1. Fuel retention in W as function of dpa level of radiation damage Task 01-08 B. Tyburska

2. 19.07.2010, Garching, EU TF PWI Special Expert Working Groups on Gas balance and fuel retention 2 Motivation Neutron irradiation: Defect production new traps for tritium Transmutation effects Mechanical properties changes ITER divertor [1] Dpa (E th =90 eV [18]) 0.27 Neutron wall loading [MW/m 2 ] 0.4 Operation time [s]2 10 7 Temperature [K]500-1200 Flux [(DT)/(m 2 s)]10 20 -10 22

3. 19.07.2010, Garching, EU TF PWI Special Expert Working Groups on Gas balance and fuel retention 3 Heavy ions as a surrogate for neutrons Large clusters, dense cascades Large energy transfer Lack of radioactivity Short implantation time–damage rate 10 4 higher Potential chemical composition changes–avoided by self- implantation Good temperature control–water cooling Low cost Peaked damage profile, short depth of penetration Difference in recoil spectra No transmutation effects

4. 19.07.2010, Garching, EU TF PWI Special Expert Working Groups on Gas balance and fuel retention 4 Defect morphology MethodNeutronW self-implantation FIM (Field Ion Microscopy) Vacancies (V), interstitials (I), vacancy clusters (VC), no voids [2-8] V, I, VCs, no voids [9-10] TEM (Transmission Electron Microscope) ? PA (Positron Annihilation) V, I, VCs, no voids [11-13] TDS (Thermal Desorption Spectroscopy) ~800 K- D desorption from the ion-induced defects (VCs) [14] Recovery temperature 1200-1350 K [2-5] 1200 K [15-16]

5. 19.07.2010, Garching, EU TF PWI Special Expert Working Groups on Gas balance and fuel retention 5 1. experiment Material: Rolled W from Goodfellow, outgassed 1200 K, 2h D retention dependence on dpa (undamaged, damaged, and recovered W) : Number of traps produced by displacement damage NRA Characterization of ion-induced defects TDS Dpa value given at its peak, calculated for E th = 90 eV

6. 19.07.2010, Garching, EU TF PWI Special Expert Working Groups on Gas balance and fuel retention 6 Deuterium depth profiles

7. 19.07.2010, Garching, EU TF PWI Special Expert Working Groups on Gas balance and fuel retention 7 TDS spectra

8. 19.07.2010, Garching, EU TF PWI Special Expert Working Groups on Gas balance and fuel retention 8 Trapped concentration

9. 19.07.2010, Garching, EU TF PWI Special Expert Working Groups on Gas balance and fuel retention 9 Conclusions Deuterium depth profiles – D is trapped in irradiation-induced defects, with a trapped concentration ~1.3 %, – D concentration up to 6 m was saturated at 0.27 dpa, TDS measurements – D was trapped at the radiation-induced defects associated with peak at ~820K Effect of annealing – Annealing at 1200 K almost fully removes ion-induced defect. Deuterium depth profiles – D is trapped in irradiation-induced defects, with a trapped concentration ~1.3 %, – D concentration up to 6 m was saturated at 0.27 dpa, TDS measurements – D was trapped at the radiation-induced defects associated with peak at ~820K Effect of annealing – Annealing at 1200 K almost fully removes ion-induced defect.

10. 19.07.2010, Garching, EU TF PWI Special Expert Working Groups on Gas balance and fuel retention 10 2. experiment Material: Rolled W from Goodfellow, thick targets outgassed 1200 K, 2h D retention dependence on temperature: Number of traps produced by displacement damage NRA Dpa value given at its peak, calculated for E th = 90 eV

11. 19.07.2010, Garching, EU TF PWI Special Expert Working Groups on Gas balance and fuel retention 11 Deuterium depth profiles

12. 19.07.2010, Garching, EU TF PWI Special Expert Working Groups on Gas balance and fuel retention 12 Temperature dependence Front side: D plasma-defect synergetic effect

