ILE, Osaka
Concept of Laser Fusion Power Plant Based on First Ignition
T. Norimatsu 1), Y. Kozaki 2), N. Miyanaga 1), J. Kawanaka 1), H. Azechi 1), H. Furukawa 3),
and K. Tomabechi 4)
1) Institute of Laser Engineering, Osaka University, Suita, Osaka 5650871 Japan.
2) National Institute for Fusion Science, Oroshi, Toki, Gifu, 5095292 Japan3) Institute for Laser Technology, Nishi-ku, Osaka, 5500004, Japan.4) Previous Advisor of Central Research Institute of Electric Power
Industry
ILE, Osaka
Reactor Design Committee was organized to clarify the feasibility of Laser Fusion Plant based
on Fast Ignitionby IFE Forum and ILE, Osaka University
• Chair; A. Tomabechi• Co-chair; Y. Kozaki (IFE, Forum)
T. Norimatsu (ILE, Osaka)
Laser Working Group
N. Miyanaga (ILE),
Y. Suzuki (Laser Front Technol.),
K. Ueda (Univ. Elector-Com.),
N. Tuchiya (Nishin Co.)
Y. Oowadano (AIST),
T. Jitsuno (ILE),
M. Nakatsuka (ILE),
H. Fujita (ILE),
K. Yoshida (Osaka Inst. Technol.),
J. Kawanaka (ILE),
H. Nakano (Kinki Univ.),
Y. Fujimoto (ILE),
H. Kubomura (HP),
T. Kawashima (HP),
S. Matsuoka(HP),
T. Ikegawa(HP),
K. Tusbakimoto (ILE),
J. Nishimae (Mitsubishi Elec.),
H. Furukawa (ILT)
Target Working Group
T. Norimatsu (ILE),
M. Nishikawa (Kyushu Univ.),
T. Konishi (Kyoto Univ.),
T. Endo (Hiroshima Univ.),
H. Yoshida (Gifu Univ.),
M. Nakai (ILE)
Plant system Working Group
Y. Kozaki (ILE),
Y. Soman (Mitsubishi Heavy Ind.),
K. Okano (CRIEPI),
Y. Furukawa (ILT),
Y. Sakawa (Nagoya Univ.),
A. Sagara (NIFS),
T. Norimatsu (ILE)
Purpose1) to make a reliable scenario for the fast
ignition power plant basing on the latest knowledge of elemental technologies,
2) to identify the research goal of the elements
3) to make the critical path clear.
Core plasma Working Group
H. Azechi (ILE),
Y. Nakao (Kyushu Univ.),
H. Sakagami (Hyogo Unv.),
H. Shiraga (ILE),
R. Kodama (ILE),
H., Nagatomo(ILE),
T. Johzaki (ILE)
ILE, Osaka
KOYO-F is a commercial or very “close to” commercial power plant.
レーザー核融合エネルギー開発のロ-ドマップ
炉工学技術開発(ブランケット, 液体金属, トリチウム, 炉材料), ITER R&D成果
FIREX-I
概念設計 工学設計実験炉(LFER)
繰返工学試験
設計
FIREX-II
建設 運転 I,II 運転 III
2005 2010 2015 2020 2025 2030 2035
実証炉(DEMO)
▲発電実証
実用発電実証 ▲
モジュール 100J 1kJ 10kJ
ターゲット照射技術開発
炉チェンバー技術開発 液体壁ブランケット開発
炉用レーザー開発(DPSSL)
▲点火燃焼
先進レーザー開発
Load map toward Laser Fusion Energy
Conceptual design Tech. designExperimental Reactor (LFER)
Ignition and burn
Electric power generation
Demo reactor
Electric power to networkHi-rep test
Target injection and tracking
Blanket, heat cycle
Design
LFER
Module development
Laser development Advanced Laser
Reactor technologies for commercial plant (Life time)
Heating to ignition temperature
Laser 200kJ/1HzGain 50Fusion Yield 10MJElectric power 2MW
Laser 1.2MJ/16HzGain 160Fusion Yield 200MJElectric power 1280 MW
ILE, Osaka
What is new?
