Exploring the Frontiers of Burning Science

Dale Meade and the FIRE Team
ITC-12 / APFA ’01 Meeting
December 14, 2001
Toki, Japan

http://fire.pppl.gov

Is an Opportunity Emerging for Fusion in the U. S.?
Secretary of Energy – Abraham - DOE Mission and Priorities – Oct. 24, 2001
(to DOE Lab Directors and DOE)
“I would add to this list two priorities that deserve special mention. The first
involves the unique technological contribution we can make to our energy andnational security by finding new sources of energy. Whether it is fusion or ahydrogen economy, or ideas that we have not yet explored, I believe we need toleapfrog the status quo and prepare for a future that, under any scenario, requires a
revolution in how we find, produce and deliver energy.”“I intend, therefore, that this Department take a leadership role in exploring how we
can identify and use potentially abundant new sources of energy with dramatic
environmental benefits.”

By end of January conduct a strategic missions review to:...identify new sources of energy......

Federal Reserve Chairman Greenspan - On Energy Supply – Nov. 13, 2001
(Rice University)“In the more distant future remains the potential of fusion power. A significant
breakthrough in this area has been sought for years but seems discouragingly
beyond reach. But success could provide a major contribution to our nation's future
power needs. The input costs of fusion power would be minor, and it produces
negligible nuclear waste or pollutants.”

What should we do to be ready?

Activities in the U. S. to Assess Next Steps in MFE• House of Representatives passed the Energy Authorization Bill (HR 4) on
August 1, 2001. The U. S. Senate has prepared a similar bill regarding fusion.
1. Calls for strengthening the base fusion sciences program
2. Directs DOE to submit a plan for construction of a U.S. Burning Plasma
Experiment to Congress by July 2004. In addition, DOE may also develop
a plan for United States participation in an international burning plasma
experiment for the same purpose, if it’s construction is highly likely andcost effective for the U. S. relative to a domestic experiment.
• Fusion Energy Sciences Advisory Committee (FESAC) endorses
recommendations of FESAC Burning Plasma Panel.
• National Research Council is preparing a proposal to review burning plasma
physics as required by HR 4 and recommended by FESAC.
• Preparations are beginning for a Snowmass Summer Study 2002 that willemphasize burning plasmas. International participation is encouraged.
Full text on http://fire.pppl.gov

Fusion Frontiers to be Explored by the
Next Stage of Fusion Research• Burning Plasma Physics- strong nonlinear coupling inherent in a fusion dominated plasma- access, explore and understand fusion dominated plasmas• Advanced Toroidal Physics- develop and test physics needed for an attractive MFE reactor- couple with burning plasma physics• Boundary Physics and Plasma Technology (coupled with above)- high particle and heat flux
- couple core and divertor- fusion plasma - tritium inventory and helium pumping• Neutron Resistant Materials (separate facility)- high fluence testing using “ point” neutron source• Superconducting Coil Technology does not have to be coupled tophysics experiments - only if needed for physics objectives• Nuclear Component Testing should wait for the correct reactor materials

The Multi-Machine Strategy for Magnetic Fusion
Second Phase
ScientificFeasibility
Three Large Tokamaks

Third Phase

Fourth Phase

Burning Plasma
Scientific BaseElectric Power
Feasibility

Commercialization
Phase
Economic
Feasibility

International Program

JT-60 U

Burning D-T

JET

Adv. Long Pulse D-D

TFTR

Materials Develop

Choice ofConfiguration

Scientific Foundation

Advanced
DEMO

Attractive
Commercial
Prototype

Non-Tokamak Configurations

Technology Demonstration

Long Pulse Adv. Stellarator

Tokamak burning plasma infrastructure could also
provide facility to test non-tokamak configurations.

