a seminar report on nuclear micro battery

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A Seminar Report
On
NUCLEAR MICRO - BATTERY
Submitted by
VISHNU M T
in partial fulfilment for the award of the degree of
Bachelor of Technology (B. Tech)
in
INSTRUMENTATION TECHNOLOGY
DEPARTMENT OF INSTRUMENTATION
COCHIN UNIVERSITY OF SCIENCE AND TECHNOLOGY
KOCHI-682022
OCTOBER 2015

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CERTIFICATE
This is to certify that the seminar report entitled
NUCLEAR MICRO-BATTERY
is a bonafide record of the work done by MR. VISHNU M T ,
Roll No: 90012068 under our supervision in partial fulfilment of the
requirements for the award of Degree of Bachelor of Technology in
Instrumentation Technology from Cochin University of Science and
Technology, Kochi for the year 2015-2016
OCTOBER 2015
Dr. K.N Madhusoodanan
Professor, Dept. of Instrumentation
Seminar Co-coordinator
Dr. K RajeevKumar
Professor and Head of Department
Dept. of Instrumentation

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ACKNOWLEDGEMENT
It is matter of great pleasure for me to submit this seminar report on
“NUCLEAR MICRO-BATTERY”, as a part of curriculum forward
of “Bachelor of Technology with specialization in Instrumentation
Technology” degree of Department Of Instrumentation, CUSAT.
I am extremely thankful to Dr. K. Rajeev Kumar, Head Of Department,
Department of Instrumentation, CUSAT for permitting me to undertake
this work.
I express my heartfelt gratitude to my respected Seminar guide
Dr. K.N. Madhusoodanan for his kind and inspiring advice which
helped me to understand the subject and its semantic significance. He
enriched me with valuable suggestions regarding my topic and
presentation issues. I am also very thankful to my colleagues who
helped and co-operated with me in conducting the seminar by their
active participation.
At the last but not least, I am thankful to my parents, who have
encouraged & inspired me in every possible way.

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ABSTRACT
Nuclear batteries harvest energy from radioactive specks and supply power to micro
electromechanical systems (MEMS). This paper describes the viability of nuclear batteries for
powering realistic MEMS devices. Nuclear batteries are not nuclear reactors in miniatures, but
the energy comes from high-energy particles spontaneously emitted by radioactive elements.
Isotopes currently being used include alpha and low energy beta emitters. Gama emitters have
not been considered because they would require a substantial amount of shielding. The sources
are available in both solid and liquid form. Nuclear batteries use the incredible amount of
energy released naturally by tiny bits of radioactive material without any fission or fusion
taking place inside the battery. These devices use thin radioactive films that pack in energy at
densities thousands of times greater than those of lithium-ion batteries. Because of the high
energy density nuclear batteries are extremely small in size. Considering the small size and
shape of the battery the scientists who developed that battery fancifully call it as "DAINTIEST
DYNAMO". The word 'dainty' means pretty

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Table of Contents
Chapter page no:
1. INTRODUCTION 6
2. HISTORICAL DEVELOPMENTS 8
3. ENERGY PRODUCTION MECHANISM 9
4. FUEL CONSIDERATIONS 19
5. ISOTOPE SELECTION 20
6. INCORPORATION OF SOURCE INTO DEVICE 22
7. ADVANTAGES 24
8. DISADVANTAGES 25
9. APPLICATIONS 26
10.CONCLUSION 30
11.REFERENCES 31

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INTRODUCTION
A burgeoning need exists today for small, compact, reliable, lightweight and self-contained
rugged power supplies to provide electrical power in such applications as electric automobiles,
homes, industrial, agricultural, recreational, remote monitoring systems, spacecraft and deep-
sea probes. Radar, advanced communication satellites and especially high technology weapon
platforms will require much larger power source than today’s power systems can deliver. For
the very high power applications, nuclear reactors appear to be the answer. However, for
intermediate power range, 10 to 100 kilowatts (kW), the nuclear reactor presents formidable
technical problems.
Because of the short and unpredictable lifespan of chemical batteries, however,
regular replacements would be required to keep these devices humming. Also, enough
chemical fuel to provide 100 kW for any significant period of time would be too heavy and
bulky for practical use. Fuel cells and solar cells require little maintenance, and the latter need
plenty of sun.
Thus the demand to exploit the radioactive energy has become inevitably high.
Several methods have been developed for conversion of radioactive energy released during the
decay of natural radioactive elements into electrical energy. A grapefruit-sized radioisotope
thermo- electric generator that utilized heat produced from alpha particles emitted as
plutonium-238 decay was developed during the early 1950’s.
Since then the nuclear has taken a significant consideration in the energy source of
future. Also, with the advancement of the technology the requirement for the lasting energy
sources has been increased to a great extent. The solution to the long term energy source is, of
course, the nuclear batteries with a life span measured in decades and has the potential to be
nearly 200 times more efficient than the currently used ordinary batteries. These incredibly
long-lasting batteries are still in the theoretical and developmental stage of existence, but they
promise to provide clean, safe, almost endless energy.
Unlike conventional nuclear power generating devices, these power cells do not rely on
a nuclear reaction or chemical process do not produce radioactive waste products. The
nuclear battery technology is geared towards applications where power is needed in
inaccessible places or under extreme conditions.