• Core plasma– Gain estimation and ρR simulation were carried out using
latest simulation codes.• Lasers
– Cooled Yb:YAG ceramic was newly chosen for both compression and heating lasers
• Target– Thermal cavitation technique was employed for fuel loading
in batch process.• Chamber
– Stagnation-free, liquid wall chamber with cascade flow was proposed for the modular reactors.
ILE, Osaka
The detail physics of the Fast Ignition are investigated with computational simulations
Core plasma
Simulation of non-spherical implosion for FIREX-I experiment (by PINOCO-2D)
Generation of high energy electron (by FISCOF2D)
Heating of core plasma by the high energy electrons is simulated (by FIBMET)
0 5 10 15 20102
103
104
105
106
107
1.8 MeV
0.35 MeV
5.0 MeV
Elec
tron
num
ber [
arb.
uni
t]
Electron energy [MeV]
cone
0 1 2 3 4 5 6 70.25
0.30
0.35
0.40
0.45
0.50
T core
[ke
V]Time [ps]
Te Ti
ne,rear= 2nc
ne,rear= 100nc
ne,rear= 10nc
Beam condition
0 1 2 3 4 5 6 70.25
0.30
0.35
0.40
0.45
0.50
T core
[ke
V]Time [ps]
Te Ti
ne,rear= 2nc
ne,rear= 100nc
ne,rear= 10nc
Beam condition
w/ initial perturbation
w/O initial perturbation
Electron spectrum generated by the laser plasma interaction in the cone geometry
Magnetic field in the cone geometry. The hot electrons are transported along cone surface guided by static magnetic and electric field.
CH-DT shell target with gold cone is imploded by GXII laser. Even though, initial perturbation exists on the target surface, high density core plasma is formed.
In this simulation, initial condition of core plasma is determined by the implosion simulation, PINOCO-2D. Boundary condition of Input hot electron is determined by FISCOF2D.Temporal profiles of bulk-electron and ion temperatures averaged over the dense core region (r > 10g/cc) obtained for the three different REB conditions (ne,rear = 2, 10 and 100 nc)
ILE, Osaka
ILE OsakaAlthough dynamics of cone-guided implosion is quite different from conventional spherical one, high ρR for ignition can be achieved
•existence of the cone causesnon-symmetric slip boundaryablated plasma
•implosion velocity
•timing of maximum density•hot spot
•shock hits the surface of the cone
ρR=2.4g/cm2
Core plasma
ILE, Osaka
Actual energy and power of heating laser required for fast ignition after S. Atzeni, (Phy.Plasmas’99)
d
Rrb
Assuming high energy electron range ;ρ d = 0.6 g/cm2
• Eh = 140{ρ/(100g/cc)}-1.85 kJ• Pb = 2.6{ρ/(100g/cc)}-1.0 PW• Ib = 2.4X1019 {ρ/(100g/cc)}0.95 W/cm2
• rb = 60{ρ/(100g/cc)}-0.975 µm EL= 60 - 100 kJ
Core plasma
Fast Ignition Gain Performance
ILE, Osaka
ρ = 300g/cc,
Energy coupling; ηimp = 5% for implosion & ηheat = 30% for core heating
Pulse width of >10 ps would be accepted for the heating laser. This result relaxes requirements for heating laser. We can use transmitting optics.
0 20 40 60 80 100 120 1401E111E121E131E141E151E161E171E18
Fu
sion
pow
er [W
]
Time [ps]
Core heating duration ( τ = 10ps)
High gain
Transition phase to explosive burning
FIREX-I
FIREX-II
0 20 40 60 80 100 120 1401E111E121E131E141E151E161E171E18
Fu
sion
pow
er [W
]
Time [ps]
Fusi
on p
ower
[W]
Time [ps]
Core heating duration ( τ = 10ps)
High gain
Transition phase to explosive burning
FIREX-I
FIREX-IIρR=0.7g/cm2
Eab=3.5kJ
ρR=1.2g/cm2
Eab=18.4kJ
ρR=2.7g/cm2
Eab=18.4kJ
This is a good news. We can use conventional transmitting optics.
