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Department of Electrical Engineering_AGI_Jaipur_2013-2014 Page 1
1. Introduction 3
2. What are nuclear power batteries? 5
3. Types of nuclear batteries 6
a. Thermal converters 6
i. Thermionic Converters 6
ii. Radioisotope thermoelectric generator 7
iii. Thermo photovoltaic cells 9
iv. Alkali-metal thermal to electric converter 10
b. Non-thermal converter 13
i. Direct charging generators 13
ii. Betavotaic 13
iii. Alphavoltaics 15
iv. Optoelectric 15
v. Reciprocating electromechanical battery 16
4. Fuel consideration 17
5. Advantages 20
6. Drawbacks 21
7. Applications 22
8. Conclusion 26
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LIST OF FIGURE
NAME PG. NO.
1. THERMIONIC CONVERTER 7
2. RADIOISOTOPE THERMOELECTRIC GENERATOR 8
3. THERMOPHOTOVOLTAIC CELLS 10
4. AMTEC Direct Energy Conversion 12
5. BETAVOLTAIC CELL 14
6. Radioisotope piezoelectric generator 16
7. Power Density 19
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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
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
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technology is geared towards applications where power is needed in inaccessible places or under
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
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WHAT ARE NUCLEAR POWER BATTERIES?
The terms atomic battery, nuclear battery, tritium battery and radioisotope generator are used to
describe a device which uses energy from the decay of a radioactive isotope to generate
electricity. Like nuclear reactors they generate electricity from atomic energy, but differ in that
they do not use a chain reaction. Compared to other batteries they are very costly, but have
extremely long life and high energy density, and so they are mainly used as power sources for
equipment that must operate unattended for long periods of time, such as spacecraft, pacemakers,
underwater systems and automated scientific stations in remote parts of the world.
Nuclear battery technology began in 1913, when Henry Moseley first demonstrated the beta cell.
The field received considerable in-depth research attention for applications requiring long-life
power sources for space needs during the 50s and 60s. In 1954 RCA researched a small atomic
battery for small radio receivers and hearing aids. After RCA development, over the years after
many types and methods has been developed. The scientific principles are well known, but
modern nano-scale technology and new wide band gap semiconductors have created new devices
and interesting material properties not previously available.
Batteries using the energy of radioisotope decay to provide long-lived power (10–20 years) are
being developed internationally. Conversion techniques can be grouped into two types: thermal
and non-thermal. The thermal converters (whose output power is a function of a temperature
differential) include thermoelectric and thermionic generators. The non-thermal converters
(whose output power is not a function of a temperature difference) extract a fraction of the
incident energy as it is being degraded into heat rather than using thermal energy to run electrons
in a cycle. Atomic batteries usually have an efficiency of 0.1–5%. High efficiency betavoltaics
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TYPES OF NUCLEAR BATTERIES
Nuclear batteries are mainly classified into two main categories:
I. THERMAL CONVERTERS
The thermal converters are the devices which convert heat energy to electrical energy i.e. whose
output power is a function of a temperature differential. Thermal converters are also classified
into four types.
1. THERMIONIC CONVERTER
A thermionic converter consists of a hot electrode which thermionically emits electrons over a
potential energy barrier to a cooler electrode, producing a useful electric power output. Caesium
vapor is used to optimize the electrode work functions and provide an ion supply (by surface
contact ionization or electron impact ionization in a plasma) to neutralize the electron space
The scientific aspects of thermionic energy conversion primarily concern the fields of surface
physics and plasma physics. The electrode surface properties determine the magnitude of
electron emission current and electric potential at the electrode surfaces and the plasma
properties determine the transport of electron current from the emitter to the collector. All
practical thermionic converters to date employ caesium vapor between the electrodes, which
determines both the surface and plasma properties. Caesium is employed because it is the most
easily ionized of all stable elements.