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.
Microelectromechanical Systems (MEMS) have not gained wide use because they lack the on
device power required by many important applications. Several forms of energy could be
Considered to supply this needed power (solar, fossil fuels, etc.), but nuclear sources provide
an intriguing option in terms of power density and lifetime. This paper describes several
approaches for establishing the viability of nuclear sources for powering realistic MEMS
devices. Isotopes currently being used include alpha and low-energy beta emitters. The sources
are in both solid and liquid form, and a technique for plating a solid source from a liquid source
has been investigated. Several approaches are being explored for the production of MEMS
power sources. The first concept is a junction-type battery. The second concept involves a more
direct use of the charged particles produced by the decay: the creation of a resonator by
inducing movement due to attraction or repulsion resulting from the collection of charged
particles. Performance results are provided for each of these concepts.
The researchers envision its uses in pacemakers and other medical devices that would otherwise
require surgery to repair or replace. Additionally, deep-space probes and deep-sea sensors,
which are beyond the reach of repair, would benefit from such technology. In the near future
this technology is said to make its way into commonly used day to day products like mobile
and laptops and even the smallest of the devices used at home. Surely these are the batteries of
the near future

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HISTORICAL DEVELOPMENTS
The idea of nuclear battery was introduced in the beginning of 1950, and was patented on
March 3rd, 1959 to tracer lab. Even though the idea was given more than 30 years before, no
significant progress was made on the subject because the yield was very less.
A radio isotope electric power system developed by inventor Paul Brown was a scientific
breakthrough in nuclear power. Brown’s first prototype power cell produced 100,000 times as
much energy per gram of strontium -90(the energy source) than the most powerful thermal
battery yet in existence. The magnetic energy emitted by the alpha and beta particles inherent
in nuclear material. Alpha and beta particles are produced by the radioactive decay of certain
naturally occurring and man –made nuclear material (radio nuclides). The electric charges of
the alpha and beta particles have been captured and converted to electricity for existing nuclear
batteries, but the amount of power generated from such batteries has been very small.
Alpha and beta particles also possess kinetic energy, by successive collisions of the
particles with air molecules or other molecules. The bulk of the R &D of nuclear batteries in
the past has been concerned with this heat energy which is readily observable and measurable.
The magnetic energy given off by alpha and beta particles is several orders of magnitude
greater than the kinetic energy or the direct electric energy produced by these same particles.
However, the myriads of tiny magnetic fields existing at any time cannot be individually
recognized or measured. This energy is not captured locally in nature to produce heat or
mechanical effects, but instead the energy escapes undetected.
Brown invented an approach to “organize” these magnetic fields so that the great amounts
of otherwise unobservable energy could be harnessed. The first cell constructed (that melted
the wire components) employed the most powerful source known, radium-226, as the energy
source.
The main drawback of Mr. Brown’s prototype was its low efficiency, and the reason for that
was when the radioactive material decays, many of the electrons lost from the semiconductor
material. With the enhancement of more regular pitting and introduction better fuels the
nu0clear batteries are thought to be the next generation batteries and there is hardly
ny doubt that these batteries will be available in stores within another decade.

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ENERGY PRODUCTION MECHANISM
Betavoltaics
Betavoltaics is an alternative energy technology that promises vastly extended
battery life and power density over current technologies. Betavoltaics are generators of
electrical current, in effect a form of a battery, which use energy from a radioactive source
emitting beta particles (electrons). The functioning of a betavoltaics device is somewhat similar
to a solar panel, which converts photons (light) into electric current.
Betavoltaic technique uses a silicon wafer to capture electrons emitted by a
radioactive gas, such as tritium. It is similar to the mechanics of converting sunlight into
electricity in a solar panel. The flat silicon wafer is coated with a diode material to create a
potential barrier. The radiation absorbed in the vicinity of and potential barrier like a p-n
junction or a metal-semiconductor contact would generate separate electron-hole pairs which
in turn flow in an electric circuit due to the voltaic effect. Of course, this occurs to a varying
degree in different materials and geometries.
A pictorial representation of a basic Betavoltaic conversion as shown in figure 1.
Electrode A (P-region) has a positive potential while electrode B (N-region) is negative with
the potential difference provided by me conventional means.
Figure 1
The junction between the two electrodes is comprised of a suitably ionisable medium
exposed to decay particles emitted from a radioactive source.
The energy conversion mechanism for this arrangement involves energy flow in
different.

