Major Conclusions of the MFE Study
1. Why a burning plasma

Navratil

2. Burning plasma options

Baker

3. Assessment of contributions of the options

Van Dam

4. Assessment of the feasibility of the options

Taylor

5. Assessment of fusion development paths

Taylor

6. Relation to the national program

PragerCONCLUSION 1

The study of burning plasmas, in which self-heating fromfusion reactions dominates plasma behavior, is at thefrontier of magnetic fusion energy science.
The next major step in magnetic fusion research should bea burning plasma program, which is essential to thescience focus and energy goal of fusion research.

BURNING PLASMAS IS A CRUCIAL ELEMENT IN THE PROGRAM• Study of burning plasmas is a crucial and missing element in thefusion energy sciences program.
• The capability to study burning plasmas will take us a large step
forward in demonstrating magnetic fusion as a source of practicalfusion energy.

WE ARE READY TO TAKE A BURNING PLASMA STEP

• The tokamak is now at the stage of scientific maturity that we areready to undertake the essential step of burning plasma research.
• Present experiments cannot achieve the conditions necessary for aburning plasma.
• A new experimental facility is required to address the importantscientific issues in the burning plasma regime.
• The conditions needed to study the key physics phenomena
expected in the burning plasma state have been identified.

BURNING PLASMAS AFFORD UNIQUEOPPORTUNITY FOR DISCOVERY• Burning plasmas afford unique opportunities to explore, for the firsttime, high-temperature-plasma behavior in the regime of strong selfheating in the laboratory.
• Production of a strongly, self-heated fusion plasma will allow thediscovery and study of a number of new phenomena. These include
the effects of:– Energetic, fusion-produced alpha particles on plasma stability
and turbulence.
– The strong, nonlinear coupling that will occur between fusionalpha particles, the pressure driven current, turbulent transport,
MHD stability, and boundary-plasma behavior.
– Stability, control, and propagation of the fusion burn and fusion
ignition transient phenomena.

ADVANCED TOKAMAK (AT) RESEARCH CAPABILITY IS HIGHLYDESIRABLE IN ANY BURNING PLASMA EXPERIMENT• Recent physics advances in tokamak research, aimed at steady-stateand high performance, demonstrate the potential to significantly
increase the economic attractiveness of the tokamak. Therefore,
Advanced Tokamak (AT) research capability is highly desirable inany burning plasma experiment option.

A BURNING PLASMA WILL MAKE IMPORTANT
CONTRIBUTIONS TO THE FUSION PROGRAM• Physics and technology learned in a tokamak-based burning plasma
would be transferable to other configurations• Scientific flexibility, excellent diagnostics, and close coupling totheory and simulation are critical features of a program in burning
plasmas. Such a program would contribute significantly to thephysics basis for fusion energy systems based on the tokamak- andother toroidal magnetic configurations.
• The experience gained in burning plasma diagnostics, essential toobtaining data to advance fusion plasma science, will be highly
applicable to burning plasmas in other magnetic configurations.

CONCLUSION 2
The three experiments proposed to achieve burning
plasma operation range from compact, high field, copper
magnet devices to a reactor-scale superconductingmagnet device. These approaches address a spectrum ofboth physics and fusion technology, and vary widely inoverall mission, schedule and cost.

MISSION STATEMENT PROVIDED BY THE IGNITOR TEAM•IGNITOR is a facility whose mission isto achieve fusion ignition conditions
in deuterium-tritium plasmas for aduration that exceeds the intrinsic
plasma physics time scales. It utilizes
high-field copper magnets to achievea self-heated plasma for pulse lengths
comparable to the current
redistribution time. IGNITOR will
study the physics of the ignition
process and alpha particle
confinement as well as the heating
and control of a burning plasma
subject to thermonuclear instabilities.

MISSION STATEMENT PROVIDED BY THE FIRE TEAM•

FIRE is a facility whose mission is toattain, explore, understand andoptimize magnetically-confined
fusion-dominated plasmas. FIRE
would study burning plasma physics
in conventional regimes with Q of
about 10 and high-beta advanced
tokamak regimes with Q of about 5
under quasi-stationary conditions.
FIRE employs a plasma configuration
with strong plasma shaping, double
null poloidal divertors, reactor levelplasma exhaust power densities andpulsed cryogenically cooled copper
coils as a reduced cost approach toachieve this mission.

