LIFE: Laser Inertial Fusion-based Energy

LIFE:
Laser Inertial
Fusion-based
Energy
Presented by
Jeff Latkowski
LIFE Chief Engineer
Fusion Power Associates
December 3 rd , 2009

LIFE power flow for a hotspot pure fusion system
Laser
2.8 MJ (1ω),
2.3 MJ (2ω) @ 15 Hz
14% η
303 MWe
(27% recirc)
42 MW
laser
25 MWe
G fusion = 51
Pumps /
aux. power
1807 MW
fusion
1001 MWe
G blanket = 1.2
Power cycle
η = 61%
To
grid
2168 MW
thermal
1329 MWe 839 MWth
Process heat

Laser diodes and He gas cooling enable a NIF-like
architecture to meet LIFE high rep rate high efficiency
requirements
High Power Diode Arrays
100 kW peak power
High Speed Gas Cooling
3 W/cm 2 cooling (average)
These technologies have been developed as part of the Mercury
Project and allows ultra-compact laser architectures
Moses, 24th Annual ASPE Meeting 7

Advanced lasers and modular systems
make the facility small and enable
rapid construction and maintenance
20 m
• Modular (advanced
architecture) lasers that
could be factory built
• Separate first wall &
blanket modules for
rapid & independent
replacement

NIF-1009-17579

NIF-1009-17579

Injection demonstration at GA to simulate the full length of a
LIFE fueling system have demonstrated many objectives
• Injection at 6 Hz and 400 m/s to 5 mm accuracy demonstrated
• • Additional Injection R&D at 6 Hz needed (burst for mode) cryogenic 400 m/sec targets to and 200 µm higher demonstrated accuracy
• Additional R&D needed for Cryogenic targets and >10 Hz
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12

Target fratricide and heating during
injection are manageable
• DT ice preheat of 100 mK is deemed acceptable (and conservative):
—Target injector parameters satisfy fratricide constraints:
– Injector nozzle ~15 m from chamber center
– Two mean free paths of neutron shielding (~15 cm) on shutter
– 250 m/s injection velocity
• Hohlraum acts as thermal insulator to protect capsule during injection:
—Radiation heating to capsule:
– Polyimide transmits in the IR
– Radiation shield (Al/polyimide/Al) gives 99% reflectivity
—Convective heating of polyimide window dominates:
– Heat transfer coefficient ~8 W/m 2 -K at window edge
– Window heats to ~80% of decomposition temperature
• Several options for reducing target injection risk:
—Higher velocities / shorter distances reduced heating time
—Tailored target output reduced chamber gas density
—Injection with cool gas plume reduced ∆T and h

August 2, 2007 Laser ICF Fusion/Fission Discussion 15

X-rays and ion fluxes are simply mitigated
Parameter Value
Target yield 120 MJ
Repetition rate 15 Hz
Fusion power 1800 MW
Chamber radius 4 m
X-rays 14 MJ (12%)
Ions 12 MJ (10%)
Chamber fill gas can attenuate
x-rays and ions to protect the
first wall
Spectral Fluence
Au, p, d, t, etc.
10 0
10 -2
10 -4
10 -6
10 -8
10 -10
0-11 deg.
11-21 deg.
21-30 deg.
30-39 deg.
39-51 deg.
51-60 deg.
60-71 deg.
71-81 deg.
81-90 deg.
0.01 0.1 1 10 100
x
Photon energy [keV]
1
0 n

Thermally robust targets allow for a protective
chamber gas to absorb all ions and 90% of x-rays
4 m
n
ions
x-rays
2.5 µg/cm 3 Xe
T(°C)
C)
1800
1600
1400
1200
1000
800
600
− 9 − 8 − 7 − 6 − 5 − 4 − 3 − 2
log(t(s))
Protective background gas re-radiates
ion and x-ray energy over a timescale
thermal conduction can effectively
remove it

Chamber conditions must support laser
beam propagation for the next shot
• Base case design is robust with respect to chamber design:
— 120 MJ fusion yield @ 15 Hz
— 4 m radius
— 2.5 µg/cc xenon
• Chamber design trades-off:
— First wall protection stop ions & attenuate x-rays in Xe/Kr
— Target heating during injection dominated by IR from 1 st wall
— Laser beam propagation ~1% inverse Bremsstrahlung loss
• System optimization is likely to result in smaller chambers:
— Beam propagation with increased gas densities
— Gas cocktails for better x-ray attenuation
— Tailored target output for fewer x-rays

Chamber designed for rapid replacement
Coolant
extraction
plenum
Laser beam
tubes
Coolant
injection
plenum
Vacuum
vessel
First wall
module
Blanket
module

Modular chambers have independent first walls
that can be replaced without moving the blanket
First wall
module
Blanket
module
Coolant injection
& extraction plena

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Summary
• LIFE systems will be highly modular and more
compact than NIF
• The high degree of separability inherent to IFE
translates into a significant development path
advantage
• LIFE could be fielded as a pure fusion plant or as a
hybrid to complete waste-related missions
• A pilot plant could be operational a decade after NIF
ignition and that a commercial power plant could be
running a decade after that