Note: Descriptions are shown in the official language in which they were submitted.
WO94/164~ 21 ~ ~40 6 PCT~S93/12541
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Description
Self-Catalyzed Nuclear Fusion of Lithium-6 and
Deuterium Using Alpha Particles
Technical Field
The present invention pertains to lithium-
deuterium fusion in a metallic lattice to produce alpha
particle emitter sources or thermal energy.
Background Art
Electrically charged particles such as bare
electrons or protons or muons are known to be Fermions
and to obey Fermi-Dirac statistics. Two like elementary
charged particles, such as two protons, have like elec-
trical charges so that they tend to repel one another.
Further, two like Fermions obey the Pauli exclusion prin-
ciple so that, if the particles possess identical quantum
numbers, the two identical particles will not occupy the
same region of space at the same time, even if the iden-
tical particles have no net electrical charge. The com-
bination of two Fermions in a nucleus, such as a neutron
and a proton, which together form the nucleus of a
deuterium atom or ion, behaves as another type of parti-
cle, called a Boson, which obeys Bose-Einstein statistics
rather than Fermi-Dirac statistics. This has been dis-
cussed by K. Birgitta Whaley, a theoretical chemist
speaking at the Dallas meeting of the American Chemical
Society in April, 1989.
Particles that obey Bose-Einstein statistics
("Bosons") tend to accumulate in the same region of space
under some circumstances, in contrast to staying apart as
like Fermions tend to do. This tendency of Bosons to
accumulate in the same region of space is indicated by a
quantum thermodynamic expression for the pressure in a
system of Bosons developed and discussed in Statistical
PhYsics by L.D. Landau and E.M. Lifshitz, Addison-Wesley
Co., 1958, p. 159. In this expression for pressure, the
WO94/1~ 215 3 4 0 6 PCT~S93/~541
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pressure developed by a system of Bosons is less than the
pressure developed by a system of particles that are nei-
ther Fermions nor Bosons at the same concentration and
temperature. This suggests that the Boson particles ex-
perience a modest attraction for one another that has itsorigin in quantum mechanical forces.
Whaley has speculated that, because of the
quantum effect features of particles such as deuterium
nuclei, the natural repulsion between two such nuclei can
be blocked inside a crystal so that the deuterium ions
are not held apart by the combination of strong coulomb
forces and quantum forces. Some workers speculate that,
because deuterium nuclei might be brought very close to-
gether inside a crystal, the deuterium nuclei could com-
bine in a fusion process at enhanced rates, as comparedto the infinitesimal rates observed at ordinary fluid
densities for deuterium nuclei.
Lithium ions have been widely used in the elec-
trolyte added to heavy water in certain experiments in-
volving palladium by Pons and Fleischmann and many otherresearchers. The electrolyte used most commonly is LioD,
wherein most or all of the hydrogen in LiOH is replaced
by deuterium. Most reports of generation of heat by
these experiments indicated that the LiOD electrolyte had
been used. In March, 1990, two physicists speculated
that the excess enthalpy generated may come from a
reaction known in nuclear physics:
Li6 + D -> 2He4 + 22.4 MeV.
The excess energy of 22.4 MeV is carried by the kinetic
energy of the two helium nuclei (alpha particles), and
thought to be dissipated directly in the host lattice
used, which is usually palladium.
It is known that lithium reacts with hydrogen
to form LiH, in which the hydrogen acts as the negative
ion. This is evidenced by the fact that when this sub-
stance is electrolyzed, the hydrogen is liberated at the
anode. Therefore it would be expected that the close
proximity of lithium-6 ions and deuterium ions within the
~094/1~4b PCT~S93/~541
2I ~340 6
palladium lattice could lead to a strong chemical bond
with the deuterium acting as a negative ion and the lith-
ium-6 as a positive ion. In contrast, in the case of two
deuterons the coulomb force would tend to push them
mutually away.
