1 DEUTERIUM RETENTION IN TUNGSTEN EXPOSED TO CARBON-SEEDED DEUTERIUM PLASMA * Igor I. Arkhipov,...

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  • DEUTERIUM RETENTION IN TUNGSTEN EXPOSED TO CARBON-SEEDED DEUTERIUM PLASMA * Igor I. Arkhipov, Vladimir Kh. Alimov, Dmitrii A. KomarovRion A. Causey*, Robert D. Kolasinski*

    A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, RAS, Moscow, Russia

    *Sandia National Laboratories, Livermore, USAOutlineIntroduction ExperimentalResults & Discussion Conclusions*This work was supported by the United States Department of Energy under Contract 512244 with Sandia National Laboratories

  • Irradiation conditionsIntroduction[1] G.Federici et al., J. Nucl. Mater. 313-316 (2003) 11-22[2] J.P. Coad, et.al., J. Nucl. Mater. 313-316 (2003) 419-423[3] F.C. Sze et.al., J. Nucl. Mater. 266-269 (1999) 1212-1218[4] M.Poon, et al., J. Nucl. Mater. 337-339 (2005) 629-633[5] This work

  • Irradiation conditionsIntroduction[1] G.Federici et al., J. Nucl. Mater. 313-316 (2003) 11-22[2] J.P. Coad, et.al., J. Nucl. Mater. 313-316 (2003) 419-423[3] F.C. Sze et.al., J. Nucl. Mater. 266-269 (1999) 1212-1218[4] M. Poon, et al., J. Nucl. Mater. 337-339 (2005) 629-633[5] This work

  • Distribution of erosion/deposition areas in the JET divertor (1999-2001)**P.Coad, et al., J. Nucl. Mater. 313-316 (2003) 419IntroductionMaterial migration in divertor tokamaks

  • Sputtering yields curves for fusion relevant materials for irradiation by deuterium*(Physical sputtering yields for some ion mass are plotted in the case of W)

    *G.F. Matthews, J. Nucl. Mater. 337-339 (2005) 1-9Introduction100Erosion of carbon by deuterium

  • Scheme of erosion/re-deposition processes within the divertor*

    *G.F. Matthews, J. Nucl. Mater. 337-339 (2005) 1-9IntroductionMaterial migration in divertor tokamaks

  • Ion impact energy at the outer divertor target for a completely detached N2 seeded shorts in JET. The effect of ELMs of different sizes is shown*

    Introduction*G.F. Matthews, J. Nucl. Mater. 337-339 (2005) 1-9Erosion of tungsten by tritium

  • D retention in C seeded D-plasma exposed W Experimental resultsDominant factors: 1. substrate temperature 2. whether carbon is deposited on the W surface

    There is a carbon-impurity concentration of beginning of C-deposition: 0.75% at 850 K 1% at 750 KUncontaminated surface: 1. Blisters, bubbles and/or pits are formed 2. D retention decreases with temperature increase

    C-contaminated surface: 1. a-C:D film or/and W2C layer are formed 2. D retention in C-contaminated W larger than in uncontaminated oneThe most of deuterium are residing in the carbon filmsThin a-C:D film or W2C layer can significantly decrease D-retention in WIntroduction

  • D retention in C seeded D-plasma exposed W Experimental resultsDominant factors: 1. substrate temperature 2. whether carbon is deposited on the W surface

    There is a carbon-impurity concentration of beginning of C-deposition: 0.75% at 850 K 1% at 750 KUncontaminated surface: 1. Blisters, bubbles and/or pits are formed 2. D retention decreases with temperature increase

    C-contaminated surface: 1. a-C:D film or/and W2C layer are formed 2. D retention in C-contaminated W larger than in uncontaminated oneThe most of deuterium are residing in the carbon filmsThin a-C:D film or W2C layer can significantly decrease D-retention in WIntroduction

  • D retention in C seeded D-plasma exposed W Experimental resultsDominant factors: 1. substrate temperature 2. whether carbon is deposited on the W surface

    There is a carbon-impurity concentration of beginning of C-deposition: 0.75% at 850 K 1% at 750 KUncontaminated surface: 1. Blisters, bubbles and/or pits are formed 2. D retention decreases with temperature increase

    C-contaminated surface: 1. a-C:D film or/and W2C layer are formed 2. D retention in C-contaminated W larger than in uncontaminated oneThe most of deuterium are residing in the carbon filmsThin a-C:D film or W2C layer can significantly decrease D-retention in WIntroduction

  • D retention in C seeded D-plasma exposed W Experimental resultsDominant factors: 1. substrate temperature 2. whether carbon is deposited on the W surface

    There is a carbon-impurity concentration of beginning of C-deposition: 0.75% at 850 K 1% at 750 KUncontaminated surface: 1. Blisters, bubbles and/or pits are formed 2. D retention decreases with temperature increase

    C-contaminated surface: 1. a-C:D film or/and W2C layer are formed 2. D retention in C-contaminated W larger than in uncontaminated oneThe most of deuterium are residing in the carbon filmsThin a-C:D film or W2C layer can significantly decrease D-retention in WIntroduction

  • Sputtering yields curves for fusion relevant materials for irradiation by deuterium*(Physical sputtering yields for some ion mass are plotted in the case of W)

    *G.F. Matthews, J. Nucl. Mater. 337-339 (2005) 1-9Introduction100Erosion of tungsten by carbon

  • W erosion as function of Te and C impurity concentration*

    *K. Schmid, J. Roth, J. Nucl. Mater. 313-316 (2003) 302-310IntroductionErosion of tungsten by carbon

  • In this work:Partially contaminated surface in C-seeded D-plasmaIntroduction

  • Top view of magnetron cathode surfaceExperimentalTa mask(680.5 mm3)

