2. INTRODUCTION:-
A nuclear reactor, or atomic
pile.
It is designed & operated for
the purpose of sustaining a
nuclear fission chain reaction
at controlled predetermined
rate.
Helpful in production of heat,
mechanical & electrical
energy, radioactive isotopes,
weapons materials & nuclear
research.
4. COMPONENTS:-
FUEL ELEMENTS:-
Material containing
the fissile isotopes, called
reactor fuel or nuclear
fuel.
Varied composition,
natural uranium to highly
enriched in U²³⁵, Pu²³⁹ or
U²³³.
Basic source are uranium
& thorium.
U²³⁵ 0.71% by wt. produce
the nuclear energy.
5. FUEL RODS:-
A long, slender,
zirconium metal tube
containing pellets of
fissionable material,
which provide fuel for
nuclear reactors.
Fuel rods are
assembled into bundles
called fuel assemblies,
which are loaded
individually into the
reactor core.
6.
7. MODERATORS:-
Rapidly reduce the high
energy of fission
neutrons.
Neutrons ejected by he
fission must be slow
down by the collision
with the atom of
comparable mass that
do not absorb them.
E.g.
Ordinary water,
graphite, helium, heavy
water,
8. CORE:-
A nuclear reactor core is the portion of a nuclear
reactor containing the nuclear fuel components
where the nuclear reactions take place and the
heat is generated.
9. COOLANT:-
Heat generated in the
core is removed by the
coolant.
Ordinary & heavy
water.
Liquid metals like Na, K
at high temp .
Benzene, polyphenyls ,
air, CO₂ , CH₄, H₂ & He.
10. CONTROL RODS:-
The power level of
neutron is controlled by
controlling the neutron
flux, that is achieved by
using some neutron
absorbing material.
BORON , most
commonly used due to
high M.P & absorption.
Cadmium is also used.
11. SHIELDING:-
Consist up of layer
of concrete that
surrounds the core.
Absorbs both
gamma rays &
neutrons.
Good structural
material & have
enough hydrogen
to moderate the
fast neutrons.
13. FISSION:-
Fissile isotopes present in the fuel rods receives
the neutron & undergo fission reaction.
Releases two lighter nuclei & three more neutrons.
So the chain of fission reaction starts & goes on
increasing.
Produces heat (K.E) , gamma rays, free neutrons.
14. HEAT PRODUCTION:-
The reactor core generates heat in a
number of ways:
The K.E of fission products is
converted to thermal energy when
these nuclei collide with nearby
atoms.
The reactor absorbs some of the
gamma rays produced during fission
and converts their energy into heat.
Heat is produced by the radioactive
decay of fission products and
materials that have been activated by
neutron absorption.
15. Moderator may slow down the speed of fission
reaction by decreasing the energy of neutrons.
16. Control rods will absorbs the excess of
neutrons & hence will control the rate of
fission reaction & heat production.
17. COOLING:-
A nuclear reactor coolant,
usually water but
sometimes a gas
circulated the reactor
core to absorb the heat
generated.
This heat is then used to
generate steam.
Steam turns on the
turbine, & produces the
electricity.
Water being cold is
collected side by &
transfers again in the
reactor’s core & works as
moderator
23. ADVANTAGES:-
Produces no polluting
gases.
Does not contribute to
global warming.
Very low fuel costs.
Low fuel quantity reduces
mining and transportation
effects on environment.
High technology research
required benefits other
industries.
Power station has very
long lifetime.
24. DISADVANTAGES:-
Waste is radioactive and safe
disposal is very difficult and
expensive.
Local thermal pollution from
wastewater affects marine life.
Large-scale accidents can be
catastrophic.
Public perception of nuclear
power is negative.
Costs of building and safely
decommissioning are very high.
Cannot react quickly to
changes in electricity demand.