It is also known that some metals will readily
accept substantial amounts of hydrogen or its isotopes
into the interior of such metals and that such metals can
be used to filter hydrogen isotopes from a stream of oth-
er substances. In U.S. Pat. No. 4,774,065, granted Sep-
tember 27, 1988 to R. Penzhorne et al., it is disclosed
that a hot palladium membrane will filter tritium and
deuterium from C0 molecules. The palladium membrane dis-
closed by Penzhorne et al. was used to filter exhaust gas
from a fusion reactor. In "Advanced Inorganic Chemistry"
by F. Albert Cotton and Geoffrey Wilkinson, published
1972, it is stated that one of the unique characteristics
of metallic palladium and Pd-Ag and Pd-Au alloys is the
high rate of diffusion of hydrogen gas through a metal
membrane compared to the diffusion rates in other metals
such as nickel or iridium. There is no doubt that
pressure-temperature-composition curves indicate the
presence of palladium hydride phases. In "General
Chemistry for Colleges" by Herman T. Brisioe it is stated
that as much as 900 ml of hydrogen can be adsorbed in 1
ml of finely divided palladium. This adsorbed hydrogen
is very chemically active. The increased activity of
adsorbed hydrogen in palladium indicates it exists in the
atomic form instead of molecular form. Catalysts such as
finely divided palladium increase the speed of reactions
even at low temperatures. Also, finely divided nickel is
a catalyst and adsorber of hydrogen. Additionally
accumulator structures for packing and storing deuterium
and lithium have been disclosed in the published PCT
applications PCT/US91/01067, PCT/US91/03280,
PCT/US91/03281, and PCT/US91/03503 of Jerome Drexler.
The nuclear fusion of deuterium and lithium-6
is well known. For example, such a nuclear reaction can
WO94/1~4~ ~ PCT~S93/12541
2~s34Q6
be obtained by bombarding a Li6 atom with a deuteron
having a bombarding energy of only 20,000 volts. The
fusion of Li6 and D nuclei is considered favorable in
that it is aneutronic, that is, it generates no harmful
neutrons. However, in order to achieve frequent and
continuous fusion, extremely high temperatures, approach-
ing 100 million degrees, have been considered necessary.
Some researchers have attempted to obtain room
temperature fusion using muon particles as catalysts.
Luis W. Alvarez, was awarded the Nobel Prize in physics
in 1968 for his work on muon-catalyzed room temperature
fusion which he achieved in 1956. Although the process
worked, it was extremely expensive and it was not energy
efficient. Very expensive high energy particle
accelerators were needed to generate the muons, and once
generated, the muons lasted only about two millionths of
a second. Since the lifetime of the muon particle is so
brief, each particle was only able to catalyze a limited
number of fusion reactions.
Lord Ernest Rutherford's experiments during the
early 1900's, measuring the scattering of alpha particles
passing through metals, provided the first information on
the interaction between energetic alpha particles and
nuclei in metallic lattices. Other early researchers who
contributed to the knowledge of alpha particles
interacting with nuclei in metals include H. Seiger, J.
Chadwick, and Marsden.
These early researchers used radium C' as the
source of high kinetic energy alpha particles having an
energy of 7.8 MeV. Since radium C' has a half life of
only one microsecond it is necessary to have some radium
C and radium B mixed in which emit beta and gamma rays as
they decay in less than one hour to radium. Thus when
radium is used to generate alpha particles, beta and
gamma rays are also present which is not normally
desirable.
It is an object of this invention to create a
self-sustaining nuclear fusion reaction at ambient
W094/1~K 21 5 3 4 0 6 PCT~S93/12541
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temperatures. Another object of the invention is to
generate heat from nuclear fusion without the generation
of neutrons or only a negligible number. Another object
of the invention is to achieve self-sustaining chain
reaction-type nuclear fusion which is energy efficient.
Still another object is to create an emitter source of
high energy alpha particles which does not emit gamma
rays or only a negligible number.