Core plasma
ILE, Osaka
Target for KOYO-F
Fuel shell DT(gas) (<0.01mg/cc) 1,500µm
DT(Solid) (250mg/cc+10mg/cc Foam) 300µmGas barrier (CHO, 1.07g/cc) 2 µmCH foam insulator (250mg/cc) 150 µmOuter diameter 1,952 µmMas of fuel 2.57mg
Total Mas of shell 4.45mg
Basic specification Compression laser 1.1 MJ Heating laser 70kJ Gain 165 Fusion yield 200MJ
Cone Material Li17Pb83 Length 11mm Diameter 5.4 mm Mas 520 mg
3.9 mm
15o9 mm
11 mm
5.4 mm3 mm4.0 mm
Plastic coating
Prabolic mirror
Foam insulator Solid DT+Foam
ILE, Osaka
Critical issues toward high gain
• Can we achieve low adiabat α ?– Current experiments α >2.5
Pulse control, target design are the key.
Self-Ignition
High-Gain
Driven-Ignition
ELtot [kJ]G
ain,
Q
α = 3
10 100 10000.1
1
10
100 α = 2
FIREX-1
FIREX-2
Wet wall reactor
Dry wall reactor
Self-Ignition
High-Gain
Driven-Ignition
ELtot [kJ]G
ain,
Q
α = 3
10 100 10000.1
1
10
100 α = 2
FIREX-1
FIREX-2
FIREX-1
FIREX-2
Wet wall reactor
Dry wall reactor
104
106
108
0.1 1
Neu
tron
Yie
ld
Heating Laser Power (PW)
η = 15%
Heating efficiency η = 30%
Ignition Equivalent Laser Intensity
•Can we deposit 20-30% heating laser energy in a 60 µm diameter x 100 µm area?
•Current theory 15-20 % by 1D• 40% by 2D
?
The Answer will be obtained withFIREX projects.
Lasers
ILE, Osaka
Compression and heating lasers based on identical amplifier
architecture
Compression laser
Main pulse Foot pulse
Energy/pulse 1.1 MJ TBD 100 kJ
Wavelength UV (3ω) 343 nm Visible (2ω) 515 nm 1030 nm
Laser material Cooled Yb:YAG ceramic
Efficiency Efficient Sacrifice of efficiency ( Sacrifice of efficiency )
Heating laser
Band width Narrow bandBroad band
1.6 THzBroad band (rectangular pulse)
~3 nm
Method forbroad band
Arrayed beam with different wavelength
~0.1 nm@1030 nm(0.08 THz@343 nm)
Broad-band OPA pumped by 3ω,
Spectral angular dispersion
Broad-band OPCPA pumped by 2ω
OPA: optical parametric amplifierOPCPA : optical parametric chirped pulse amplifier
ILE, Osaka
Lasers Originally Yb:YAG has high quantum efficiency of 90%. Why Cooled Yb:YAG now ?
Because there are dramatic Improvements in;
1. Wide Tuning Range of Emission Cross Section (Saturation Fluence)
Realize an efficient energy extraction without optics damages
2. 4-Level Laser System
Enough Laser gain even in diode-pump
3. Improved Thermal Characteristics
High average power operation
Room Temperature
Pump
Laser
Re-absorption
Laser Diode・Low Brightness
400~800cm-1
Quasi-3-Level
2F7/2
2F5/2
Low Temperature
No Re-absorption
4-Level
Lasers
ILE, Osaka
Cooled Yb:YAG ceramic is promising as the laser driver material.
Cooled Yb:YAG ceramic
熱ショックパラメーター
R
T (
W/c
m)
飽和パラメーター hν/σ (J/cm2)
1
10
100
0.10.1 1 10 100
望ましい領域
Glass
Yb:S-FAP
熱破壊
Disordered crystal
crystal
Crystal
Nd:CNGG
寄生発振限界
小口径
モジュール
Nd:SiO2
LHG-8
LSG-91H
LHG-10BK-7
Yb:YAG
HAP4
Nd:Y:CaF2
光学破壊限界
Nd:YAG
ceramics
crystal
ceramics
?