The surface property of primary interest is the work function, which is the barrier that limits
electron emission current from the surface and essentially is the heat of vaporization of electrons
from the surface. The work function is determined primarily by a layer of caesium atoms
adsorbed on the electrode surfaces. The properties of the interelectrode plasma are determined by
the mode of operation of the thermionic converter. In the ignited (or “arc”) mode the plasma is
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maintained via ionization internally by hot plasma electrons (~ 3300 K); in the unignited mode
the plasma is maintained via injection of externally-produced positive ions into a cold plasma; in
the hybrid mode the plasma is maintained by ions from a hot-plasma interelectrode region
transferred into a cold-plasma interelectrode region.
Fig. 1 THERMIONIC CONVERTER
2. RADIOISOTOPE THERMOELECTRIC GENERATOR
A radioisotope thermoelectric generator (RTG, RITEG) is an electrical generator that obtains its
power from radioactive decay. In such a device, the heat released by the decay of a suitable
radioactive material is converted into electricity by the See beck effect using an array of
thermocouples. RTGs have been used as power sources in satellites, space probes and unmanned
remote facilities, such as a series of lighthouses built by the former Soviet Union inside the
Arctic Circle. RTGs are usually the most desirable power source for robotic or unmaintained
situations needing a few hundred watts (or less) of power for durations too long for fuel cells,
batteries, or generators to provide economically, and in places where solar cells are not practical.
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Safe use of RTGs requires containment of the radioisotopes long after the productive life of the
unit. RTGs were developed in the US during the late 1950s by Mound Laboratories in
Miamisburg, Ohio under contract with the United States Atomic Energy Commission.
Critics argue that they could cause environmental and security problems as leakage or theft of
the radioactive material could pass unnoticed for years, particularly as the locations of some of
these lighthouses are no longer known due to poor record keeping. In one instance, the
radioactive compartments were opened by a thief. In another case, three woodsmen in Georgia
came across two ceramic RTG heat sources that had been stripped of their shielding. Two of the
three were later hospitalized with severe radiation burns after carrying the sources on their backs.
The units were eventually recovered and isolated. There are approximately 1,000 such RTGs in
Russia. All of them have long exhausted their 10-year engineered life spans. They are likely no
longer functional, and may be in need of dismantling. Some of them have become the prey of
metal hunters, who strip the RTGs' metal casings, regardless of the risk of radioactive
Fig. 2 RADIOISOTOPE THERMOELECTRIC GENERATOR
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3. THERMOPHOTOVOLTAIC CELLS
Thermo photovoltaic (TPV) energy conversion is a direct conversion process from heat
differentials to electricity via photons. A basic thermophotovoltaic system consists of a thermal
emitter and a photovoltaic diode cell.
The temperature of the thermal emitter varies between different systems from about 900 °C to
about 1300 °C, although in principle TPV devices can extract energy from any emitter with
temperature elevated above that of the photovoltaic device (forming an optical heat engine). The
emitter can be a piece of solid material or a specially engineered structure. A conventional solar
cell is effectively a TPV device in which the Sun functions as the emitter. Thermal emission is
the spontaneous emission of photons due to thermal motion of charges in the material. For
normal TPV temperatures, this radiation is mostly at near infrared and infrared frequencies. The
photovoltaic diodes can absorb some of these radiated photons and convert them into free charge
carriers, that is electricity.
Thermophotovoltaic systems have few, if any, moving parts and are therefore very quiet and
require low maintenance. These properties make thermophotovoltaic systems suitable for
remote-site and portable electricity-generating applications. Their efficiency-cost properties,
however, are often rather poor compared to other electricity-generating technologies. Current
research in the area aims at increasing the system efficiencies while keeping the system cost low.
In the design of a TPV system, it is usually desired to match the optical properties of thermal
emission (wavelength, polarization, direction) with the most efficient conversion characteristics
of the photovoltaic cell, since unconverted thermal emission is a major source of inefficiency.
Most groups focus on gallium antimonide (GaSb) cells. Germanium (Ge) is also suitable.
Much research and development in TPVs therefore concerns methods for controlling the
TPV cells have often been proposed as auxiliary power conversion devices for regeneration of
lost heat in other power generation systems, such as steam turbine systems or solar cells.A
prototype TPV hybrid car was even built.
