Uranium is a naturally occurring radioactive metal that is mined from the earth's crust. The nuclear fuel cycle involves mining uranium ore, milling it into yellowcake, converting yellowcake into uranium hexafluoride gas, enriching the gas to increase the percentage of fissile uranium-235 isotope, fabricating enriched uranium into fuel rods, using the rods in nuclear reactors to produce energy via fission, and reprocessing or storing spent fuel rods. Pakistan has uranium reserves that are mined primarily using in situ leaching. The main use of uranium is to fuel nuclear power plants, but it also has applications in dating the age of the earth, powering naval vessels, and producing
2. CONTENTS
What is Uranium
Production Of Uranium
Nuclear Fuel Cycle
Uranium in Pakistan
Applications of Uranium
Conclusions
3. WHAT IS URANIUM???
Uranium is a silvery-white metallic
element in the actinide series of the
periodic table . It has a symbol U and
atomic number 92. A uranium of the
51st abundant element in the Earth's
crust
4. HISTORY OF URANIUM
Uranium was discovered in 1789 by Martin Klaproth, a
German chemist, who isolated an oxide of uranium
while analyzing pitchblende samples
Uranium was named after the planet Uranus, in 1791.
5. CONT…
Antoine Henri Becquerel discovered radioactivity by using
uranium in 1896.
It was discovered in 1938 that uranium could be split to release
energy that is fission. This was accomplished by Otto Hahn and
Fritz Strassman.
6. CHARACTERISTICS OF URANIUM
•Uranium is weakly radioactive metal.
•It is malleable, ductile, slightly paramagnetic.
• Strongly electropositive and is a poor electrical conductor.
• Uranium metal has very high density
•. Uranium-235 was the first isotope that was found to be fissile.
•Uranium-235 can be used to make an atomic bomb. The first nuclear
bomb used in war relied on uranium fission.
7. ISOTOPES OF URANIUM
In nature, uranium is found as uranium-238 (99.2739–
99.2752%), uranium-235 (0.7198–0.7202 %), and a very
small amount of uranium-234 (0.0050–0.0059%). The three
naturally occurring isotopes of uranium are each radioactive
8. CONT..
In a typical sample of natural
uranium, most of the mass
(99.3%) would consist of atoms
of U-238, and a very small
portion of the total mass (0.7%)
would consist of atoms of U-235.
9. PRODUCTION OF URANIUM
Nuclear fuel cycle
The nuclear fuel cycle is the series of industrial processes which
involve the production of uranium and use in nuclear energy power
reactors. It involves
Mining of Uranium
Milling of Uranium
Enrichment of Uranium
Fabrication
Reprocessing of used fuel
11. MINING OF URANIUM
The process or business of extracting the precious or valuable
metals from the earth either in their native state or in their ores is
called mining.
. Mining of Uranium can be;
Underground mining
Open pit mining
In situ leaching
12. MILLING OF URANIUM
Process of conversion of extracted uranium ore to a usable
form called yellow cake is called milling
.
The ore is first crushed to a fine powder by passing raw uranium
ore through crushers and grinders. This is further processed with
concentrated acid, alkaline, or peroxide solutions to leach out the
uranium. Yellowcake is what remains after drying and filtering.
13. CONVERSION OF YELLOW CAKE TO UF6
Yellow cake is converted into UF6 through series of chemical
reactions because in enrichment Uf6 will b used.
14. ENRICHMENT OF URANIUM
Uranium enrichment is the technology in which percent
composition of uranium-235 is increased through different
processes.
Because Uranium-235 is the only naturally occurring fissile
isotope .Natural uranium is 99.284% 238U isotope, with 235U
only constituting about 0.711% of its weight.
16. METHODS OF ENRICHMENT
Gaseous diffusion.
Gas centrifuge
Electromagnetic separation
Laser enrichment
17. CONT..
Gas centrifuge
Principle
Rotation of cylinders creates a strong centrifugal force which
moves the the heavier gas molecules containing U 238 to outside
of cylinder and lighter U235 molecules collect closer to the center.
19. CONT..
Gaseous Diffusion
Principle
Gaseous diffusion forces uranium hexafluoride gas through series
of semi-permeable membranes which separates the isotopes from
each other; The lighter, smaller U-235 moves through the
membrane easier than the larger heavier U-238
21. CONT..
Electromagnetic separation.
In the electromagnetic isotope separation process (EMIS),
metallic uranium is first vaporized, and then ionized to positively
charged ions. The cations are then accelerated and
subsequently deflected by magnetic fields onto their respective
collection targets (like mass spectrometry)
23. FUEL FABRICATION
Fuel fabrication convert enriched UF6 into fuel for nuclear
reactors. (UO2) The UO2 powder is pressed into fuel pellets.The
pellets are then encased in metal tubes to form fuel rods, which
are then arranged into a fuel assembly and ready for introduction
into a reactor.
24. REACTOR
Inside a nuclear reactor the nuclei of uranium-235 atoms split
(fission) and, in the process, release energy. This energy is used
to heat water and turn it into steam. The steam is used to drive a
turbine connected to a generator that produces electricity. The
fissioning of uranium is used as a source of heat in a nuclear
power plant in the same way that the burning of coal, gas or oil is
used as a source of heat in a fossil fuel power plant
25. USED FUEL
After 12-24 months the 'spent fuel' is removed from the reactor
because it is no longer practical to continue to use as a fuel
.The amount of energy produced from a fuel bundle varies with
the type of reactor and the policy of the reactor operator.
Typically, some 46 million kilowatt-hours of electricity are
produced from one tonne of natural uranium. The production of
this amount of electrical power from fossil fuels would require
the burning of over 20,000 tonnes of black coal or 8.5 million
cubic metres of gas.
26. REPROCESSING
Used fuel is about 95% uranium-238 but it also contains up to 1%
uranium-235 that has not fissioned, about 1% plutonium and 3%
fission products
In a reprocessing facility the used fuel is separated into its three
components: uranium, plutonium and waste, by chopping up the
fuel rods and dissolving them in acid to separate the various
materials.
It enables recycling of the uranium and plutonium into fresh fuel,
and produces a significantly reduced amount of waste
27. ..
Uranium recycling
The uranium recovered from reprocessing, which typically
contains a slightly higher concentration of U-235 than occurs in
nature, can be reused as fuel after similar ways of conversion and
enrichment.(as described above).
Cont
28. URANIUM RESERVES IN PAKISTAN
Baghalchore
Uranium was discovered in May 1959 by the Geological Survey
of Pakistan at Bagalchore (Bagalchur), near Dera Ghazi
Khan, in the southern part of the province of Punjab.
Ore grade at Bagalchore was initially described as ranging from
0.05–0.5 percent, with an average of approximately 0.15 percent
uranium.
The Bagalchore mine was reported to be nearly exhausted by
1998.
29. CONT..
A second uranium mine was opened at Qabul Khel in 1992, and
mining of deposits at the Nangana and Taunsa deposits (both
located near Dera Ghazi Khan) started in 1996 and 2002
respectively, all using in situ leaching technology.
30. APPLICATIONS OF URANIUM
The main use of uranium is to fuel nuclear plants. One kilogram
of U-234 can produce about 80 terajoules of energy
(8×1013 joules) assuming complete fission
Before the discovery of radioactivity, uranium was primarily used
in small amounts for yellow glass and pottery glazes.
Uranium was also used in photographic chemicals especially
uranium nitrate as a toner, in lamp filaments.
31. CONT…
Because of its long half life it is being used in dating the age of the
earth.
Uranium metal is used as a target for high-powered x-ray
machines.
Uranium is used to power nuclear powered submarines and ships.