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in equilibrium and no energy comes out of the system. We shall call this ground state E0. stages:
Stage 1:- Before the radioactive source is introduced, a difference in potential between to
electrodes is provided by a conventional means. An electric load RL is connected across the
electrodes A and B. Although a potential difference exists, no current flows through the load
RL because the electrical forces are
Stage 2:- Next, we introduce the radioactive source, say a beta emitter, to the system. Now,
the energy of the beta particle Eb generates electron- hole pair in the junction by imparting
kinetic energy which knocks electrons out of the neutral atoms. This amount of energy E1, is
known as the ionization potential of the junction.
Stage 3:- Further the beta particle imparts an amount of energy in excess of ionization potential.
This additional energy raises the electron energy to an elevated level E2. Of course the beta
[particle dose not impart its energy to a single ion pair, but a single beta particle will generate
as many as thousands of electron- hole pairs. The total number of ions per unit volume of the
junction is dependent upon the junction material.
Stage 4:- next, the electric field present in the junction acts on the ions and drives the electrons
into electrode A. the electrons collected in electrode A together with the electron deficiency of
electrode B establishes Fermi voltage between the electrodes. Naturally, the electrons in
electrode A seek to give up their energy and go back to their ground state (law of entropy).
Stage 5:- the Fermi voltage derives electrons from the electrode A through the load where they
give up their energy in accordance with conventional electrical theory. A voltage drop occurs
across the load as the electrons give an amount of energy E3. Then the amount of energy
available to be removed from the system is

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E3= Eb - E1 – L1-L2
Where L1 is the converter loss and L2 is the loss in the electrical circuit.
Stage 6:- the electrons, after passing to the load have an amount of energy E4.from the load,
the electrons are then driven into the electrode B where it is allowed to recombine with a
junction ion, releasing the recombination energy E4 in the form of heat this completes the circuit
and the electron has returned to its original ground state.
The end result is that the radioactive source acts as a constant current generator. Then
the energy balance equation can be written as
E0=Eb –E1 –E3-L1-L2
Diagram of micro machined pn junction
Until now betavoltaics has been unable to match solar-cell efficiency. The reason is
simple: when the gas decays, its electrons shoot out in all directions. Many of them are lost. A
new Betavoltaic device using porous silicone diodes was proposed to increase their efficiency.
The flat silicon surface, where the electrons are captured and converted to a current, and turned
into a 3- dimensional surface by adding deep pits. Each pit is about 1 micron wide. That is four
hundred-thousandths of an inch. They are more than 40 microns deep. When the radioactive
gas occupies these pits, it creates the maximum opportunity for harnessing the reaction.

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Direct charging generators
1) High Q LC TANK circuit
In this type, the primary generator consists of a high –Q LC tank circuit. The energy
imparted to radioactive decay products during the spontaneous disintegrations of radioactive
material is utilized to sustain and amplify the oscillations in the high-Q LC tank circuit the
circuit inductance comprises a coil wound on a core composed of radioactive nuclides
connected in series with the primary winding of a power transformer. The core is fabricated
from a mixture of three radioactive materials which decay primarily by alpha emission and
provides a greater flux of radioactive decay products than the equivalent amount of single
radioactive nuclei.
Figure 3 is a schematic diagram of an LC equivalent resonant circuit
Equitant circuit of the direct charging generator as shown in the figure 3.An LCR circuit
1 is comprised of a capacitor 3, inductor file, transformer T primary winding 9 and resistance
11 connected in series. It is assumed that the electrical conductors connecting the various circuit
elements and forming the inductor file and primary winding 9 are perfect conductors; i.e., no
DC resistance. Resistor 11 is a lump resistance equivalent to total DC resistance of the actual
circuit components and conductors. The inductor 5 is wound on a core 7 which is composed of
a mixture of radioactive elements decaying primarily by alpha particle emission.
When the current flows in electrical circuit, energy is dissipated or lost in the form of heat.
Thus, when oscillations are induced in an LCR circuit, the oscillations will gradually damp out
due to the loss of energy in the circuit unless energy is continuously added to the circuit to
sustain the oscillations. In the LCR circuit shown in figure 3, a portion of the energy imparted
to the decay products such as alpha particles. During the radioactive decay of the materials
inductor core 7 is introduced into the circuit 1, when the decay products are absorbed by the
conductor which forms inductor 5. Once oscillations have been induced in the LCR circuit 1,