MISSION STATEMENT PROVIDED BY THE ITER TEAM•

The overall objective of ITER is todemonstrate the scientific andtechnological flexibility of fusionenergy. ITER would accomplish thisobjective be demonstrating controlled
ignition and extended burn of
deuterium-tritium plasmas, withsteady-state as an ultimate goal, bydemonstrating technologies essential
to a reactor in an integrated system,
and by performing integrated testing of
the high heat flux and nuclear
components required to utilize fusionenergy for practical purposes.

CONSTRUCTION SCHEDULES FOR THE THREE OPTIONS•

Construction schedules were reported as 5 years for IGNITOR, 6
years for FIRE, and 9 years for ITER.

•

FIRE is not at the same level of readiness as ITER and IGNITOR andwill require some additional time to be ready for construction.

•

ITER must complete international negotiations and agreement
before construction can commence.

COST OF THE THREE OPTIONS

Cost information was obtained from the ITER and FIRE teams and wasassessed within the limited resources available for the Snowmass
work. All costs were converted to 2002-US dollars. ITER assumes aninternational cost-sharing approach while FIRE costs are estimated asa US project.

COST ASSESSMENT OF ITER•

The purpose of the ITER cost information is to provide accurate relative
estimates of the “value” of all the tasks necessary for construction tofacilitate international negotiations on task sharing. The cost information isbased on a large engineering effort (about 1000 PPY) and a large R&D effort(about $900M) with prototypes of all key components. Also, the ITER cost
information (about 85 procurement packages) is based on input from theindustries in all the parties. The estimate of the ITER total “value”, whenconverted to 2002 US dollars, is about $5 billion. The actual cost estimate is
to be developed by each party using their own procedures, including theuse of contingency. Thus, the ITER cost information does not included
explicit contingency.

•

The US will need to carefully estimate the cost of any potential
contributions to ITER. These estimates should include adequate
contingency and any additional required R&D to mitigate against potential
cost increases.

COST ASSESSMENT OF FIRE•

The estimate for FIRE is about $1.2 B including about a 25%
contingency. It is based on an advanced pre-conceptual designusing in-house and some vendor estimates. However, substantial
further engineering is needed as well as some supporting R&D.

COST ASSESSMENT OF IGNITOR•

As an Italian project, IGNITOR has been designed in detail withsupporting R&D. It has a detailed cost estimate which is
confidential for business purposes and was not made available tothe assessment team.

Conclusion 3
IGNITOR, FIRE, and ITER would enable studies of the physics
of burning plasma, advance fusion technology, and contribute to
the development of fusion energy. The contributions of the three
approaches would differ considerably.
•••

IGNITOR offers an opportunity for the early study of nonstationary burning plasmas aiming at ignition.
FIRE offers an opportunity for the study of burning plasma
physics in conventional and advanced tokamak configurations
under quasi-stationary conditions and would contribute toplasma technology.
ITER offers an opportunity for the study of burning plasma
physics in conventional and advanced tokamak configurations
for long durations with steady state as the ultimate goal, andwould contribute to the development and integration ofplasma and fusion technology.

The contributions of the three approaches
would differ considerably.
For the three candidate burning plasma devices, we will list key benefits:i.e., the capabilities for studies of the physics and technology of burning
plasmas (assuming that each facility will achieve its proposed performance).

Common benefits from all three candidate devices
PHYSICS
1.
Strongly-coupled physics issues of equilibrium, stability, transport,
wave-particle interactions, fast ion physics, and boundary physics inthe regime of dominant self-heating.
TECHNOLOGY
2.
Plasma support technologies (heating, fuel delivery, exhaust, plasmafacing components, and magnets) will benefit most becauseparameters and plasma conditions will be close to those required for
power production.
3.
Nuclear technologies (remote handling, vacuum vessel, blankets,
safety and materials) will advance as a result of the experience of
operating in a nuclear environment. The level of benefit will dependon tritium inventory, pulse length, duty factor, and lifetime fluence.