Spherical Torus, RFP
Spheromak, FRC, MTF

1985

2005

Reduced Technical Risk

2050

2020
Streamlined Management Structure

Increased Technical Flexibility

Better Product/Lower Overall Cost

Faster Implementation(The overall Multi-Machine Strategy includes IFE)

Outline• Objectives for a Next Step Experiment in Magnetic Fusion• Burning Plasma Performance Considerations• Compact High Field Approach - General Parameters• Advanced Tokamak Longer Pulse Possibilities• SummaryNext Step Option Program Advisory Committee• Members: Tony Taylor (Chair), Gerald Navratil, Ray Fonck, David Gates,
Dave Hill, Wayne Houlberg, Tom Jarboe, Mitsuro Kikuchi, Earl Marmar, Raffi
Nazikian, Craig Petty, Rene Raffray, Paul Thomas, James VanDam• Meetings
July 20-21, 2000 at General Atomics, San Diego, CA.
January 17-18, 2001 at MIT, Cambridge, MA
July 10-11, 2001 at Univ. Wisc, Madison, WI
November 29-30, 2001 at LLNL, Livermore, CA• Charge for First meetings
Scientific value of a Burning Plasma experiment
Scientific readiness to proceed with such an experiment
Is the FIRE mission scientifically appropriate?
Is the initial FIRE design point optimal?
Preparation for Snowmass Assessment• Extensive PAC Reports provide detailed recommendations for the FIRE activity
to address. NSO-PAC reports are on FIRE (http://fire.pppl.gov), will discuss inmore detail under FY 2001-03 Plans.

Contributors to the FIRE Design Study
FIRE is a design study for a major Next Step Option in magnetic fusion and is
carried out through the Virtual Laboratory for Technology. FIRE has benefited
from the prior design and R&D activities on BPX, TPX and ITER.
Advanced Energy Systems
Argonne National Laboratory
DAD Associates
General Atomics Technology
Georgia Institute of Technology
Idaho National Engineering Laboratory
Lawrence Livermore National Laboratory
Massachusetts Institute of Technology
Oak Ridge National Laboratory
Princeton Plasma Physics Laboratory
Sandia National Laboratory
Stone and Webster
The Boeing Company
University of Illinois
University of Wisconsin

Fusion Science Objectives for a
Major Next Step Burning Plasma Experiment
Explore and understand the strong non-linear coupling that isfundamental to fusion-dominated plasma behavior (self-organization)• Energy and particle transport (extend confinement predictability)• Macroscopic stability (β-limit, wall stabilization, NTMs)• Wave-particle interactions (fast alpha particle driven effects)• Plasma boundary (density limit, power and particle flow)• Test/Develop techniques to control and optimize fusion-dominated plasmas.
• Sustain fusion-dominated plasmas - high-power-density exhaust of plasma
particles and energy, alpha ash exhaust, study effects of profile evolution due toalpha heating on macro stability, transport barriers and energetic particle modes.
• Explore and understand various advanced operating modes and configurations infusion-dominated plasmas to provide generic knowledge for fusion and non-fusion
plasma science, and to provide a foundation for attractive fusion applications.

Advanced Burning Plasma Exp't Requirements
Burning Plasma Physics (Elmy H-Mode)Q≥ 5,fα = Pα/Pheat≥ 50%, ~ 66% as target, up to 83% at Q = 25

TAE/EPMstable at nominal point, able to access unstable~ 10 as target,

ignition not precluded

Advanced Toroidal Physics (Reversed Shear ITB)
fbs = Ibs/Ip≥ 50% as target AT

βN~ 2.5, no wall

up to 75% allowed~ 3.6, n = 1 wall stabilizedQuasi-stationary
Pressure profile evolution and burn control> 10 τE

Alpha ash accumulation/pumping> several τHe

Plasma current profile evolution

1 to 3 τskin

Divertor pumping and heat removal

several τdivertor, τfirst wallOptimization of a Burning Plasma Experiment• Consider an inductively driven tokamak with copper alloy TF and PF coils
precooled to LN temperature that warm up adiabatically during the pulse.
• Seek minimum R while varying A and space allocation for TF/PF coils for a
specified plasma performance - Q and pulse length with physics and eng. limits.
0.45 τJ
4T

3.2
3.0

R
(m)

ITER98(y,2)
Q = 10, H = 1.1, n/nGW < 0.75
scalingqcyl = 3.0, κ > 1.8,
Paux = 15 MW, 20 s flat top for BT, Ip n(0)/<n> = 1.2

