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UCRL—53559
DE86 006996
The High-Yield Lithium-
Injection Fusion-Energy
(HYLIFE) Reactor
Compiled by:
James A. Blink, William
J.
Hogan,
Jack Hovingh, Wayne R. Meier, and
John H. Pitts
Editors:
Kellie L. Essary
Kevin E. Lewis
Manuscript date: December 23, 1985
LAWRENCE LIVERMORE NATIONAL LABORATORY
Universitv of California • Livermore, California • 94550
Available from: National Technical Information Service • U.S. Department of Commerce
5285 Port Royal Road • Springfield, VA
22161"
A03 per copy • (Microfiche AOl )
Contents
Abstract 1
1.
Introduction 1
2.
HYLIFE Reaction Chamber 2
2.1 Evolution of the Final Design 2
2.2 Summary of Final Design Parameters 3
2.3 Neutronics 3
2.3.1 Energy Deposition 8
2.3.2 Tritium Breeding 8
2.3.3 Radiation Damage 10
2.4 Liquid-Metal Jet-Array Hydrodynamics 11
2.4.1 Hydrodynamic R.-sponse to the Fusion-Energy Deposition 11
2.4.2 Jet Stability 13
2.4.3 Beam Apertures 14
2.4.4 Condensation and Reestablishment of Liquid-Metal Jet Array 15
2.5 Structural Design 15
2.5.1 Nozzle Plate 15
2.5.2 First Structural Wall 15
2.5.3 Materials Considerations 17
3.
Supporting Systems 18
3.1 Driver Options 18
3.2 Design and Protection of Final Optics 20
3.3 Fuel-Pellet Injection 22
3.4 Vacuum Svslem 23
3.5 Tritium Extraction 23
4.
Primary Steam-Supply System and Balance cf Plant 24
5.
Safetv and Environmental Protection 26
5.1 Fire Safetv- 26
5.2 \uclear Safetv 26
6. Costs . 27
7.
Conclusions 29
Acknowledgments 30
References 31
Appendix A. Annotated Bibliography 37
iit
The High-Yield Lithium-
Injection Fusion-Energy
(HYLIFE) Reactor
Abstract
The High-Yield Lithium-Injection Fusion Energy (HYLIFE) concept to convert iner-
tial confinement fusion energy into electric power has undergone intensive research and
refinement at LLNL since 1978. This paper reports on the final HYLIFE design, focusing
on five major areas: the HYLIFE reaction chamber (which includes neutronics, liquid-
metal jet-array hydrodynamics, and structural design), supporting systems, primary
steam system and balance of plant, safety and environmental protection, and costs. An
annotated bibliography of reports applicable to HYLIFE is also provided.
We conclude that HYLIFE is a particularly viable concept for the safe, clean produc-
tion of electrical energy. The liquid-metal jet array, HYLIFE's key design feature, protects
the surrounding structural components from x rays, fusion fuel-pellet debris, neutron
damage and activation, and high temperatures and stresses, allowing the structure to last
for the plant's entire 30-year lifetime without being replaced.
1.
Introduction
When we look beyond the energy needs of
the present generation, it is clear that humankind
will eventually be forced to turn from hydrocar-
bon fuels to find longer-iasting energy sources. Of
the three major possible sources of future en-
ergy—solar technology, fission breeders, and
fusion—fusion is an option that merits continued
intensive development.
In our relatively low-gravity terrestrial envi-
ronment, fusion can be produced ir two way: by
magnetic confinement and by inertial confine-
ment. Magnetic confinement fusion (MCF) uses a
magnetic field to contain a low-density plasma for
a relatively long time. In contrast inertial confine
ment fusion (ICF) achieves the same fusion output
by confining a very dense plasma with the plas-
ma's own inertia for a necessarily short time.
ICF technology is less developed than MCF;
however, it offers certain engineering advantages
over MCF for the creation of a practical reactor.
One major advantage is the large allowable dis-
tance between the laser or ion-beam driver and
the fusion reaction chamber. This distance pre-
vents neutron activation of the driver equipment
and allows a single driver to support several reac-
tion chambers. In addition, the drher system can
be external to the reactor containment structure,
allowing easier access for maintenance purposes.
Another important advantage of ICF is its
comps'itively relaxed vacuum requirement of
^iOPa (^10 'Torr), compared with ^100//Pa
to lOmPa
(-}0'
Q
to 10"Torr) for MCF. This re-
laxed vacuum requirement allows us to place a
liquid-metal jet array between :he fusion reactions
and the structural walls to absorb the fusion neu-
trons,
x ravs, and fusion fuel-peilet debris. The
liquid-metal array is the key feature of the
HYLIFE reaction chamber, which is illustrated
along with the associated power plar.t in Fig. 1.
With the protection provided by the liquid metal,
the first structural wall (FSW)—tha; wall closest to
the fusion reactions—becomes appreciably less
radioactive and suffers less radiation damage per
unit of net energy produced than do MCF or ICF
reactors with unp:otected walls. The liquid metal
moderates and absorbs about 90% of the neutron
energy. Our research shows that with current
technology and materials we can build structural
walls protected by a liquid-metal jet array capable
of lasting the power plant's entire 30-year lifetime.
The above advantages, plus ICF's high-power
density and small containment volume, should
lead to reasonably low-cost electricity.
A
Figure 1. The HYLIFE reaction chamber and power plant. The two driver beams are shown entering
the plant at the lower right side of the figure.
2.
HYLIFE Reaction Chamber
2.1 Evolution of the Final Design
In 1978, we began a formal study of the
HYLIFE concept at LLNL. Over the next few
years,
we reported on the progress of this study in
the LLNL Laser Program Annual Report and in
other scientific publications. Our goal was to de-
velop a practical, clean reactor design that used
current technology and took advantage of ICF's
inherent benefits. We believe we have met our
goal.
