Nuclear fission is a process by which certain heavy atomic nuclei split into two, most often after collision with a neutron. The process produces heat and also releases neutrons; these neutrons can go on to cause further fissions, allowing a chain reaction to be sustained. Fission is the basic reaction that underlies our use of nuclear energy.

1. Applications Of Nuclear Energy
Mohamed Gamal Mohamed Salem

2. Introduction
• Nuclear fission is a process by which certain heavy atomic nuclei split into
two, most often after collision with a neutron. The process produces heat and
also releases neutrons; these neutrons can go on to cause further fissions,
allowing a chain reaction to be sustained. Fission is the basic reaction that
underlies our use of nuclear energy.
• Most of the energy produced by nuclear fission appears as heat in the nuclear
reactor core and this heat is transported away from the core by conventional
methods, namely by means of a cooling liquid or gas. The rest of the power
generation system is almost identical in type to the way in which heat is
utilized in any other generating station whether powered by coal, oil, gas or
sunlight. Often the heat is used to produce steam which is then fed to a steam
turbine that drives electric generators.
• In some plants hot gas rather than steam is used to drive the turbines. In
the case of steam generating nuclear power plants the part of the plant
that consists of the reactor and the primary or first-stage cooling systems
(pumps, heat exchangers, etc.) is known as the nuclear steam supply
system and the rest, the conventional use of the steam, is called the
balance of plant . This monograph will not deal with this conventional
power generation technology but will focus on the nuclear reactor, its
production of heat and the primary coolant loop that cools the reactor
core.
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3. Main components of nuclear reactors
• A nuclear power plant comprises a number of systems and components, including the
reactor itself and the so-called conventional island or turbine hall, that together are
designed to harness and control the energy of nuclear fission, and to turn it into electricity
.Though there are many types of nuclear reactors, they have several components in
common: fuel, moderator, coolant and control rods.
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4. • 1 – Reactor : fuel (light blue) heats up pressurized water.
Control rods (grey) absorb neutrons to control or halt the
fission process.
• 2 – Coolant and moderator: fuel and control rods are
surrounded by water (primary circuit) that serves as coolant
and moderator.
• 3 – Steam generator: water heated by the nuclear reactor
transfers heat through thousands of tubes to a secondary
circuit of water to create high-pressure steam.
• 4 – Turbo-generator set: steam drives the turbine, which
spins the generator to produce electricity.
• 5 – Condenser: removes heat to convert steam back to
water, which is pumped back to the steam generator.
• 6 – Cooling tower: removes heat from the cooling water
that circulated through the condenser, before returning it
to the source at near-ambient temperature.8 August 2018 4

5. • Nuclear fuel
 Uranium is the only fissile material found in nature; hence,
almost all reactors use uranium fuel. As noted above, 238U
makes up more than 99% of natural uranium, with most of the
remainder (0.71%) being 235U. The latter easily fissions after
absorbing either a thermal or a fast neutron. Most uranium for
use in nuclear fuel is “enriched” so as to contain a higher
concentration of 235U than found in nature, typically in the
range of 2-5%.
 238U fissions relatively rarely, only after absorbing a fast
neutron of a particular energy. More commonly neutron capture
occurs, eventually transforming 238U into 239Pu. This isotope of
plutonium is able to fission with thermal or fast neutrons.
Hence, as nuclear fuel is irradiated in a reactor the fission of
239Pu contributes a growing proportion of the energy output
(eventually up to 30%). Some reactors also use fuel in which
plutonium extracted from spent fuel is blended with depleted
uranium. This fuel is called mixed-oxide fuel (MOX); in this case
the fission of 239Pu is the main source of energy production.
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6. • Moderator
 A moderator is necessary in most reactors to slow down the fast neutrons
created during fission to the thermal energy range so as to increase their
efficiency in causing further fissions. The moderator must be a light material
that will allow the neutrons to slow down through collisions without being
captured. In most reactors, ordinary (or “light”) water is used. Other
moderators used in some less common reactor types are graphite and heavy
water (water formed with the heavier deuterium isotope of hydrogen). Fast
reactors, based on fission of plutonium fuel by fast neutrons, do not have a
moderator.
• Coolant
 The coolant circulates through the reactor core to absorb and remove the heat
produced by nuclear fission, thus maintaining the temperature of the fuel
within normal limits. It transfers this heat to the turbine-generator system to
produce electricity. If water is used as the coolant, steam can be produced
directly by the reactor and fed to the turbines, this is the concept of a boiling
water reactor. Alternatively, heated water from the reactor can be passed
through heat-exchangers (steam generators) which produce steam for the
turbines as in a pressurized water reactor. Other coolants in use in some
reactor types are heavy water and gases such as carbon dioxide or helium.
Designs for some advanced reactors use molten metals such as sodium, lead or
alloys of lead as the coolant.
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7. • Control rods
Control rods are made of materials that absorb neutrons,
for example, boron, silver, indium, cadmium and hafnium.
In normal operation, their position in the reactor core is
adjusted to regulate the number of neutrons available for
fission and thus to control the level and spatial distribution
of power in the reactor. In an emergency, the control rods
can be rapidly inserted by operators or by automatic
systems to shut down the reactor.
• Turbine
 The turbine is connected to an electric generator with a
revolving axel in a compartment located above the steam
generator. Since the energy from the water is converted
into steam, the steam rises and pushes the blades of
multiple turbines. This process spins the turbines which
causes a powerful magnet inside the generator to also
spin. This, as a result, produces electricity
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8. Reactor types in use worldwide
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9. • Pressurised water reactors
• Ordinary water is used as both coolant and moderator. The coolant is kept at
high pressure (about 15.5 MPa or 2 250 psi) to keep it as a liquid. It is contained
within the pressure boundary formed by the reactor pressure vessel and piping
in the primary coolant system, and is circulated through the core using powerful
pumps. Heat is transferred within steam generators to a separate, secondary
coolant circuit, where water is boiled to create steam. This steam drives the
electricity producing turbine generators.
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10. • Boiling water reactors
• There were 92 BWRs in operation worldwide at the end of 2010. As in PWRs,
ordinary water acts as both coolant and moderator. The coolant is kept at a
lower pressure than in a PWR (about 7 Mpa or 1 000 psi) allowing it to boil as it
absorbs heat from the reactor. The resultant steam is passed directly to the
turbine generators to produce electricity (see Figure 2.6). While the absence of
steam generators simplifies the design, the absence of a secondary circuit can
result in some radioactive contamination of the turbine.
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11. 8 August 2018 11