Key benefits from IGNITORPHYSICS
1.
Capability to address the science of self-heated plasmas in a reactorrelevant regime of small ρ* (many Larmor orbits) for globally MHDstable plasmas at low βN (normalized plasma pressure).
2.
Capability to study sawtooth stability at low beta with isotropic alphaparticles and self-consistent pressure profile determined by dominantalpha heating.
TECHNOLOGY
3.
Development of high-field copper magnets with advanced structuralfeatures, including bucking & wedging and magnetic press.
4.
Development of high-frequency RF antennas for wave heating in aburning plasma environment.

Key benefits from FIRE
PHYSICS
1.
Capability to address the science of self-heated plasmas in reactorrelevant regimes of small ρ* (many Larmor orbits) and high βN(normalized plasma pressure) with a large fraction of non-inductive
current sustained for up to a few current relaxation times.
2.
Exploration of high self-driven current regimes with strong shaping
and active MHD stability control.
3.
Study of removal of helium ash and impurities with exhaust pumping.
TECHNOLOGY
4.
Development of electrical insulation for high-field pulsed copper
magnets in high neutron fluence environment.
5.
Development of high heat flux plasma-facing components withsteady-state heat removal capability (tungsten/beryllium).

Key benefits from ITERPHYSICS
1.
Capability to address the science of self-heated plasmas in reactorrelevant regimes of small ρ* (many Larmor orbits) and high βN(plasma pressure), and with the capability of full non-inductive current
drive sustained in near steady state conditions.
2.
Exploration of high self-driven current regimes with a flexible array ofheating, current drive, and rotational drive systems.
3.
Exploration of alpha particle-driven instabilities in a reactor-relevant
range of temperatures.
4.
Investigation of temperature control and removal of helium ash andimpurities with strong exhaust pumping.
TECHNOLOGY
5.
Integration of steady-state reactor-relevant fusion technology: largescale high-field superconducting magnets; long-pulse high-heat-load
plasma-facing components; control systems; heating systems.
6.
Testing of blanket modules for breeding tritium.

CONCLUSION 4
Feasibility Assessment•

There are no outstanding engineering-feasibility issues to prevent thesuccessful design and fabrication of any of the three options.

•However, the three approaches are at different levels of design and
R&D.

•

There is confidence that ITER and FIRE will achieve burning plasma
performance in H–mode based on an extensive experimental database.

•

IGNITOR would achieve similar performance if it either obtains H–mode
confinement or an enhancement over the standard tokamak L–mode.

•

However, the likelihood of achieving these enhancements remains anunresolved issue between the assessors and the IGNITOR team.

The three options are at very different stages ofengineering development• ITER and IGNITOR have well-developed engineering designs.
• ITER has been supported by a comprehensive R&D program.
Also, ITER has demonstrated full-scale prototypes for all major
components of the fusion core and their maintenance.
• FIRE is at the advanced pre-conceptual design level. It has
benefited from previous R&D for CIT/BPX and, most recently,
from ITER R&D.
• IGNITOR has carried out R&D and built full-size prototypes on all
key components.

Projections for the three options are based onpresent understanding of tokamak physics•

Based on 0D and 1.5D modeling, all three devices have baseline scenarios
which appear capable of reaching Q = 5 – 15 with the advocates’ assumptions.
ITER and FIRE scenarios are based on standard ELMing H–mode and arereasonable extrapolations from the existing database.

•

IGNITOR’s baseline scenarios, based on cold edged L–mode, depend on a
combination of enhanced energy confinement and/or density peaking for whicha firm basis has not been established. An unresolved issue arose as to whether
an adequate database exists (proposers) or does not exist (assessors) for
assessing confinement projections in the proposed IGNITOR operationalmodes: L–mode limiter or H–mode with x-point(s) near the wall. Further
research and demonstration discharges are recommended.

•

More accurate prediction of fusion performance of the three devices is not
currently possible due to known uncertainties in the transport models. An
ongoing effort within the base fusion science program is underway to improve
the projections through increased understanding of transport.

A number of issues have been identified
Some Examples•

ITER and FIRE: the predicted ELM-power loads are at the upperboundary of acceptable energy deposition; ELM-control andamelioration is needed.

•

FIRE: control of the neoclassical tearing mode by lower hybrid current
drive is not sufficiently validated.

•

FIRE: radiation damage of magnet insulators.

•

ITER: tritium retention is a concern with carbon-based divertor
materials.
These issues are the subjects of continuing R&D.

