Displacement damage stabilization by hydrogen presence under simultaneous W ion damaging and D ion exposure S. Markelj 1 , T. Schwarz-Selinger 2 , M. Pe čovnik 1 , M. Kelemen 1,3 1 Jo ž ef Stefan Institute, Ljubljana, Slovenia 2 Max-Planck-Institut für Plasmaphysik (IPP), Garching, Germany c Jo ž ef Stefan International Postgraduate School, Jamova cesta 39, 1000 Ljubljana, Slovenia WP PFC This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 and 2019-2020 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission .
WP PFC Tungsten – plasma facing material Fusion device scenario D/T plasma exposure + neutron irradiation D,T n - 14 MeV S. Markelj et al. | MoD PMI 2019, Japan | Page 2
WP PFC Tungsten – plasma facing material D,T Neutron bombardment n - 14 MeV = Displacement damage creation Dislocation Vacancy Vacancy cluster Self-Interstitials Interstitials Damage Damage creation at RT creation at + elevated damage temperatures annealing S. Markelj et al. | MoD PMI 2019, Japan | Page 3
WP PFC Tungsten – plasma facing material D,T Neutron bombardment Fuel implantation n - 14 MeV = Displacement damage • ions and neutrals - energy few creation eV – keV; • High fluxes up to 10 24 m -2 s -1 Dislocation Vacancy Implantation Recombination Adsorption Reflection Desorption Trapping Vacancy cluster Self-Interstitials Interstitials Diffusion Hydrogen Metal atom Damage Damage creation at RT creation at Fuel transport: + Fuel elevated diffusion damage retention temperatures trapping annealing de-trapping S. Markelj et al. | MoD PMI 2019, Japan | Page 4
WP PFC Tungsten – plasma facing material Neutron bombardment Fuel implantation = Displacement damage • ions and neutrals - energy few creation eV – keV; • High fluxes up to 10 24 m -2 s -1 Dislocation Vacancy Implantation Recombination Adsorption Reflection Desorption Trapping Vacancy cluster Self-Interstitials Interstitials Diffusion Hydrogen Metal atom Damage Damage creation at RT creation at Fuel transport: + Fuel elevated diffusion damage retention temperatures trapping annealing de-trapping S. Markelj et al. | MoD PMI 2019, Japan | Page 5
WP PFC Outline Different displacement damaging procedures Comparison between: Sequential W ion irradiation and D exposure Simultaneous W ion irradiation and D exposure Comparison atoms versus ions Conclusions S. Markelj et al. | MoD PMI 2019, Japan | Page 6
WP PFC 14 MeV neutron irradiation Displacement damage creation Influence of neutron irradiation on D retention 20 µm activation of samples, long irradiation time, 14 MeV neutrons not available (fission neutrons)! 20 µm W self-damaging High energy ion damaging 20 MeV W in W MeV W ion irradiation = Surrogate for neutron irradiation 1 µm • Dense cascades and no chemical effect • No transmutation SRIM calculation of ion trajectory Ion damaging neutron damaging Few µm Few cm S. Markelj et al. | MoD PMI 2019, Japan | Page 7
WP PFC Displacement damage creation MeV W ion irradiation W self-damaging W ion irradiation by MeV W ions • Creation of displacement damage W ions 20 MeV 7.9x10 17 W/m 2 W 6+ 20 MeV Recrystallized W 0.23 dpa KP bulk W Damaged layer characterization by Scanning Transmission Electron Microscopy [Zaloznik et al. Phys Scr. T167 (2016) 014031 ] S. Markelj et al. | MoD PMI 2019, Japan | Page 8
WP PFC Displacement damage creation MeV W ion irradiation W ion irradiation by MeV W ions • Creation of displacement damage • Increased fuel retention in ion damaged W material from ~ 10 -3 at. % ↗ ~ 1 at. % • D saturation observed at damage dose > 0.2dpa for RT W irradiation! [Alimov et al. JNM 2013, Hoen et al. NF 2012, Schwarz-Selinger FEC 2018] D atom exposure @ 600 K 10.8/20 MeV W irradiated D D D D D W D D D D D D bulk W S. Markelj et al. | MoD PMI 2019, Japan | Page 9
WP PFC Simultaneous W/D exposure W ions D ions/atoms Simultaneous W/D exposure: W ion irradiation @ different high D exposure temperatures ≈ 2µm recrystallized bulk W S. Markelj et al. | MoD PMI 2019, Japan | Page 10
WP PFC Simultaneous W/D-D exposure D ions/atoms Simultaneous W/D-D exposure: W ion irradiation @ different high D exposure temperatures - D exposure @ low temperature to ≈ 2µm populate created traps recrystallized D retention a way to determine defect concentration bulk W S. Markelj et al. | MoD PMI 2019, Japan | Page 11
