1) Nuclear power plants generate energy through nuclear fission and fusion reactions. Fission occurs when atoms are split, while fusion occurs when small atoms join to form larger atoms.
2) India operates several nuclear power plants that use fission to generate heat and convert it to electricity. The plants use uranium as fuel, which is mined around the world.
3) The fuel production process involves mining and milling uranium ore, converting it to gas, enriching the uranium-235 content, and fabricating fuel pellets that are assembled into rods and reactor cores. Fast breeder reactors can produce more fissile plutonium fuel than they consume.
4. NUCLEAR REACTIONS
FISSION
• Fission would be defined as
the division of single atom
into multiple atoms of small
size.
FUSION
• Fusion would be defined as
the joining of two or more
small atoms to form a large
atom.
5. ENERGY
(FROM)
FISSION
Nuclear energy originates
from the splitting of
uranium atoms. This
generates heat.
BURN-UP
Burnup also known
as fuel utilization,it is a
measure of how much
energy is extracted from a
primary nuclear fuel source.
6. RADIO ACTIVITY
In Radio Activity Radioactive decay takes
place.
Radioactive decay is the process in which
an unstable atomic nucleus loses energy.
By emitting radiation, such as an alpha
particle, beta particle with neutrino or only a
neutrino in the case of electron .
7. FISSION REACTOR TYPES
Fast Breeder Reactors (FBR)
Aqueous Homogeneous Reactors (AHR)
Heavy Water Moderated Reactors (HWR)
Pressurized Water Reactors (PWR)
Boiling Water Reactors (BWR)
Organic-Cooled Power Reactors (OCPR)
Sodium Graphite Reactors (SGR)
Gas-Cooled Reactors (GCR)
8. NUCLEAR POWER PLANTS
IN INDIA
• Rajasthan Atomic Power Station Rawatbhata
India capacity 1180Mwe
• Kalpakkam (Madras) Atomic Power Station
India capacity 440Mwe
• Kudankulam Nuclear Power Plant (KNPP) India
capacity 2000Mwe
• Narora Atomic Power Station India capacity
440Mwe
9. The term “breeder” refers to
the types of configurations
which can be the breeding
ratio higher than 1.
That means such reactors
produce more fissionable fuel
than they consume
(i.e. more fissionable Pu-239
is produced from non-
fissionable uranium-238, than
consumed initial U-235+Pu-
239 fuel).
The bombardment of uranium-238 with
neutrons triggers two successive beta
decays with the production of
plutonium. The amount of plutonium
produced depends on the breeding
ratio.
10. TYPES OF BREEDER REACTOR
• Fast breeder reactor (FBR). The superior neutron
economy of a fast neutron reactor makes it possible to
build a reactor that, after its initial fuel charge of
plutonium, requires only natural (or even depleted)
uranium feedstock as input to its fuel cycle. breeding
ratio of over 1.2.
• Thermal breeder reactor The excellent neutron
capture characteristics of fissile uranium-233 make it
possible to build a moderated reactor that, after its
initial fuel charge of enriched uranium, plutonium,
requires only thorium as input to its fuel cycle.
Thorium-232 produces uranium-233 after neutron
capture and beta decay.
12. The most common breeding reaction is that
of plutonium-239 from non-fissionable
uranium-238.
The term "fast breeder" refers to the types
of configurations which can actually produce
more fissionable fuel than they use, such as
the LMFBR(Liquid metal fast breeder reactor).
It is possible because the non-fissionable
uranium-238 is 140 times more abundant than
the fissionable U-235 and can be efficiently
converted into Pu-239 by the neutrons from a
fission chain reaction.
FAST BREEDING REACTION
15. Uranium is a naturally-occurring element in the Earth's
crust.
Traces of it occur almost everywhere, although mining
takes place in locations where it is naturally
concentrated.
.
Uranium mines operate in some twenty countries,
though about half of world production comes from just
ten mines in six countries, in Canada, Australia, Niger,
Kazakhstan, Russia and Namibia.
Uranium is the primary fuel for nuclear reactor.
SOURCE OF FUEL
16. PRODUCTION OF NUCLEAR FUELS
To make nuclear fuel from the uranium ore requires first for
the uranium to be extracted from the rock in which it is found,
then enriched in the uranium-235 isotope, before being made
into pellets that are loaded into assemblies of nuclear fuel
rods.
At conventional mines, the ore goes through a mill where it is
first crushed. It is then ground in water to produce a slurry of
fine ore particles suspended in the water. The slurry is leached
with sulphuric acid to dissolve the uranium oxides, leaving the
remaining rock and other minerals undissolved, as mine
tailings
Contd...,
17. PRODUCTION OF NUCLEAR FUELS
However, nearly half the world's mines now use a mining
method called in situ leaching . This means that the mining is
accomplished without any major ground disturbance.
Groundwater with a lot of oxygen injected into it is circulated
through the uranium ore, extracting the uranium. The
solution with dissolved uranium is pumped to the surface.
Both mining methods produce a liquid with uranium dissolved
in it. This is filtered and the uranium then separated by ion
exchange, precipitated from the solution, filtered and dried to
produce a uranium oxide concentrate, which is then sealed in
drums. This concentrate may be a bright yellow colour, hence
known as 'yellowcake', or if dried at high temperatures it is
khaki.
The uranium oxide is only mildly radioactive
18. ENRICHMENT
The vast majority of all nuclear power reactors require 'enriched' uranium
fuel in which the proportion of the uranium-235 isotope has been raised
from the natural level of 0.7% to about 3.5% to 5%. The enrichment
process needs to have the uranium in gaseous form, so on the way from
the mine it goes through a conversion plant which turns the uranium oxide
into uranium hexafluoride.
The enrichment plant concentrates the useful uranium-235, leaving about
85% of the uranium by separating gaseous uranium hexafluoride into two
streams: One stream is enriched to the required level of uranium-235 and
then passes to the next stage of the fuel cycle. The other stream is
depleted in uranium-235 and is called 'tails' or depleted uranium. It is
mostly uranium-238 and has little immediate use.
Today's enrichment plants use the centrifuge process, with thousands of
rapidly-spinning vertical tubes. Research is being conducted into laser
enrichment, which appears to be a promising new technology
20. FABRICATION OF FUEL
• Fuel fabrication is the last step in the process
of turning uranium into nuclear fuel rods.
• Batched into assemblies, the fuel rods form
the majority of a reactor core's structure.
Nuclear fuel assemblies are specifically
designed for particular types of reactors and
are made to exacting standards.
• Utilities and fabricators have collaborated to
greatly improve fuel assembly performance,
and an international accident-tolerant fuel
program is under way.
uranium dioxide powder is pressed,to form
small fuel pellets, which are then heated to
make a hard ceramic material. The pellets are
then inserted into thin tubes to form fuel rods.
These fuel rods are then grouped together to
form fuel assemblies, which are several meters
long.
