2. • A nuclear power plant (NPP) is a thermal
power station in which the heat source is one
or more nuclear reactors. As in a conventional
thermal power station the heat is used to
generate steam which drives a steam turbine
connected to a generator which produces
electricity.
3. SYSTEMS IN NUCLEAR POWER PLANT
Nuclear reactors
Steam turbine
Generator
Cooling system
Safety valves
Feedwater pump
Emergency power supply
4. People in a nuclear power plant
• Nuclear engineers
• Reactor operators
• Health physicists
• Emergency response team personnel
• Nuclear Regulatory Commission Resident
Inspectors
5. Plant location
• In many countries, plants are often located on the coast, in
order to provide a ready source of cooling water for the
essential service water system.
• As a consequence the design needs to take the risk of
flooding and tsunamis into account.
• The World Energy Council (WEC) argues disaster risks are
changing and increasing the likelihood of disasters such as
earthquakes, cyclones, hurricanes, typhoons, flooding.
• Climate change and increased temperatures, lower
precipitation levels and an increase in the frequency and
severity of droughts may lead to fresh water shortages.
• Seawater is corrosive and so nuclear energy supply is likely
to be negatively affected by the fresh water shortage.
• This generic problem may become increasingly significant
over time.
6. nuclear safety systems
• The three primary objectives of nuclear safety
systems as defined by the Nuclear Regulatory
Commission are to shut down the reactor,
maintain it in a shutdown condition, and prevent
the release of radioactive material during events
and accidents.
• These objectives are accomplished using a variety
of equipment, which is part of different systems,
of which each performs specific functions
7. ADVANTAGES OF NUCLEAR POWER PLANTS
1. Almost 0 emissions (very low greenhouse gas emissions).
They can be sited almost anywhere unlike oil which is
mostly imported.
2. The plants almost never experience problems if not from
human error, which almost never happens anyway because
the plant only needs like 10 people to operate it.
A small amount of matter creates a large amount of energy.
3. A lot of energy is generated from a single power plant.
4. Current nuclear waste in the US is over 90% Uranium. If
reprocessing were made legal again in the US we would
have enough nuclear material to last hundreds of years.
5. A truckload of Uranium is equivalent in energy to 10,000+
truckloads of coal. (Assuming the Uranium is fully utilized.)
8. • A nuclear aircraft carrier can circle the globe
continuously for 30 years on its original fuel while a
diesel fueled carrier has a range of only about 3000
miles before having to refuel.
• Modern reactors have two to ten times more
efficiency than the old generation reactors currently in
use around the US.
• New reactor types have been designed to make it
physically impossible to melt down. As the core gets
hotter the reaction gets slower, hence a run-away
reaction leading to a melt-down is not possible.
• Theoretical reactors (traveling wave) are proposed to
completely eliminate any long-lived nuclear waste
created from the process
9. • Breeder reactors create more usable fuel than they
use.
• Theoretical Thorium reactors have many of the
benefits of Uranium reactors while removing much
of the risk for proliferation as it is impossible to get
weapons-grade nuclear materials from Thorium.
10. DISADVANTAGES OF NUCLEAR POWER
PLANT
• Nuclear plants are more expensive to build and maintain.
Proliferation concerns - breeder reactors yield products that
could potentially be stolen and turned into an atomic weapon.
Waste products are dangerous and need to be carefully stored
for long periods of time.
• The spent fuel is highly radioactive and has to be carefully
stored for many years or decades after use.
• This adds to the costs.
• There is presently no adequate safe long-term storage for
radioactive and chemical waste produced from early reactors,
such as those in Hanford, Washington, some of which will
need to be safely sealed and stored for thousands of years.
11. • A lot of waste from early reactors was stored in containers
meant for only a few decades, but is well past expiration
and, resultingly, leaks are furthering contamination.
• Nuclear power plants can be dangerous to its surroundings
and employees. It would cost a lot to clean in case of
spillages.
• There exist safety concerns if the plant is not operated
correctly or conditions arise that were unforeseen when the
plant was developed, as happened at the Fukushima plant in
Japan; the core melted down following an earthquake and
tsunami the plant was not designed to handle despite the
world's strongest earthquake codes.