Advanced operating regimes are pursued on each
option• Each device presents a reasonable set of advanced scenarios
based on present understanding. ITER and FIRE have moderateand strong shaping respectively and the control tool set neededto address the issues of high beta and steady-state related to
Advanced Tokamak regimes. FIRE has the capability to sustain
these regimes for 1 – 3 current redistribution times, while ITER’s
capability to operate for up to 3000 s allows near steady-state
operation. IGNITOR presents credible advanced performance
scenarios using current ramps and intense heating to produce
internal transport barriers on a transient basis.

CONCLUSION 5.
Fusion Development Path!The
Thedevelopment
developmentpath
pathtotorealize
realizefusion
fusionasasaapracticalpracticalenergy
energy!
sourceincludes
includesfour
fourmajor
majorscientificscientificelements:
elements:
source1)Fundamental
Fundamentalunderstanding
understandingof
ofthe
theunderlying
underlyingsciencescienceandand1)technologyand
andoptimization
optimizationof
ofmagnetic
magneticconfiguration
configuration
technology2)Burning
Burningplasma
plasmaphysics
physics2)3)HighHighperformance,
performance,steady-statesteady-stateoperation
operation
3)4)Development
Developmentof
oflow-activation
low-activationmaterials
materialsand
andfusion
fusion4)
technologies
technologies

Low Activation Materials and Fusion Technologies
Are Needed for Fusion Development! Fusion
Fusionpower
powertechnologies
technologiesare
areaapacepacesetting
settingelement
elementof
of!
fusiondevelopment.
development.Development
Developmentof
offusion
fusionpower
power
fusiontechnologiesrequires:
requires:technologies#"Strong
Strongbase
baseprogram
programincluding
includingtesting
testingof
ofcomponents
componentsin
in#"
non-nuclearenvironment
environmentas
aswellwellasasfission
fissionreactors.
reactors.
non-nuclear#$ Material
Materialprogram
programincluding
includingan
anintense
intenseneutron
neutronsource
source#$todevelop
developand
andqualify
qualifylow-activation
low-activationmaterial.
material.
to#% AAComponent
ComponentTest
TestFacility
Facility forforintegration
integrationand
andtesttestofof#%powertechnologies
technologiesin
infusion
fusionenvironment.
environment.
power

ITER-Based Development Path

! An
Aninternational
internationaltokamak
tokamakresearchresearchprogram
programcenteredcenteredaroundaround!
ITERandandincluding
includingthese
thesenational
nationalperformance-extension
performance-extension
ITER
deviceshave
havethethehighest
highestchancechanceof
ofsuccesssuccessin
inexploring
exploring
devicesburningplasma
plasmaphysics
physicsin
insteady
steadystate.
state.
burning! ITER
ITERwill
willprovide
providevaluablevaluabledata
dataononintegration
integrationof
ofpower-plant
power-plant!
relevantplasma
plasmasupport
supporttechnologies.
technologies.
relevant! Assuming
Assuming successful
successful outcome
outcome (demonstration(demonstration ofof highhigh!
performance AT
AT burningburning plasma),
plasma), an
an ITER-based
ITER-based
performancedevelopment path
path would
would lead
lead toto thethe shortest
shortest development
development
development
timetotoaademonstration
demonstrationpower
powerplant.
plant.
timeMajor Facilities

Base Plasma physics

ITER-Based Development Path
Theory & Simulation
ST, stellarator, RFP, other ICCs
Innovative
Configuration
ETR

Tokamak physics

Decision point
ITER

Tokamak DEMO

14-MeV neutron source

Component Test Facility

Base Technologies

DEMO

Fusion power technologies

Plasma support technologies

FIRE-Based Development Path

! FIRE-based
FIRE-baseddevelopment
developmentplan
planreduces
reducesinitial
initialfacility
facility!
investmentcosts
costsand
andallows
allowsoptimization
optimizationof
ofexperiments
experimentsfor
forinvestment
separablemissions.
missions.
separable! ItIt isis aa lower
lower risk
risk option
option as
as itit requires
requires “smaller”“smaller” extrapolation
extrapolation!
inphysics
physicsand
andtechnology
technologybasis.
basis.
in! Assuming
Assuming successful
successful outcome,outcome, aa FIRE-based
FIRE-based development
development!
path provides
provides further
further optimization
optimization before
before integration
integration steps,
steps,
path
allowing aa more
more advanced
advanced and/or
and/or lessless costly
costly integration
integration step
step
allowing
tofollow.
follow.
toBase Plasma physics