TPV research is a very active area. Among others, the University of Houston TPV Radioisotope
Power Conversion Technology development effort is aiming at combining thermophotovoltaic
cell concurrently with thermocouples to provide a 3 to 4-fold improvement in system efficiency
over current radioisotope thermoelectric generators.
TPVs have significant promise for efficient and economically viable power systems for both
military and commercial applications. Compared to traditional nonrenewable energy sources,
burner TPVs have little NOx emissions and are virtually silent. Solar TPVs, on the other hand,
are a source of entirely renewable energy with no emissions. Compared to photovoltaics, TPVs
can be more efficient owing to recycling of unabsorbed photons. However, the structure of TPVs
is more complex, and losses at each energy conversion step can result in a lower efficiency than
that of photovoltaics. Further developments must be made to the absorber/emitter and PV cell to
realize its full potential as a renewable energy source. Unlike PVs, however, when TPVs are
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used with a burner source, they provide on-demand energy. As a result, no form of energy
storage is needed. In addition, owing to the PV‟s proximity to the radiative source, TPVs can
generate current densities 300 times that of conventional PVs.
Fig. 3 THERMOPHOTOVOLTAIC CELLS
4. ALKALI-METAL THERMAL TO ELECTRIC CONVERTER
The alkali metal thermal to electric converter (AMTEC), originally called the sodium heat engine
(SHE) was invented by Joseph T. Kummer and Neill Weber at Ford in 1966.
This device accepts a heat input in a range from about 900 K–1300 K and produces direct current
with predicted device efficiencies of 15-40%. In the AMTEC sodium is driven around a closed
thermodynamic cycle between a high temperature heat reservoir and a cooler reservoir at the heat
rejection temperature. The unique feature of the AMTEC cycle is that sodium ion conduction
between a high pressure or activity region and a low pressure or activity region on either side of
a highly ionically conducting refractory solid electrolyte, is thermodynamically nearly equivalent
to an isothermal expansion of sodium vapor between the same high and low pressure.
Electrochemical oxidation of neutral sodium at the anode leads to sodium ions which traverse the
solid electrolyte and electrons which travel from the anode through an external circuit where they
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perform electrical work, to the low pressure cathode, where they recombine with the ions to
produce low pressure sodium gas. The sodium gas generated at the cathode then travels to a
condenser at the heat rejection temperature of perhaps 400–700 K where liquid sodium reforms.
The AMTEC thus is an electrochemical concentration cell which converts the work generated by
expansion of sodium vapor directly into electric power.
The converter is based on the electrolyte used in the sodium-sulfur battery, sodium beta"-
alumina, a crystalline phase of somewhat variable composition containing aluminum oxide,
Al2O3, and sodium oxide, Na2O, in a nominal ratio of 5:1, and a small amount of the oxide of a
small cation metal, usually lithium or magnesium, which stabilizes the beta" crystal structure.
The sodium beta"-alumina solid electrolyte (BASE) [ceramic] is nearly insulating with respect to
transport of electrons, and is a thermodynamically stable phase in contact with both liquid
sodium and sodium at low pressure.
Single cell AMTECs with open voltages as high as > 1.55 V and maximum power density as
high as > 0.50 W/cm² at temperature of 1173K (900°C) have been obtained with long term stable
refractory metal electrodes.
Efficiency of AMTEC cells has reached 16% in the laboratory. High voltage multi-tube modules
are predicted to be 20% to 25% efficient, and power densities up to 0.2 kilowatts per liter appear
to be achievable in the near future. Calculations show that replacing sodium with a potassium
working fluid increases the peak efficiency from 28% to 31% at 1100 K with a 1 mm thick
AMTEC requires energy input at modest elevated temperatures, and not at a specific wavelength,
it is easily adapted to any heat source, including radioisotope, concentrated solar, external
combustion, or nuclear reactor. A solar thermal power conversion system based on an AMTEC
has advantages over other technologies (including photovoltaic systems) in terms of the total
power that can be achieved with such a system and the simplicity of the system (which includes
the collector, energy storage (thermal storage with phase change material) and power conversion
in a compact unit). The overall system could achieve as high as 14 W/kg with present collector
technology and future AMTEC conversion efficiencies. The energy storage system outperforms
batteries, and the temperatures at which the system operates allows long life and reduced radiator
size (heat reject temperature of 600 K). Deep-space applications would use radioisotope
thermoelectric generators; hybrid systems are in design.
