ETN_PFM European Fusion Training Scheme

Transcription

1 ETN_PFM European Fusion Training Scheme Major Topic 4: Neutron Radiation effects on materials for PFC Sehila M González de Vicente Activities from 15 th March 2007 up to now

2 TRAININGS/INTRODUCTION TO WP4 ACTIVITY Bibliography - Plasma surface interaction - Erosion/Deposition issues at JET - Structural materials: High performance steels -ITER TEXTOR and JET tiles analysis -EDX/SEM analysis - AES/XPS measurements Basic course, visits and specific seminars - Basic principles of nuclear fusion - Plasma wall interaction - Modelling of Radiation Damage - Material science - Radiation effects on Materials - Visit of BR2 and BR3 (SCK CEN, Mol) - Visit of TEXTOR (TEC - Forschungszentrum Jülich) - Visit of JET (Culham Science Centre, U.K.)

3 PROJECTS IN PROGRESS TEXTOR TILES JET TILES PLASMATRON XPS Analysis - Samples preparation: Dimple grinding - SEM Microscope XPS Analysis - Samples preparation: Dimple grinding - SEM Microscope Machine start up Study about the possible uses for this device M-B distribution of accelerated ions Amount of Tritium to run one single experiment Be-Cu joints irradiation Modelling FeCr

4 SOME RESULTS

5 PLASMA WALL INTERACTION (PWI) Plasma-wall-interaction (PWI) research Wall and divertor power loads Erosion and deposition properties Impurity control Tritium inventary and recycling mechanisms ITER primary materials choice Bottom line: reach technically acceptable limits and to achieve a sufficient lifetime of the plasma facing components (PFCs) These questions will dominate operational constrains in ITER and beyond, where the optimization of the core plasma performance and wall erosion, tritium retention and lifetime issues cannot be decoupled

6 PLASMATRON: Brief facility description Cold self-sustained volumetric plasma Volume:18 litres Target diameter: ~25cm Ion energies: ev Magnetic field: 0.2T Pulse duration: steady state Flux density target: ~ ions/m 2.s Designed for PWI studies Installation for operation in glove box A gas mixture with a certain D/T ratio can be created in a volume by measuring the pressure and the mass flow of D/T coming from volumes containing D and T. Both loops have a separate control system Tominetti S. et al., Vuoto26 (1997)

7 Dimple performance This Precision Dimpling Instrument can be used to expose nearsurface concentration gradients or to produce tapered sections through surface coatings

8 TEXTOR graphite samples Non - contaminated samples (no beryllium and tritium) Tile 20: µm deposition (but flaking possible) Tile 21: ~100 nm - 1µm deposition Substrate: fine grain graphite (~10mm) Plasma discharges: Area averaged fluence: ~ /m 2 Dimples SEM image

9 SEM Measurements Example: Tile: 21 Thick deposition ~ 100 nm 1µm Sample: 21d Dimple: a Performance: Speed 2, load 2, 30s Tile: 20 Thick deposition ~ 10-20µm Sample: 20c Dimple: b Performance: Maximum speed, load 4, 30s Figure 2: Dimples on 21d sample e 3: Dimples on 20c sample

10 TEXTOR graphite samples Sample 20 d 20 f 20 c Dimple a a b c d e a b c Depth (µm) Various dimples were made by different speed/time of grinding wheel. The depth obtained is in the range of 5 to 25 µm by profilometry (0.1µm resolution). This should allow to study the deposition in a better way by XPS. a d b c 11 6 d 12

11 XPS analysis TEXTOR non contaminated samples (I) Tile 20: Surface analysis of Outside, Crater and deepest layer of depth profile C peak O peak Counts Crater Outside Depth profile Counts Crater Outside Depth profile E (ev) E (ev) The surface preparation technique for XPS analysis in depth with the grinding machine allows studying deposition profiles. But some side effects have to be taken into account and therefore, care should be taken in the analysis: some mixing of the true depth profile and material removal that falls into the crater coming from the surface.

