Nuclear energy
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Transcript of Nuclear energy
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Atomic Mass Unit
Energy in Nuclear Reaction
Nuclear Fission
Nuclear Power Plant Utilisation
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Nuclear Fusion
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Electricity Generation from Chain Reaction
a.m.u is usually used to quantify the mass of subatomic particles like protons, neutrons and electrons.
1 a.m.u is equal to 1/12 of the mass of carbon-12 atom.
a.m.u can also be written as u.
1 u = 1/12 x mass of one carbon-12 atom= 1/12 x 1.99265 x 10-26 kg= 1.66 x 10-27 kg
Useful in computation of energy released in nuclear reaction.
Splitting of a heavy nucleus into two lighter
nuclei
neutrontarget
nucleus
neutron
neutron
neutron
fission product
fission product
Release enormous amount of
energy
A few hundred million times the energy released in an equivalent chemical reaction.
kinetic fragments
n
n n
nn
n
n
Combining of two lighter nuclei to form a heavier nucleus Initially, under an applied force, 2 lighter nuclei fuse together to form a heavier nucleus and energy. At a critical level, the energy released can self sustain the fusion reaction. Neutron
Deuterium Helium
Tritium
Energy
Energy released in nuclear fusion is very much more than in nuclear fission
Appear as kinetic energy of heavier nucleus and energy of neutron, proton or gamma rays
10 g
4 g
5.9999 g
ENERGY
Mass and energy are not conserved separately.
The total “mass-energy” before and after the exchange is conserved.
They can be exchanged from one form to the other.
E= mc2
energy released (J)
speed of light= 3.00 x 108 ms-1
loss of mass or mass defect (kg)
Example
Mass defect, m = 226.025406 u – (222.017574 u + 4.002603 u)= 0.005229 u= 0.005229 x 1.66 x 10-27 kg= 8.68 x 10-30 kg
Therefore, energy released, E = mc2
= 8.68 x 10-30 x (3.00 x 108)2
= 7.81 x 10-13 J
226Ra
88
222 4Rn + He
86 2Ra = 226.025406 u, Rn = 222.017574 u,
He = 4.002603 u, 1 u =1.66 x 10-27 kgc = 3.00 x 108 ms-1
222226
4
2
88 86
Trigger chain reaction
Release enormous energy
Energy conversion in reactor
Electricity generation
Water reactors Generation III reactors
Boiling water reactors
Gas-cooled reactors
Pressurised water reactors
Pressurised heavy-water reactors
Light water reactors
Heavy water reactors
High temperature gas-cooled reactors
Fast neutron reactors
Boiling water reactor
Pressurised water reactor
Pressurised Heavy-Water Reactor
Light-water graphite-moderated reactor
Liquid-Metal-Cooled Fast-Breeder Reactor (LMFBR)
Heavy Water Reactor
High Temperature Gas-Cooled Reactors
Fast neutron reactor
nuclei split by
neutrons, releasing
large amount of
energy Prevent radiation
leakage from reactor core
rotated by flow of
steam under high
pressure
absorb neutrons. Reduce rate of fission
reactionmoderator slow down neutrons
produced by fission
coils rotated by turbines. Electricity
generated by electromagnetic
induction
Boil water into
steam
GCR: Function
Layout of GCR
Fission of uranium-235 nuclei produces energy in the form of heat
Gas passing through the reactor core is heated up
Heat energy from the hot gas boils the water into steam
Flow of steam drives the turbines
Turbines turn the coils in the generator to produce electricity
Cold gas goes back to the reactor core to be heated again
Steam condenses back to water
GCR: Process flow
Nuclear energy from fission
Heat energy carried by the hot gas
Kinetic energy of the steam
Kinetic energy of the turbines
Electrical energy
Energy conversions in GCR
More than 400 nuclear power stations, producing 17% of the world’s electricity
East & South Asia, more than 100 nuclear power reactors in operation
29% 38%
Exposure to excessive radiation
Expensive Misused as
weapons of mass destruction
Minimal carbon dioxide emission
More stable price compared to fossil fuel
Need less fuel
Advantages Disadvantages