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the energy absorbed by the inductor 5 form the radioactive decay of the core7 material will
sustain the oscillations as long as the amount of energy absorbed is equal to the amount of
energy dissipated in the ohmic resistance of the circuit 1.If the absorbed energy is greater than
the amount of energy lost through ohmic heating, the oscillations will be amplified. This excess
energy can be delivered to a load 17 connected across the transformer T secondary winding 13.
The process involved in the conversion of the energy released by the spontaneous
disintegration of a radioactive material into electrical energy are numerous and complex.
Materials that are naturally radioactive, decay by the emission of either an alpha particle or a
beta particle and gamma rays may accompany either process. Radioactive materials that decay
primarily by alpha particle emission are preferred as inductor core 7 materials. Alpha particles
are emitted a very high speeds, in the order of 1.6*107 meters per second (m/s) and
consequently have very high kinetic energy. Alpha particles emitted in radium, for example,
decays are found to consist of two groups, those with a kinetic energy of 48.79*105 electron
volts (eV) and those having energy of 46.95*105 electron volts. This kinetic energy must be
dissipated when the alpha particles are absorbed by the conductor forming inductor 5. During
the absorption process, each alpha particle will collide with one or more atoms in the conductor
knocking electron from their orbits and imparting some kinetic energy to the electrons. This
results in increase number of conduction electrons in the conductor there by increasing its
conductivity.
Since the alpha particle is a positively charged ion, while the alpha particle is moving it
will have an associated magnetic field. When the alpha particle is stopped by the conductor,
the magnetic field will collapse thereby inducing a pulse of current in the conductor producing
a net increase in the current flowing in the circuit 1. Also, there will be additional electrons
stripped from orbit due to ionization reduced by the positively charged alpha particles.

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Figure 4 is a wiring diagram of a constructed nuclear battery
Referring to figure 4, the nuclear battery is constructed in a cylindrical configuration. Inductor
5 is constructed of copper wire wound in a single layer around the radioactive core 7. Decay
products, such as alpha particles, are emitted radially outward from the core 7 as indicated by
arrows 2 to be absorbed by the copper conductor forming inductor 5. Eight transformers are
arranged in a circular pattern to form a cylinder concentric with and surrounding inductor 5.
The transformers have primary windings 9a-9h connected in series which are then connected
in series with inductor 5 and capacitor 3 to form an LCR circuit. The central core 7, inductor5
and the eight transformers 15 are positioned within a cylindrical shaped container 19. Copper
wire is wound in a single layer on the outside wall and the inside wall of cylinder 19 to form
windings 23 and21 respectively. The transformers 15, secondary windings 13a-13h and
windings 21 and 23 are connected in series to output terminals 25 and 27. The configuration of
inductor 5 is designed to ensure maximum eradication of the copper conductor by the
radioactive core source 7. The cylindrical configuration of the power transformer ensures
maximum transformer efficiency with minimum magnetic flux leakages.
2) SELF-RECIPROCATING CANTILEVER
This concept involves a more direct use of the charged particles produced by the decay of the
radioactive source: the creation of a resonator by inducing movement due to attraction or
repulsion resulting from the collection of charged particles. As the charge is collected, the
deflection of a cantilever beam increases until it contacts a grounded element, thus discharging
the beam and causing it to return to its original position. This process will repeat as long

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as the source is active. This concept has been tested experimentally with positive results. Figure
5 shows the experimental setup, in which the charges emitted from the source are collected in
the beam to
Generate the electrostatic force that drives it. The radioactive source used was 63Ni with an
activity er. A probe tip is
glued to the beam to better detect and measure the movement of the beam. Both the source and
the beam are mounted on a glass base for electrical insulation. The glass base is clamped so
that the beam
Itself m spaced
gridlines
connected to a VCR is used to record the movement of the beam and its periodicity. As the
radioactive beta source decays, it emits electrons. The copper beam collects these electrons
from the source, and the source itself would become positively charged since it keeps losing
electrons; therefore, in the ideal case, there would be an electrostatic force applied on the beam
that would bend it. However, in atmospheric conditions, no movement of the beam is observed,
due to the ionization of the surrounding air. For that reason, the experiment has been
Under vacuum (typically from 30 mTorr to 50 mTorr), where there is no extraneous
Ionization and the bending of the beam can be observed.
Self-reciprocating cantilever experimental set up
In order to understand the behavior of the system we have developed an analytical model for
both the charge collection and deflection of the cantilever. The charge collecting process is
govern

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Where dQ is the amount of charge collected by the beam during a given time dt, α represents
the current emitted by the radioactive source, V is the voltage across the source and the beam
and R is the effective resistance between them. The second term on the right hand side
represents the current leakage arising from the ionization of the air. Since V = Q / C, where C
is the capacitance of the beam and the source, the previous equation can be rearranged to obtain:
Shows a typical experimental result, in which the initial distance is 3.5 mm and the
Vacuum is 50 mTorr .
Deflection vs. time at a pressure of 50 mTorr
This equation can be readily solved:

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In Figure we observe that the beam bends very slowly. Therefore, the electrostatic force on the
beam can be taken as balanced by the elastic force from the beam itself. Since the electrostatic
force is proportional to Q2 and the distance between the beam and the source can be taken as a
constant, being the deflection of the beam, we have:
K is the elastic constant of the beam, α can be assumed to be constant since 63Ni has a half life
of more than 100 years, R in the experiment is also a constant because the pressure is
maintained and no breakdown of the air happened, otherwise the beam will bounce back. C can
also be assumed to be constant because it has been observed experimentally that the deflection
of the beam is very small compared to the initial distance between the beam and the radioactive
source. Therefore:
Figure compares the deflection measured experimentally with the values obtained
analytically according to the discussion shown above, by fitting R. We observe a very good
match between them.
Comparison between the experimental and analytical values for the deflection
This model, however, does not include the periodic behavior of this device. Current

