A SEMINAR PRESENTATION ON

NUCLEAR BATTERY A PORTABLE ENERGY SOURCE

Presented By:- Abiresh Mishra

1011019118ICE-’B’

Guided By:- Mr. Abhisek ParidaAssistant ProfessorDepartment of ICE

Contents

1.Why Nuclear Battery?2.Historical Developments3.Understanding the terms used.4.Direct charging generators.5.Betavoltaics6.Fuel considerations.7.Nuclear accelerated generators.8.Applications9.Advantages10.Conclusion11.References

Why Nuclear Battery?1. Chemical batteries require frequent

replacements and are bulky.2. Fuel and Solar cells are expensive and requires

sunlight respectively.3. Need for compact, reliable, light weight and long

life power supplies.4. Nuclear Battery uses emissions from

radioisotope to generate electricity so there is no fear of hazardous radiations.

5. Nuclear batteries have lifespan up to decades.6. Can be used in easily inaccessible and extreme

conditions and reduce the rate of replacements.

Understanding the terms used

Radiations•Alpha - These are fast moving helium atoms.  They have high energy, typically in the MeV range. They also are magnetic in nature •Beta - These are fast moving electrons.  They typically have energies in the range of a few hundred keV to several MeV.•Gamma - These are photons, just like light, except of much higher energy.

RadioisotopesRadioisotopes are artificially produced, unstable atoms of a chemical element, which have a different number of neutrons in the nucleus, but the same number of protons and the same chemical properties.

Fig- Sources of radiation[1]

ENERGY PRODUCTION MECHANISM 1. Direct charging generators

 This form of nuclear-electric generator dates back to 1913. This method makes use of kinetic energy as well as the magnetic property of Alpha particles to generate current.

It consists of a core composed of radioactive elements.

Primary generator consists of a LC tank circuit.

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LC circuit produces the oscillations required for transformer operation.Few applications have been found in the past for the extremely low currents and inconveniently high voltages. Oscillator/transformer systems are employed to reduce the voltages, then rectifiers are used to transform the AC power back to direct current.The Moseley model guided other efforts to build experimental batteries generating electricity from the emissions of radioactive elements.

Direct charging generators (cont..)

1 -- Capacitor 2 -- Inductor 3 -- Core with radioactive elements 4 -- Transformer T primary winding 5 -- Resistance 6 -- Secondary winding 7 -- Load

Schematic Diagram of an LC Resonant Circuit

Fig 1-Schematic OF LC Ckt

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3

5

4 76

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Equivalent Circuit diagram of Direct Charging Generator

1 -- Capacitor 2 -- Inductor 3 -- Core with radioactive elements 4 -- Transformer T primary winding 5 -- Secondary winding 6 -- Load

Load

Fig 2-Equivalent ckt diagram of DCG[2]Ref-Google Image

2. Betavoltaics

1. Betavoltaics is an alternative energy technology that promises vastly extended battery life and power density over current technologies.

2. Uses energy from beta particles.3. Beta particles emitted by radioactive gas is captured in

Silicon wafer coated with diode material.4. It is similar to the mechanism of converting sunlight

into electricity in a solar panel.5. Absorbed radiation creates electron-hole pair which in

turn results in the generation of electric current.

Beta Voltaic cell (Google Image)

Representation of basic beta voltaic conversion

•Electrode A (P-region) has a positive potential while electrode B (N-region) is negative.

Fig 3- Beta voltaic cell [2]

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Application Of Betavoltaics1. The primary use for betavoltaics is for remote and

long-term use, such as spacecraft requiring electrical power for a decade or two.

2. Recent progress has prompted some to suggest using betavoltaics to trickle-charge conventional batteries in consumer devices, such as cell phones and laptop computers.

3. As early as 1973, betavoltaics were suggested for use in long-term medical devices such as pacemakers

Google Image

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Drawbacks Of Betavoltaics

1. As radioactive material emits, it slowly decreases in activity . Thus, over time a betavoltaic device will provide less power.

2. For practical devices, this decrease occurs over a period of many years.

3. For tritium devices, the half-life is 12.32 years. 4.  UK government's Health Protection Agency

Advisory Group on Ionizing Radiation declared the health risks of tritium exposure.

3.FUEL CONSIDERATIONS

The major criterions considered in the selection of fuels are:Avoidance of gamma in the decay chain Half life( Should be more)Cost should be less.