•

15
MA

2.8

•

13.3
MA

2.6

5T

•

2.4

τJ = flat top time/ current redistribution time

0.93 τJ
6T

11.8
MA

2.2
2.0

7 T 1.5 τ
J
8T
10.6
9T
MA 9.6
MA 8.7MA• •2.2 τJ
10 T 11 T
8.0
7.4
MA MA

• • •

ITER - FEAT

2.8 τJ
12 T•

S. Jardin and
C. Kessel

6.7
MA

FIRE

1.8
2.0

2.5

3.0

3.5

Aspect Ratio, A

4.0

4.5

5.0

ARIES-RS (8T),ASSTR (11T)

What is the optimum for advanced steady-state modes?

Fusion Ignition Research Experiment
http://fire.pppl.gov(FIRE)
Design Features• R = 2.14 m, a = 0.595 m• B = 10 T
• Wmag= 5.2 GJ• Ip = 7.7 MA• Paux ≤ 20 MW• Q ≈ 10, Pfusion ~ 150 MW• Burn Time ≈ 20 s
• Tokamak Cost ≈ $375M (FY99)• Total Project Cost ≈ $1.2B
at Green Field site.

Mission:Attain, explore, understand and optimize magnetically confined
fusion-dominated plasmas.

FIRE Baseline for Snowmass Assessment
Wedged TF Coils (16), 15 plates/coil*
Inner Leg BeCu C17510, (HTS later)
remainder OFHC C10200
Compression Ring

AT Features• DN divertor

Double Wall Vacuum
Vessel (316 S/S)

• strong shaping

All PF and CS Coils*
OFHC C10200• very low ripple < 0.3%
• internal coils
2.14m• space for wallstabilizers• inside pellet
injection• large access ports

Internal Shielding( 60% steel & 40%water)
Vertical Feedback and Error
Field Correction Coils
Passive Stabilizer Plates
space for wall mode stabilizers
W-pin Outer Divertor Plate
Cu backing plate, actively cooled

Direct and Guided Inside Pellet Injection*Coil systems cooled to 77 °K prior to pulse, rising to 373 °K by end of pulse.
FIRE Cross/Persp- 5/25//DOE

Basic Parameters and Features of FIRE

R, major radiusa, minor radius
κx, κ95
δx, δ95
q95, safety factor at 95% flux surface
Bt, toroidal magnetic field
Toroidal magnet energy
Ip, plasma current
Magnetic field flat top, burn time
Pulse repetition time
ICRF heating power, maximum
Neutral beam heating
Lower Hybrid Current Drive
Plasma fuelingFirst wall materials
First wall cooling
Divertor configuration
Divertor plate
Divertor plate cooling
Fusion Power/ Fusion Power Density
Neutron wall loading
Lifetime Fusion Production
Total pulses at full field/power
Tritium site inventory

2.14 m0.595 m2.0, 1.77
0.7, 0.55(AT) - 0.4(OH)>3
10 T with 16 coils, 0.3% ripple @ Outer MP
5.8 GJ
7.7 MA
28 s at 10 T in dd, 20s @ Pdt ~ 150 MW)~3hr @ full field and full pulse length
20 MW, 100MHz for 2ΩT, 4 mid-plane ports
None planned, (NI-NBI backup to be evaluated)
Upgrade for AT-CD phase, ~20 MW, 5.6 GHz
Pellet injection (≥2.5km/s vertical launch inside
mag axis, guided slower speed pellets)
Be tiles, no carbon
Conduction cooled to water cooled Cu plates
Double null, fixed X point, detached mode
W rods on Cu backing plate (ITER R&D)
Inner plate-conduction, outer plate/baffle- water
150 - 200 MW, ~6 - 8 MW m-3 in plasma~ 2.3 MW m-2 Limits pulse length in some AT modes
5 TJ (BPX had 6.5 TJ)
3,000 (same as BPX), 30,000 at 2/3 Bt and Ip
Goal 5 - 15 g, (< 30 g, Low Hazard Nuclear Facility)

FIRE is a Modest Extrapolation in Plasma Confinement
Dimensionless
Parameters

ITER-EDA, Q ~ 50
X ITER-FEAT, Q = 10
X FIRE, Q = 10

ω cτ = B τρ* = ρ/aν* = νc/νbβ
BτEth

Similarity
ParameterBR

5/4

Kadomtsev, 1975

BτEth ~ ρ*–2.88 β –0.69 ν* –0.08

Transport Issues/Benefits from a Major Next Step Tokamak Experiment• Predicting confinement and performance is a central issue for a next step
experiment that challenges our understanding and predictive capability.