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experiments show a minimum period of about 30 minutes, at which time the electrostatic
energy is released as electric current. Further studies are being done in this area, trying to
identify the key characteristics of the system in order to be able to design the device with the
period and energy release level appropriate for each particular application.
3) Optoelectrics
An optoelectric nuclear battery has been proposed by researchers of the kurchatov institute in
Moscow. A beta emitter such as technetium-99 are strontium-90 is suspended in a gas or liquid
containing luminescent gas molecules of the exciter type, constituting “dust plasma”. This
permits a nearly lossless emission of beta electrons from the emitting dust particles for
excitation of the gases whose exciter line is selected for the conversion of the radioactivity into
a surrounding photovoltaic layer such that a comparably light weight low pressure, high
efficiency battery can be realized. These nuclides are low cost radioactive of nuclear power
reactors. The diameter of the dust particles is so small (few micrometers) that the electrons
from the beta decay leave the dust particles nearly without loss. The surrounding weakly
ionized plasma consists of gases or gas mixtures (e.g. krypton, argon, xenon) with exciter lines,
such that a considerable amount of the energy of the beta electrons is converted into this light
the surrounding walls contain photovoltaic layers with wide forbidden zones as egg. Diamond
which converts the optical energy generated from the radiation into electric energy.
The battery would consist of an exciter of argon, xenon, or krypton (or a mixture of
two or three of them) in a pressure vessel with an internal mirrored surface, finely-ground
radioisotope and an intermittent ultrasonic stirrer, illuminating photocell with a band gap .
tuned for the exciter. When the electrons of the beta active nuclides (e.g. krypton-85 or argon-
39) are excited, in the narrow exciter band at a minimum thermal losses, the radiations so
obtained is converted into electricity in a high band gap photovoltaic layer (e.g. in a p-n diode)
very efficiently the electric power per weight compared with existing radionuclide batteries
can then be increased by a factor 10 to 50 and more. If the pressure-vessel is carbon fiber /
epoxy the weight to power ratio is said to be comparable to an air breathing engine with fuel
tanks. The advantage of this design is that precision electrode assemblies are not needed and
most beta particles escape the finely-divided bulk material to contribute to the batteries net
power. The disadvantage consists in the high price of the radionuclide and in the high pressure
of up to 10MPa (100bar) and more for the gas that requires an expensive and heavy container.

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FUEL CONSIDERATIONS
The major criterions considered in the selection of fuels are:
 Avoidance of gamma in the decay chain
 Half life
 Particle range
 Watch out for (alpha, n)reactions
Any radioisotope in the form of a solid that gives off alpha or beta particles can be
utilized in the nuclear battery. The first cell constructed (that melted the wire
components) employed the most powerful source known, radium-226, as the energy
source. However, radium-226 gives rise through decay to the daughter product bismuth-
214, which gives off strong gamma radiation that requires shielding for safety. This
adds a weight penalty in mobile applications.
Radium-226 is a naturally occurring isotope which is formed very slowly by the
decay of uranium-238. Radium-226 in equilibrium is present at about 1 gram per 3
million grams of uranium in the earths crust. Uranium mill wastes are readily available
source of radium-226 in very abundant quantities. Uranium mill wastes contain far
more energy in the radium-226 than is represented by the fission energy derived form
the produced uranium.
Strontium-90 gives off no gamma radiation so it does not necessitate the use of
thick lead shielding for safety.strrrontium-90 does not exist in nature, but it is one of
the several radioactive waste products resulting from nuclear fission. The utilizable
energy from strontium-90 substantially exceeds the energy derived from the nuclear
fission which gave rise to this isotope.
Once the present stores of nuclear wastes have been mined, the future supplies of strontium-90
will depend on the amount of nuclear electricity generated hence strontium-90 decay may
ultimately become a premium fuel for such special uses as for perpetually powered wheel chairs
and portable computers. Plutonium-238 dioxide is used for space application. Half life of

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tantalum-180m is about 1015 years. In its ground state, tantalum-180 (180Ta) is very unstable
and decays to other nuclei in about
8 hours but its isomeric state, 180m Ta, is found in natural samples. Tantalum 180m hence can
be used for switchable nuclear batteries.
ISOTOPE SELECTION
A critical aspect of the creation of microbatteries for MEMS devices is the choice of the isotope
to be used as a power source. Some requirements for this isotope include safety, reliability,
cost, and activity. Since the size of the device is an issue in this particular application, gamma
emitters have not been considered because they would require a substantial amount of
shielding. Both pure alpha and low energy beta emitters have been used. The alpha emitters
have an advantage due to the short range of the alpha particles. This short range allows
increased efficiency and
thus provides more design flexibility, assuming that a sufficient activity can be achieved. The
halflife of the isotopes must be high enough so that the useful life of the battery is sufficient
for typical applications, and low enough to provide sufficient activity. In addition, the new
isotope resulting after decay should be stable, or it should decay without emitting gamma
radiation. The isotopes currently in use for this work are