Cooling
Artificial control ofemission cross section
Practical use ofceramic technology
2Saturation parameter
Ther
mal
sho
ck p
aram
eter
Parasitic osc. limit Damage threshold
Thermal fracture
Optimal areaSmallmodule
ILE, Osaka
We experimentally confirmed performance of cooled Yb;YAG
-1 0 1Position (mm)
Inte
nsity
Gaussian fit
Horizontal profile
0
2
4
6
8
0 20 40 60 80 100 120 140 160
g 0(c
m-1
)
Crystal Temperature (K)
g0 = 8 cm-1
at 1.3 kW/cm2
CalculationUsing the observed σem and σab
Dope : 25 at.%Thickness: 1 mm
0
2
4
6
8
0
2
4
6
8
0 20 40 60 80 100 120 140 1600 20 40 60 80 100 120 140 160
g 0(c
m-1
)
Crystal Temperature (K)
g0 = 8 cm-1
at 1.3 kW/cm2
g0 = 8 cm-1
at 1.3 kW/cm2
CalculationUsing the observed σem and σab
CalculationUsing the observed σem and σab
Dope : 25 at.%Thickness: 1 mm
10 100
10
100
1000
3 30 3003
30
300
1% single0.7% ceramics
Temperature (K)
Ther
mal
Con
duct
ivity
(W/m
K)
ILE, Osaka
Overall Efficiencyfrom Electricity to Laser
Implosion Laser Heating Laser
Laser Power 17.6 MW(1.1MJ, 16 Hz) 1.6 MW(0.1MJ, 16Hz)
LD Electrical – LD Optical 60%
LD Optical – 1ω 42%
LD Electrical – 1ω 25.2% (= 0.6 x 0.42)
1ω – 3ω 70% -
1ω – 2ω - 80%
OPCPA Eff. - 40%
Pulse Compression Eff. - 80%
Transportation Eff. 90% 90%
Harmonic Generation and Transportation 63% 23%
Electric Input Power 111 MW 27.6 W
Crystal Heating Power 7 MW 0.7MW
Cooler Electric Power 23 MW 2.1 MW
Electric Power Demands 134 MW 30 MW
Total Electric Power 164 MW
Overall Efficiency 12% (13% + 5.4%)
Lasers
ILE, Osaka
Beam arrays of implosion and hearting lasers
Compression laser beam(343 nm)
Absorber
8x8 incoherentarrays
Heating laser beam (1030 nm)
Foot pulse beam(515 nm)
Heating laser beam
80cm×80cm,32 beams
∆λ = 0.1 nm@fundamental(∆ν = 0.08 THz)
(Grating DT = 3 J/cm2)
(DT = 10 J/cm2)
210cm×210cm,21x21 coherent arrays or
9 bundles of 7x7 coherent arrays
Foot pulse beam(515nm)
Lasers
ILE, Osaka
Illustration of main amplifier using active mirror concept
FiberOscillator
Pre-Amplifier(~ kJ, NIR) Main-Amplifier
(~ MJ, NIR)
3rd Harmonics
2nd Harmonics
PulseCompresso
r
compression Laser(1.1MJ, blue, ns)
Heating Laser(0.1MJ, NIR, ps)
OPCPA
PulseStretcher
Mode-lockOscillator
60kJ x 8 beams
ILE, Osaka
Large diameter laser beams will be distributed to 4 modular reactors using
rotating corner cubes.
FiberOscillator
Pre-Amplifier(~ kJ, NIR) Main-Amplifier
(~ MJ, NIR)
3rd Harmonics
2nd Harmonics
PulseCompresso
r
compression Laser(1.1MJ, blue, ns)
Heating Laser(0.1MJ, NIR, ps)
OPCPA
PulseStretcher
Mode-lockOscillator
・コーナーキューブミラー: 既設激光XII号光路長調整機構に使用 ・ハニカム構造ミラーによる軽量化 (試作段階完了)
1
3
分配ビーム配置
回転コーナーキューブミラー
回転軸
蹴り出しミラー
入射ビーム
平行度 < 10 µrad(工作精度) → ポインティング精度* < 10 µrad (歳差運動の影響無し)
像転送 → センタリング精度* < 1cm(回転周期変動= 0.1%)
* : 最終集光系上で
回転速度モニター
42
(3 rpm)
Rotating corner cubeat 4 Hz
Accuracy for pointing < 10 µrad
No influence of axis vibration
Accuracy for centering <0,5 cm
Layout of distributed beams
Input beam
Lasers
ILE, Osaka
Cooling system with 2MW at 200K can be constructed with existing technology.