Summary of the Invention
This object has been achieved through self-
catalyzed nuclear fusion of lithium-6 and deuterium using
alpha particles. This is accomplished by densely packing
ions of Li6 and D into the metallic lattices of an ion
accumulator structure. The metallic lattices of an ion
accumulator structure allow ions of Li6 and D to enter
and to be packed together in close proximity to each
other or as Li6D molecules in a material such as
palladium. Next, a source of energetic alpha particles,
such as radium, brought into scattering proximity with
the Li6 and D nuclei is used to bombard the Li6 and D
nuclei packed together in the accumulator structure. The
alpha particles, Li6 and D are all Bosons which obey the
Bose-Einstein statistics. The alpha particles have a
sufficiently high kinetic energy such that they can
penetrate the surface of the palladium for a short
distance when the alpha particle source is brought near
the palladium surface, thereby causing a scattering
encounter of the alpha particles with the nuclei of Li6
and D, imparting motion, i.e. recoil, to one or both of
those nuclei leading to a nucleus-to-nucleus compression
effect of the Li6 and D nuclei within the metallic
lattice. As a result, the probability that these nuclei
will combine and fuse is increased. When these nuclei
fuse, two highly energetic alpha particles are emitted.
The emitted alpha particles may, in the same manner
described, trigger additional Li6 + D nuclear fusion
W094/1~K PCT~S93/~541
2153~06
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reactions and additional high energy alpha particle
emissions.
Since alpha particles may be easily and inex-
pensively generated, the present invention does not suf-
fer from the cost inefficiencies of muon-catalyzed sys-
tems. Thus, high energy alpha particles from a
radioactive alpha emitter can be used only to initiate a
continuous cycle of aneutronic fusions and high energy
alpha particle emissions, such that a self-sustained
chain reaction-type nuclear fusion is achieved at ambient
temperatures. Since alpha particles are generated by the
fusing Li6 and D in the palladium lattices in a self-
sustained manner, the palladium ion accumulator may be
used as an alpha particle emitter source.
Brief Description of the Drawings
Fig. 1 is a simplified perspective view of a
torus-shaped reaction apparatus in accord with the
present invention.
Fig. 2 is a sectional view of the apparatus of
Fig. 1 taken along lines 2-2.
Figs. 3 and 4 are top views of passive baffles
or ion accumulator baffles in accord with the present
invention.
Fig. 5 is a perspective view of a slurry
accumulator structure in accord with the present
nventlon .
Figs. 6 and 7 are sectional views of insulated
particulate accumulator structures in accord with the
present invention.
Fig. 8 is a sectional view of a spiral
accumulator structure.
Fig. 9 is a perspective view of small spiral or
rolled foil accumulator structures.
Fig. 10 is a plan sectional view of a portion
of a reaction apparatus showing confinement of accu-
mulator structures of the kind shown in Figs. 6, 7, 8 or
9 between passive baffles of the kind shown in Fig. 3.
WO94/1~4K 21 S3q o ~ PCT~S93/~541
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Fig. 11 is a plan sectional view of a portion
of a reaction apparatus showing rods cantilevered from
baffles of the kind shown in Fig. 3.
Best Mode for Carrying Out the Invention
With reference to Fig. 1, a torus-shaped
reactor structure 11, as disclosed in published PCT
application US91/03503, and containing within it alpha
particle sources 44 and 53 as shown in Fig. 10 or Fig. 11
and ion accumulator structures in accord with the present
invention is shown. Reactor structure 11 is sealed to
prevent light water and other contaminants in the
atmosphere from entering it. A fluid 13 is driven by a
pump or pumps 15 through the structure. The fluid 13 is
concentrated heavy water ionized by enriched lithium
deuteroxide, LioD containing at least 50~ Li60D.
Deuterium gas is bubbled into the heavy water and
dissolved in it. The D-D gas provides a source of
negative deuterium ions due to some dissociation and
ionization. In order to create thermal energy in accord
with the present invention, it is necessary to pack
lithium-6 and deuterium ions into a tight metallic
lattice. Such a lattice is available in a material such
as palladium or alloys such as Pd-Ag and Pd-Au, contained
for example within the accumulator structures in the form
of porous baffles 17 of Figs. 3 or 4 and the particulate
slurry 29 shown in Fig. 5. To maximize this packing and
to increase the amount of deuterium gas in the heavy
water the internal pressure may be raised as high as one
hundred atmospheres or more, which a torus-shaped
structure can withstand.