• Methods Available
1. 0-D Statistical based models (eg ITER scalings for H-Mode)dimensionless variables ala wind tunnel
projections from individual points(Barabaschi) or similar points(DM)2. 1 1/2-D (WHIST, TSC, Baldur, ASTRA)
profiles and time evolution
3. Physics based core transport models- gyrokinetic/gyrofluid (PPPL-IFS, GLF 23)- multi-mode model
4. Edge Pedestal and density limit models• What experimental capabilities or features in a next step experiment areneeded to better resolve and understand transport issues?

Empirical Guidelines for Estimating Confinement
Confinement (Elmy H-mode) - ITER98(y,2) based on today's data baseτE = 0.144 I0.93 R1.39a0.58 n200.41B0.15Ai0.19κ0.78 Pheat-0.69 H(y,2)
Density Limit - Based on today's tokamak data basen20 ≤ 0.8 nGW = 0.8 Ip/πa2,n(0)/<n> = 1.2

Beta Limit - theory and tokamak data baseβ ≤ βN(Ip/aB),βN < 2.0 conventional, βN ~ 3.5 advanced mode

H-Mode Power Threshold - Based on today's tokamak data base
0.58

Pth ≥ (2.84/Ai) n20

0.82

B

0.81

Ra

Helium Ash Confinement τHe = 5 τE,, same as ITER-FEAT

impurities = 3% Be, 0% W

FIRE’s Operating Density and Triangularity are
Near the Optimum for the Elmy H-Mode• The optimum density for the
H-Mode is n/nGW ≈ 0.6 - 0.7• H-mode confinement
increases with δ• δ ≈ 0.7 FIRE• δ ≈ 0.5 ITER-FEAT• Elm size is reduced for
δ > 0.5• Zeff decreases with density(Mathews/ITER scaling)

Ongena et al, JET Results EPS 2001

• DN versus SN ?
Cordey et al, H = function ( δ, n/nGW, n(0)/<n>) EPS 2001
FIRE H-Mode 4

Parameters for H-Modes in Potential Next Step D-T Plasmas
ITER-FEAT (15 MA): Q = 10, H = 0.95, FIRE*(7.7 MA): Q = 10, H = 1.03, JET-U (6 MA): Q = 0.64, H = 1.1
600

Size - Number of Gyro-Radii

0.12

500

a/ρi

0 . 1 4 Normalized Collisionality

0.10

400

ν* 0 . 0 8

300

0.06

200
100

ITER-FEAT

0.04

ITER-FEAT

FIRE*
JET-U

0.02

FIRE*
JET-U

0

0
0.5

0.6

0.7

0.8

0.9

0.5

1

0.6

0.8

0.9

1

n / nGWn / nGW
0.12

0.7

EPM/TAE Driving Term

Duration - Skin times

2.5

ITER-FEAT
0.10

R∇βα

2.0

FIRE*
JET-U

0.08

τburn
τskin 1 . 5

0.06

1.0
0.04

ITER-FEAT
0.5

0.02
0.00
0.5

FIRE*
JET-U

0.0
0.6

0.7

0.8

n / nGW

0.9

1

0.5

0.6

0.7

0.8

n / nGW

0.9

1

Projections to FIRE Compared to Envisioned Reactors
ARIES-AT, Najmabadi,

30
25

Q = 50FIRST “ITER” Reactor
Toschi et al
Pfusion = 150 MW

20n/nGW = 0.7
n(0)/<n>V = 1.5Q15n(0)/<n>V = 1.2
FIRE
10T, 7.7MA, R = 2.14m, A = 3.6
1.7 τskin

