facing Components

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Effect of Orientation and Draining on Linear Spray Array Thermal Management

ASME 2007 InterPACK Conference, Volume 2 ◽

10.1115/ipack2007-33833 ◽

2007 ◽

Author(s):

Benjamin M. Regner ◽

Timothy A. Shedd

Keyword(s):

Heat Transfer ◽

Fluid Management ◽

High Heat ◽

Practical Implementation ◽

High Heat Flux ◽

Large Area ◽

Candidate Solution ◽

The Impact ◽

Volumetric Flux ◽

Uniform Droplet

Spray cooling is a candidate solution for high heat flux cooling applications, and previous work has investigated the impact of parameters of conical sprays such as volumetric flux and Sauter mean diameter on heat transfer performance. However, there has been little work on the impact of drainage and spray orientation on spray performances. In addition, conical sprays are not very practical for large area coverage in compact packages, so this study, presents a novel arrangment that uses linear sprays impinging at an angle such that fluid management and uniform droplet coverage of large areas are both improved. Results for the heat transfer coefficient and CHF of a constrained, practical implementation of a spray array (as opposed to a laboratory-only geometry) are presented for FC-72, FC-40 and HFE-7000.

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R&D on divertor plasma facing components at the Institute for Plasma Research

Nukleonika ◽

10.1515/nuka-2015-0053 ◽

2015 ◽

Vol 60 (2) ◽

pp. 285-288 ◽

Cited By ~ 3

Author(s):

Yashashri Patil ◽

S. Khirwadkar ◽

S. M. Belsare ◽

Rajamannar Swamy ◽

M. S. Khan ◽

...

Keyword(s):

Heat Transfer ◽

Heat Flux ◽

Surface Temperature ◽

Infrared Thermography ◽

High Heat ◽

High Heat Flux ◽

Acceptance Criteria ◽

Plasma Facing Components ◽

Type Test ◽

Plasma Research

Abstract This paper is focused on various aspects of the development and testing of water cooled divertor PFCs. Divertor PFCs are mainly designed to absorb the heat and particle fluxes outflowing from the core plasma of fusion devices like ITER. The Divertor and First Wall Technology Development Division at the Institute for Plasma Research (IPR), India, is extensively working on development and testing of divertor plasma facing components (PFCs). Tungsten and graphite macro-brush type test mock-ups were produced using vacuum brazing furnace technique and tungsten monoblock type of test mock-ups were obtained by hot radial pressing (HRP) technique. Heat transfer performance of the developed test mock-ups was tested using high heat flux tests with different heat load conditions as well as the surface temperature monitoring using transient infrared thermography technique. Recently we have established the High Heat Flux Test Facility (HHFTF) at IPR with an electron gun EH300V (M/s Von Ardenne Anlagentechnik GmbH, Germany) having maximum power 200 kW. Two tungsten monoblock type test mock-ups were probed using HHFTF. Both of the test mock-ups successfully sustained 316 thermal cycles during high heat flux (HHF) tests. The test mock-ups were non-destructively tested using infrared thermography before and after the HHF tests. In this note we describe the detailed procedure used for testing macro-brush and monoblock type test mock-ups using in-house transient infrared thermography set-up. An acceptance criteria limit was defined for small scale macro-brush type of mock-ups using DTrefmax value and the surface temperature measured during the HHF tests. It is concluded that the heat transfer behavior of a plasma facing component was checked by the HHF tests followed by transient IR thermography. The acceptance criteria DTrefmax limit for a graphite macro-brush mock-up was found to be ~3°C while for a tungsten macro-brush mock-up it was ~5°C.

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