Referring now to Fig. 2, a sectional view of
the reactor structure of Fig. 1 taken along line 10-10 is
shown exposing the porous baffles 17. Baffles 17 may be
made of palladium and act as ion accumulators, as
illustrated in Fig. 4, or may be inactive porous baffles,
as shown in Fig. 3, used to confine the palladium parti-
culate accumulator structures described below. When the
WO94/1~ PCT~S93/~541
2ls3~o6
Li6 and D ions enter into the palladium lattice, the
palladium lattice slightly increases in volume to
accommodate them. Palladium with such an increased
volume is referred to as beta palladium. The positive
Li6 ion and the negative D ion can combine to form Li6D
molecule or can simply remain in close proximity. The
Li6 and D nuclei in the palladium lattice also add an
important new feature to the palladium lattice, in that
the nuclei pair are now available to scatter incoming
alpha particles. Preferably, for long-term operation, at
least 30 percent of the relevant palladium lattice sites
should be loaded with pairs of Li6 and D; however,
loading ratios of 15 percent may be made to work.
Lattice loading ratios found to yield pressures and
temperatures which are too high for the reactor vessel
indicate a chain reaction proceeding too rapidly and
should be avoided. The ratio of Li6 to Li7 may be
lowered if temperatures and pressures indicate they will
approach reactor design safety limits.
All of the baffles are porous, except for one,
baffle 19, which may be open or closed, which serves to
separate an inlet port 21 from an outlet port 23. Pump
15, which is representative of one or more pumps, serves
to establish flow from the inlet port out to the outlet
port during start-up and during fueling operations. The
inlet port 21 and outlet port 23 are closed during the
normal nuclear fusion cycle. With a pump, kinetic energy
may be imparted to ions so that ion flow rates may
greatly exceed those in a Fleischmann-Pons electro-
chemical cell. After the torus is filled with the heavy
water the baffle valve 19 is opened and ports 21 and 23
are closed and the fluid circulates around the torus.
Once the fluid reaches the desired temperature, heat is
removed through a heat exchanger 25, a helical liquid-
filled pipe wrapped about reactor structure 11. The
torus reactor structure is sealed from the atmosphere and
is known to withstand high pressures. It may be operated
up to 100 atmospheres or even higher by applying the
wo 94/16~K 2 1 5 3 ~ 0 6 PCT~S93/~541
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pressure through an inlet port which is sealed off after
the desired pressure is reached. The high pressure
greatly increases the solubility of deuterium gas in the
heavy water and facilitates the loading of the lithium
and deuterium into the metallic lattices of the accumu-
lator structure. Pump or pumps 15 serve to establish
flow through the torus. The fluid circulates around the
structure 11.
The copper pipe 25 contains a heat exchange
fluid medium which is flowing sufficiently rapidly to
remove heat which is conductively transferred into the
conductive pipe. This hot fluid may be used to drive a
turbine for the generation of electricity.
In Fig. 3, the baffle 17 has an array of
apertures 27 which have the advantage of allowing a
greater fluid flow at reduced pressure. This baffle will
confine palladium lattice structures of the type shown in
Figs. 6-9 between baffles so long as the structures are
bigger than the apertures of the baffle. On the other
hand, in the baffle structure of Fig. 4, apertures are
pinhole sized, giving rise to higher pressure in the
containment vessel. The size and spacing of pinholes
should be adjusted so that desired flow rates may be
achieved without undue pressure. Either of these baffles
may be passive and contain accumulator components between
them. They may also be active ion accumulators. In this
case, the accumulator contains palladium on a structure
having a thickness so that the accumulator will not
readily rupture.
Fig. 5 shows an alternate accumulator structure
wherein metallic palladium particulates 29 form a slurry
which is resident in the torus-shaped reactor represented
by section 31. The particulates in the slurry have the
advantage of presenting a greater surface area to the
heavy water. If a slurry is used, the pinhole baffle
structure previously described is used to contain the
particulates. The particulates may be bare palladium
particles or other forms as shown in Figs. 6-9. The
WO94/164~ PCT~S93/~41
21S3~0~
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palladium particulates are permeated by lithium and
deuterium, just as the palladium baffle structures. If
the heavy water flow is increased, the upper layers of
the slurry, by sheer forces, exposing fresh underlayers
which become permeated with lithium and deuterium.
