1 / 22

Divertor Design Considerations for CFETR

Divertor Design Considerations for CFETR. Minyou Ye University of Science and Technology of China Houyang Guo a nd Institute of Plasma Physics, Chinese Academy of Sciences 2 nd International Workshop on CFTER May 30 – June 1, Hefei , China. OUTLINE. OUTLINE.

zanta
Download Presentation

Divertor Design Considerations for CFETR

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. Divertor Design Considerations for CFETR Minyou Ye University of Science and Technology of China Houyang Guo and Institute of Plasma Physics, Chinese Academy of Sciences 2ndInternational Workshop on CFTERMay 30 – June 1, Hefei, China

  2. OUTLINE

  3. OUTLINE

  4. CFETR-main parameters (CFETR-00-00-03)

  5. Integral Approach Is Mandatory for the Design of Plasma-Wall Interface

  6. Divertor Is a Key Component for CFETR

  7. Main Challenges for Divertor • Exhaust the major part of the plasma thermal power, reducing heat flux below limitation of target materials. • Removethe fusion reaction helium ash from core plasma while screening impurities from wall. • Maintain acceptable erosion rate in terms of reactor lifetime.

  8. Selection of High Heat Flux Materialsfor DEMO Divertor Target Availability, Cost Melting Point >2000 K Thermal Conductivity >50 W/mK B. Unterberg, 20th PSI Conf. 2012, Germany Low/Medium Activation e.g. TRC Irradiation

  9. Major Problem for W is Melting under Transient Heat Load R. Haange, ITER STAC-12,/2012, Cadarache W melting parameter: emelt 50 MJm-2s-1/2 • Disruptions and unmitigated ELMs are predicted to melt W target for ITER (above). • This will also apply to CFTER Disruption & ELM mitigation are mandatory. • W Melting detection and RH are required to repair W damage.

  10. CFETR Faces Much Greater Challenges than ITER due to Larger Duty Cycle ≥ 0.3 ~ 0.5 General migration pattern seen in today’s devices: main wall erosion, convection into divertor deposition R. Pitts, 2012 KSTAR Meeting • 9 years JET operation ~ 3 ITER QDT = 10 pulses in terms of divertor fluence, important for target erosion and T-retention  Much more serious for CFETR

  11. OUTLINE

  12. ITER-Like Vertical Target Structure full W divertor Inner vertical target (W) Outer vertical target (W) • detachment near strike points. • Reducing peak heat fluxes near strike points Dome (W) Pumping slot Reflector plates (W) Cassette body (SS)

  13. ITER-Like Vertical Target Structure • Subsystems to Integrate in lower part of vacuum vessel: • divertor cassettes with plasma facing components • - cooling system to exhaust plasma and neutronic heat deposition • cryopumps to exhaust neutralized gas • diagnostics to monitor plasma re-attachment • Fuelling system to promote plasma detachment / mitigate re-attachment • RH equipment to maintain components and maintenance operations • System integration : bring together all the component subsystems into one system ensuring that the subsystems function together as a system

  14. SD or DN ? • Advantages of DN: • Larger plasma-wetted area, facilitating power exhaust • Allowing pumping via both top and bottom, facilitating particle exhaust • Naturally large triangularity, facilitating advanced tokamakoperation • Advantages of SN: • Accommodating large plasma volume • Maximizing TBR

  15. OUTLINE

  16. Snow-Fake Divertor to Reduce Peak Heat Load “SNOWFALKE”: USING SECOND-ORDER NULL OF POLOIDAL FIELD TO IMPROVE DIVERTOR PERFORMANCE Features of snowflake divertors • Larger flux-expansion near the PF null • Increased connection length • Increased magnetic shear in the pedestal region (ELM suppression) • Modified blob transport (stronger flux-tube squeezing near the null-point) • Possibility to create this configuration with existing set of PF coils on the existing devices (TCV, NSTX, DIII-D….) • Possibility to create “snowflake” in ITER-scale machines with PF coils situated outside TF coils D. D. Ryutov, PoP 14, 064502 2007 DIII-D

  17. Snow-Fake Divertor to Reduce Peak Heat Load NSTX Snowflake Divertor V.A. Soukhanovskii, NSTX-PAC 31, PPPL, April 17-19, 2012 • Reduction from 3-7 MW/m2 to 0.5-1 MW/m2 between ELMs; Reduction from ~20 MW/m2 to 2-8 MW/m2 at ELM peak.

  18. Snow-Fake Divertor to Reduce Peak Heat Load NSTX Snowflake Divertor V.A. Soukhanovskii, NSTX-PAC 31, PPPL, April 17-19, 2012 • Reduction from 3-7 MW/m2 to 0.5-1 MW/m2 between ELMs; Reduction from ~20 MW/m2 to 2-8 MW/m2 at ELM peak.

  19. Super-X / Isolated Dovertor?

  20. High Temperature Operation? • [P. Norajitra et al., Fus. Eng. Des. 83 (2008) 893.] He-cooled modular divertor with jet cooling (finger concept, KIT)

  21. Approaches to CFETR Divertor Design Optimize Magnetic configurations and target geometry : 1. Optimize Magnetic configurations --- physics design group 2. Design target geometry 3. Calculate distributions of particles and heat using SOLPS code 4. Optimize target geometry Start engineering conceptual design: 1. Preliminary design on target, heat sink, support structure, cooling structure and cassette body… 2. Electromagnetic analysis of the divertor components (DINA/MIT+ANSYS) 3. Neutron volumetric heating calculations (code?) 4. Thermo-mechanical analysis and structure analysis (ANSYS) 5. Optimize divertor structure design

  22. Summary • Start to design ITER-like divertor; further look into other new divertor configurations, e.g., snowflake, isolated divertor configurations. • Start to design single null divertor; examine impact of DN on fusion gain and TBR

More Related