105

JET H-Mode** Data Base

0
0.7

0.8

0.9

1

1.1

H98(y,2)

1.2

1.3

1.4

Physics Based Model GLF23
Pedestal
Temperature
Requirements for Q=10
Predictionsofw

Flat nePeaked ne*

IGNITOR

5.1

5.0

5.1

FIRE *

4.1

4.0

3.4

5.8

5.6

5.4

Devicevl
ITER-FEAT

Peaked ne w/ reversed q

w flat density cases have monotonic safety factor profile* n eo / n ped = 1.5 with n ped held fixed from flat density casev 10 MW auxiliary heating* 11.4 MW auxiliary heatingl 50 MW auxiliary heating

Need a model for the pedestal temperature, FIRE has the advantage ofhighest triangularity and low density n/nGW = 0.6 - 0.7

DIII–DNATIONAL FUSION FACILITYSAN DIEGO- BP2001
J. KinseyJEKand
R. Waltz

1 1/2-D Simulation of Elmy H-Mode in FIRE (TSC)
R = 2.14m, A = 3.6, 10 T, 7.7 MA, ~ 20 s flat top

Power (MW)
50

Bt

Bt

40

Q ≈ 1230

Alpha Power
Ip

20

Ip
Auxiliary Power10
Ohmic Power
0
-5
0

4

8

12

16
20
24
28
32
Time (s)• ITER98(y,2) scaling with H(y,2) = 1.1, n(0)/<n> = 1.2, and n/nGW = 0.67

• Burn Time ≈ 20 s ≈ 21 τE ≈ 4 τHe ≈ 2 τskin

Q = Pfusion/(Paux + Poh)GLF23 Predicts an Internal Transport Barrier in FIRE as a
Result of Shafranov-Shift Stabilization of the ITG Mode
• Barrier only forms if some density peaking is present.

• Diamagnetic component of ExB shear helps after ITB is formed.
20

7

Te
Ti

Q = 106

T (keV)

15

5
10

4
3

q

5.0

2
0.0

1
0

0.2

0.4

0.6

^

ρ
DIII–DNATIONAL FUSION FACILITYSAN DIEGO

JEK - BP2001

0.8

1

Kinsey, Waltz and Staebler
UFA BPS Workshop 2

FIRE could Access the “Long Pulse” Advanced
Tokamak Mode Frontier at Reduced Toroidal Field.
(power supply 5.42 v/t oc)

Flattop Duration (seconds)

1000

TPX

KSTAR

FIRE TF Flattop

JT-60 Mod •100

JET, JT-60U

DIII-D

10
2

3

4

5

6

7

8

9

10

Toroidal Field (Tesla)
Note: FIRE is ≈ the same physical size as TPX and KSTAR.
At Q = 10 parameters, typical skin time in FIRE is 13 s and is 200 s in ITER-FEAT .

The Number of Skin Times curve assumes a constant skin time of 13s.

The main limit to long pulses is the divertor and first wall
- a generic problem for magnetic fusion.

TSC Simulation of a “Fusion Dominated” Plasma
8.5 T, 5.4 MA, t(flattop) = 32 s

Q = 7.8, fα = 61%

fBS = 65%H(y,2) = 1.6,
βN = 3.5,n(0)/<n> = 1.5

FIRE Would Explore the Edge
Physics and In-Vessel Technology Frontier
B=8T
R = 5.5 m
Pfusion= ~ 150 MW

B = 10 T
R = 2.14 m

Pfusion= 2170 MW~ 3X

Volume= 27 m3

FIRE

Volume= 350 m3

ARIES-RS The “Goal”

Fusion Power Density (MW/m3)

JET
0.2

FIRE
5.5

ARIES-RS
6

Neutron Wall Loading (MW/m2)

0.2

2.3

4

Divertor Challenge (Ploss/NR)

~5

~10

~35

Power Density on Div Plate (MW/m2)

3~15-19 → 6~5Burn Duration (s)420*

steady* Note: FIRE outer divertor plate is in steady-stateFIRE’s Divertor can Handle Attached(<25 MW/m2)and Detached(5 MW/m2) OperationP< 200 MWfusionReference Design is semi-detached operation with <15 MW / m2.