Eventually, the entire slurry becomes sufficiently
permeated that fusion reactions begin to yield measurable
amounts of heat. Fig. 6 shows palladium particulates 33
coated with a nonconductive water porous polymer 35 which
is permeable by lithium and deuterium ions. Such a
polymer may be gelatin or polyvinyl alcohol. Such a
coating reduces the contamination of the palladium
surface and exposes the entire surface palladium for ion
accumulation. The palladium particulates in either
coated or uncoated form may be mixed with nonreactive
ceramic particulates or silicon dioxide particulates.
The sizes of the particulates and their ratios are
selected for optimum economic design, that is, maximizing
the ratio of ion absorption rate to dollar investment.
In Fig. 7, the particulates 37 have a partial
polymer coating 39 about approximately 50~ of the surface
area. This provides a balance between uncoated particu-
lates and fully coated particulates and may be used for
economic design optimization in conjunction with other
particulates.
Fig. 8 shows an alternative accumulator
structure wherein a polymer sheet 41 is housed in the
containment structure 43 which may be a section of the
torus-shaped reactor. The sheet has a plurality of
palladium particulates 45 adhered to the surface, in the
fashion of rough sandpaper. The sandpaper-like structure
is rolled into a spiral which fits into the containment
structure with the center of the spiral parallel or
colinear with the axis of the toroidal confinement
structure. As an alternative to a single spiral
occupying sections of the toroidal confinement vessel,
Fig. 9 shows that small spiral strips 47 also having
palladium particulates adhered to one or both sides in a
WO9411~K 21 5 3 ~ o ~ PCT~S93/~541
--11--
sandpaper-like texture, may be stuffed into the
containment vessel. Fig. 9 also represents rolled-up
palladium foils.
Fig. 10 shows a plurality of reactor
compartments 41, 43, 45 each housing accumulator
structures of the type described with reference to Figs.
6-9. Radioactive radium C' particulates, which are a
source of energetic alpha particles are indicated by a
square, while palladium accumulator components are
indicated by circles. Approximately one milligram of
radioactive radium C' is sufficient to ignite a reaction
among approximately 50 palladium accumulator components.
Baffles 47 are of the type shown in Fig. 3, permitting
fluid flow through the baffles, but not permitting motion
of accumulator structures past the baffles. The baffles
themselves may or may not contain palladium accumulator
structures.
In Fig. 11, baffles 47 support the cantilevered
rods 51 which extend into the chamber defined between
adjacent baffles. The rods position alpha emitting
radium isotopes from radium C' on tips 53 thereby bring-
ing the radium into a geometrically central location for
activation of Li6D nuclear reactions within distributed
palladium structures which fill the zones between the
baffles, but are not shown. The radioactive radium
continuously emits alpha particles which catalyze Li6D
nuclear reactions. The rods 51 may be fixed or extend-
able or retractable.
The packing of the palladium lattice occurs
over a period of time in which the moving ionized
lithium-6 and deuterium containing fluid comes into
~ contact with the palladium. The lithium and deuterium
ions pack the lattice interstices over a number of hours.
The affinity of negative deuterium ions for positive
lithium ions allows the ions to come rather close
together, perhaps chemically combining into LiD, a well
known compound. In this situation, there is a very low
probability requiring a very long time for lithium and
WO94/1~4~ PCT~S93/~541
21$34~ 12
deuterium nuclei fusing, which ultimately happens,
yielding energetic alpha particles. It is known from
nuclear research that many Li6D molecules can fuse
simultaneously under shock wave compression. The present
invention achieves similar compression as Li6 nuclei and
D nuclei are compressed towards each other in the lattice
by energetic alpha particles moving through the lattice
structure causing recoil of the nuclei toward one
another, increasing the probability of nuclear fusion.
In this patent application specification when
the term palladium is used, it is meant to include
palladium metal, palladium metal on a substrate or alloys
of Pd-Ag or perhaps Pd-Au which are highly adsorptive of
hydrogen and its isotopes as mentioned in the prior art.
Also palladium or alloys of Pd-Ag may be coated up to a
maximum preferred thickness of 20 microns and a minimum
preferred thickness of 5 microns onto a silver base which
would lead to a very high concentration of Li6 and D at
the interface since lithium does not diffuse easily into
silver. Also, for applications of these principles
involving surface effects sponge nickel may be used.