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To explore the viability of the nuclear micro battery concept, some scoping calculations need
to be carried out. Using 210Po as an example, one can analyze the best case scenario, assuming
that the nuclear battery is created using pure 210Po. In this case, the activity would be
approximately 4,500 Ci per gram or 43,000 Ci per cubic centimeter. Thus, for a characteristic
source volume of 10-5 cubic centimeters (0.1 cm x 0.1cm x 10 microns), one obtains
approximately 0.5 Ci. Based on the results of previous experimental studies, the available
power would be on the order of 0.5 mW (about 1 mW/Ci). The power required for MEMS
devices can
range from Nano watts to microwatts. A typical case is that of a low power CMOS driven
mechanical cantilever forming an air-gap capacitor with the substrate. Typical MEMS
capacitors have 10 femtoFarad capacitance and resonant frequencies of 10s of kHz. The power
dissipated for charging such an electromechanical capacitor would be in the range of 10 to 100
nanowatts. Therefore, a pure source provides more than sufficient activity to power a practical
device

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INCORPORATION OF SOURCES INTO THE DEVICE
Three methods of incorporating radioactive material into the MEMS devices are being studied.
These are 1) activation of layers within the MEMS device, 2) addition of liquid radioactive
material into fabricated devices, and 3) addition of solid radioactive material into fabricated
devices. In the first approach, the parent material for the radioactive daughter or granddaughter
would be manufactured as part of the MEMS device, most likely near the surface of the device.
After fabrication of the device, the parent material would be exposed to the radiation field in
our TRIGA
reactor for a period of time until the desired radiation source strength is achieved. Highly
absorbing neutron or charged particle materials would be used to mask other components of
the device which are to remain non-radioactive. In addition, the material used for the activation
would be chosen such that it has a high activation cross-section, thus maximizing the activation
of the “source” and minimizing competing activity produced in surrounding structures. In the
second and third approaches, radioactive sources are introduced into the MEMS device after
fabrication. In the case of a liquid source, a reservoir must be created within the device, along
with a channel providing access to the reservoir. The reservoir can then be filled, relying on
capillary action to create the flow, and the channel can then be sealed off if needed. In the case
of a solid source, the radioactive material will have to be deposited in selected sites on the
device. We currently have two approaches to create this type of sources:
Electroless plating is the plating of nickel without the use of electrodes but by chemical
reduction [1]. Metallic nickel is produced by the chemical reduction of nickel solutions with
hypophosphite using an autocatalytic bath. The plating metal can be deposited in the pure form
on to the plated surfaces. The bath is an aqueous solution of nickel salt and contains relatively
low concentration of hypophosphite. This type of nickel plating can be used on a large group
of metals, such as steel, iron, platinum, silver, nickel, gold, copper, cobalt, palladium and
aluminum. Throughout the plating process, the bath needs to be heated to maintain it at a
temperature in the range of 90 – 100 °C to promote the chemical reduction reaction. The boiling
temperature of
the bath is to be avoided. At lower temperatures the reaction proceeds slowly and at higher
temperatures the bath evaporates. The important factor influencing the plating process is the
pH. The pH needs to be maintained at 4.5-6 for plating to occur. A lower pH results in no
plating at all. We have successfully plated gold-coated silicon pieces of dimensions 2mm by
2mm, following this procedure. Plating of nickel on gold was observed in about 15 minutes.
These solid sources can then be incorporated into a MEMS device.
“
We have obtained glass microspheres (25 to 53 μm in diameter) that will emit low energy 3H
beta radiation. These are obtained by irradiating 6Li glass silicate non-radioactive microspheres
in the UW Nuclear Reactor. Using this procedure, we can produce activities of up to 12.8 mCi
per gram and per hour of irradiation. Then, these

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radioactive microspheres can be introduced in the MEMS device in the appropriate cavity.
These latter approaches will allow for higher power densities than the direct reactor activation
approach, but will provide less flexibility with respect to device design. We are currently
exploring the tradeoffs of the different options, and will shortly release all the data needed to
assess the viability of all of these approaches.
Waste Disposal
Our analysis proves that the environmental impact of disposing of these micro-devices once
their useful life has ended, as well as the associated costs are minimal. Since after three half-
lives the activity of the isotope has decayed to about 10% of the original activity, the micro-
batteries would be below background radiation level at the following times:

