Overview of the ARIES
“Pathways” Program
Farrokh Najmabadi
UC San Diego
8th International Symposium on Fusion Nuclear Technology
Heidelberg, Germany
01– 05 October 2007,
US DOE has made no Commitment
to Fusion Demo
 US Fusion program is viewed as a Science
Program and not an energy program.
 FESAC activities
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FESAC Fusion Development Path Panel (2003)
FESAC Strategic Planning Panel (2007)
 Community activities
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Proposal for many devices.
 ARIES pathways program
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A 3-year activity started in 2007.
A 35,000 ft view
of fusion development
landscape
Early US Fusion Development Path
Partially integrated test of
fusion plasmas and fusion
technologies (Testing in
“prototypical” environment)
Full Integration of fusion
plasma with fusion
technologies (Test in
“actual” environment)
A “1st of the kind”
Power Plant!
“Fusion Power: Research and Development Requirements.”
Division of Controlled Thermonuclear Research (AEC).
US Fusion Development Path
(FESAC Report, 2003)
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Theory, Simulation and Basic Plasma Science
Configuration Optimization
Concept Exploration/Proof of Principle
MFE
Program
MFE PE(s)
Burning Plasma
Complete ITER Ops Phase 1
MFE ITER (or FIRE)
Materials Testing
Materials Science/Development
Complete IFMIF Ops 80 dpa
Prelim. IFMIF Ops 150 dpa
MFE IFMIF
Component Testing
Engineering Science/ Technology Development
Internal Components Design
MFE CTF
Demonstration
Design Studies
US Demo
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Demo Mission From FESAC Development
Path Panel
 US Demo Mission: “Successful operation of the Demo convinces
the users (Public, Regulators, Industry, power producers) that a
commercial power plant can successfully meet all its objectives.”

The ``first-generation'' plant MUST be attractive in terms of economics,
safety, regulation, and environmental characteristics.
 Demo is used to label different devices with different mission
among parties.
 The “perceived” required characteristics of an attractive power
plant are different among parties.
 What is needed to convince the funding agencies that fusion is a
viable power source are different among parties.
In the ITER area,
we need to develop
a 5,000 ft view of Fusion
Development Landscape
The ARIES “Pathways” Program
 What are the remaining major R&D areas?
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What is the data base needed to field a Demo and a
commercial power plant?
What is the impact of each R&D item on the attractiveness
of the final product (metrics for prioritization of R&D)?
 Which of the remaining major R&D areas can be explored in
existing devices or simulation facilities (i.e., fission reactors)?
 What other major facilities are needed (CTF, Fast track, etc.)
 We need to create the data base and experience necessary to
convince investors and regulators that fusion is a viable power
source.
 Validation in an integrated, prototypical environment is needed
before proceeding to Demo.
Elements of ARIES Pathways Program
 Required data base:
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A system-based (concurrent physics/engineering) approach
to identify interconnected physics/engineering constraints
and issues , e.g., Power and particle management, Fuel
management, Operation (reliability, maintenance, off-normal
events), Safety, etc.
“Technical Readiness Level” approach to judge the maturity
of the technology
 Metrics for prioritization of R&D:
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A new approach to Systems Analysis, surveying the design
space (instead of finding only an optimum design point)
 Industrial advisory Committee
Our system-based approach has
Highlighted several operation issues
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Acceptable variations in plasma power (n, T, …) during
normal operation and impact on power handling equipment
(Blankets are currently designed for steady loads.)
Impact of power plant start-up scenarios (regulations dictate
certification tests at different power levels) on plasma
scenarios and power handling equipment.
Precise, in-situ control of tritium breeding (too much
breeding leads to very large inventories).
Characterization of the Impact of off-normal events on
power plant operation.
Industrial approach to testing to develop highly reliable
components.
Excess T production is a concern
Excess Tritium production for 3GW fusion power
Tritium Inventory (kg)
50
TBR=1.2
TBR=1.1
40
TBR=1.05
30
20
Initial Inventory
for a new plant
10
TBR=1.01
0
0
1
2
3
Years of Operation
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Technical Readiness Levels provides
a basis for development path analysis
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TRLs are a set of 9 levels for assessing the maturity of a
technology (level1: “Basis principles observed” to level 9:
“Total system used successfully in project operations”).
Developed by NASA and are adopted by US DOD and DOE.
Provide a framework for assessing a development strategy.
Initial application of TRLs to fusion system clearly underlines
the relative immaturity of fusion technologies compare to
plasma physics.
TRLs are very helpful in defining R&D steps and facilities.
Example: Fuel performance
development in GNEP project
A new approach to System analysis
to better understand the trade-offs
 Typical system analysis of fusion system seek an optimum
set of parameters (minimum cost) based on a set of
constraints.
 Our experience indicates that such “optimum” design points
are usually driven by the constraints.
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In some cases, a large design window is available when the
constraint is “slightly” relaxed, allowing a more “robust” and
credible design.
 Our new approach is to develop a large data base of
candidate design points for a power plant and examine the
available design space using modern visualization and data
mining techniques.
 The data bases currently contains over 106 selfconsistent physics points and undergoing detailed
analysis with engineering and costing packages.
Example of Design space for fusion
power plants
Contours of COE
The first meeting of the ARIES Industrial
advisory Committee meeting was held in
June 2007.
 ARIES Program had a “utility advisory committee” in 90s.
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Their input was used subsequently in all ARIES Designs.
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They helped define mission of a Demonstration Power
Plant (used in FESAC Development Path Panel report)
 Our new Industrial Advisory Committee includes members
from US utilities, Vendors, Architect/Engineers, and regulatory
agencies.
 Discussions in the first meeting of our new Industrial Advisory
Committee revolved around the following two questions.
Are the Prior EPRI Criteria for Practical
Fusion Power Systems still valid?
 EPRI Criteria for Practical Fusion Power include: economics,
public acceptance, and regulatory simplicity.
Economics:
 Utilities will only be motivated to build a fusion power plant if it offers better
economics than other options. The impact of environmental concerns on
future energy prices, however, is not known.
 High reliability and availability are critical: Suggested targets are 70% for
Demo and 90% for commercial plant.
 Steady state operation is essential. The Balance of Plant of a pulsed power
source would be very expensive.
 There is a large effort in developing high-efficiency power conversion system
for fossil fuels. Fusion should try to capitalize on these efforts.
Public Acceptance: There is a large public sensitivity toward tritium.
What are the feature of a Demo relative to
a commercial plant?
 What are the feature of a Demo relative to a commercial plant?
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DEMO must have essentially all the features of the
commercial plant. It is the role of the DEMO to demonstrate
those features and technologies so that the risk of the
commercial plant is acceptable for private investment.
IAC observations on fusion
development
 Relies on large scale, expensive facilities
 Limited scope of data in relevant conditions
 Difficult learning period between facilities (long lead times,
$$$)
 Solution may be to use smaller facilities, integrated with
large scale simulations to minimize risk for DEMO.
Can we use massive simulations to
shorten the development time?
 A major shift to modeling and simulation to minimize testing
requirements and development costs in engineering disciplines.
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Relying on 3-D multi-physics codes which are based on first principle
to analyze components.
 This approach, however, requires a different development
approach:
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Accurate understanding of fundamental physics principles (single
effect issues)
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Experiment planning such that it highlights multi-physics interaction
(instead of traditional approach of testing integrated systems to failure
repeatedly).
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Final validation in an integrated, prototypical environment.
Thank you!
Any Questions?