Radioactive alpha particle emitters, such as
radium C', can be used to initiate fusion of Li6 and D
nuclei. The alpha emitters are introduced into the
reactor structure, mixed with accumulator structures in a
concentration such that emitters will be in near contact
to the surface of palladium structures. The following
describes four different fusion ignition embodiments. A
pile of palladium-based particulates that have accumu-
lated lithons and negative deuterium ions in the form ofpairs of Li6 and D nuclei may be used in conjunction with
a fusion triggering arrangement. In one fusion trigger-
ing embodiment, particulates of radium C' are mixed in
with the palladium particulates, as in Fig. lO where the
palladium particulates may be of the type shown in Figs.
5, 6, 7, 8 or 9. The 7.8 MeV alpha particles produced by
radium C' will penetrate the surface of the palladium
and trigger the fusion of the lithium-6 and deuterium
~094/1~4~ PCT~S93/~541
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nuclei, creating 11.2 MeV alpha particles to trigger
additional fusion reactions nearby and triggering more
fusion reactions and more alpha particles. The fusion
process moves through the metallic lattices around and
through the particulate burning up the Li6 and D fuel and
generating alpha particles for a finite period of time.
Since 11.2 MeV alpha particles can travel more than
several centimeters through air or more than 100 microns
through aluminum, the alpha particles generated in one
palladium particulate, which is part of an accumulator
structure, can travel to another palladium particulate
starting the fusion reaction in that particulate. At the
same time, fusion reactions further into the interior of
the same palladium particulate lattice may occur as sec-
ondary alpha particles are generated in all directions.
A second fusion-starting embodiment involves
some alpha particle emitters comprising palladium
particulates filled with fusing Li6 + D in a state of
nuclear fusion positioned to be easily and safely removed
from the reactor with a tool from one pile of particles
and dropped into another pile of Li6 + D saturated
palladium particles, starting the fusion reaction in the
second pile of particles, as shown in Fig. 10 where the R
in the squares can also represent these artificially
radioactive palladium particulates. Note that the only
difference between the first and second embodiments is
that in the first case the naturally radioactive material
radium C' is used and in the second an artificially
radioactive palladium particulate is used.
In a third embodiment a rod with an artificial-
ly radioactive palladium tip as described in the second
embodiment has its tip inserted into a bed of lithium and
deuterium saturated palladium particulates or components
causing the alpha particles radiating from the rod tip to
initiate fusion reactions. Alternatively, radium C' may
be placed at the tip of the rod. The two forms of this
third embodiment are illustrated in Fig. 11 where the
baffles supporting the rods 51 are removable.
WO94/16~K PCT~S93/~541
2153406
A fourth embodiment of an alpha particle fusion
triggering system is illustrated by Fig. 5 where a very
large number of very small palladium particulates adsorb
Li6 and D from the heavy water-based fluid in which they
are immersed. The pressure inside the torus section is
raised to increase the amount of deuterium gas dissolved
in the fluid and the D and Li6 adsorbed in the palladium.
The close proximity of the Li6 and D nuclei are known to
create a finite probability such that over an extended
period of time a nuclear fusion event is likely. By
enormously increasing the number of particulates involved
and the loading of the palladium lattice sites of each
particulate with the said nuclei pairs the probability
greatly increases for a first fusion event to occur and
the time necessary for that first nuclear event to occur
may be reduced to weeks, days or even hours. Shock and
vibration of the palladium lattices and a temperature
rise also increase the probability of initial random
fusions. The two 11.2 MeV alpha particles produced by
such a fusion can trigger more than one subsequent fusion
and thereby sustaining a chain reaction.
The amount of energy resulting from the fusion
reaction of Li6 + D -> 2He4 can be determined by the
mass defect, or mass difference, between the constituents
(Li6 and D) and the remaining nucleus (2He4) using the
relation E = mc2.
The mass of the constituents and the remaining
nucleus are commonly defined by atomic mass units (u).
An atomic mass unit is defined as 1/12 of the mass of the
neutral carbon atom having 12 total nuclear particles.
