Burning Plasma Gap Between ITER and DEMO. Dale Meade Fusion Innovation Research and Energy. US-Japan Workshop Fusion Power Plants and Related Advanced Technologies March 5-7, 2008 UCSD, San Diego, CA. Outline. Issues for DEMO (summary of FESAC Report) Burning Plasma Issues
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Fusion Innovation Research and Energy
Fusion Power Plants and Related Advanced Technologies
March 5-7, 2008
UCSD, San Diego, CA
Issues for DEMO (summary of FESAC Report)
Burning Plasma Issues
Gaps in Burning Plasma Issues
Priorities, Gaps and Opportunities: Towards a Long Range Strategic Plan for Magnetic Fusion Energy
Report on FESAC web site: http://www.science.doe.gov/ofes/fesac.shtmlFull Greenwald presentation to FPA (Dec 5, 2007)http://fire.pppl.gov/
1. Fusion Power Gain ( Pf => Qp => ntE, Ti, Lawson)
2. Fusion Power Density (Gn => Pf/Vp => p2, p/B02, p/Bmax2 )
(These are sub-issues under Integrated High Performance Steady State Burning Plasma Issue in the FESAC Panel Report)
QFPP ≈ 30
Q Gap: Today to FPP ~ 50, ITER to FPP ~ 6
Note: Duration Also
Plasma Pressure Gap: from today ~ 6 and 106 in duration
from ITER ~ 3and 103 in duration
Need to update and identify AT modes
M Kikuchi - IAEA 2006
Fusion Power Source Sustainment Metric and Gap
Gap: Today to FPP is very large, ITER to FPP ~ 104
Contributions from EAST,KSTAR, JT-60SA for non-burning plasma
Need a metric for coupling of hi Q(alpha defined profile) and fBS
Also need high Te for high hcd
1. Operation must be on the thermally stable branch of PopCon
• ITER will establish this for a modest AT regime with bN ≤ 3
and fBS ≈ 50%. Is this good enough for a 1st Demo?
2. Need to establish how far the AT regime (negative shear) can be pushed toward high bootstrap % with a pressure profile defined by strong alpha heating.
3. A highly reliable disruption avoidance system compatible with item 2 must be developed.
4. Develop techniques to eliminate large ELMs.
• The AT regimes envisioned require high Te in the core for efficient current drive, and highish Ti at the plasma edge pedestal but low T in the divertor plasma to reduce erosion.
• Significant radiation is required near the plasma edge and on the divertor to spread the thermal exhaust power over a larger area.
• Impact of self-conditioning of PFCs at long pulses and impact of hi Twall on edge plasma and hence confinement.
• Are the existing confinement data base and associated scaling relations for Carbon PFCs relevant to DEMO or FPP?
A Range of Advanced Tokamak Power Plants is Possible
• Is ARIES-I’ an acceptable 1st generation Fusion Power Plant?
The physics can evolve continuously to ARIES-RS and then to ARIES-AT
• First D-T experiments on TFTR and JET confirmed expectations for weakly burning plasmas with fractional alpha heating ~ 10%
• ITER is expected to confirm “steady-state” burning plasma (Q = 5) with 50 % alpha heating and 50% bootstrap fraction. Increases in performance are limited by the power handling capability of first wall and neutron heating of TF conductor.
• Significant gap will still exist between ITER and DEMO
• control of hi-gain Q > 20 (fa > 80%) and hi-bootstrap fraction fbs > 70%
• Possibilities to Bridge the Gap
• Simulations of alpha heating in DD long pulse AT tokamaks • Additional advanced burning plasma experiment
• Upgrade ITER
• Start with ARIES-1 like DEMO and evolve to ARIES-RS, AT