15m
28m
Electric input power 3600+1500kWCooling water 1300m3/h (32-37oC)Cooling power 2MW at 200K
(δT=5K)Efficiency >30%Coolant R507A(High)+R23(Low)
Image of 600kW, two coolants refrigerator*This image was produced by Maekawa MFG. Co. LTD.
Lasers
ILE, Osaka
After fast ignition, share of lasers in the construction cost became minor.
Required laser energy became ¼ after fast ignition.
Number of LDs became 1/3 after use of Cooled Yb:YAG
Fast ignition KOYO-FCentral ignition KOYO
Chamber
ILE, Osaka
KOYO-F with 32 beams for compression and one heating beam
• Vertically off-set irradiation
• Cascade surface flow with mixing channel
• SiC panels coated with wetable metal
• Tilted first panel to make no stagnation point of ablated vapor
• Compact rotary shutters with 3 synchronized disks
Chamber
ILE, Osaka
The surface flow is mixed with inner cold flow step by step to reduce the
surface temperature.
If the surface flow is a laminar flow, vapor pressure is too high to reach designated pressure of 5-10 Pa.
This concept was experimentally confirmed by Dr. Kunugi.
Chamber
ILE, Osaka
To prevent stagnation of ablated LiPb, front panels were tilted by 30 degree.
Tilted front panels
Cone type ceiling t=0 ms
t=10ms
t=20ms
Position of mass center of ablated vapor
ILE, Osaka
Beam port will be protected using a magnetic field.
• Preliminary numerical simulation indicates that the tip of beam port can be protected from alpha particles.– B=1 T, pulse operation.– Alpha, 6.3×1017 n/m2, τ=0.18 µs
• Electrons are treated as a fluid and alpha particles are treatedas ions.
H. Nakajima and Y. Kajimura, Private communication
3m
Coil
Inner diameter 15cm
Outer diameter 35 cm
200 MJ/.shot
ILE, Osaka
Final optics will be protected with synchronized rotary shutter, magnetic field, and buffer gas.
1 m s2nd shot
3rd shot4th shot
1s1 0 µ s 1 0 0 µ s 10ms 1 0 0ms
2nd shutter 16rps
3rd shutter 4rps
1st shutter 32rps
Target injectionMiss fired target
1st bluster wave from the wall
v=3,000m/s @20,000K
v=150 m/s
Charged particlies from plasma 1 - 2 µ s alpha 0.2 - 0.4 µ s X-rays 10 ns
Blaster waves
1000
1500
2000
Tem
pera
true
of
inne
r sur
face
(K)
Open
Open
Open
2500
500
Gas temperature (Local peak)
Wall surfaceHole on 1st disk
Hole on 2nd disk
Hole on 3rd disk
32 Hz 16 Hz 4Hz
Vapor
60cm
B=1T, 2m
0.5m100m/s
Magnetic field for ions
Rotary shutter for neutral gas
Buffer gas for slow neutral vapor
Chamber
ILE, Osaka
Thermal flow of KOYO-F
SGTurbin
500℃
300℃300℃
50MW
210MW70MW
70MW
240MW
80MW
80MW
500℃
F2+F3 (80cm)12.84 ton/s
Average flow 7.8 cm/s
F1 (20cm)8.56 ton/s
Average flow 24.3 cm/s
Flow rate 21.4 ton/s
904MW
Watercycle
Chamber
LiPb cycle
δt=0.5 oC/shot δt=1.3 oC/shot
ILE, Osaka
Residual gases can be evacuated with lead diffusion pumps.
