Transcript Mike Holland Briefing - Advanced Energy Technology Program

11/17/99
Briefing for
Dr. Michael Holland
Office of Management and Budget
November 19, 1999
Washington, DC
by
Dr. Charles C. Baker
Director, Virtual Laboratory for Technology
University of California, San Diego
Prof. Farrokh Najmabadi
Head, National Fusion Power Plant Studies Program (ARIES)
University of California, San Diego
Dr. Steven Jardin
Princeton Plasma Physics Laboratory
VLT
Virtual Laboratory for Technology
11/17/99
Main Topics
• The role of enabling technology in the Fusion
Energy Sciences Program.
Science requires technology.
• Contributions of advanced design and analysis
activities.
Continuing guidance to fusion science program.
• Contributions to advances in engineering and
material sciences.
Benefits to other fields of science.
VLT
Virtual Laboratory for Technology
11/17/99
Plasma science and technology is a partnership..
Three Themes
1. Technology enables plasma science research and is
critical to the advancement of MFE confinement and
IFE driver concepts.
2. Technology and materials innovation are necessary
to develop our vision of an attractive fusion
energy source.
3. Technology research makes substantial
contributions to fundamental engineering and
materials sciences.
Advanced design and analysis activities guide fusion research.
VLT
Virtual Laboratory for Technology
The Technology Program is a
multi-institutional national resource.
11/17/99
MIT
GIT
LANL
ANL
ORNL
INEEL
ILL.
RPI
SRL
LLNL
PNL
VLT
UCB
SNL
PPPL
UCSD
UCLA
UCSB
Raytheon
TSI
Maryland
WIS.
SAIC
Lockheed
Martin
General
Atomics
Boeing
Bechtel
Laboratories
Universities
Industries
VLT
Virtual Laboratory for Technology
11/17/99
A Virtual Laboratory for Technology
Mission:
Provide leadership and coordination
for community participation in the
Technology Program including
recommendations on priorities and
Resources.
VLT
Virtual Laboratory for Technology
For Fusion Energy Science
Visit the VLT Web site at: http://vlt.ucsd.edu
• Mechanism for organizing and integrating widely distributed
performing institutions.
• Includes MFE technologies and IFE chamber and target technologies.
• Enhanced use of peer review to ensure high quality of research activities.
• VLT Director serves as a principal representative and spokesperson for
Technology in the larger fusion community.
VLT
Virtual Laboratory for Technology
11/17/99
Advanced Design and Analysis activities
incorporate state-of-the-art scientific models and
help guide fusion research.
• National Fusion Power Plant Studies Program.
Recent studies completed:
–ARIES-RS reversed-shear tokamak;
–ARIES-ST spherical torus.
Current focus is on advanced tokamaks.
• Assessment of near-term applications of fusion
neutrons.
• Assessment of IFE critical issues.
• Concept exploration studies.
• Studies of markets, customers, and the role of
fusion in a sustainable global energy strategy.
VLT
Virtual Laboratory for Technology
11/17/99
Advanced Design Program Performs Integrated
Analysis
• Detailed and in-depth analysis is necessary to make scientific
progress and impact the R&D program:
 Interaction and trade-off among plasma parameters (MHD b limit,
heating & current-drive, divertor, transport);
 Interfaces between fusion plasma and other components (e.g.,
restriction on plasma elongation by location of stabilizer, and
triangularity by inboard divertor slot)
 Invoke physics and engineering constraints which are not in
present-day experiments (e.g., simultaneous high power and high
particle flux to divertor)
• In many areas models and tools necessary to analyze fusion
systems are developed.
VLT
Virtual Laboratory for Technology
11/17/99
Advanced Design Program Identifies Key R&D Issues and
Provides a Vision for the Program
What is important
Progress in
Plasma Physics:
What is possible
ARIES Program
Physics Limits
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Macroscopic stability
Wave-particle interaction
Microturbulence & transport
Plasma-material interaction
Stimulus for new ideas
Theory Program
What has been achieved
What to demonstrate
Experiments
ARIES studies have influenced research priorities in each of these areas and have been guided
by new experimental trends and theoretical concepts.
VLT
Virtual Laboratory for Technology
11/17/99
Advanced Design Program Has Had A
Major Impact on Tokamak Research
Major Physics Results
• Introduced the trade-off between plasma b and
•
bootstrap current.
Showed that high-field magnets can be utilized
to compensate for low b.
• Showed that true benefit of 2nd Stability regime
was to reduce the current-drive power not
increased b.
Impact on the Program
Initiation of Advanced Tokamak
Research.
 KSTAR construction and TPX
experiment design were influenced
significantly.