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ADVANTAGES
The most important feat of nuclear cells is the life span they offer, a minimum of 10years!
This is whopping when considered that it provides nonstop electric energy for the seconds
spanning these 10long years, which may simply mean that we keep our laptop or any hand held
devices switched-on for 10 years nonstop. Contrary to fears associated with conventional
batteries nuclear cells offers reliable electricity, without any drop in the yield or potential
during its entire operational period. Thus the longevity and reliability coupled together would
suffice the small factored energy needs for at least a couple of decades.
The largest concern of nuclear batteries comes from the fact that it involves the use of
radioactive materials. This means throughout the process of making a nuclear battery to final
disposal, all radiation protection standards must be met. Balancing the safety measures such as
shielding and regulation while still keeping the size and power advantages will determine the
economic feasibility of nuclear batteries. Safeties with respect to the containers are also
adequately taken care as the battery cases are hermetically sealed. Thus the risk of safety
hazards involving radioactive material stands reduced.
As the energy associated with fissile material is several times higher than conventional
sources, the cells are comparatively much lighter and thus facilitates high energy densities to
be achieved. Similarly, the efficiency of such cells is much higher simply because radioactive
materials in little waste generation. Thus substituting the future energy needs with nuclear cells
and replacing the already existing ones with these, the world can be seen transformed by
reducing the green house effects and associated risks. This should come as a handy savior for
almost all developed and developing nations. Moreover the nuclear produced therein are
substances that don’t occur naturally. For example strontium does not exist in nature but it is
one of the several radioactive waste products resulting from nuclear fission.

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DISADVANTAGES
First and foremost, as is the case with most breathtaking technologies, the high
initial cost of production involved is a drawback but as the product goes operational and gets
into bulk production, the price is sure to drop. The size of nuclear batteries for certain specific
applications may cause problems, but can be done away with as time goes by. For example,
size of Xcell used for laptop battery is much more than the conventional battery used in the
laptops.
Though radioactive materials sport high efficiency, the conversion methodologies used
presently are not much of any wonder and at the best matches’ conventional energy sources.
However, laboratory results have yielded much higher efficiencies, but are yet to be released
into the alpha stage.
A minor blow may come in the way of existing regional and country specific laws
regarding the use and disposal of radioactive materials. As these are not unique worldwide and
are subject to political horrors and ideology prevalent in the country. The introduction legally
requires these to be scrapped or amended. It can be however be hoped that, given the
revolutionary importance of this substance, things would come in favor gradually.
Above all, to gain social acceptance, a new technology must be beneficial and
demonstrate enough trouble free operation that people begin to see it as a “normal”
phenomenon. Nuclear energy began to loose this status following a series of major accidents
in its formative years. Acceptance accorded to nuclear power should be trust-based rather than
technology based. In other words acceptance might be related to public trust of the
organizations and individuals utilizing the technology as opposed to based on understanding of
the available evidence regarding the technology.

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APPLICATIONS
Nuclear batteries find many fold applications due to its long life time and improved
reliability. In the ensuing era, the replacing of conventional chemical batteries will be of
enormous advantages. This innovative technology will surely bring break-through in the
current technology which was muddled up in the power limitations. MEMS devices, with
their integrated nuclear micro-battery will be used in large variety of applications, as
sensors, actuators, resonators, etc. It will be ensured that their use does not result
in any unsafe exposure to radiation.
Space applications
In space applications, nuclear power units offer advantages over solar cells, fuel cells
and ordinary batteries because of the following circumstances:
1. When the satellite orbits pass through radiation belts such as the van-Allen belts
around the Earth that could destroy the solar cells
2. Operations on the Moon or Mars where long periods of darkness require heavy
batteries to supply power when solar cells would not have access to sunlight
3. Space missions in the opaque atmospheres such as Jupiter, where solar cells
would be useless because of lack of light.
4. At a distance far from the sun for long duration missions where fuel cells,
batteries and solar arrays would be too large and heavy.
5. Heating the electronics and storage batteries in the deep cold of space at minus
245° F is a necessity.
So in the future it is ensured that these nuclear batteries will replace all the existing power
supplies due to its incredible advantages over the other. The applications which require a high
power, a high life time, a compact design over the density, an atmospheric conditions-
independent it is quite a sure shot that future will be of ‘Nuclear Batteries’. NASA is on the
hot pursuit of harnessing this technology in space applications.
MedicalApplications
The medical field finds a lot of applications with the nuclear battery due to their
increased longevity and better reliability. It would be suited for medical devices like
pacemakers, implanted deep fibrillations or other implanted devices that would otherwise
require surgery to replace or repair the best out of the box is use in ‘cardiac pacemakers’.