12. Application of Nuclear Power
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13. Medical applications
• There are many applications of radiation in the medical field, ranging from
diagnostics, to treatment and disease management. Many of these use
radioactive elements (more specifically radio isotopes) produced from either
reactors or cyclotrons.
• Necsa through NTP is one of the world’s leading supplier of radioactive
elements and is playing the leading role in supporting the practice of nuclear
medicine globally. iThemba Laboratory for Accelerator Based Sciences also
provides facilities for treatment of cancers using neutron and proton therapy.
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14. • X-ray image, and 3 dimensional CT scan
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15. Medical Diagnosis and Therapy
• Positron Emission Tomography (PET) study
metabolism, brain and heart functions uses
radioisotopes (positron emitters such as
fluorine-18)
beating heart brain scan
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16. Industrial Applications
• Industries around the world use radioactive materials in a
variety of ways to improve productivity and safety, and to
obtain information that could not be obtained in other
ways. The applications include fields such as civil
engineering, materials analysis, measuring devices, process
control in factories, oil and mineral exploration, and
checking oil and gas pipelines for leaks and weaknesses.
These uses directly and indirectly influence our everyday
lives.
• For example, measuring devices containing radioactive
materials are used in tasks such as:
 testing the moisture content of soil during road
construction,
 measuring the thickness of paper and plastics during
manufacturing,
 checking the height of fluid when filling bottles in factories.
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17. • Self luminous light source based on radioactive
element Tritium8 August 2018 17

18. Agricultural Applications
 In agriculture, radioactive materials are used to improve food
crops, preserve food, and control insect pests. They are also used
to measure soil moisture content, erosion rate and the efficiency
of fertilizer uptake.
 Food irradiation
 The use of gamma rays and electron beams in irradiating foods to
control disease causing micro-organisms and to extend shelf life
of food products is growing through out the world.
 Insect control
 Radioisotopes assist in enhancing food production. One method is
the control of insects, including the control of screw worms, fruit
flies and tsetse flies, is through the Sterile Insect Technique. The
tsetse fly causes the transmission of a parasitic disease,
trypanosomiasis, which slowly destroys livestock herds in sub
Saharan Africa. It also causes the spread of the human form of the
disease, known as sleeping sickness. Diseases transmitted by
tsetse flies kill over 250,000 people per year.
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19. Archaeological Applications
• Archaeological findings can be dated by
measuring their natural radioactivity using a
technique called carbon dating, which is based
on measuring the radiation release profile of the
materials.
• This is a useful tool in geological, anthropological
and archaeological research
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20. Radioactive dating (archeology)
• carbon-14 “clock”
• carbon-14 (β- decay):T1/2 = 5,730
years
• Determine the age of ancient
organic (carbon-based) materials
such as wood, bones or cloth.
Useful for times t < 10 * T1/2 (
about 50,000 years).
Egyptian mummy
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21. Consumer Products
• Smoke Detector
• Ionization of air by a radioactive source produces a current.
• Smoke traps the electrons and reduces the current.
• Setting off the alarm.
• Many smoke detectors installed in nearly 90percent of U.S.
homes—rely on a tiny radioactive source to sound an alarm when
smoke is present.
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22. Space
• Unmanned spacecraft rely on radioisotope thermoelectric generators(RTGs)for
the power they need for space exploration.
• RTGs use heat from Plutonium to generate electricity.
• The craft use this electricity to run the computers that control their operation
and collect and process the vast amounts of data, including images, that are
sent back to Earth.
• A typical RTG produces about 300 watts of electricity and will operate
unattended form any years.
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23. References
• nuclear energy today
https://www.oecd-nea.org/pub/nuclearenergytoday/6885-
nuclear-energy-today.pdf
• Nuclear Power Generation
https://www.nrc.gov/reading-rm/basic-ref/students/for-
educators/01.pdf
• Nuclear power plant – Wikipedia
https://en.wikipedia.org/wiki/Nuclear_power_plant
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