• Demonstrated that (1) in pulsed-tokamaks the
plasma b is limited by ohmic profile constraint,
(2) physics of pulsed and steady-state tokamaks
are essentially the same; (3) steady-state outperforms pulsed operation because of
technological constraints.
• Developed reversed-shear equilibria appropriate
to power plants. It included a self-consistent
divertor/plasma edge conditions with acceptable
impact on ideal MHD, current drive, and power
balance.
 Major theoretical and experimental
activities on advanced tokamaks.
ARIES-RS is the present goals of
advanced tokamak research (DIII-D, CMod, FIRE).
Recognition at Snowmass that any
burning plasma experiments must have
advanced tokamak capability.
VLT
Virtual Laboratory for Technology
11/17/99
Tokamak Research Has Been Influenced
by the Advanced Design Program
Current focus of tokamak research
bA/S ( Plasma b)
“Conventional”
high-b tokamaks
(Pulsed operation)
PU: Pulsed Operation
SS: 2nd Stability
FS: 1st Stability, steady-state
RS: Reversed-shear
2nd Stability
high-b tokamaks
(Too much bootstrap)
Advanced tokamak
(balance d bootstrap)
bp /A ( Bootstrap current fraction)
VLT
Virtual Laboratory for Technology
11/17/99
Advanced Design Program Has Had
A Major Impact on Alternative Concept Research
Major Scientific Results
• Spherical Torus: Developed the first selfconsistent stability and current-drive calculations
of high-b, high bootstrap current ST equilibria.
Showed that high plasma elongation (k = 3) is
necessary. Showed resistive ST center-posts can
be designed to operate in power-plant conditions
• Stellarator: Developed a new stellarator
magnetic configuration to address the issue of
large size.
• Reversed-Field Pinch: Identified the need to
operate with a highly radiative core, poloidal
divertors, and an efficient current drive system so
that a compact RFP can be realized.
Impact on the Program
 NSTX is influenced by ARES-ST
The next step in ST program, DTST, uses
ARIES-ST as the target.
Initiated a large interest in compact
stellarator research in US.
Experiments on ZT-40 with a highly
radiative core and helicity-injection currentdrive. ZT-P device was built to study
poloidal divertors for RFPS;
Design and experimental program on ZT-H
were modified to address these issues.
VLT
Virtual Laboratory for Technology
11/17/99
The ARIES-ST Study Has Identified Key Directions for
Spherical Tokamak Research
•
Substantial progress is made towards
optimization of ST equilibria with >95%
bootstrap fraction:
 b = 54%, k = 3
•
A feasible center-post design has been
developed.
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Several methods for start-up have been
identified.
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Current-drive options are limited.
•
1000-MWe ST power plants are
comparable in size and cost to
advanced tokamak power plants.
VLT
Virtual Laboratory for Technology
11/17/99
Advanced Design Program Has Had A Major Impact on
Fusion Technology Research
Major Fusion Engineering Results
• Introduced SiC composites as a highperformance fusion material.
• Explored gas injection and impurity radiation to
reduce heat load in the divertors.
• Innovative superconducting magnet designs
using plates and a structural cap (later used in
ITER).
• Demonstrated benefits of RF systems (especially
fast waves) for current drive and the respective
launchers (e.g., folded wave-guides).
• Introduction of advanced manufacturing
techniques which reduce the unit costs of
components drastically.
• Emphasis on safety & environmental aspects of
Impact on the Program
Large world-wide research activity on
SiC composites material.
Experiments in linear plasma machine
and later in large tokamaks.
Current goals of magnet R&D program.
Spurred interest in RF current drive
experiments (e.g., fast-wave current
drive in DIII-D in mid 90s).
Application in next-generation
experiments.
Direct impact on research on fusion
materials and chamber technologies
fusion.
VLT
Virtual Laboratory for Technology
11/17/99
Impact of Latest Developments in Other Scientific
Disciplines Are Continuously Considered.
Examples include:
• SiC Composites (Aerospace)
• High-temperature superconductor
• Advanced manufacturing techniques (Aerospace)
• Advanced engineered material for high heat-flux
components
VLT
Virtual Laboratory for Technology
11/17/99
Engineered Microstructure of Porous Media Enables High
Heat Flux Removal
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Enhanced heat transfer surface area
Increased turbulence and boundary layer
modification near heat transfer surface
Reduced radiation opacity
Ultramet Foam
ESLI High Porosity Fibrous material
VLT
Virtual Laboratory for Technology
11/17/99
National Advanced Design Program Allows Fusion Scientists
to Investigate Fusion Systems Together
• The team comprises key members from major fusion centers (universities,
national laboratories, and industry). A typical team member spends 25% of
his time on this activity. About 2/3 of resources is allocated to universities
this year. Seven students were supported last year.