While space power systems are of intrinsic interest, terrestrial applications will offer large scale
applications for AMTEC systems. At the +25% efficiency projected for the device and projected
costs of $350/kW, AMTEC is expected to prove useful for a very wide variety of distributed
generation applications including self-powered fans for high efficiency furnaces and water
heaters and recreational vehicle power supplies cathodic protection of pipelines, remote
telemetry from oil well sites are other areas where this type of electrical generation might be
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used. The potential to scavenge waste heat may allow for integration of this technology into
general residential and commercial cogeneration schemes although costs per kilowatt-hour
would have to drop substantially from current projections.
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II. NON-THERMAL CONVERTERS
Non-thermal converters extract a fraction of the nuclear energy as it is being degraded into heat.
Their outputs are not functions of temperature differences as are thermoelectric and thermionic
converters. Non-thermal generators can be grouped into five classes.
1. DIRECT CHARGING GENERATORS
In the first type, the primary generators consists of a capacitor which is charged by the current of
charged particles from a radioactive layer deposited on one of the electrodes. Spacing can be
either vacuum or dielectric. Negatively charged beta particles or positively charged alpha
particles, positrons or fission fragments may be utilized. Although this form of nuclear-electric
generator dates back to 1913, few applications have been found in the past for the extremely low
currents and inconveniently high voltages provided by direct charging generators.
Oscillator/transformer systems are employed to reduce the voltages, then rectifiers are used to
transform the AC power back to Direct Current.
English physicist H.G.J. Moseley constructed the first of these. Moseley‟s apparatus consisted of
a glass globe silvered on the inside with a radium emitter mounted on the tip of a wire at the
center. The charged particles from the radium created a flow of electricity as they moved quickly
from the radium to the inside surface of the sphere. As late as 1945 the Moseley model guided
other efforts to build experimental batteries generating electricity from the emissions of
Betavoltaics are generators of electrical current, in effect a form of battery, which use energy
from a radioactive source emitting beta particles (electrons). A common source used is the
hydrogen isotope, tritium. Unlike most nuclear power sources, which use nuclear radiation to
generate heat, which then is used to generate electricity (thermoelectric and thermionic sources),
betavoltaics use a non-thermal conversion process; converting the electron-hole pairs produced
by the ionization trail of beta particles traversing a semiconductor.
Betavoltaic power sources are particularly well-suited to low-power electrical applications where
long life of the energy source is needed, such as implantable medical devices or military and
The primary use for betavoltaics is for remote and long-term use, such as spacecraft requiring
electrical power for a decade or two. Recent progress has prompted some to suggest using
betavoltaics to trickle-charge conventional batteries in consumer devices, such as cell phones and
laptop computers. As early as 1973, betavoltaics were suggested for use in long-term medical
devices such as pacemakers.
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Although betavoltaics use a radioactive material as a power source, the beta particles used are
low energy and easily stopped by shielding, as compared to the gamma rays generated by more
dangerous radioactive materials. With proper device construction (that is, proper containment), a
betavoltaic device would not emit dangerous radiation. Leakage of the enclosed material would
engender health risks, just as leakage of the materials in other types of batteries leads to
significant health and environmental concerns.
As radioactive material emits, it slowly decreases in activity. Thus, over time a betavoltaic
device will provide less power. For practical devices, this decrease occurs over a period of many
years. For tritium devices, the half-life is 12.32 years. In device design, one must account for
what battery characteristics are required at end-of-life, and ensure that the beginning-of-life
properties take into account the desired usable lifetime.
Liability connected with environmental laws and human exposure to tritium and its beta decay
must also be taken into consideration during risk assessment and product development.