It is known that:
lu = 1.660566 x 10-27 kg.
The energy equivalent of lu is found from the
relation E = mc2:
E = (1.660566 x 1027 kg)(2.998 x 108 m~s~1)2
= 1.492 x 10-10 J = 931.5 MeV
In atomic mass units, the masses of the rele-
vant atoms are known to be:
WO94/l~K 2 PCT~S93/12541
-15- ~6
Li6 = 6.01513 u
D = 2.01410 u
He4 = 4.00260 u
Therefore, the mass defect of the nuclear reac-
tion can be determined as follows:
(Li6 + D) - (2He4) = mass defect
(6.01513 u + 2.01410 u) - 2(4.00260 u) = mass defect
(8.02923 u) - (8.00520 u) - mass defect
.02403 u = mass defect
Using the energy equivalent of lu found above,
the energy equivalent of this mass defect can be deter-
mined:
(.02403 u)(931.5 MeV u~1) = 22.3839 MeV.
Hence, the reaction can be written as:
Li6 + D - > 2He4 + 22.4 MeV,
where each of the emitted alpha particles has a kinetic
energy of approximately 11.2 MeV.
The alpha particles required herein have a suf-
ficiently high kinetic energy such that when they undergo
noncontacting coulomb-type collisions with the nucleus of
Li6 or D ions they will impart motion to the nucleus of
that ion, which is commonly referred to as nucleus
recoil. The initial energy of each alpha particle used
to trigger the fusion reaction is preferably between 6-12
MeV.
Some of the kinetic energy and momentum of the
bombarding alpha particle is imparted to the bombarded
nucleus which recoils. The scattering angle of the alpha
particles from a nucleus is somewhat proportional to the
energy transferred. Depending on the direction of motion
of the deuterium or lithium-6 recoil nucleus, some of
them will approach each other and combine in a nuclear
fusion reaction. The fusion of the Li6 and D ions
produces additional high energy alpha particles. The
particles released as a result of the fusion then bombard
the nuclei of nearby Li6 and D ions causing some to
recoil toward each other. Hence, more Li6 and D fusions
occur and even more high energy alpha particles are
WO94/1~K 2 ¦S3 46 PCT~S93/12541
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produced. Thus, by initiating the fusion of Li6 and D
ions through a beam of high energy alpha particles, a
continuous self-sustaining chain reaction nuclear fusion
is attained. A more detailed description of the fusion
process is set forth below.
It is known that alpha particles from radium C'
having an energy of 7.8 MeV will easily penetrate 4 mi-
crons of gold and can penetrate 100 microns of aluminum.
From this information, it can be estimated that 11.2 MeV
alpha particles produced from the fusion of Li6 and D
ions, will penetrate up to 30 microns or 300,000
angstroms of the palladium present in the accumulator
structure. Since the atomic spacing or palladium atoms
in palladium metal is 3 angstroms, the alpha particles
would traverse approximately 100,000 palladium atom
sites.
The reason that the 11.2 MeV alpha particles
can traverse 100,000 palladium atoms is because they are
only 0.000024 ~ in diameter and therefore easily pass
through the 3 ~ diameter palladium atoms. On the other
hand, a complete helium atom with its two electrons, has
a diameter of 1.86 ~ and would not move very far through
a palladium lattice. The nuclear reaction Li6 + D
creates energetic alpha particles, i.e. the helium-4
nucleus, not helium atoms in the lattice confinement
environment of the present invention.
Thus, alpha particles penetrating the palladium
loaded with Li6 and D nuclei will have non-contacting
scattering encounters with the nuclei of palladium atoms,
deuterium atoms, and lithium-6 atoms. These encounters
with the palladium atoms will compress the nuclei-to-
nuclei spacing of some of the Li6D nuclei pairs, thereby
increasing the probability of nuclear fusion. The
palladium lattice plays at least two important roles.
Initially it confines Li and D during scattering
encounters and later absorbs kinetic energy of the fusion
reaction through the alpha particle collisions with the
WO94/1~K 21`S~ o~ PCT~S93112541
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palladium atoms, which cause the desired heating of the
palladium metal.