  • Irradiation conditions[1] G.Federici et al., J. Nucl. Mater. 313-316 (2003) 11-22[2] J.P. Coad, et.al., J. Nucl. Mater. 313-316 (2003) 419-423[3] F.C. Sze et.al., J. Nucl. Mater. 266-269 (1999) 1212-1218[4] M.Poon, et al., J. Nucl. Mater. 337-339 (2005) 629-633[5] This work

    Experimental

  • Irradiation conditionsExperimental[1] G.Federici et al., J. Nucl. Mater. 313-316 (2003) 11-22[2] J.P. Coad, et.al., J. Nucl. Mater. 313-316 (2003) 419-423[3] F.C. Sze et.al., J. Nucl. Mater. 266-269 (1999) 1212-1218[4] M.Poon, et al., J. Nucl. Mater. 337-339 (2005) 629-633[5] This work*EiZUsheath + 2Ti Te(3Z+1), Usheath3Te/e0 TiTe/2Ei- ion impact energyZ- charge state of the impacting ionUsheath- sheath potentialTe& Ti temperatures of electrons and ions

  • Irradiation conditionsExperimental[1] G.Federici et al., J. Nucl. Mater. 313-316 (2003) 11-22[2] J.P. Coad, et.al., J. Nucl. Mater. 313-316 (2003) 419-423[3] F.C. Sze et.al., J. Nucl. Mater. 266-269 (1999) 1212-1218[4] M.Poon, et al., J. Nucl. Mater. 337-339 (2005) 629-633[5] This work

  • W erosion as function of Te and C impurity concentration*

    *K. Schmid, J. Roth, J. Nucl. Mater. 313-316 (2003) 302-310IntroductionErosion of tungsten by carbon

  • Experimental conditionsExperimental[1] R. Fraunfelder, J. Vac. Sci.Technol. 6 (1969) 388[2] K. Schmid, J. Roth, J. Nucl. Mater. 313-316 (2003) 302-310* T=770 K**T=1030 K

  • Erosion of tungstenExperimentalEstimation: V erosion=1.5-2 m/30 min ~1 nm/s ~61019 at.W/m2sClosed areaPlasma-impact areaInterference fringes(Linnik micro-interferometer)Initial surfaceEroded surface

  • Sputtering yields curves for fusion relevant materials for irradiation by deuterium*(Physical sputtering yields for some ion mass are plotted in the case of W)

    *G.F. Matthews, J. Nucl. Mater. 337-339 (2005) 1-9ExperimentalErosion of tungsten by carbon

  • Experimental conditionsExperimental[1] R. Fraunfelder, J. Vac. Sci.Technol. 6 (1969) 388[2] K. Schmid, J. Roth, J. Nucl. Mater. 313-316 (2003) 302-310* T=770 K**T=1030 K1%C in plasma: 1018 C/m2s 1017 W/m2s

  • The threshold energies of sputtering

    Experimental

  • DEUTERIUM RETENTION IN TUNGSTEN AT HIGH LEVEL OF SURFACE EROSIONExperimental

  • Experimental conditionsExperimental[1] R. Fraunfelder, J. Vac. Sci.Technol. 6 (1969) 388[2] K. Schmid, J. Roth, J. Nucl. Mater. 313-316 (2003) 302-310* T= 773 K**T=1030 K

  • Diffusion coefficient for C in a wide concentration range for C in W**K. Schmid, J. Roth, J. Nucl. Mater. 313-316 (2003) 302-310Introduction

  • Experimental conditionsExperimental[1] R. Fraunfelder, J. Vac. Sci.Technol. 6 (1969) 388[2] K. Schmid, J. Roth, J. Nucl. Mater. 313-316 (2003) 302-310* T= 773 K**T=1030 K

  • Experimental conditionsExperimental[1] R. Fraunfelder, J. Vac. Sci.Technol. 6 (1969) 388[2] K. Schmid, J. Roth, J. Nucl. Mater. 313-316 (2003) 302-310* T= 773 K**T=1030 K

  • H diffusivity vs temperature for W773 KE. Serra, G. Benamati, O.V. Ogorodnikova, J. Nucl. Mater. 255 (1998) 105-115Experimental

  • H diffusivity vs temperature for W773 KR. Fraunfelder, J. Vac. Sci.Technol. 6 (1969) 388Experimental

  • H diffusivity vs temperature for W773 KA.P. Zakharov, V.M. Sharapov, E.I. Evko, Soviet Mater. Sci. 9 (1973) 149Experimental

  • Experimental conditionsExperimental[1] R. Fraunfelder, J. Vac. Sci.Technol. 6 (1969) 388[2] K. Schmid, J. Roth, J. Nucl. Mater. 313-316 (2003) 302-310* T= 773 K**T=1030 KKdiffusion ~ 1 10-9 m2s-1 h=(Dt)1/2~ 1mm

  • Methods of the analysisExperimentalMechanically & electrochemically polishedHot-rolled tungsten foil (99.0 at.%) Size = 680.5 mm3

    C/D-plasma irradiation: planar DC magnetron Eions (D2+; C+; N+, O+, Ta+)= 400 eV Flux=11019 D/m2s, 30 min Deuterium profiles:Nuclear Reaction Analysis (NRA): 0 - 0.5 m: D(3He,)H reaction0.5 - 7 m: D(3He,p)4He reactionDeuterium retention:Thermal Desorption Spectroscopy (TDS)D2 & HD molecules were detected by QMSTemperature range: 300-1100 KHeating rate = 3.2 K/sProfiles & chemical state of impurities:X-ray Photoelectron Spectroscopy (XPS)Depth profiles of C, O, W 3 kev Ar+, 22 mm2, 0.4 m