TCM-8 meeting, 2010, April 14 ENEA Frascati, Italy
JT-60SA Plasma Regimes and
Research Plan
Y. Kamada
JAEA
1
The JT-60SA Project
The JT-60SA project is conducted under the BA Satellite Tokamak
Programme by Europe and Japan, and the Japanese National Programme.
The project mission is to contribute to early realization of fusion energy by
supporting exploitation of ITER and by complementing ITER with
resolving key physics and engineering issues for DEMO reactors.
JT-60SA and ITER should be
operated as a ‘set’, in order to
realize the Fusion Energy
for both
* science and technology
* scientists
2
JT-60SA Plasma Regimes
JT-60SA is a fully superconducting tokamak capable of confining break-even
equivalent class high-temperature deuterium plasmas (Ip-max=5.5 MA) lasting for a
duration (typically 100s) longer than the timescales characterizing the key plasma
processes, such as current diffusion and particle recycling.
JT-60SA should pursue full non-inductive steady-state operations with high bN (>
no-wall ideal MHD stability limits).
6
5
JT-60SA Target
bN
4
3
JT-60U
2
Existing
Tokamaks
1
0
0
20
40
DEMO
reactors
ITER
Steady-state
ITER
Inductive
60
80 100 400 3000
Sustainment Time (s)
3
EU & JA Share Procurements
Design of the key components has been almost completed.
The JT-60SA project has been entered its manufacturing stage.
Naka site
Compressor Building
700t
Power Supplies
Magnet Interface
150t
TF coils&Testing
Water Cooling
System
CS, EF coils
Cryogenic
System
NBI
16m
Laser scattering
Cryostat
Diagnostics
ECRF
Rad. safety
Vacuum Vessel
Assembly
Disassembly
Body: 350t
Base: 260t
Cont/data
In-vessel Components
Remote Handling
4
Project Schedule
5
JT-60SA: Highly Shaped Large
Superconducting Tokamak
•
A wide range of plasma equilibrium covering a high plasma shaping factor
of S=q95Ip/(aBt) ~7 and a low aspect ratio of A~2.5 with a sufficient inductive
plasma current flattop and additional heating up to 41 MW during 100 s.
The plasma size is ~ 0.5 x ITER = between ITER and other
superconducting tokamaks.
An integrated knowledge of superconducting tokamaks SST-1, EAST,
KSTAR, TORE-SUPRA, JT-60SA and ITER will establish a reliable nuclear
fusion science and technology towards DEMO.
6
Typical Plasma Parameters
Ip=5.5MA,
Double Null
Ip=4.6MA
ITERshape
7
Ip=5.5MA Discharge Example
8
High bN , high bootstrap Steady-state operation
9
High bN steady-state operation space
10
Research needs for ITER & DEMO
11
12
JT-60SA device has been designed in order to satisfy
the central research needs for ITER and DEMO
JT-60SA device
Fully Superconducting Large Tokamak
Highly Shaped Plasma Configuration
Strong Heating and Current Drive Power with Variety & Long Pulse
Large Capability of Stability Control
Large Capability of Divertor Power Handling and Particle Control
Variety of High Resolution Diagnostics
13
41MWx100s High Power Heating with Variety
variety of heating/current-drive/ momentum-input combinations
NB: 34MWx100s
Positive-ion-source NB
85keV
12units x 2MW=24MW
COx2u, 4MW
CTRx2u, 4MW
Perpx8u, 16MW
Negative-ion-source NB
500keV, 10MW
Off-axis for NBCD
NB
ECRF
ECRF: 110GHz, 7MW x 100s
9 Gyrotrons,
4 Launchers with movable mirror
>5kHz modulation
14
In-vessel components for stability control
 RFX
15
Divertor Structure for heat & particle control
16
Research phases and status of key components
JT-60SA operation starts earlier than ITER’s hydrogen operation by ~5 years. The
tight schedule of ITER up to DT1 requires sufficient explorations of the key physics
and operational techniques in satellite devices. => Experiences and achievements
in JT-60SA are indispensable for smooth and reliable progress of ITER.