Divertor Module Components for FIRE
SandiaTwo W Brush Armor Configurations
Tested at 25 MW/m2

Finger Plate forOuter Divertor Module
Carbon targets used in most experiments today are notcompatible with tritiun inventory requirements of fusion reactors.

Potential Next Step Burning Plasma Experiments

B = 13 T
R = 1.3 m

B = 5.5 T
R = 6.2 m

B=8T
R = 5.5 m

B=7T
R=5m
B = 3.8 T
B = 10 T
R = 2.14 m R = 2.9 m

IGNITOR

FIRE

JET U
PCAST 5

Cost Drivers

ARIES-RS (1 GWe)

ITER-FEATIGNITOR

FIRE

JET U

PCAST

ARIES-RS

Plasma Volume (m3)Plasma Surface (m2)

11
36

27
60

108
160

95
150

350
420

828
610

Plasma Current (MA)
Magnet Energy (GJ)

12
5

7.7
5

6
1.6

15
40

11.3
85

15
50

Fusion Power (MW)

100

150

30

400

2170

400

Burn Duration (s), inductive
τ Burn/ τ CR

~1

20
~20

10
0.6

120
1

steadysteady

400
2

1.2

~0.6

6.7

10.6*

4.6

Cost Estimate ($B-2000$)

ITER-FEAT* first , $5.3 B for 10th of a kind
AR RS/ITERs/PCAST/FIRE/IGN

Timetable for Exploring the Burning Plasma Frontier
10
National Ignition Facility (NIF)
Laser Megajoule (LMJ)

8

FusionGain 6Alpha Dominated

U.S Burning Plasma
FIRE (?)

4

ITER(?)

2
TFTR
0
1990

1995

JET
?

2000

2005

?

2010

2015

Year
• Even with ITER, the MFE program will be unable to address the alpha-dominatedburning plasma issues for ≥ 15 years.
• Compact High-Field Tokamak Burning Plasma Experiment(s) would be a naturalextension of the ongoing “advanced” tokamak program and could begin alphadominated experiments by ~ 10 years.

• More than one high gain burning plasma facility is needed in the world program.
• The Snowmass 2002 Summer Study will provide a forum to assessing approaches.
The NRC Review in 2002 will assess contributions to broader science issues..

FESAC Recommendation and ITER Plan for Burning Plasmas
CY

2003

2002

2001

2005

2004

Community Outreach and Involvement
2004 Fusion Assessment(FESAC Priorities Report)

NSO Assessment
Snowmas 2002 ∆FESAC Recommendations
on Burning Plasmas
August 2, 2001∆

FESAC Action

HR 4 - Securing America's Energy Future∆ Plan for U.S BP to Congress andmaybe also a Plan to join Intern'l BP∆

NRC Review∆∆

DOE Decision Process
ITER - EDA∆

FY05 DOE

FY05 Cong FY05 Appropriations∆ Early Construction Start

ITER Negotiations

FY06 DOE• Japan Site Offer• EU Site Offer• Draft Agreement

FY06 Cong FY06 Appropriations∆ Later
Construction Start• Preferred Site
• Final Agreement• Final Agreement Signed

ITER Plan• ILE• ITER Const Authorization

Summary• A Window of Opportunity may be opening for U.S. Energy R&D. We should
be ready. The Modular or Multi-Machine Strategy has advantages foraddressing the science and technolgy issues of fusion.
• A compact high field tokamak, like FIRE, has the potential:• address the important burning plasma issues,• investigate the strong non-linear coupling between BP and AT,• stimulate the development of reactor relevant PFC technology, and• provide generic BP science and possibly BP infrastructure fornon-tokamak BP experiments.
• Some areas that need additional work to realize this potential include:• Apply recent enhanced confinement and advanced modes to FIRE
• Understand conditions for enhanced confinement regimes• Compare DN relative to SN - confinement, stability, divertor, etc• Complete disruption analysis, develop better disruption control/mitigation.
• Respond to FIRE Engineering Review and NSO PAC on specificphysics R&D and engineering design and R&D issues.

http://fire.pppl.gov