Any radioisotope in the form of a solid that gives off alpha or beta particles can be utilized in the nuclear battery. The most powerful source of energy known is radium-226. However Strontium-90 may also be used in this Battery

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Promethium

Promethium-147 is obtained as the oxide or chloride, in milligram quantities.This isotope does not emit gamma rays, and its radiation has a relatively small penetration depth in matter and a relatively long half-life.In atomic batteries, the beta particles emitted by promethium-147 are converted into electric current by sandwiching a small Pm source between two semiconductor plates. These batteries have a useful lifetime of about five years.The first promethium-based battery was assembled in 1964 and generated a few milliwatts of power.

Fig-PromethiumGoogle Image

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4.Nuclear Accelerated Generator technology

David Weber, owner and founder of Executive Engineering, is developing a technology, the nuclear accelerated generator (NAG).The main breakthrough represented by the technology is the direct conversion of nuclear energy into low-power electrical energy.NAG technology is intended for use with isotopes that emit beta-minus radiation .Isotopes that are theoretically compatible with the technology include strontium-90 (Sr-90), nickle-63 (Ni-63), and promethium-147.

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This mechanism has the potential to extract between 60% to 85% of the available energy from the electrons ejected from a beta-radiation-emitting isotope in a large-scale NAG system. Weber calculated that a 0.2 mg sample of Pm-147 would enable 0.25 W MEMS devices .

Google Image

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FUEL SOURCEIsotopes are the fuel of all Nuclear Accelerated Generators.Radioactive isotopes are continually being produced as part of radioactive wasteCurrent estimates place the amount of such waste in the United States at over 100 million gallons.Isotope production at existing levels costs less than the current cost of fuel even if only assuming a longevity of one half life and no trade-in value.Once placed as fuel into a NAG, these radioactive fuels could theoretically last from approximately three years to more than 400 years

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Application Nuclear isotopic power will bring to fruition such

things as particle beam weapons, ion-powered space planes, nuclear powered jet aircraft, high-powered laser canons, nuclear powered tanks, nuclear powered naval ships and, even, cryogenic coolers.

Nag devices could also be easily adapted to power large metropolitan areas, forward military bases and any other application where dependable power is needed in remote areas for any reason.

 NAG devices do all these things, it can do it cheaper and more efficiently than current technology.

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Advantages Since the Isotope supplies all the power the device requires to operate no outside power source are needed.Since the availability of the atomic isotopes is more than ample, costs of this fuel should be considerably less than either conventional atomic fuel or fossil fuel. Further, since the casement of the NAG is not very expensive, the cost of replacing damaged and/or broken parts is quite small.NAG is one of the safes devices on the planet. We cannot get a meltdown situation, blow it up, or use the isotope to make a bomb. From an emission point of view, it is a safe device to handle. The device is self-contained with little or no X-Rays .No Beta particles are ever emitted outside the casing of the device. 

APPLICATIONS

1. Space applications: Unaffected by long period of darkness and

radiation belts like Van-Allen belt. Compact and lighter in weight. Can avoid refrigeration/heating equipments

required for storage batteries. High power for long time independent of

atmospheric conditions. NASA is trying to harness this technology in

space applications.

2. Medical applications: In Cardiac pacemakers. Batteries should have reliability and longevity to avoid frequent replacements.

3. Mobile devices:Nuclear powered laptop battery X cell-N has 7000-8000 times more life than normal laptop batteries.

4. AutomobilesNo need for frequent recharging as in case of present electric vehicles.5. Under-water sea probes and sea sensors

APPLICATIONS (cont..)

7.ADVANTAGESLife span- minimum of 10 years.

Reliable electricity.

Amount of energy obtained is very high.

Lighter with high energy density.

Less waste generation.

Reduces green house and associated effects

Fuel used is the nuclear waste from nuclear fission.

8.CONCLUSION

Small compact devices of future require small batteries.

Nuclear batteries increase functionality, reliability and longevity.

Until final disposal all Radiation Protection Standards must be met.

Batteries of the near future.

9.References[1] J. P. Blanchard  "Stretching the boundaries of nuclear technology",  The Bridge,  vol. 32,  no. 4,  pp.27 -32. 2002[2] H. Guo and A. Lal  "Nano power beta

voltaic micro batteries",  IEEE Proc. 12th Int. Conf. Solid State Sens., Actuators Microsyst,  pp.36 -39. 2003

[3] H. Loferski, J.J Elleman, "Construction of a promethium-147 atomic battery,". IEEE Trans., on Electron Devices, vol. 3, pp. 738–746, Dec. 1964