A5086431688- Fusion materials and technologies
- Magnetic confinement fusion research
- Nuclear Materials and Properties
- Nuclear reactor physics and engineering
- Laser-induced spectroscopy and plasma
- Microstructure and mechanical properties
- Aluminum Alloys Composites Properties
- Superconducting Materials and Applications
- Nuclear Physics and Applications
- Laser-Plasma Interactions and Diagnostics
- Magnesium Alloys: Properties and Applications
- Ion-surface interactions and analysis
- Metallurgical Processes and Thermodynamics
- Plasma Diagnostics and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Metal and Thin Film Mechanics
- Diamond and Carbon-based Materials Research
- Mycotoxins in Agriculture and Food
- Solar and Space Plasma Dynamics
- Metallurgy and Material Forming
- Spacecraft and Cryogenic Technologies
- Cancer Genomics and Diagnostics
- Metal Forming Simulation Techniques
- Advanced Welding Techniques Analysis
- Nuclear materials and radiation effects
Institut de Recherche sur la Fusion par Confinement Magnétique
2017-2024
CEA Cadarache
2019-2024
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2019-2023
Italian Resuscitation Council
2019
National Research Council
2019
Seoul National University
2014-2018
European Organization for Nuclear Research
2017
Abstract WEST is an MA class superconducting, actively cooled, full tungsten (W) tokamak, designed to operate in long pulses up 1000 s. In support of ITER operation and DEMO conceptual activities, key missions are: (i) qualification high heat flux plasma-facing components integrating both technological physics aspects relevant particle exhaust conditions, particularly for the monoblocks foreseen divertor; (ii) integrated steady-state at confinement, with a focus on power issues. During phase...
Abstract As part of the development proven diagnostics allowing characterization ITER’s PFUs (Plasma Facing Units) without dismantling, LIBS (Laser-Induced Breakdown Spectroscopy) is a serious candidate for determining multi-elemental composition. In this article, we report measurement campaign carried out within WEST tokamak using an original device based on following technological choices. (1) The laser source and spectrometer are placed outside tokamak. (2) pulses conveyed by optical...
Abstract ITER will operate with a tungsten divertor, material featuring surface morphology changes when exposed to helium plasmas, in particular the formation of so called fuzz under specific conditions. Investigating interactions between plasma facing components and plasmas tokamak environment is therefore key point consolidate predictions for divertor performance lifetime. To this end, dedicated campaign was performed full WEST tokamak, cumulating ∼2000 s repetitive L mode discharges. It...
After three years of operation (2017–2019) and four experimental campaigns (C1 to C4), the first phase WEST tokamak has now come an end. During that period, operated with tungsten coated copper-based carbon-based plasma facing components in order comply a full metallic environment. A set components, called units, using ITER monoblock technology was also installed onto one sector lower divertor test their behaviour real This paper gives overview ageing these during situ visual inspections. It...
Abstract The net erosion and deposition patterns in the inner outer divertor of WEST were determined after different experimental campaigns (C3 C4) first operational phase using ion beam analyses scanning electron microscopy techniques. performed on four entire tiles from inertially cooled, W-coated units with an additional Mo marker coating covered a further W coating. Strong occurred at expected location strike line area campaign-averaged rate >0.1 nm s −1 . On high field side area,...
Abstract The consequences of tungsten (W) melting on divertor lifetime and plasma operation are high priority issues for ITER. Sustained controlled W-melting experiment has been achieved the first time in WEST a poloidal sharp leading edge an actively cooled ITER-like facing unit (PFU). A series dedicated power steady state discharges were performed to reach point tungsten. was exposed parallel heat flux about 100 MW.m −2 up 5 s providing melt phase 2 without noticeable impact (radiated...
Abstract This paper summarizes the emissivity measurements performed on plasma-facing units (PFU) of WEST lower divertor during first phase running with a mix actively cooled ITER-like PFUs made bulk tungsten (W) and inertially graphite coating tungsten. In situ assessments laboratory after removing W-coated ITER-grade from device are shown. The exhibit complex pattern strong variation as function space time mainly explained magnetic equilibrium (strike point location) well plasma...
Two populations of dust particles were found during the first phase operation WEST. The one that dominates by size and weight comes from delamination tungsten coatings covering graphite tiles emission droplets molten materials off-normal events. Sizes vary several microns to tens microns. More generally, micron-sized due erosion all present in vacuum vessel collected. In addition, nanocavities at surface sampled after He plasmas attributed trapping form nanobubbles. Tungsten nanoparticles...