17
Divertor & Wall Material Research for DEMO
Extended Research Phase:
Installation of the metallic divertor targets and first wall together with an
advanced shape divertor will be conducted based on progress of the research
in the world tokamaks including ITER.
Replaceable Divertor Cassette
Integrated Research Phase:
The material of the divertor target and the first
wall is now considered to be carbon before
achievement of the JT-60SA’s main mission of
the high-b steady-state.
However, possibility of replacement to metallic
materials will be discussed based on the results
in JET, ASDEX-U, FTU.
18
JT-60SA Research Plan
19
ITER & DEMO-relevant non-dimensional regime
JT-60SA allows explorations in the ITER- and DEMO-relevant
plasma regimes in terms of non-dimensional plasma parameters
at high plasma densities in the range of 1×1020/m3.
20
ITER & DEMO-relevant heating condition / scan
JT-60SA allows
dominant electron heating, scan of power ratio to electron
high power heating with low central fueling
high power heating with low external torque input
( incl. scan of rotation)
ECH (110GHz, 7MW)
N-NB (500keV, 10MW)
=> Electron Heating dominant
Low Particle input
Low Torque input
P-NB (85keV, 24 MW)
=> Ion Heating dominant
Perp-NB & balanced CO/CTR-NB
=> low torque input
( torque input scan)
21
Study on highly self-regulating plasmas for DEMO
High beta & high bootstrap fraction => strong linkages among j(r), p(r), Vt(r)
+ Global linkage / Global structure including core & pedestal
+ Linkage among transport coefficients & roles of MHD activities
=> JT-60SA allows understanding & control of this plasma system at ITER- & DEMOrelevant non-dimensional parameters (r*,n*, bN, bp, q95…)
JT-60SA plasma
actuator system
allows separated
controls for heating,
current drive,
rotation drive &
fueling.
22
Demonstration & Study of High Beta (>non-wall limit) for DEMO
JT-60SA allows exploitations of high beta regimes with
the high shape factor S up to 7, the stabilizing shell, the
RWM control coils, the error field correction coils, and
the high power heating & CD & momentum-input.
For DEMO, minimum rotation for RWM
stabilization has to be studied
=> w/o control coils.
Identification of the disruption limits at high bN.
Stabilizing
plate
RWM
control
coils
bNno-wall = 3.12
bNideal-wall
critical
bN
= 4.32 =4.40 23
JT-60SA supports ITER’s main mission & commissioning
with high Ip, high power, high density plasmas
JT-60SA provides data & techniques for
* H-mode operations towards Q=10
L-H transition
Pedestal Structure
H-mode confinement ( incl. compatibility with
radiative divertor, RMP, etc.)
•Disruption behavior,
and disruption prediction & mitigation using the same
techniques planed in ITER.
JT-60SA has sufficient power
for L-H transition & H-mode
confinement studies at
Ip=5.5MA & ne=1020m-3.
•Operation scenario optimization with
superconducting
PF coils.
•Divertor heat load mitigation ( incl. ELMs) and particle
controllability
•with 10MW high energy (500keV) N-NB;
NB Current Drive studies (incl. off-axis NBCD),
AE mode stability & effects on fast-ion transport,
Interactions between high energy ions and MHD instabilities
24
ELM mitigation for ITER and DEMO
JT-60SA’s high Ip high power H-mode plasmas allow
type I ELM studies at sufficiently low edge collisionality.
1) ELM mitigation by RMP & pellet inj. for ITER.
Error field correction / generation
coils are used for RMP
JT-60SA
4.6MA (ITER-like)
5.5MA (DN, LN) ITER
2.3MA (SS)
0.25
DIII-D
JET
ASDEX-U
small(co)
small(bal)
small(ctr)
middle(co)
middle(bal)
middle(ctr)
large(co)
large(bal)
large(ctr)
0.2
WELM / Wped
ELM energy loss fraction
2) JT-60SA’s high triangularity plasmas
allow small ELM regimes ( i.e. grassy ELM)
for DEMO. (DEMO-equivalent shape )
=> ELM mitigation without RMP.
