fusie

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The seven impossibilities of fusion power
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Thermal insulation as good as styrofoam
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1960 1970 1980 1990 2000
Ohmic heating power coupled to confining field
heating resolution control modelling
12
temperature (keV)
stored energy
0
total heating power
plasma radius
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1960 1970 1980 1990 2000
Additional heating decouple heating confining B
heating resolution control modelling
?
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temperature (keV)
stored energy
Ohmic
W
0
total heating power
plasma radius
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1960 1970 1980 1990 2000
1982 ASDEX discovery of higher confinement mode.
heating resolution control modelling
?
12
temperature (keV)
stored energy
Ohmic
W
Additional heating
0
total heating power
plasma radius
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1960 1970 1980 1990 2000
90ties development of internal transport
barriers.
heating resolution control modelling
?
12
transport barrier
H
H
temperature (keV)
stored energy
Ohmic
L
L
W
Additional heating
0
total heating power
plasma radius
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simulation Erik Min (FOM)
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Gyro code Jeff Candy (GA)
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The seven impossibilities of fusion power
OK
ITER
ITER
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Materials you could put on the sun
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Alcator C-Mod (MIT)
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Scrape-off layer 2 cm thick Power density 1
GW/m2
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• How to reduce 1 GW/m2 to a tolerable value?
• geometry of divertor
• radiate 90 of the power
• detach the plasma (Tlt10 eV)

JET
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• Plasma facing materials issues
• Erosion
• Redeposition
• Melting
• Tritium retention
• Choice of materials Carbon, Tungsten, Berylium

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• Plasma facing materials issues
• Erosion
• Redeposition
• Melting
• Tritium retention
• Choice of materials Carbon, Tungsten, Beryllium.
• Additional constraint neutron fluence
• activation
• swelling
• reduction of heat conductivity

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• Sheath
• Electron mobility ? plasma charges positive.
• Bohm criterium ? n.cs
• cs sound speed ? Te0.5
• Sheath potential ? few x Te
• Te determines flux and impact energy!
• Heat flux q ? 8 x ? x Te

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Physical sputtering (Impact energy gt 20-30
eV) vs chemical erosion.
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carbon deposits in TEXTOR (FZ-Julich)
50 micron
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High-power linear plasma generators at FOM
Rijnhuizen operational
Pilot-PSI under construction Magnum-PSI
(Poster van Eck/Koppers)
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Plasma-Surface interaction
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Plasma-Surface interaction
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Magnum-PSI
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Neutron fluence
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Material issues in fusion
Neutron fluence Heat flux Plasma environment
Reliability Replaceability Compatibility with
plasma
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Permanent
5-6 year
2 year
Magnet
Coolant manifold
Blanket
Vessel
Cold shield
Divertor
(Power Plant Conceptual Study)
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Material development parallels with fission
200
fusion power plant
radiation damage (dpa)
Gen II Fission
ITER
0
0 Temperature (C) 1200
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Lifetime of fusion reactor wall
7 year
316 SS
Ti-mod 316 SS
Cr steels
Limited due to void swelling, Fusion reactor 30
dpa/y
0 year
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IFMIF - International Fusion Materials
Irradiation Facility
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Waste?
Comparable to ashes of coal plant ? Acceptable
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Material development
aerospace
fission
superconducting magnets
fusion materials
lithography
inertial fusion
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Material issues in fusion
Plasma-facing material Structural
material Magnets Joints Windows Insulators Fibers
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Magnets gt 25 of ITER cost
6 PF coils 240 ton draad
18 TF coils 420 ton draad
6 CS coils 120 ton draad
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Superconducting high-field magnets Research at
Twente University
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Fuel cycle, the tritium must be bred
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For a breeding ratio of 1.1, a tritium has to go
round the plant 1000 times without being trapped
Breeder unit
Pb17-Li inlet
Plasma
Pb17-Li outlet
First wall
Liquid-Lead breeding concept
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The seven impossibilities of fusion power
OK
ITER
ITER
IFMIF
ITER
ITER
ITER