nuclear battery

1. NUCLEAR BATTERIES

2. Contents
▪ What is nuclear battery ?
▪ Radioactive decay
▪ some radioactive isotopes used in nuclear batteries
▪ Types of nuclear batteries & their working
▪ Advantages and disadvantages
▪ Applications

3. What is nuclear battery ?
▪ It is a device which uses energy from the decay of 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 or no nuclear fission
and fusion takes place.
▪ Nuclear battery technology began in 1913, when Henry Moseley first
demonstrated the beta cell.
▪ Its life-time can lie between 10 to 100 years.

4. Radio active decay
▪ An unstable nucleus of radioactive atom wants to achieve stability. It
can do this by emitting radioactive particles which are- α particles,
β particles and γ waves.
▪ There are three types of radioactive decay-
1. α decay
2. β decay and
3. γ decay

5. Alpha Decay
• Alpha decay emits α particles.
• When an atom spits out two protons and
two neutrons from its nucleus, this little
bundle is called an alpha particle.
• the daughter nucleus, after the emission of
α particle has now atomic number two less
than the parent nucleus and atomic mass
four less than the parent nucleus.

6. β Decay
▪ It includes three process of radioactive
disintegration-
1. Electron Emission (β- decay)
▪ Neutron in the parent nucleus decays into a
proton that remains in the daughter nucleus
by emitting an energetic Electron and an
antineutrino.
▪ Thus β- decay results in a daughter nucleus in
which proton (atomic no.) is one more than
its parent nucleus but the mass no. remains
same.
▪ Energetic electron is called as β- particle.

7. 2.) Positron Emission (β+ Decay)
▪ Proton in the parent nucleus decays into
a neutron that remains in the daughter
nucleus by emitting a positron (anti
electron) and a neutrino.
▪ Thus β+decay results in a daughter
nucleus in which proton (atomic no.) is
one less than its parent nucleus but the
mass no. remains same.
β Decay

8. β Decay
3.) Electron capture
▪ The electron of innermost shell (K or L
shell) is captured by a nuclear proton to
produce a neutron and a neutrino is
emitted.
▪ Thus electron capture results in a
daughter nucleus in which proton (atomic
no.) is one less than its parent nucleus
but the mass no. remains same.

9. γ decay
▪ Nucleus changes from a higher energy
state to a lower energy state through the
emission of electromagnetic radiations
(photons).
▪ Number of protons and neutrons in the
nucleus does not change in this process.
▪ Thus parent and daughter atoms are of
the same chemical element.

10. Some radioactive isotopes used in nuclear
batteries
▪ Nuclear batteries uses radioisotopes producing low energy beta particles and
sometimes alpha of varying energies.
 Tritium
 Nickel- 63 tested
 Promethium- 147
 Technetium- 99
 Plutonium- 238
 curium- 242
 Curium- 244 used
 Strontium- 90

11. Type of nuclear batteries & their
working

12. Type of nuclear batteries & their
working
I. Thermal convertors- whose output power is a function of
temperature differential. Heat energy of Radioactive particles is
used.Their types are-
i. Thermionic convertors
ii. Thermophotovoltaic cells

13. i. Thermionic converters
▪ A thermionic converter consists of a hot electrode which
thermionically emits electrons over a space charge barrier to a cooler
electrode, producing electric current.

14. Thermophotovoltaic cells
▪ Thermophotovoltaic cells work by the same principles as a
photovoltaic cell, except that they convert infrared light (rather than
visible light) emitted by a hot surface, into electricity.

15. 2. Non-thermal converter- Its output power is not a function of
temperature differential. It uses the charge or ionization energy of
radioactive particles instead of thermal energy. Its types are-
I. Direct charging generators
II. Alpha and beta voltaic
III. opto electric
IV. Reciprocating Electromechanical Atomic Batteries
Type of nuclear batteries & their working

16. Direct charging generators
▪ the primary generator 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.

17. Alpha & Beta voltaic
▪ As the radioactive source decays, the α or β particles emits and ionize
the semiconductor material atoms due to which electrons and holes
are excited.
▪ Electrons attract toward anode and holes attract towards cathode
due to which potential difference is created across the electrodes.

18. Reciprocating Electromechanical Atomic
Batteries
▪ The self-reciprocating cantilever consists of a radioactive
source of thickness very small and of area 4square mm.
▪ above this thin film there is a cantilever beam. It is made of a
rectangular piece of silicon.
▪ On this cantilever beam there is a copper sheet attached to
it. Also above this cantilever there is a piezoelectric plate.
▪ First the beta particles, which are high-energy electrons, fly
spontaneously from the radioactive source.These electrons
get collected on the copper sheet. Copper sheet becomes
negatively charged.Thus an electrostatic force of attraction
is established between the silicon cantilever and radioactive
source. Due to this force the cantilever bends down.

19. ▪ The piece of piezoelectric material bonded to the top of the silicon
cantilever bends along with it.The mechanical stresses of the bend
unbalances the charge distribution inside the piezoelectric crystal
structure, producing a voltage in electrodes attached to the top and
bottom of the crystal.
▪ After some time, the cantilever come close enough to the source to
discharge the accumulated electrons by direct contact. At that
moment, electrons flow back to the source, and the electrostatic
attractive force vanishes.
▪ The cantilever then springs back and oscillates like a diving board
after a diver jumps, and the recurring mechanical deformation of the
piezoelectric plate produces a series of electric pulses.
Reciprocating Electromechanical Atomic Batteries

20. Applications
▪ They 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
Automated scientific stations in remote part of the world.

21. Advantages
▪ Life span is very long.
▪ Reliable electricity
▪ Amount of energy obtained is very high.
▪ Lighter with high energy density.
▪ Less waste generation.
▪ Fuel used is the nuclear waste from nuclear fission.

22. Disadvantages
▪ High initial cost of production as its in the experimental stage.
▪ Energy conversion methodologies are not much advanced.
▪ Regional and country- specific laws regarding use and disposal of
radioactive fuels.
▪ To gain social acceptance.

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