LIFE: Laser Inertial Fusion-based

Energy

Presented byJeff Latkowski

LIFE Chief Engineer

Fusion Power AssociatesDecember 3rd, 2009

Laser2.8 MJ (1ω),

2.3 MJ (2ω) @ 15 Hz14% η

Power cycleη = 61%

Gfusion = 5142 MWlaser

1807 MWfusion

Gblanket = 1.2

2168 MWthermal

303 MWe(27% recirc)

25 MWe

Pumps /aux. power

Togrid

1001 MWeProcess heat

1329 MWe 839 MWth

LIFE power flow for a hotspot pure fusion system

5

6

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Laser diodes and He gas cooling enable a NIF-like architecture to meet LIFE high rep rate high efficiency requirements

These technologies have been developed as part of the Mercury Project and allows ultra-compact laser architectures

High Speed Gas CoolingHigh Power Diode Arrays

3 W/cm2 cooling (average)100 kW peak power

8

20 m

Advanced lasers and modular systems make the facility small and enable rapid construction and maintenance

• Modular (advanced architecture) lasers that could be factory built

• Separate first wall & blanket modules for rapid & independent replacement

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Injection demonstration at GA to simulate the full length of a LIFE fueling system have demonstrated many objectives

• Injection at 6 Hz (burst mode) 400 m/sec to 200 µm demonstrated• Additional R&D needed for Cryogenic targets and >10 Hz

12Moses, 24th Annual ASPE Meeting

• Injection at 6 Hz and 400 m/s to 5 mm accuracy demonstrated• Additional R&D needed for cryogenic targets and higher accuracy

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/m2-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

10-10

10-8

10-6

10-4

10-2

100

0.01 0.1 1 10 100

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.

Photon energy [keV]

Chamber fill gas can attenuate x-rays and ions to protect the first wall

Parameter Value

Target yield 120 MJRepetition rate 15 HzFusion power 1800 MW

Chamber radius 4 mX-rays 14 MJ (12%)Ions 12 MJ (10%)

n10

xAu, p, d, t, etc.

Spec

tral

Flu

ence

x-rays

ions

n

2.5 µg/cm3 Xe

4 m

Thermally robust targets allow for a protective chamber gas to absorb all ions and 90% of x-rays

9− 8− 7− 6− 5− 4− 3− 2−600

800

1000

1200

1400

1600

1800

C)

log(t(s))T(

°C)

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 1st 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

First wall module

Blanket module

Vacuum vessel

Coolant extraction plenum

Coolant injectionplenum

Laser beam tubes

Modular chambers have independent first walls that can be replaced without moving the blanket

First wall module

Blanketmodule

Coolant injection & extraction plena

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• LIFE systems will be highly modular and morecompact 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

Summary