In this report, we summarize the final
HYLIFE design and in Appendix A present *n an-
notated bibliography that directs the reader to
sources containing more detailed information
than presented here.
The final HYLIFE design has evolved horn a
large number of independent studies on various
aspects of the chamber and power plant, causing
some inconsistencies in the magnitudes of various
parameters reported in earlier publications. For
this reason, parameter values given in this report
should be used instead of magnitudes
documented earlier. Considerable effort was put
forth to make the final HYLIFE design internally
consistent; detailed analyses performed at earlier
design points were repeated for the final design
point only when they would alter our conclusions
about basic feasibility.
2
2.2 Summary of Final Design
Parameters
The HYLIFE chamber design
1,2
uses a con-
tinuously falling liquid-metal blanket composed
of 175 jets, each 0.2 m in diameter at the reactor
midplane. (The HYLIFE chamber design is shown
in Fig. 2, and the de- m characteristics are listed
in Table 1.) We chose lithium as the liquid metal
for our baseline desigi., Ithough one other op-
tion, a eutectic containing 17 at.% lithium and 83
at.% lead, was studied. Lithium and the lithium-
lead eutectic have their respective advantages.
Lithium has low density, which allows low pump-
ing power and lower stresses on the primary loop
piping, and it does not become radioactive. The
lithium-lead eutectic is less chemically reactive
than lithium and poses less of a fire hazard; how-
ever, it does become activated.
To protect the FSW from \ rays, fuel-pellet
debris, and most of the neutron energy, we de-
signed the liquid-metal jet array with an effective
thickness of 0.74 m at the reactor midplane. Our
calculations show that with the liquid-metal jet-
array protection the total radiation damage due to
helium production and displaced atoms in the
FSW and nozzle plate after 30 years of plant oper-
ation would not -,'ied the accepted damage lim-
its.
3
^
This long-lite design offers two important
advantages: It eliminates the need to periodically
replace structural elements, and it reduces the to-
tal amount of activated material produced.
The jet array is arranged to allow short-
wavelength-laser illumination of the fusion fueJ
pellet from two sides by two 6-m-tall x 2-m-wide
mirror arrays mounted 60 m from the chamber
center. We used an allowable mirror fluence of
20 J/cm
2
with short wavelength (1/4 to 1/3 jUm),
pulse-shaped laser light which has the bulk of its
energy in the last 5 to 10 ns. A heavy-ion-beam
driver
6
could also be accommodated, but the va-
por density would need to be reduced to that
needed for ballistic ion propagation. This could be
accomplished by reducing the lithium tempera-
ture or by using Li
17
Pb
83
.
The jet array will completely disassemble
with each fusion pulse and must be reestablished
before the next pulse. Because only about 4% of
the 1800-MJ fusion yield is converted to kinetic
energy of liquid and gas, transient mechanical
stress can be kept low. For this reason, the FSW
can be designed to survive the roughly one billion
fusion pulses that occur in the plant's lifetime.
The HYLIFE power plant uses heated liquid
metal to operate steam generators and produce
electricity. Eleven electromagnetic pumps, each
with 7.8-m
3
/s capacity,
7
circulate the liquid lith-
ium through the reaction chamber. Two smaller
pumps (4.9 m
3
/s) force some of the lithium
through four Li-Na intermediate heat exchangers
(IHXs). The heated sodium (Na) from the IHXs
drives 12 steam generators. The power balance of
a laser-driven HYLIFE power plant is shown in
Fig.
3.
To ensure safety with a minimum of operator
intervention, the HYLIFE design incorporates pas-
sive features, such as filling the reactor and other
surrounding rooms with inert gas to prevent fires.
These features are discussed in Sec. 5.1.
HYLIFE is designed to have minimal environ-
mental impact. The liquid-lithium coolant con-
tains the tritium chemically, and a maximum of
only a few kCi/d (about 0.01% of the tritium flow)
would diffuse through the heat exchanger into the
sodium (assuming zero tritium pressure in the so-
dium).
Design features that reduce the diffusion
rate,
incorporate Na cold-trapping, or recover tri-
tium from the water loop would limit tritium
emissions to the environment to an acceptable
level of 10 to 100 Ci/d. Use of the lithium jet array
and a low-alloy steel, 2-1/4 Cr-1 Mo, produces an
activated structure that can be buried as low-level
waste within 50 years after the plant is shut down.
2.3 Neutronics
We used TARTNP
8
(a coupled neutron-
photon Monte Carlo transport code) and LI.NL's
Evaluated Nuclear Data Library (ENDL)' to ana-
lyze the neutron-energy deposition and tritium-
breeding characteristics of the HYLIFE design.
The results reported in this section are for an ear-
lier liquid-metal jet-array configuration, which
had an effective lithium thickness of 1.0 m. (In the
final design, the effective thickness was reduced
to 0.74 m.) While the spatial distribution would be
different for the final design, the overall energy
deposicion and tritium-breeding ratio would not
change significantly.
Each DT fusion reaction produces a 14.1-MeV
neutron, in ICF, this neutron is produced within a
region of highly compressed DT, which can have
a significant moderating effect on the neutrons.
The effects of the compressed fuel in the fusion
pellet on the 14.1-MeV neutrons are included in
the calculation. A 14.1-MeV-neutron source is uni-
formly distributed throughout a spherical zone of
compressed DT witn a density-radius product pR
•A 3.0 g/cm
2
. This fuel pR is typical of expected
reactor-class fusion fuel pellets.
3