Naturally, this increases both time-to-market and the already high cost associated with tritium. A
2007 report by the UK government's Health Protection Agency Advisory Group on Ionizing
Radiation declared the health risks of tritium exposure to be double those previously set by the
International Commission on Radiological Protection located in Sweden.
Fig. 5 BETAVOLTAIC CELL
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Alpha voltaic power sources are devices that use a semiconductor junction to produce electrical
particle from energetic alpha particles.
An opto-electric nuclear battery is a device that converts nuclear energy into light, which it then
uses to generate electrical energy. A beta-emitter such as technetium-99 or strontium-90 is
suspended in a gas or liquid containing luminescent gas molecules of the excimer type,
constituting a "dust plasma." This permits a nearly lossless emission of beta electrons from the
emitting dust particles. The electrons then excite the gases whose excimer line is selected for the
conversion of the radioactivity into a surrounding photovoltaic layer such that a lightweight, low-
pressure, high-efficiency battery can be realised. These nuclides are relatively low-cost
radioactive waste from nuclear power reactors. The diameter of the dust particles is so small (a
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 (such as krypton,
argon, and xenon) with excimer 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 e.g. diamond which convert the optical energy generated from the
radiation into electrical energy.
The battery would consist of an excimer 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 a photocell with a bandgap tuned for the excimer.
When the beta active nuclides (e.g., krypton-85 or argon-39) emit beta particles, they excite their
own electrons in the narrow excimer band at a minimum of thermal losses that this radiation is
converted in a high band gap photovoltaic layer (e.g. in p-n diamond) very efficiently into
electricity. 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 battery's net power.
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5. RECIPROCATING ELECTROMECHANICAL ATOMIC BATTERIES
A Radioisotope piezoelectric generator converts energy stored in the radioactive material directly
into motion to generate electricity by the repeated deformation of a piezoelectric material. This
approach creates a high-impedance source and, unlike chemical batteries, the devices will work
in a very wide range of temperatures.
A piezoelectric cantilever is mounted directly above a base of the radioactive isotope nickel-63.
All of the radiation emitted as the millicurie-level nickel-63 thin film decays is in the form of
beta radiation, which consists of electrons. As the cantilever accumulates the emitted electrons, it
builds up a negative charge at the same time that the isotope film becomes positively charged.
The beta particles essentially transfer electronic charge from the thin film to the cantilever. The
opposite charges cause the cantilever to bend toward the isotope film. Just as the cantilever
touches the thin-film isotope, the charge jumps the gap. That permits current to flow back onto
the isotope, equalizing the charge and resetting the cantilever. As long as the isotope is decaying
- a process that can last for decades - the tiny cantilever will continue its up-and-down motion.
As the cantilever directly generates electricity when deformed, a charge pulse is released each
time the cantilever cycles.
Radioactive isotopes can continue to release energy over periods ranging from weeks to decades.
The half-life of nickel-63, for example, is over 100 years. Thus, a battery using this isotope
might continue to supply useful energy for at least half that time. Researchers have demonstrated
devices with about 7% efficiency with high frequencies of 120 Hz to low-frequency (every three
hours) self-reciprocating actuators.
Fig. 6 Radioisotope piezoelectric generator
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The major criterions considered in the selection of fuels are:
Avoidance of gamma in the decay chain
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.
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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
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.
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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 non stop 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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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
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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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.
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.
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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 fibrillators or other implanted devices that would otherwise require surgery to
replace or repair the best out of the box is use in „cardiac pacemakers‟. 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 house keeping 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.
Department of Electrical Engineering_AGI_Jaipur_2013-2014 Page 24
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 years 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 least upto 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.
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
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
Department of Electrical Engineering_AGI_Jaipur_2013-2014 Page 25
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 micro
electronics 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
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.
Department of Electrical Engineering_AGI_Jaipur_2013-2014 Page 26
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 indispensible. 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.
Department of Electrical Engineering_AGI_Jaipur_2013-2014 Page 27
# “Power from radioisotopes,” USAEC, Division of Technical Information