• Decisions are made by consensus in order to obtain the best technical
solution without institutional bias.
• Team is flexible and expert groups and advocates are brought in as needed to
ensure the flow of the latest information from R&D program. As such, highleverage issues are readily transferred back to the R&D program.
• Workshops and “Town Meetings” are held for direct discussion and
dissemination of the results
• Because we draw from expertise of the national program, we are unique in the
world in the ability to provide a fully integrated analysis of power plant
options including plasma physics, fusion technology, economics and safety.
VLT
Virtual Laboratory for Technology
11/17/99
IFE Chambers Requirements and Options
• About 100 MJ of X-rays and debris Ions are released by the target over about
10 ns. For a practical chamber size, the energy load on an “un-protected”
chamber wall is about 2GW/m2
Options:
• Gas Protection: Low-density high-Z gas in the chamber absorbs X-rays and
debris and radiate in 0.1 to 100 ms.
• Wetted Walls: Thin liquid layer absorbs the incident energy. The evaporated
material recondenses on the chamber wall.
• Thick Liquid Wall: Energy yield is absorbed by regenerating liquid walls.
• For each option, the chamber environment should return to its “normal”
condition in about 100 to 200 ms.
VLT
Virtual Laboratory for Technology
11/17/99
Integrated Analysis of IFE Chambers Requires
State-of-the-Art Analysis in Several Areas
• Material response to intense target yield: Response of the solid and
liquid material (chamber wall and final optics) and gases to intense
target emissions (plasma, X-rays, neutrons).
• Chamber clearing: Understanding the limits on chamber clearing rates
set by radiation cooling from optically thick and/or thin plasma-gas
regimes, followed by molecular recombination, and then condensation
on surfaces or droplets.
• Beam Transport: Investigation of beam transport (lasers/heavy ions)
through final optics and chamber in plasma-gas environment.
• Target Injection and Heating: Understanding the effects of target
heating on cryogenic fuel layers due to thermal radiation, conduction,
and convection in the chamber. Investigation of the impact of chamber
environment on target trajectory.
VLT
Virtual Laboratory for Technology
11/17/99
National Advanced Design Program Is a HighLeverage Research Effort
• High Quality of Science: Detailed and in-depth analysis is necessary to make scientific
progress.
• High-Leverage Research: Integrated design & analysis beyond current experiments
identifies key R&D Issues.
• Community input and consensus: An environment is created for fusion scientists to
investigate fusion systems together. Team members bring in the latest information from
R&D program. State-of-art analysis, innovation, and high-leverage issues are readily
transferred back to the R&D program.
• Interaction with other disciplines: Impact of latest development in other scientific fields
on fusion systems are evaluated.
• Impact on Education: Approximately 2/3 of the research is performed by universities
(UCSD, U. Wisc., RPI, MIT). Seven students were supported by this activity last year.
• A high-leverage niche on the international fusion program. It is recognized
internationally as a credible driving force towards an attractive end product and influences
world-wide fusion research.
VLT
Virtual Laboratory for Technology
11/17/99
The unique environment of a fusion plasma
requires advances in the engineering sciences.
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Materials science
Fluid dynamics and magnetohydrodynamics
Plasma-material interactions
Surface science and atomic physics
Heat and mass transfer, thermomechanics
Chemistry
Aerosol science
Magnet science and superconductivity
Beams, accelerators & coherent radiation
generation
• Nuclear science
VLT
Virtual Laboratory for Technology
11/17/99
Technology Research Contributes to Engineering
and Materials Science
Molecular dynamics
simulations provide
fundamental understanding of damage
mechanisms and
allow extrapolations
from fission data
Liquid metal magnetohydrodynamics and
turbulence in open (free surface) and closed
channel flows push the frontiers of fluid sciences
Surface physics, combined with molecular
processes in a magnetized plasma boundary
region, lead to highly complex phenomena with
relevance to plasma processing and other
near-term applications
VLT
Virtual Laboratory for Technology
11/17/99
Plasma Technologies are required for fusion science.
Achieve and Sustain Advanced Plasma Performance:
Fusion power density:
pf ~ <b2 > B4
Burn condition:
nTt ~ (b/c)a2 B2
• Profile Control Technologies:
• Heating/current drive/fueling:
• Increase b and b limits
• Reduce c, generate ITB
• Disruption Mitigation/Control:
• Pellet/gas/liquid injection:
• Enable operation near
ultimate b potential
• Magnet Technology:
• High performance, low cost:
• Improved strand, insulation,
structural materials, thermal
isolation, quench protection, joints
• PFCs/PMI:
• Plasma boundary control for edge
transport barriers
• High heat flux/low erosion PFC’s to
cope with higher power densities
VLT
Virtual Laboratory for Technology
11/17/99
The Levitated Dipole Experiment (LDX)
A Science-Technology Partnership
1.3 MA, 0.8 m diameter, 5T
Floating Coil
Experiment for HighTemperature Plasma
Experiments and Fusion
Science Research
The development of the LDX superconductor is a good example of
mutually beneficial efforts between fusion and high energy physics
technology development.
