Prospect of a High Performance, High Radia5on, SteadyState Scenario for CFETR Vincent Chan 1,2 , Jiangang Li 3 , Yuanxi Wan 1 and the CFETR Physics Team 1 USTC 2 General Atomics 3 ASIPP Presented at the 4 th IAEA Demo Workshop Karlsruhe, Germany Nov 15-18, 2016 1
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IAEA Demo Workshop 2016 Chan(draft3) Meeting... · Steady-State with High Duty Cycle is Key to Meeting CFETR Mission 3 Metrics ITER CFETR Phase 1-2 DEMO Neutron wall loading (MW/m
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Prospect of a High Performance, High Radia5on, Steady-‐State Scenario for CFETR
Vincent Chan1,2, Jiangang Li3, Yuanxi Wan1 and the CFETR Physics Team
1 USTC 2 General Atomics
3 ASIPP
Presented at the 4th IAEA Demo Workshop Karlsruhe, Germany Nov 15-18, 2016
1
- Complementing ITER
- Demonstration of fusion energy
production (50-200 MW for Phase I)
- Demonstration of high duty factor, 0.3
– 0.5
- Demonstration of tritium self-
sufficiency with TBR > 1
- Exploring options for DEMO blanket
and divertor solution
- Solution for easy remote
maintenance of in-vessel
components
CFETR Shares Many Characteristics with DEMO
2
Steady-State with High Duty Cycle is Key to Meeting CFETR Mission
0D System Code Used to Scope out CFETR Baseline and Advanced Scenarios
B. Wan, Plasma Science IEEE, 42 (2014) V. Chan, NF 55 (2015) 4
Does not iden*fy specific steady-‐state scenario
Paths to Steady-State Have Experimental Basis
5
Projec5ons From Experiments
Reverse Shear
Hybrid Mode
F.Turco, POP 2015
S.Y. Ding, APS invited talk 2016
ELM control Radia5ve divertor
Challenge: -‐ High fbs -‐ qmin control
Challenge -‐ Flux pumping? -‐ Avoid 2/1
• 0D system code has missing physics
- Pedestal contribution
- Physics-based transport i.e. only assumes H factor
- Profile information and stability
- Achievable βN and fbs
• IM informs key engineering design requirements
- H&CD, Divertor heat and particle fluxes
- Plasma control
• Critical to CFETR diagnostics design and operation
Integrated Modeling (IM) Used to Quantify Reverse Shear (RS) Scenario and Connect with Engineering Design
6
• Physics code suite - TGYRO with NEO and TGLF transport; EPED - ONETWO/NUBEAM/TORAY/GENRAY for sources and sinks;
Ip evolution - EFIT for equilibrium; GATO, ELITE, BOUT++, NIMROD, Nova-
K for stability - SOLPS and OEDGE/DIVIMP for SOL and divertor • Evolving electron density, Te and Ti, and momentum - D&T/He/impurity profiles same as ne and obey quasi-
neutrality - Boundary conditions at pivot point ~ top of pedestal • SOL solution matches core parameters at pivot point
Physics-Based Models and Modeling Assumptions
7
OMFIT Framework Facilitates Self-Consistent Integrated Scenario Development
O. Meneghini, POP 23 (2016) 8
Self-Consistent Transport, Equilibrium and Pedestal: Fully Non-Inductive RS Solution
9
Characteris5cs: - Strong reverse
shear - qmin > 2 - Moderate ITB
forma*on
Optimization of Electron Cyclotron Frequency and Launch Location
E. Poly, Nucl. Fus. 53 (2013) 10
ECCD for controling qmin
Optimization of Neutral Beam Energy
11
• NB has reasonable CD efficiency and is efficient in providing plasma rota*on for good confinement
• NB launch angle is constrained to avoid both large shine through and edge hea*ng.
Use of a Two-NB Strategy
12
• Fixed high energy NB at 300 keV; op*mize low energy NB • 50 keV NB yields the highest Q and lowest edge hea*ng
Confinement Factor Responsible for Differences between OD and 1.5D Predictions
13
H98=1.3 is not achievable even with NB rota*on for baseline case
R=5.7m BT=5T
Pedestal Collisionality has Significant Impact on Fusion Gain
14
• Keeping pedestal pressure fixed, pedestal density is varied • Density increases, DPF unchanged -‐> Q increases significantly • Higher pedestal collisionality might also benefit ELM control PDM=pedestal density mul*plier DPF=density peaking factor
Turbulence Responsible for Weak Density Profile Change with Pedestal Collisionality
15
TEM and ITG turbulence influence par*cle transport in opposite direc*ons resul*ng in weaker profile change
RF Dominated Steady-State Scenario is Another Option
16
NB competes with Tri*um Blanket for port space
Higher BT CFETR (R=6.7m, BT=6T) has Higher Fusion Gain
17
• Confinement improves with larger R and BT ⇒ Lower CD power and higher fusion gain
- High performance, radia5ve core compa5ble with detached divertor
- Performance op5mized using NB and pedestal control - Both NB-‐dominated and RF-‐dominated op5ons are available
- A broad opera5on range in βN and βp, stable with wall at r/a=1.2 - Radia5on in the core acceptable up to Zeff ~ 3.0 - Helium dilu5on fHe cannot exceeds 0.2 to meet Pfus target
Future work will focus on Phase II op5miza5on of the R=6.7m CFETR consistent with steady-‐state and a radia5ve divertor solu5on
Conclusion
29
A reverse-shear, steady-state scenario with performance that meets the CFETR mission has been demonstrated
Acknowledgement
30
Key contributors: J.L. Chen, X. Jian, D. Zhao, L. Lao, C.K. Pan, Z.Y. Li, N. Shi, X.J. Liu, Y.F. Zhou, S.F. Mao, G.Q. Li, P. Zhu, G. Zhuang, M.Y. Ye We are grateful to GA, PPPL, Wisconsin, LLNL, U. York, MPG-‐IPP and U. Toronto for the use of their physics code suites
31
BACK UP SLIDES
• Safety factor and q95
• Rotation profile
• Pedestal collisionality
• Operational space in β
• Radiative core compatible with divertor
Control Aspects in Optimizing CFETR Performance for Reverse Shear Scenario
32
TGYRO Flux Convergence Indicative of Transport Steady-State
J. Candy, POP 16 (2009) 33
All transport channels are evolved to steady-‐state
TGLF Physics-Based Transport Model Improving with Multi-scale GYRO Simulation
34
Low-n ELM Stabilized by Wall at r/a=1.2
35
Heat Flux to Divertor Consistent with Divertor Plate Angle