WP PFC Sequential W-D exposure W ions D ions Sequential W-D exposure: W ion irradiation @ different high temperatures - @ low temperature D exposure ≈ 1.2 µm to populate created traps recrystallized D retention a way to determine defect concentration bulk W S. Markelj et al. | MoD PMI 2019, Japan | Page 12
WP PFC Experiment with atoms – 0.28 eV/D Simultaneous/sequential W/D, W-D atom loading Defect population - exposure D atoms @ 600 K – fluence 3.7 ×10 23 D/m 2 2 Collimator slits 4 mm In-beam mesh charge A collector Analysis methods: W 6+ E=10.8 MeV Deuterium depth profile measurement by Nuclear Reaction Analysis (NRA) Sample at high t emperatures ≤ 1000K TDS – final step – D desorption kinetics and D Heater amount Simultaneous/sequential W irradiation and D atom exposure at high temperatures for 4 h W fluence = 1.4x10 18 W/m 2 Atom flux=5.4x10 18 D/m 2 s Dose→ 0.47 dpa KP Γ D =8x10 22 D/m 2 Displ. Rate = 3*10 -5 dpa/s S. Markelj et al. | MoD PMI 2019, Japan | Page 13
Effect of D presence – atom exposure WP PFC Comparison of D concentration Neutron damaging simulated by self implantation Simultaneous W ion damaging and D atom loading Comparison to different damaging procedures Sequential: Damage at T EXP ; D population at 600 K S. Markelj et al. | MoD PMI 2019, Japan | Page 14
Effect of D presence – atom exposure WP PFC Comparison of D concentration Neutron damaging simulated by self implantation Simultaneous W ion damaging and D atom loading Comparison to different damaging procedures Sequential: Damage at T EXP ; D population at 600 K Simultaneous: Damage & D exposure at T EXP ; D population at 600 K Observed synergistic effects but not dramatic – 30 % increase Competition between defect annihilation at elevated temp. and defect stabilization by D For more details see: • S. Markelj, et al, Nuclear Materials and Energy 12 (2017) 169. • E. Hodille et al. Nucl. Fusion 59 (2019) 016011 S. Markelj et al. | MoD PMI 2019, Japan | Page 15
WP PFC Experiment with ions – 300 eV/D Simultaneous/sequential W/D, W-D ion loading Defect population - exposure D ions @ 450 K – fluence 2.7×10 23 D/m 2 Analysis methods: Deuterium depth profile measurement by Nuclear Reaction Analysis (NRA) TDS – final step – D desorption kinetics and D amount • S. Markelj et al, Nucl. Fusion (2019) in press Ion energy 300 eV/D W fluence = 1.0x10 18 W/m 2 • M. Pecovnik et al. submitted to Ion flux=1.3x10 18 D/m 2 s Dose→ 0.35 dpa KP Nucl. Fusion Γ D =1.9x10 22 D/m 2 Displ. Rate = 2.4*10 -5 dpa/s S. Markelj et al. | MoD PMI 2019, Japan | Page 16
WP PFC TDS - Sequential experiment W ion damaging at Sequential W-D; W damaging @ 300 K 300 K – sequential D atom exposure at 600K Single peak Two de-trapping energies 1.82 eV and 2.06 eV D ion exposure at 450K Double peak Five de-trapping energies 1.35 eV - 2.09 eV 3x higher D amount Rate equation modelling (MHIMS, Hodille et al. JNM 2017) S. Markelj et al. | MoD PMI 2019, Japan | Page 17
WP PFC Simultaneous W/D exposure W ions D ions Simultaneous W/D exposure: W ion irradiation @ 450 K D ion exposure ≈ 2µm 4h simultaneous W/D W ions – flux 𝟘. 𝟖𝟒 × 𝟐𝟏 𝟐𝟒 W/m 2 s – 0.34 dpa D ions - Ion flux=1.4x10 18 D/m 2 s Γ D =2.0x10 22 D/m 2 recrystallized bulk W S. Markelj et al. | MoD PMI 2019, Japan | Page 18
Simultaneous W/D exposure @ 450 K WP PFC D depth profile S. Markelj et al. | MoD PMI 2019, Japan | Page 19
WP PFC Simultaneous W/D-D exposure @ 450 K D ions Simultaneous W/D-D exposure: W ion irradiation @ 450 K D ion exposure + D ion exposure @ 450 K – to populate created ≈ 2µm traps 4h simultaneous W/D W ions – flux 𝟘. 𝟖𝟒 × 𝟐𝟏 𝟐𝟒 W/m 2 s – 0.34 dpa recrystallized D ions - Ion flux=1.4x10 18 D/m 2 s. bulk W D fluence=2.0x10 22 D/m 2 + 41h D ion exposure - D fluence 2.1×10 23 D/m 2 S. Markelj et al. | MoD PMI 2019, Japan | Page 20
Simultaneous W/D-D exposure @ 450 K WP PFC D depth profile S. Markelj et al. | MoD PMI 2019, Japan | Page 21
WP PFC Sequential W-D exposure W ions D ions/atoms Sequential W-D exposure: W ion irradiation @ 450 K + @ 450 K to populate D ion exposure ≈ 1.2 µm created traps 4h W irradiation W ions – flux 𝟘. 𝟖𝟒 × 𝟐𝟏 𝟐𝟒 W/m 2 s – 0.34 dpa recrystallized + bulk W 39 h D ion exposure - D fluence 2.0×10 23 D/m 2 S. Markelj et al. | MoD PMI 2019, Japan | Page 22
WP PFC D depth profile comparison @ 450 K S. Markelj et al. | MoD PMI 2019, Japan | Page 23
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