Status and Prospects of Nuclear Fusion Using Magnetic Confinement Hartmut Zohm Max-Planck-Institut...
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Transcript of Status and Prospects of Nuclear Fusion Using Magnetic Confinement Hartmut Zohm Max-Planck-Institut...
Status and Prospects of Nuclear Fusion Using Magnetic Confinement
Hartmut Zohm
Max-Planck-Institut für Plasmaphysik, Garching, Germany
Invited Talk given at DPG Frühjahrstagung, AKE, Berlin, 17.03.2014
• Nuclear Fusion using Magnetic Confinement
• Fusion Roadmap and Roadmap Elements
• The German Contribution
• Summary and Conclusions
• Nuclear Fusion using Magnetic Confinement
• Fusion Roadmap and Roadmap Elements
• The German Contribution
• Summary and Conclusions
A simplistic view on a Fusion Power Plant
The ‚amplifier‘ is a thermonuclear plasma burning hydrogen to helium
Centre of the sun: T ~ 15 Mio K, n 1032 m-3, p ~ 2.5 x 1011 bar
Pin = 50 MW
(initiate and control burn)
Pout = 2-3 GWth
(aiming at 1 GWe)
A bit closer look…
Fusion reactor: magnetically confined plasma, D + T → He + n + 17.6 MeV
Centre of reactor: T = 250 Mio K, n = 1020 m-3, p = 8 bar
3.5 MeV 14.1 MeV-heating wall loading
Pin = 50 MW
(initiate and control burn)
Pout = 2-3 GWth
(aiming at 1 GWe)
Schematic layout of a Fusion Power Plant
The goal is to generate and sustain a plasma of 25 keV and 1020 m-3
This can be done in a toroidal system to avoid end losses
helical magnetic field lines to compensate particle drifts
Magnetic confinement
'Stellarator': magnetic field exclusively produced by coils
Example: Wendelstein 7-X (IPP Greifswald)
Plasma can be confined in a magnetic field
'Tokamak': poloidal field component from current on plasma
Simple concept, but not inherently stationary!
Example: ASDEX Upgrade (IPP Garching)
Plasma can be confined in a magnetic field
The promise of fusion power plants
Supply of base load electricity (not dependent on externals)
• complementary to stochastic sources like wind or solar
Sustainable energy source (fusion fuel available for many 1000s of years)
• Deuterium e.g. from sea water
• T will be bred from Li in the innermost part of the reactor Fusion energy will be environmentally friendly
• no CO2 emission
• no uncontrolled chain reaction
• radioactive waste (= structural materials) relatively short-lived
The road to Fusion Energy holds many challenges
Fusion plasma physics
• heat insulation of the confined plasma
• exhaust of heat and particles
• magnetohydrodynamic (MHD) stability of configuration
• self-heating of the plasma by fusion born -particles
Fusion specific technology
• plasma heating
• fuel cycle including internal T-breeding from Li
• development of suitable materials in contact with plasma
The road to Fusion Energy holds many challenges
Fusion plasma physics
• heat insulation of the confined plasma
• exhaust of heat and particles
• magnetohydrodynamic (MHD) stability of configuration
• self-heating of the plasma by fusion born -particles
Fusion specific technology
• plasma heating
• fuel cycle including internal T-breeding from Li
• development of suitable structural and first wall materials
• Nuclear Fusion using Magnetic Confinement
• Fusion Roadmap and Roadmap Elements
• The German Contribution
• Summary and Conclusions
The European Roadmap to Fusion Electricity
JET (EU)3 m
80 m3
~ 16 MWth
(D-T)
ITER6.2 m
800 m3
~ 400 MWth
(D-T)
Major Radius
Volume
Fusion Power
ASDEX Upgrade (IPP)1.65 m
14 m3
1.5 MW
(D-T equivalent)
A step-ladder of fusion experiments to ITER
The machine has to be big in order to have sufficient heat insulation (E)
ITER = proof of principle for dominantly -heated plasmas
DEMO = proof of principle for reliable large scale electricity production
DEMO must be larger: 6.2 m 8.5 m, 400 MW ~ 2 GW
This brings new challenges for physics (and technology)
• higher density, higher pressure (stability!)
• higher power density (Pfus~R3, Atarget~ R)
• need for long pulse or steady state (tokamak presently a pulsed system)
We will not run out of work in near future!
• also alternative magnetic confinement concepts must be studied
The step from ITER to DEMO
Tokamak (ASDEX Upgrade, JET, ITER)
ITER = proof of principle for dominantly -heated plasmas
DEMO = proof of principle for reliable large scale electricity production
DEMO must be larger: 6.2 m 7.5 m, 400 MW ~ 2 GW
This brings new challenges for physics (and technology)
• higher density, higher pressure (stability!)