Pb蒸気拡散
ポンプ
トリチウム
回収処理系へ
A'A
10000.00
LiPb 上部ブランケット 300 ℃
A-A' 断面図
LiPb液体壁チェンバ-概念図 1/100 単位mm
φ6000.00
Fusion output 200 MJ / pulse, 800 MW,Pulse rep-rate s 4 Hz Chamber inner radius 3.0 m, upper wall distance from burning center 10.0 m Pulse heat load max. 32 J / cm2 , upper wall 2.9 J / cm2 average heat load max. 128 W / cm2 , upper wall 11.5 W / cm2 Neutron wall load max. 5.6 MW / m2, upper wall 0.5 MW / m2
A A’
ドライ
スクロール
ポンプ
6m
Φ 0.55m
粗びきポンプ区画
( 1 x 1 x 1m)
5m
Pb拡散
ポンプ
Lead diffusion pump
To tritium recovery system
Dry pump
ILE, Osaka
Tritium necessary for one fuel loading system is about 100g
n=20 x 80 (for 13 min at 2 Hz)
12 cm
Air lock
Air lockAir lockCooling zone Freezing zoneLoading zone
Liquid N2
Liquid He
20 K He 100 torr
19 K DT 128 torr
19 K DT 128 torr
10 K DT 1 torr
DT Pump
DT Pump
2nd Tritium barrier
Vacuum vessel
3 hr
Vacuum Pump
TRS IS & Strage
To injector
Laser Not to scale
Tritium inventory76 g as liquid
0.82 g as vapor
4g in 1600 targets
1.2 g/13 min
5mg/s
ILE, Osaka
Tritium in gas phase and LiPb leach their ultimate concentrations in 30 sec 6 hr, respectively.
3 mg/s
5Pa, 0.16g as gas
Gap for tritium recovery
Tritium barrier
2.8〜28 g in LiPb
0.1 ppm〜1ppm
TBR=1.3
30% burning rate
Tritium of 1 kg is necessary as the initial inventory for 1200MWeplant.
Tritium can be recovered as fuel but diffusion through the heat cycle seems most critical.
Chamber
ILE, Osaka
We estimated the ablation process using ACORE. Stopping power in ionized vapor
was calculated.
Atomic Process Code
Ionization Degree, Population, Energy Level
Stopping Power Code EOS Code Emissivity and Opacity Code
Stopping power Ionization DegreePressure, Specifiic heat
Emissivity, Opacity
ACORE (Ablation COde for REactor)
0
4
8
12
Number Density
(cm -3)1014
1018
1022
Temperature (eV)
10
1
0.1
0.01
Z*
Ziegler’s model
−dEdx
= ni Inll∑
n∑ Pnl π
Z0 e2
Inl
⎛
⎝ ⎜ ⎞
⎠ ⎟
2
Gv
vnl
⎛ ⎝ ⎜
⎞ ⎠ ⎟
102
103
104
105
106
0 0.5 1 1.5 2 2.5 3 3.5
ni = nl , Te = 2024 K
liquid
Ref.
present- dE
/ d
x (M
eV/c
m)
E (MeV)
Present model
G V( ) =α 3/2
V 2 α +23
1 + β( )ln 2.7 + V( )⎡ ⎣ ⎢
⎤ ⎦ ⎥
4 2 20
02 2
4 4e e
e e e
e Z n n edE hKdx m v n v m
π π⎛ ⎞− = ⎜ ⎟⎜ ⎟
⎝ ⎠
Ziegler
Corrected Bethe
Ionization rate of Pb
Chamber
ILE, Osaka
Density, Temperature and velocity profile of ablated material.
1020
1021
1022
1023
-200
0
200
400
600
800
1000
-0.2 0 0.2 0.4 0.6 0.8 1 1.2
Time = 1932 ns
Number Density
Velocity
Num
ber
Den
sity
(cm
-3)
Velocity (m
/s)
x (mm)500
1000
1500
2000
2500
3000
3500
4000
4500
-0.2 0 0.2 0.4 0.6 0.8 1 1.2
R = 3 m
595.5 ns
1932 nsT
empe
ratu
re (K
)
x (mm)
102
103
104
105
106
107
108
109
0.0 0.5 1.0 1.5 2.0
alfaalfa (debri)deuteriumtritiumprotonherium3
Inte
nsit
y (W
/cm
2 )
Time (µs)
1020
1021
1022
1023
-0.2 0 0.2 0.4 0.6 0.8 1 1.2
R = 3 m
595.5 ns
1932 ns
Num
ber
Den
sity
(cm
-3)
x (mm)
Chamber
ILE, Osaka
Lot of 0.1 µm radius clusters are formed after adiabatic expansion.