27. 27
Batteries used in implantable cardiac pace makers-present unique challenges to their
developers and manufacturers in terms of high levels of safety and reliability and it often
poses threat to the end-customer. In addition, the batteries must have longevity to avoid
frequent replacement. The technological advances in leads/electrodes have reduced energy
requirements by two orders of magnitude. Microelectronics advances sharply reduce internal
current drain, concurrently decreasing size and increasing functionality, reliability and
longevity. It is reported that about 600,000 pacemakers are implanted each year worldwide
and the total number of people with various types of implanted pacemaker has already
crossed 3,000,000. A cardiac pacemaker uses half of its battery power for cardiac stimulation
and the other half for housekeeping tasks such as monitoring and data logging. The first
implanted cardiac pacemaker used nickel-cadmium rechargeable battery, later on zinc-
mercury battery was developed and used which lasted for over two years. Lithium iodide
battery, developed in 1972 made the real impact to implantable cardiac pacemakers and is on
the way. But it draws the serious threat lasts for about ten years and this is a serious problem.
The life time solution is nuclear battery.
Nuclear batteries are the best reliable and it lasts lifetime. The definitions for some of
the important parts of the battery and its performances are parameters like voltage, duty cycle,
temperature, shelf life, service life, safety and reliability, internal resistance, specific energy
(watt-hour/ kg), specific power (watts/kg), and in all that means nuclear batteries stands out.
The technical advantages of nuclear batteries are in terms of its longevity, adaptable shapes
and sizes, corrosion resistance, minimum weight, excellent current drain that suits to cardiac
pacemakers.
Mobile devices
Xcell-N is a nuclear powered laptop battery that can provide between seven and eight
thousand times the life of a normal laptop battery-that is more than five year’s worth of
continuous power.
Nuclear batteries are about forgetting things around the usual charging, battery
replacing and such bottlenecks. Since chemical batteries are just near the end of their life, we
can’t expect much more from them, in its lowest accounts, a nuclear battery can endure at

28. 28
least up to five years. The Xcell-N is in continuous working for the last eight months and has
not been turned off and has never been plugged into electrical power since. Nuclear batteries
are going to replace the conventional batteries and adaptors, so the future will be of exciting
innovative new approach to powering portable devices.
Automobiles
Although it is on the initial stages of development, it is highly promised that the
nuclear batteries will find a sure niche in the automobiles replacing the weary conventional
iconic fuels there will be no case such as running out of fuel and running short of time. ‘Fox
valley auto association, USA’ already conducted many seminars on the scopes and they are on
the way of implementing this. Although the risks associated the usage of nuclear battery, even
concerned with legal restrictions are of many, but its advantages over the usual gasoline fuels
are overcoming all the obstacles.

29. 29
Military applications
The army is undertaking a transformation into a more responsive, deployable, and
sustainable force, while maintaining high levels of lethality, survivability and versatility.
In unveiling this strategy, the final resource that fit quite beneficial is ‘nuclear battery’.
“TRACE photonics, U.S. Army Armaments Research, Development and Engineering Centre”
has harnessed radioisotope power sources to provide very high energy density battery power
to the men in action. Nuclear batteries are much lighter than chemical batteries and will last
years, even decades. No power cords or transformers will be needed for the next generation of
microelectronics in which voltage-matched supplies are built into components. Safe, long-life,
reliable and stable temperature is available from the direct conversion of radioactive decay
energy to electricity. This distributed energy source is well suited to active radio frequency
equipment tags, sensors and ultra wide-band communication chips used on the modern
battlefield.
Underwater sea probes and sea sensors
The recent flare up of Tsunami, Earthquakes and other underwater destructive
phenomenon has increased the demand for sensors that keeps working for a long time and able
to withstand any crude situations. Since these batteries are geared towards applications where
power is needed in inaccessible places or under extreme conditions, the researchers envision
its use as deep-sea probes and sensors, sub-surface, coal mines and polar sensor application s,
with a focus on the oil industry.
And the next step is to adapt the technology for use in very tiny batteries that could
power micro-electro-mechanical-systems (MEMS) devices, such as those used in the optical
switches or the free floating “smart-dust” sensors being developed by the military.

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CONCLUSION
The world of tomorrow that science fiction dreams of and technology manifests might be a
very small one. It would reason that small devices would need small batteries to power them.
The use of power as heat and electricity from radioisotope will continue to be indispensable.
As the technology grows, the need for more power and more heat will undoubtedly grow along
with it.
. Clearly the current research of nuclear batteries shows promise in future applications for
sure. With implementation of this new technology credibility and feasibility of the device will
be heightened. The principal concern of nuclear batteries comes from the fact that it involves
the use of radioactive materials. This means throughout the process of making a nuclear battery
to final disposal, all radiation protection standards must be met. The economic feasibility of
the nuclear batteries will be determined by its applications and advantages. With several
features being added to this little wonder and other parallel laboratory works going on, nuclear
cells are going to be the next best thing ever invented in the human history

31. 31
REFERENCES
“Power from radioisotopes,” USAEC, Division of Technical Information
“Nuclear and radiochemistry” , Gerhardt Friedlander, Joseph.W.Kennedy and Julian
Malcolm Miller,
“Particles and Nuclei, an Introduction to the Physical Concepts”. B.Povh, K.Rith, C.
Scolz and F.Zetche.
Brown, Paul: "Resonant Nuclear Battery Supply", Raum & Zeit, 1(3) (August-
September, 1989
Powerstream.com, “The Role of Chemical Power Sources in Modern Health Care”,
Curtis F. Holmes
Powerpaper.com
Technologyreview.com
Wikipedia.com/atomic_battery