FIRE-Based Development Path
Theory & Simulation
ST, stellarator, RFP, other ICCs
Tokamak physics

Innovative
Configuration
ETR

DEMO

Advancedtokamak ETR

DEMO

Major Facilities

Decision point
FIRE
Steady-state DD (QDT ~ 1-2)
14-MeV neutron source

Base Technologies

Component Test Facility

Fusion power technologies

Plasma support technologies

Role of IGNITOR in Fusion Development! IGNITORIGNITORallows
allowsearly
earlydemonstration
demonstrationof
ofan
animportant
importantfusion
fusion!
milestone,burningburningplasmas.
plasmas.
milestone,! IGNITORIGNITORhas
hasaalowlowinitial
initialfacility
facilityinvestment
investmentcost.
cost.
!
! Because
Becauseofofits
itsshort
shortpulse
pulselength,
length,IGNITOR
IGNITORcannot
cannot!
thoroughlyinvestigate
investigateburnburncontrol
controland/or
and/oradvanced
advancedtokamak
tokamak
thoroughlymodes.
modes.
! IGNITORIGNITORcould
couldbebeananelementelementof
ofaaportfolio
portfolioofof!
experimentssupporting
supportingITER-based
ITER-basedor
orFIRE-based
FIRE-based
experiments
developmentscenarios.
scenarios.
development

Principal Advantages of Different
Development Scenarios!ITER:! Early exploration and optimization of integrated burning plasma, steady state (AT)operation, and plasma support technologies.
! Minimizes number of steps (and time) to tokamak-based fusion power.
!FIRE:! Reduces initial facility investment costs and allows optimization of experiments forseparable missions.
! Provides further optimization before integration steps.
!IGNITOR:! Early demonstration of an important fusion milestone, burning plasmas.
! Low initial facility investment cost.
!Fusion Power technologies are the pace setting element of fusion development. Their!development requires:#" Strong base program including testing of components in non-nuclear environment as wellas fission reactors.
#$ Material program including an intense neutron source to develop and qualify lowactivation material.
#% A Component Test Facility for integration and test of power technologies in fusion
environment.

Conclusion 6
A strong base science and technology program is needed toadvance essential fusion science and technology, and toparticipate effectively in, and to benefit from, the burning
plasma effort. In particular, the development path forinnovative confinement configurations would benefit fromresearch on a tokamak-based burning plasma experiment

A strong base science and technology program is needed toadvance essential fusion science and technology• An accepted premise of the fusion program• The base program includes all the key,fundamental science and technology issues
other than burning plasma science• It is critical to advance the base program in thepresence of a burning plasma experiment

A strong base program is needed to participate effectively in,and to benefit from, the burning plasma effort
for participation, we need
• the full spectrum of physicists and engineers toparticipate in the BPX• Training of new fusion scientists• Tokamak experiments to contribute to the databasesupporting a BPX
to receive benefits, we need
• Theorists to generalize the BPX results• A configuration optimization program so that BPX results
can be used to accelerate concept development

The development path for innovative confinement configurations
would benefit from research on a tokamak-based burning plasma
experimentResearch in innovative confinement configurations aims toadvance fusion plasma physics and to evolve attractive
approaches to fusion energy

Transferability of information enhances the utility of aburning plasma experimentSample list of configurations• Nonaxisymmmetric: stellarator family• q > 1axisymmetric: tokamak family
AT, ST• q < 1 axisymmetric: RFP, spheromak, FRC

Key issues and transferability• α - generated instabilities:physics of spectra, excitation,
damping extend to other configurations; geometric details
differ• α - effects on existing instabilities: drift-precession effects
transferable• Fluctuation-driven α transport: effect on electrostatic
fluctuations, sawteeth transferable• RF wave interactions with α particles : interaction physics
transferable• Burn control, nonlinear coupling: some control aspects
transferable• The unknown: ??

• Transferability requires understanding at afundamental level, through experiment, theory,computation• Nearly all past tokamak results have influenced
other configurations

BPX technology is strongly transferablee.g.,magnets
diagnostics
plasma facing components
heating sources
fueling
blankets
remote handling