12 XPS analysis TEXTOR non contaminated samples (II) Tile 20 and 21, thick and thin deposition respectively: Surface analysis of Outside, Crater and deepest layer of depth profile Counts Cu Zn peaks Crater Outside Depth profile E (ev) 950 Counts Cu Zn peaks 1050 Depth profile E (ev) Outside Crater XPS spectrum corresponding to Copper 2p³ (934 ev) and Zinc 2p1 (1045 ev) and 2p³ (1022 ev) peaks performed on the sample surface (outside), crater slope (crater) and after 3000 s of ion etching (Depth profile. Left: thick deposition specimen (tile 20), Right: thin deposition specimen (tile 21)

13 TEXTOR non contaminated samples schedule ACHIEVEMENTS Dimple grinding technique optimized - FINISHED EDX analysis of surface and craters of tiles 20 and 21 - FINISHED XPS/AES on dimple grinded TEXTOR tile FINISHED Work presented at PSI Conference Toledo. (Dimple optimization for XPS characterization of TEXTOR tile depositions, Poster P3-15)

14 Counts Counts XPS analysis JET Be contaminated samples (I) Sample 1-5: Surface analysis and Depth profile Sample: 1-5 Be 1s peak C 1s peak E b (ev) Sample: E (ev) b Counts Counts Depth profile: Be1s peaks E (ev) b Depth profile: C1s peaks E (ev) b

15 XPS analysis JET Be contaminated samples (II) Sample 3-2: Surface analysis and Depth profile Sample 3-2 Depth profile: Be1s peaks Sample 3-2 Depth profile: C1s peaks Counts Counts E (ev) b E (ev) b No BeC formation is observed in either 1 5 or 3 2 samples

16 JET Be contaminated samples ACHIEVEMENTS XPS/AES on Jet Beryllium contaminated samples: 3-2, 5-1 and (5) Work in progress after some problems with the XPS machine. (Results are shown at the beginning of this report). Plan: schedule XPS/AES - DONE Depth profile study- DONE Dimple grinding - IN PROGRESS SEM and EDX study - IN PROGRESS

17 NEXT PROJECTS JET TILES PLASMATRON XPS analysis of New tiles Campaign at JET 2009 Rutherford Backscattering Spectrometry (RBS) Different parameters calculation Study of similar devices (PISCES visit - and Magnun) Irradiation campaign in BR2 (November) + Introduction to modeling (June)

18 PARTICIPATION IN MEETINGS - New EFDA Emerging technology: Fusion Materials Topical group Research project: W and W-Alloys Development for Plasma Facing Components: Structural Application, Heat Sink, and, Armour Materials (21st January 2008); and Nano-structured ODS Ferritic Steels Development (22nd January 2008) - Discussion on collaboration between SCK CEN and FZ Jülich Presentation and discussion on the new-efda W & W alloy proposal , in FZ Jülich - Discussing and putting together the first draft of a joint proposal (SCK CEN, UC3M, CIEMAT and OCAS) for New EFDA related to ODS steels (13rd March 2008), at University Carlos III, Leganés (Madrid, Spain) - General Task Force Fusion Technology Meeting, Discussion about the new JET EFDA task proposals. 23rd, and 24th April 2008, at JET Culham Science centre

19 PUBLICATIONS PREVIOUS WORK (at CIEMAT, Madrid, Spain) - Surface electrical degradation due to ion bombardment of ITER insulators, S.M. González de Vicente*, A. Moroño, D. E. Hole, and E.R. Hodgson - Insulator degradation due to radiation induced ion and dark currents in vacuum, E.R. Hodgson, A. Moroño, and S.M. González de Vicente - Electrical surface degradation of electron irradiated sapphire and silica, A. Moroño, E.R. Hodgson and S.M. González de Vicente In the last ICFRM (December 10 14, 2007) Journal of Nuclear Materials THESIS: OPTICAL AND ELECTRICAL SURFACE DEGRADATION BY ION BOMBARDMENT OF ITER AND FUTURE FUSION REACTOR INSULATORS 11st January 2008

20 - Dimple optimizaton for XPS characterization of TEXTOR tile depositions, I. Uytdenhouwen, S. M. González de Vicente, J. P. Coad, W. Van Renthergem, S. Van den Berghe, G. Van Oost, and V. Massaut, 2008, published In the last PSI (May 10 14, 2008) Journal of Nuclear Materials - Carbide formation of Be and T contaminated CFC tiles from JET, I. Uytdenhouwen, S. M. González de Vicente, J. P. Coad, W. Van Renterghem, S. Van den Berghe, G. Van Oost, and V. Massaut, 2008, to be published In the next SOFT (September 15-19, 2008 ) Fusion Engineering and Design - Origin of surface electrical degradation of insulators due to ionic i bombardment, S.M. González de Vicente, A. Moroño, and E.R. Hodgson, 2008, to be published In the next SOFT (September 15-19, 2008 ) Fusion Engineering and Design -Surface Electrical Degradation of Helium Implanted Sapphire, S.M. González de Vicente, A. Moroño, and E.R. Hodgson, 2008, to be published In the next TOFE (September 29 October 2, 2008 )

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