0.15
0.1
JT-60SA
with FSTs
[small(co)]
with FSTs
[large(co)]
0.05
0
0.01
0.1
1
10
ne
collisionality
25
High Energy Particle Studies for ITER & DEMO
JT-60SA allows exploitations of
NB Current Drive studies (incl. off-axis NBCD),
AE mode stability & effects on fast-ion transport,
Interactions between high energy ions and MHD instabilities
with 10MW high energy (500keV) N-NB.
26
Divertor Power Handling for ITER & DEMO
CFC monoblock divertor target allows 15MW/m2.
Test at JEBIS at 15MW/m2 for 12 full-size mockups of monoblock target with 10 CFC blacks.
(30x30x30mm)
About half of mock-ups
satisfied the requirements
Qualified
targets
survived 2000
heat cycles
The ITER-like W-shaped divertor with a V-corner enhances divertor radiation.
• At lower ne compatible with lower
Ip plasmas, qpeak = 8.6 MW/m2 is
obtained with impurity seeding.
12
10
2
q [MW/m ]
• The peak heat flux can be suppressed
within the mono block capability (15
MW/m2) by gas puffing for 41 MW
injection. (ne,ave~1x1020 m-3 at fGW=0.8).
== SONIC code simulation ==
Radiation map
10.4 MW/m2
8
6
Heat flux density
on the LFS target
4
2
0
-0.05 0 0.05 0.1 0.15 0.2 0.25
Distance f rom the separatrix [m]
Fuel & Impurity Particle Control for ITER & DEMO
JT-60SA demonstrates particle controls under saturated wall condition by utilizing
variety of the fuelling and pumping systems (gas-puffing from man and divertor,
pellet injection, divrtor pumping).
Compatibility of the radiative divertor with impurity
seeding and sufficiently high fuel purity in the core
plasma should be demonstrated.
The key point is to clarify whether a wide range of
the divertor plasma controllability can be realized
independently of the main plasma operation
condition.
Divertor pumping with cryopumps allows
Pumping speed of 0 -100m3/s by 8 steps.
Divertor condition can be controlled from
attached to detached conditions with constant
main plasma density.
Detached Divertor Attached Divertor
20
monoblock CFC lim it
15
10
5
Divertor Peak
Heat Load (MW/m2)
0
10
20 -3
8 Divertor Electron Density (10 m )
6
4
Divertor Electron Temperature (eV)
2
0
40 60 80 100 120
0
20
Pumping Speed (m 3/s)
High Integrated Performance for DEMO
‘Simultaneous & steady-state sustainment of the key
performances required for DEMO’
has never been achieved => the goal of JT-60SA.
Example of JT-60SA
at Ip=2.3MA.
29
Integrated Control Scenario Development
Understanding & Control of the highly self-regulating
combined plasma system for DEMO
High-beta, high-bootstrap fraction plasma
=> a highly self regulating non-linear system
governed by strong linkages among j(r), p(r) and Vt(r) in core & pedestal.
Strong spatial linkage : Core – Pedestal – SOL – Divertor plasmas
Study controllability
& Plasma response
Determine the
minimum suitable set
of actuators & logic.
+
control margin
against operation boundaries
(In particular disruption limits )
30
Summary
The project mission of JT-60SA is to contribute to early realization
of fusion energy by supporting exploitation of ITER and by
complementing ITER for DEMO.
JT-60SA device has been designed in order to satisfy all of the
central research needs for ITER and DEMO,
in particular, ‘Simultaneous & steady-state sustainment of the key
performances required for DEMO’ & ‘Integrated Control Scenario
Development ‘.
31
JT-60SA is indispensable for ITER & DEMO
JT-60SA operation starts earlier than ITER’s hydrogen operation by ~5 years. The tight
schedule of ITER up to DT1 requires sufficient explorations of the key physics and operational
techniques in satellite devices. => Experiences and achievements in JT-60SA are indispensable
for smooth and reliable progress of ITER.
For DEMO, an integration of achievements in JT-60SA high-b steady-state plasmas and ITER
burning plasmas is required to make DEMO designs more realistic and attractive. For early
realization of DEMO, such integrated exploitation of JT-60SA and ITER is necessary.
32
33