• higher power density (Pfus~R3, Atarget~ R)
• need for long pulse or steady state (tokamak presently a pulse system)
We will not run out of work in near future!
• also alternative magnetic confinement concepts must be studied
Example: W7-X stellarator (IPP Greifswald)
The step from ITER to DEMO
Stellarator (W7-X)
The Role of Stellarators in the EU Roadmap
Using technology developed on a tokamak DEMO, stellarator can be candidate for a Fusion Power Plant in the 2050s
• Nuclear Fusion using Magnetic Confinement
• Fusion Roadmap and Roadmap Elements
• The German Contribution
• Summary and Conclusions
German Fusion Programme: Combined Expertise
Unique combination of physics and technology
Coordinated effort through ‚German DEMO Working Group‘
Stellarator Physics and Technology
Plasma WallInteractions
Fusion Tokamak Technology Physics and
Technology
German DEMO Working Group: Roadmap Elements
7 Roadmap Elements that need to be tackled in any Roadmap have been identified
RE1: Consistent Tokamak Scenarios
RE2: Consistent Stellarator Scenarios
RE3: Enduring Exhaust of Power and Particles
RE4: Safety – Public Accpetance and Licensing
RE5: Sustainability – Tritium Self-sufficiency & Low Activation
RE6: Economic Viability – Efficiency / Reliability / Availability
RE7: Stellarator Specific Technology
The following examples highlight how these Roadmap Elements bring together the expertise of Fusion Research in Germany
Tokamak Scenarios (RE1) / Economic Viability (RE6)
Realistic fully noninductive scenario may require substantial PCD
Sets the goals for future gyrotron development at f > 200 GHz Issues of controllability must be incorporated from the start
KIT, 1MW, 105 – 165 GHzSP prototype
Mode for 237 GHz coax gyrotron
Brewster-angle technology (CVD Diamond window)
TE49,29Simulation of fullynoninductive DEMO scenario
Exhaust of Power and Particles (RE3)
Combined physics / technology requirements: P/Rsep 15 MW/m, Ptarget 5 MW/m2, Te,div 5 eV
Optimised technology solution may be He-cooled divertor
W-divertor in ITER
He-cooled divertor for DEMO
Stellarator Scenarios (RE2) & Technology (RE7)
• Stellarator specifics are incorporated into tokamak systems codes
• Critical elements in physics and technology will be assessed
Plasma geometry described by Fourier coefficients of LCFS obtained from VMEC.
Existing coil design of Helias 5-B builds model basis which is scaled as input.
Model relates power crossing separatrix to effective wetted area to estimate heat load.
Plasma GeometryModular
Coils / BlanketIsland Divertor
effm
m
n
nnnm
m
m
n
nnnm
rAVNnvmuszvusz
NnvmusRvusR
,,)sin()(),,(
)cos()(),,(
max max
max
max max
max
0,
0,
Plasma geometry described by Fourier coefficients of LCFS obtained from VMEC.
Existing coil design of Helias 5-B builds model basis which is scaled as input.
Model relates power crossing separatrix to effective wetted area to estimate heat load.
Plasma GeometryModular
Coils / BlanketIsland Divertor
effm
m
n
nnnm
m
m
n
nnnm
rAVNnvmuszvusz
NnvmusRvusR
,,)sin()(),,(
)cos()(),,(
max max
max
max max
max
0,
0,
Stellarator Scenarios (RE2) & Technology (RE7)
• Stellarator specifics are incorporated into tokamak systems codes
• Critical elements in physics and technology will be assessed
Plasma geometry described by Fourier coefficients of LCFS obtained from VMEC.
Existing coil design of Helias 5-B builds model basis which is scaled as input.
Model relates power crossing separatrix to effective wetted area to estimate heat load.
Plasma GeometryModular
Coils / BlanketIsland Divertor
effm
m
n
nnnm
m
m
n
nnnm
rAVNnvmuszvusz
NnvmusRvusR
,,)sin()(),,(
)cos()(),,(
max max
max
max max
max
0,
0,
Stellarator Scenarios (RE2) & Technology (RE7)
• Stellarator specifics are incorporated into tokamak systems codes
• Critical elements in physics and technology will be assessed
• Nuclear Fusion using Magnetic Confinement
• Fusion Roadmap and Roadmap Elements
• The German Contribution
• Summary and Conclusions
Significant progress of understanding in all basic areas of Nuclear Fusion research by developing plasma physics and technology base
• core plasma parameters sufficient for generation of fusion energy
• technical systems mature for controlling thermonuclear plasma
Nuclear Fusion research is ready for the next step
• ITER will be built in an international effort
• will allow qualitatitvely new studies: exploring plasmas with dominant -heating
The step to DEMO and a Fusion Power Plant builds on ITER but must be prepared in due time
•adress physics and technology in an integrated way
•bring in the stellarator line in a consistent manner
Conclusions