(Luk’yanchuk, Zeldovich-Raizer Model)
20% of ablated vapor becomes aerosol.
Chamber
ILE, Osaka
Beam ports and ceiling will be made with porous metal and followed by condensation of vapor ablated by previous shot.
80%
20%
Diameter 0.1µm
Liquidmembrane
aerosol
Vapor ~1000m/s
Condensation rates of the fast and slow component at the first bounce are about 60% and 100%, respectively.
These rates are sufficient to keep the vapor pressure < 5 Pa and to form a 2 µm-hick, protective layer before the next laser shot.
0 2000 4000 6000 8000 1 1040
Ti
Pb
蒸気温度(K)
吸着係数
Con
dens
atio
n co
effic
ient
on
col
d su
rfac
e
Vapor temperature (K)
1
Aerosol mainly appears in slow component. Now secondary particles because the surface energy > kinetic energy
ILE, Osaka
Critical issue in chamber
• Probability for direct exposure of the same place <1/103 – 1/104
– If we assume maintenance period of 2 years and acceptable erosion of 3mm, the probability for direct exposure of the same place with α particles must be less than 1/104.
– The answer would be improve flow control, material selection, and chamber radius
• Although tilted front panels will reduce the stagnation to 1/103, few gram of LiPb vapor will stagnate at the center.– Off set irradiation would be the answer.
Dry surfaceLiquid LiPb
ILE, Osaka
Summary 1
– 1) We have examined the design windows and the issues of the fast ignition laser fusion power plants. ~1200 MWe modular power plants driven at ~16 Hz
– 2) For laser driver we have considered the DPSSL design using the Yb:YAG ceramic operating at low temperature (~200K).
– 3) We have proposed the free fall cascade liquid chamber for cooling surface quickly enough to several Hz pulses operation by short flow path. The chamber ceiling and laser beam port are protected from the thermal load by keeping the surface colder to enhance condensation of LiPb vapor.
– 4)For exhausting DT gas mixed with LiPb vapor we have designed diffusion pumps using Pb (or LiPb) vapor with effective exhaust velocity about 8 m3/s DT gas.
ILE, Osaka
Summary 2
• Core plasma, – High density compression of cone target– Heating efficiency of 30% – Adiabat a <2.5
• In the laser system– Construction of laser itself seems possible with existing
technology.– Beam steering of ignition beam may be critical.
• Chamber system– Chamber clearance– Tritium confinement
ILE, Osaka
Basic specification of KOYO-F
Net electric output 1283 MWe (320 MWe x 4)
Electric output from one module 320 MWe
Target gain 167
Fusion Yield 200 MJ
Laser energy/Beam number 1.2 MJ(Compression=1.1MJ/32beams, Heating=100kJ 1beam)
Laser material/Rep-rate Cooled Yb:YAG ceramics at 150~220K /16 Hz
Chamber structure/Rep-rate at module Cascade-type, free-fall liquid LiPb wall/4 Hz
Fusion power from a module 800 MWth
Blanket gain 1.2(design goal)
Total thermal output from a module 916 MWth
Total thermal output from a plant 3664 MWth (916 MWth x 4 )
Heat-electricity conversion efficiency 41.5 %(LiPb Temperature 500℃)
Gross electric output 1519 MWe
Laser efficiencies13.1% (compression), 5.4% (heating)、Total 11.8%(including cooling power)
Recirculating power for laser 164 MWe(1.2 MJ x 16 Hz / 0.118)
Net electric output/efficiency 1283 MWe(1519 MWe - 164 MWe - 72 MWe Aux.)/32.7%
ILE, Osaka
Plant size is 303mlong x 110mwidth x 50mhigh.
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