1 / 16

Deuterium retention on HT-7 with full metal PFMs

Deuterium retention on HT-7 with full metal PFMs. H.Y. Wang, J.S. Hu, X. Gao, B. Cao Institute of Plasma Physics, Chinese Academy of Sciences, China. 1. outline. Introduction Retention in tokamaks Motivation Method: Particle balance Retention in various materials Molybdenum PFMs

rhett
Télécharger la présentation

Deuterium retention on HT-7 with full metal PFMs

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Deuterium retention on HT-7 with full metal PFMs H.Y. Wang, J.S. Hu, X. Gao, B. Cao Institute of Plasma Physics, Chinese Academy of Sciences, China 1

  2. outline • Introduction • Retention in tokamaks • Motivation • Method: Particle balance • Retention in various materials • Molybdenum PFMs • Lithium PFMs • Boron PFMs • Summary 2

  3. Retention in tokamaks • Fuel retention on walls would lead recycling and density control problem which would terminate plasma discharge, specially in a long plasmas required in future SSO fusion devices; • Fuel retention would also cause safety problem, such as T operation in ITER. • In 2011, HT-7 PFMs was changed from C to Mo, and Li coating become main method for wall conditioning. 3

  4. Motivation • Investigation of D retention on different plasma facing materials, such as Mo, Li and B coated films. • Comparison with the previous retention on doped graphite on HT-7. • Realize the PFMs influence on fuel retention. • Provide data accumulation for EAST(PFM will be Mo/W) and ITER. 4

  5. Method • Particle Balance (PB) • Real-time • Global inventory • Couldn’t give location ofretention • Post-mortem Analysis (PA) • Location of retention • Accumulated retention • Couldn’t tell inventory of one shot or one day • During 2011 campaign of HT-7: • Mo tiles: 1.28m2 • Li coating: 28 times (totally 350g) • 1 boronization following Li coatings 5

  6. outline • Introduction • Retention in tokamaks • Motivation • Method: Particle balance • Retention in various materials • Molybdenum PFMs • Lithium coating PFMs • Boron PFMs • Conclusion 6

  7. 2.1 Retention on Mo tiles • In beginning shots, D release from walls due to disruptions. • D retention during D wall conditioning before plasma operation; • Most of plasmas was disrupted at low current， I<90KA, t<1s. • Very small fueling, <30Pa.l • After ~100 plasma discharges, the retention ratio increased, but lower than ~10%. 7

  8. 2.2 Retention on Li coated films • After Li coating • Retention ratio increased (Mo). • Required more fueling. After the 4th Li coating, the retention ratio increased 20%. 8

  9. After each coating, high retention ratio on fresh films, then it decreased slowly to a steady value; • Steady retention ratio after each coating also increased with increasing of coated Li quantity. The 27th time lithium coating Fueled gas: 1000~1500 Pa.l 9

  10. 2.3 Retention on B films • Boronization: • Followed 28 Li coatings • 3g C2B10H12 • After the boronization, • Abundant H released (80% in pumped gases); • H/(H+D) raised from 20% to 80%; • Increase retention ratio, possible due to H-D exchange; 10

  11. The inventory divide by plasma length is called retention rate • Although the Li films stable retention ratio is higher than the boron's, their stable retention rate is almost same (400 Pa.l/s). • The H/(H+D) can explain this well. 11

  12. Accumulated influence • The retention fuel increased shot by shot, there is no signal of saturation (Li, B films). 12

  13. Comparison (HT-7)

  14. outline Introduction Retention in tokamaks Motivation Method: Particle balance Retention in various materials Molybdenum PFMs Lithium coating PFMs Boron PFMs Summary 14

  15. Summary • We have systemically investigate D retention on various walls, such as Mo, Li and B coated films, in 2011 campaign of HT-7; • Compared with Mo (possible W), it was found Li and B films, also C has a high retention ratio for D retention; • The different of the retention on various walls maybe reveal its various mechanism; • This research would give same reference for D retention on Mo walls in EAST, and data accumulation for T retention in ITER.

  16. Thanks for your attention! • Acknowledgments • This research is funded by National Magnetic confinement Fusion Science Program under contract 2010GB104002 and the National Nature Science Foundation of China under contract 11075185. • Thank Bernard PEGOURIE from IRMF for his useful discussion for some basic issues. 16

More Related