Studying the ageing of tungsten monoblocks, their erosion and fuel inventory is priority WEST post-mortem analyses programme. Actively-cooled ITER-like plasma-facing units (PFUs) special W-coated marker lower divertor tiles were retrieved from after C3 C4 experimental campaigns to perform ex-situ analyses. The erosion/deposition pattern on was determined. deposition found mainly inner side which covered by layered deposits that increase in thickness radial direction a few hundreds nm maximum...
Abstract The choice of first wall material is paramount importance for the plasma start-up conditions in ITER and future fusion power plants. In this context, present work focuses on correlations between impurity sources total radiated during tungsten (W) Environment Steady-state Tokamak (WEST). objective to highlight experimental indications a preferable combination scenario materials. Until 2019, WEST featured full high Z with all limiters exposing only W surfaces plasma. To study impact...
In the WEST tokamak, ITER-like divertor targets consisting of tungsten monoblocks bonded via an OHFC-Cu compliance layer to CuCrZr cooling tubes were exposed plasma during 2018 experimental campaign in which modest heating power was available. Up 2.5 MW/m2 surface heat flux attained. Inspection components after revealed a wide variety damage at both leading and trailing monoblock edges, optical hot spots are projections along magnetic field lines toroidal gaps between onto poloidal edges....
Gross and net erosion of tungsten (W) other plasma-facing materials in the divertor region have been investigated deuterium (D) helium (He) plasmas during dedicated experiments L- H-mode on ASDEX Upgrade after full-length experimental campaigns WEST tokamak. Net was determined via post-exposure analyses plasma-exposed samples full-size wall components, we conclude that same approach is applicable to gross if marker structures with sub-millimeter dimensions are used eliminate contribution...
Assessing the performance of ITER design for tungsten (W) divertor Plasma Facing Units (PFUs) in a tokamak environment is high priority issue to ensure efficient plasma operation. This paper reviews most recent results derived from experiments and post-mortem analysis ITER-grade PFUs exposed WEST associated modelling, with focus on understanding heat loading damage evolution. Several shaping options, sharp or chamfered leading edge (LE), unshaped shaped blocks toroidal bevel as foreseen...
Abstract The mission of WEST (tungsten-W Environment in Steady-state Tokamak) is to explore long pulse operation a full tungsten (W) environment for preparing next-step fusion devices (ITER and DEMO) with focus on testing the ITER actively cooled W divertor tokamak conditions. Following successful completion phase 1 (2016-2021), 2 started December 2022 lower made entirely ITER-grade mono-blocks. A boronization prior first plasma attempt allowed smooth startup new divertor. Despite reduced...
In this paper, a method was developed to estimate in-situ the emissivity of W-coated graphite divertor tiles in WEST tokamak. This is based on double heating and take advantages temperature increase after successive plasma experiments due inertial behavior facing components. Photonic calculations have been used disentangle emitted reflected parts measured radiances from infrared system. The uncertainty as well robustness investigated thanks wide IR thermocouple coverage divertor. results...
Twelve ITER-like plasma-facing units made of tungsten were exposed in the WEST tokamak divertor, with three (PFUs) significantly overexposed to plasma heat flux: one sharp-edged PFU (vertical misalignment h = 0.8 mm) and two chamfered PFUs (h =0.6 mm 0.3 mm, respectively). This paper describes first temperature analysis obtained a very high spatial resolution infrared camera (pixel size ∼ 0.1 on misaligned edges shows consistency parallel flux derived from these measurements. The is focused...
The lower divertor of the WEST tokamak has been partially equipped with actively cooled plasma facing unit (PFU) prototypes aim testing ITER tungsten monoblock technology in a real environment. relative alignment these ITER-like PFUs and their exposure to heat flux is particular interest as risk edge melting was previously predicted numerical studies. After 2018 experimental campaign, surface evolution investigated by optical microscopy. surfaces exhibit presence hot spots at magnetic...
In order to map the complex plasma footprint observed on lower divertor of WEST experiment after its first phase operation, we analysed deposits collected ITER-like Plasma Facing Units (PFUs) exposed in C3 (deuterium plasma) and C4 helium campaigns. Our results show that these have multilayer structures mainly composed tungsten, oxygen, boron carbon, whose texture composition vary along radial direction. These traits allowed us identify three types deposits: rich (conditioning) low flux area...