13. 19.07.2010, Garching, EU TF PWI Special Expert Working Groups on Gas balance and fuel retention 13 Prediction for Iter [17] Higher trap density but diffusion slower Max. T retention at ~500 K At higher temperatures T desorption and defect recovery lower the total T inventory

14. 19.07.2010, Garching, EU TF PWI Special Expert Working Groups on Gas balance and fuel retention 14 Current work and plans 1)Effective diffusion coefficient: Different W ion incident energies and fluences Deuterium fluences: 10 23 - 5 10 26 D/m 2 = 10 23 –5 10 26 D/m 2 2) D retention dependence on the post-annealing temperature– defects responsible for trapping Different W ion incident energies and fluences – flat damage profiles Post-annealing at different recovery temperatures D plasma exposure

15. 19.07.2010, Garching, EU TF PWI Special Expert Working Groups on Gas balance and fuel retention 15 Current work and plans 3) Transmutation effects: Investigation of the W samples containing Re Re implantation of W 4) D retention as a function of dpa – various materials: Goodfellow Iter grade Japanese Iter grade 5) TEM investigation of defects: ? 6) PALS investigations of the tungsten single crystal

16. 19.07.2010, Garching, EU TF PWI Special Expert Working Groups on Gas balance and fuel retention 16 Literature [1]H.Iida at al., 2004 ITER Nuclear Analysis Report G 73 DDD 2 W 0 [2]L. K. Keys, J. Moteff, J. Nucl. Mater. 34 (1970) 260–280 [3]M. Attardo, J. M. Galligan, Phys. Stat. Sol 16 (1966) 449–457 [4]M. J. Attardo, J. M. Galligan, J. G. Y. Chow, Phys. Rev. Lett. 19 (1967) 73–74 [5]D. Jeannotte, J. M. Galligan, Phys. Rev. Lett. 19 (1967) 232–233 [6]L. K. Keys, J. P. Smith, J. Moteff, Phys. Rev. 176 (1968) 851–856 [7]T. Terao, Y. Hayashi, H. Yosida, Y. Yashiro, Scr. Metall. 12 (1978) 827–829 [8]K. Lacefield, J. Moteff, J. P. Smith, Philos. Mag. 13 (1966) 1079–1081 [9]A. F. Bobkov, V. T. Zabolotnyi, L. I. Ivanov, G. M. Kukavadze, N. A. Makhlin, A. L. Suvorov, Energ. 48 (1980) 326–327, translation to English and published by Springer, New York [10]K. L. Wilson, D. N. Seidman, NBS, Gaithersburg, in: Proc. Conf. on Defects and Defect Clusters in bcc Metals and Their Alloys. Ed. R. J. Arsenault, 216–239, 1973 [11]Z. Shengyun, X. Yongjun, W. Zhiqiang, Z. Yongnan, Z. Dongmei, D. Enpeng, Y. Daqing, M. Fukuda, M. Mihara, K. Matsuta, T. Minamisono, J. Nucl. Mater. 343 (2005) 330–332 [12]T. Troev, E. Popov, P. Staikov, N. Nankov, T. Yoshiie, Nucl. Instrum. Methods Phys. Res. B 267 (2009) 535–541 [13]B. Zgardzińska, B. Tyburska, Z. Surowiec, Proc. Conf. 39th Polish Seminar on Positron Annihilation, Mat. Sci. Forum, to be published [14] B. Tyburska, Ph.D. thesis, University of Maria Curie-Sklodowska, Lublin 2010 [15]B. Tyburska, V. Kh. Alimov, O. V. Ogorodnikova, K. Schmid, K Ertl, J. Nucl. Mater. 395 (2009) 150-155 [16]B. M. Oliver, R. A. Causey, S. A. Maloy, J. Nucl. Mater. 329-333 (2004) 977–981 [17]O. V. Ogorodnikova, B. Tyburska, V. Alimov, K. Ertl, 19th PSI, San Diego 2010 [18]Standard Practice for Neutron Radiation Damage Simulation by Charge-Particle Irradiation, E521-96, Annual Book of ASTM Standards, Vol. 12.02, American Society for Testing and Materials, Philadelphia, 1996, p. 1.