A SEMINAR ON NUCLEAR BATTERYREPRESENTED BY:-

BHUBAN CHANDRA MOHANTAROLL NO.-13-EE/35REGD. NO.-1301225034

BALASORE COLLEGE OF ENGG.& TECH. SERGARH,BALASORE-756060

CONTENTS Why Nuclear Battery ? Historical Developments Understanding the terms used Energy Production Mechanism Nuclear Accelerated Generators Advantages Disadvantages Applications Conclusion References

Why Nuclear Battery?Chemical batteries require frequent replacements

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

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

life power supplies.Nuclear batteries have lifespan upto decades and

nearly 200 times more efficient.Do not rely on nuclear reaction so, no radioactive

wastes.Uses emissions from radioactive isotope to generate

electricity.Can be used in inaccessible and extreme conditions.

HISTORICAL DEVELOPMENTSIdea was introduced in 1950 and patented to Tracer

Lab.

Radioisotope electric power system developed by Paul Brown.

He organized an approach to harness energy from the magnetic field of alpha and beta particles using Radium-226.

Low efficiency due to loss of electrons.

Understanding the term usedRadioisotopesRadioisotopes are artificially produced,Unstable atoms of a chemical element,Which have a different number of neutronIn the nucleus but the same number of Protons and same chemical properties.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 Few hundred keV to several MeV.• Gamma- These are photons, just like (Fig-Sources

of radiation) light, except of much higher energy.

Energy production mechanism1.Betavoltaics:

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

• Uses energy from beta particles.• Beta particles emitted by radioactive gas is captured

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

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

in turn results in the generation of electric current.

Representation of basic beta voltaic conversion

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

Working:Before the radioactive source is introduced , no

current flows as the electrical forces are in equilibrium.

As a beta emitter is introduced , electrons are knocked out by its energy.

Generates electron-hole pairs in the junction.When beta particle imparts more than ionization

potential the electron rises to a higher level.

Potential difference drives electrons through the load where they give up the energy.

2. Direct Charging Generators:• This method use 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.

• LC circuit produces the oscillations required for transformer operation.

Schematic Diagram of an LC resonant circuit

1 – Capacitor

2 – Inductor

3 – Core with radioactive elements

4 – Transformer T primary winding

5 – Resistance

6 - Secondary winding

7 - Load

Working:Oscillations induced in LCR circuit damp out due to

loss of energy.

Here energy is imparted to the alpha particles during the decay of elements in the core.

This energy is introduced to circuit when alpha particles are absorbed by the inductor.

Oscillations sustain until amount of energy absorbed=amount of energy dissipated in ohmic resistance.

This excess energy is delivered to the load connected across transformer T secondary winding.

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.

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.

• 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 .

Fig-Promethium

Fuel source:• Isotopes are the fuel of all Nuclear Accelerated

Generators.• Radioactive isotopes are continuously being

produced as part of radioactive waste.• Current 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

advantagesLife span- minimum of 10 years.

Reliable electricity.

Amount of energy highest.

Lighter with high energy density.

Efficient.

Reduces green house and associated effects.

Fuel used is the nuclear waste from nuclear fission.

disadvantagesHigh initial cost of production.

Energy conversion methodologies are not much advanced.

Regional and country-specific laws regarding use and disposal of radioactive fuels.

To gain social acceptance.

applications• Space applications: Unaffected by long period of darkness and

radiation. Compact and lighter in weight. Can avoid 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.• Under-water sea probes and sea

sensors: In sensors working for long time. At inaccessible and extreme conditions. Use in coal mines and polar sensor applications

too.

applications• Medical applications: In Cardiac pacemakers. Batteries should have reliability and longevity to avoid frequent replacements.• Mobile devices: Nuclear powered laptop battery Xcell-N has 7000

– 8000 times more life. No need for charging, battery replacing.• Automobiles: No need for frequent recharging as in case of

present vehicles.• Military applications: Safe, longer life

conclusionSmall compact devices of future require small batteries.

Nuclear batteries increase functionality, reliability and longevity.

Batteries of the near future.

With several features being added to this, nuclear cells are going to be next best thing ever invented in the human history.

references J. P. Blanchard  "Stretching the boundaries of nuclear technology", The Bridge, vol. 32, no. 4, pp.27 -32. 2002

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

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

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