It is also known that alpha particles from
radium C' scatter at an average angle of about 9 degrees
when projected through a single layer of gold foil 4
microns thick. Only one alpha particle in a few thousand
is scattered more than 90 or about 33 out of the l00,000
Pd lattice sites encountered. Adding the Li6 and D
nuclei at every Pd lattice site as mentioned above should
triple the number of alpha particles scattered more than
goo to roughly about one hundred. Another way of stating
this is that since so few of the alpha particles are
scattered 90 or more that almost the same number of
alpha particles will traverse the l00,000 Pd lattice
sites with or without the Li6 and D added. With the Li6
and D added at each site an alpha particle encounters
about 300,000 nuclei and only one in a few thousand will
be scattered more than 90 or roughly about l00.
If we conservatively estimate that at least 40~
of the alpha particle's kinetic energy is lost to scatter-
ings of more than 90, the average 90 plus scattering
could transfer up to about 45 KeV to the recoil nuclei.
Since a deuteron having a kinetic energy as low as 20 KeV
can cause a nuclear fusion reaction upon bombarding a Li6
nucleus, the ll.2 MeV alpha particles clearly have
adequate kinetic energy to transfer to the Li6 and D
recoil nuclei to initiate a number of nuclear fusions.
Thus if every palladium lattice site were
filled with a D nucleus and an Li6 nucleus it might be
concluded that every ll. 2 MeV alpha particle would
transfer significant recoil kinetic energy to about 67
Li6 or D nuclei.
However, this number must be reduced by a
factor of about 3 to account for the fact that when an
alpha particle transfers energy to a Li6 and D nuclei,
only about one-third of the particles obtain a velocity
directed towards the other nuclei. Of the remaining two-
thirds of the alpha particles, about one-third attain a
W094/1~4K 2 ~S3 ~ PCT~S93112541
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velocity directed away from the other nucleus and the
other one-third have a velocity that is not significantly
towards or away from the other nucleus and includes those
particles which leave the palladium before achieving a
large number of nuclei encounters. These factors reduce
the number of possible Li6 + D fusions per ll.2 MeV alpha
particle to about 22. This number is further reduced if
the loading of the palladium lattice sites with Li6 and D
is reduced from the l to l ratio or 100% loading used in
the calculation. If for example the natural isotope
ratio of commercial lithium were used with lithium-6 of
about 7.5% and lithium-7 of 92.5%, the estimated fusions
per alpha particle would drop from 22 to about l.65 if
all palladium sites were loaded with lithium and
deuterium pairs. If only two thirds of the palladium
lattice sites were filled, the fusions per alpha particle
would drop from l.65 to l.l.
If each of the two alpha particles produced
through the fusion of a Li6 + D can catalyze one or even
slightly less than one nuclear fusion reaction, a
self-catalyzing nuclear fusion reaction becomes a self-
sustained, continuous fusion reaction that is generally
referred to as a chain reaction. The reaction is
controlled through the rate of introduction of "fresh"
Li6 and D to replace the consumed Li6 and D.
If the natural lithium isotope ratio were used,
as the Li6 is consumed the natural 7.5% Li6 ratio would
decline eventually to 3% or lower and the chain reaction
would stop. This would occur not only because the Li6 is
being consumed, but also because the empty lattice sites
previously holding the Li6 ions are being replenished at
a ratio of 7.5% active Li6 and inactive Li7. Thus it is
preferred that in the LioD more than 50% of the Li be Li6
for a long term chain reaction in a commercial fuson
reactor, although Li ratios as low as 25% could work in
experimental reactors. In the commercial reactor it is
also preferred that in the relevant region of the
palladium ion accumulators the palladium lattice sites
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filled with Li6 and D pairs total at least 30% and at
least 15% in experimental reactors. To achieve this the
concentration of the Li60D in heavy water, the condition
of the palladium ion accumulator material, the degree of
Li6 enrichment of the LiOD, and the time, temperature,
and pressure during the loading of the Li6 and D are
selected to ensure that in at least some large regions of
the palladium ion accumulator at least 30% of the
palladium lattice sites are filled with pairs of Li6 and
D for commercial reactors and at least to the 15% level
for experimental reactors.