VLT
Virtual Laboratory for Technology
11/17/99
Plasma Materials Interaction Science
Is Key to Plasma Performance.
The DiMES probe in the DIII-D
tokamak provides essential data
on plasma material interactions.
Key Scientific Issues:
• Plasma erosion mechanisms
• Hydrogen retention
• Impurity generation and transport
VLT
Virtual Laboratory for Technology
11/17/99
Plasma Disruptions are a key issue involving plasma,
material and engineering science.
• Main mass loss mechanisms:
– Vaporization
– Ablation - macroscopic particles (droplets)
• Processes that decrease net mass loss of walls:
Vapor Shield
– Vapor cloud absorbs incoming energy flux W0
– Conversion to back radiation (secondary radiation)
– Decrease heat load on surface to <10% W0
Droplet Shield
– Due to ablation (splashing), the surface emits droplets; therefore, cloud of vapor
and macroscopic particles exist nearby the exposed surface.
– Droplets (macroscopic particles) absorb radiation power and decrease heat load
onto surface.
– Droplets vaporization path length depends on vapor dynamics in oblique
magnetic field.
VLT
Virtual Laboratory for Technology
11/17/99
ALPS - Advanced Limiter-divertor
Plasma-facing Systems
• Develop systems that can lead to enhanced power density,
component lifetime, and power conversion efficiency, and may
provide for plasma edge control and particle pumping.
• Present effort is on plasma edge modeling, laboratory PMI
studies of candidate liquids, and thermalhydraulics, including
MHD effects.
• Future effort is aimed at tests in
plasma devices, e.g. DIII-D (DiMES)
and, CDX-U, leading to a concept
exploration test a large existing
device.
VLT
Virtual Laboratory for Technology
11/17/99
Liquid surfaces for limiters and divertors offer
potentially significant advantages.
A Science-Technology Partnership
CLIPPER Project Facility: CDX-U Tokamak with UCSD local liquid
lithium limiter L3 and PPPL toroidal liquid lithium belt limiter.
liquid
R = 0.34 m
lithium
a = 0.22 m
local rail
A = R/a > 1.5
limiter
k<2
Bt < 0.5 Tesla
Ip < 150 kA
Prf = 300 kW
Plasma flat top 30 ms
Extensive plasma
diagnostics
center
stack
liquid
lithium
belt limiter
VLT
Virtual Laboratory for Technology
11/17/99
APEX
Exploring new concepts that substantially improve
the vision for an attractive fusion energy system.
• High Power Density
• High Thermal Efficiency
Scientific Issues
•Liquid wall - plasma
interaction
•Free surface turbulence
•Magnetohydrodynamic
effects in liquid metal flows
•Magnetohydrodynamic
effects in low-conductivity
fluid flows
•Influence of a magnetic field
on heat transfer
•Influence of a magnetic field
on heat transfer
• Inherent Low Activation
• Reduce Waste
Related Applications
•Turbulent drag reduction
•Crystal growth
•Oceanography
•Atmospheric processes
•Liquid dispersion including
droplet formation
•Solidification
•MHD propulsion
•Casting
VLT
Virtual Laboratory for Technology
11/17/99
Utilizing a conducting liquid
flowing in a strong magnetic field
requires understanding of MHD
phenomena and development of
accurate MHD modeling techniques
Plasma stability and
transport may be seriously
affected – and potentially
improved – through various
mechanisms:
control field penetration,
H/He, pumping, passive
stabilization, etc.
Liquid surface temperature
and vaporization is a critical,
tightly-coupled problem
between plasma edge and
liquid free surface conditions
including: radiation spectrum
and surface deformation,
velocity, and turbulence
characteristics
Controlling the free surface
flow configuration in complex
geometries, including
penetrations needed for plasma
maintenance, is a challenging
problem on the
cutting edge of CFD
VLT
Virtual Laboratory for Technology
11/17/99
SUMMARY
• Scientific understanding and improved magnetic
confinement and inertial driver concepts need improved
technology.
• Advanced design and analysis activities contribute to
resolution of key scientific issues and provide continuing
guidance to fusion science research.
• Enabling Technology R&D also leads to improved
understanding by advancing engineering and materials
science and near-term benefits.
• Essentially all aspects of Enabling Technology R&D are
highly leveraged with well-established international
collaborations.
VLT
Virtual Laboratory for Technology