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
Burning Plasma Gap Between ITER and DEMO
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
Fusion Energy Sciences Advisory Committee Report
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/
Criteria For Prioritization of Issues for DEMO
Finding 3: Results of Prioritization of Issues for DEMO
Burning Plasma Issues and Metrics
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)
Fusion Power Source Gain Metric and Gap
QFPP ≈ 30
Q Gap: Today to FPP ~ 50, ITER to FPP ~ 6
Note: Duration Also
Fusion Power Density Metric and Gap
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
Fusion Power Source Control Metric and Gap
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.
Fusion Power Source Interface Issues
• 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?
The Gap from ITER to Tokamak Power Plants
FESAC - Finding 6: Assessment of Gaps (1)
FESAC - Finding 6: Assessment of Gaps (2)
FESAC - Finding 6: Assessment of Gaps (3)
FESAC - Finding 6: Assessment of Gaps (4)
FESAC - Finding 6: Assessment of Gaps (5)
Relationship of Initiatives to Gaps
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
Summary of Burning Plasma Issues
• 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