• Many plants, including in the U.S., were designed with the
assumption that "rare" events never actually occur, such as
strong earthquakes on the east coast (the New Madrid
quakes of the 1800s were much stronger than any east coast
earthquake codes for nuclear reactors;
12. • A repeat of the New Madrid quakes would exceed the
designed earthquake resiliency for nuclear reactors over a
huge area due to how wide-spread rare but dangerous
eastern North American earthquake effects spread), Atlantic
tsunami (such as the 1755 Lisbon quake event, which sent
significant tsunami that caused damage from Europe to the
Caribbean) and strong hurricanes which could affect areas
such as New York that are unaccustomed to them (rare, but
possibly more likely with global warming)
• Mishaps at nuclear plants can render hundreds of square
miles of land uninhabitable and unsuitable for any use for
years, decades or longer, and kill off entire river systems
13. NUCLEAR WASTE MANAGEMENT
• All parts of the nuclear fuel cycle produce some
radioactive waste (radwaste).
• The cost of managing and disposing of these wastes
is part of the electricity cost, i.e., it is internalized and
paid for by the electricity consumer.
14. • At each stage of the fuel cycle there are
proven technologies to dispose of the
radioactive wastes safely.
• For low- and intermediate-level wastes these
are mostly being implemented. For high-level
wastes some countries await the
accumulation of enough of it to warrant
building geological repositories,
15. • The radioactivity of all nuclear waste decays with time. Each
radionuclide contained in the waste has a half-life - the time taken
for half of its atoms to decay and thus for it to lose half of its
radioactivity.
• Radionuclides with long half-lives tend to be alpha and beta
emitters - making their handling easier - while those with short
half-lives tend to emit the more penetrating gamma rays.
• Eventually, all radioactive wastes decay into non-radioactive
elements.
• The main objective in managing and disposing of radioactive (or
other) waste is to protect people and the environment. This means
isolating or diluting the waste so that the rate or concentration of
any radionuclides returned to the biosphere is harmless.
• To achieve this, practically all wastes are contained and managed -
some need deep and permanent burial - so that harmful pollution is
avoided. From nuclear power generation, none is allowed to cause
harmful pollution.
17. Mine tailings
• Traditional uranium mining generates fine sandy tailings,
which contain virtually all the naturally occurring radioactive
elements found in uranium ore.
• These are collected in engineered tailings dams and finally
covered with a layer of clay and rock to inhibit the leakage of
radon gas and ensure long-term stability.
• In the short term, the tailings material is often covered with
water. After a few months, the tailings material contains
about 75% of the radioactivity of the original ore.
• Strictly speaking these are not classified as radioactive wastes.
18. Exempt Waste & Very Low Level Wastes (VLLW)
• Radioactive waste which contains radioactive materials at a
level which is not considered harmful to people or the
surrounding environment.
• It consists mainly of demolished material (such as concrete,
plaster, bricks, metal, valves, piping etc) produced during
rehabilitation or dismantling operations on nuclear
industrial sites.
• Other industries, such as food processing, chemical, steel
etc also produce VLLW as a result of the concentration of
natural radioactivity present in certain minerals used in their
manufacturing processes (see also paper on NORM).
• The waste is therefore disposed of with domestic refuse,
although countries such as France are currently developing
facilities to store VLLW in specifically designed VLLW disposal
facilities.
19. Low-level Wastes (LLW)
• Generated from hospitals and industry, as well as the nuclear
fuel cycle.
• It comprises paper, rags, tools, clothing, filters, etc. that
contain small amounts of mostly short-lived radioactivity.
• These wastes do not require shielding during handling and
transport and are suitable for shallow land burial.
• To reduce the waste's volume, it is often compacted or
incinerated before disposal.
• LLW comprises some 90% of the volume but only 1% of the
radioactivity of all radwaste.
20. Intermediate-level Wastes (ILW)
• contains higher amounts of radioactivity and some requires
shielding, usually of lead, concrete or water. It typically
comprises resins, chemical sludges, and metal fuel cladding,
as well as contaminated materials from reactor
decommissioning.
• Smaller items and any non-solids may be solidified in concrete
or bitumen for disposal.
• ILW makes up some 7% of the volume and has 4% of the
radioactivity of all radwaste.
• The maintenance of a 1000 MWe nuclear reactor produces
less than 0.5m3 of long-lived ILW each year. If fuel is
reprocessed this is increased to 3m3.
21. High-level Wastes (HLW)
Rise from the "burning" of uranium fuel in nuclear reactors. HLW
contains the fission products and transuranic elements
generated in the reactor core. It is highly radioactive and hot,
so requires cooling and shielding.
It can be considered as the "ash" from "burning" uranium. These
wastes contain the fission products and transuranic elements
generated in the reactor core.
It is highly radioactive and hot and thus requires cooling and
shielding. HLW accounts for over 95% of the total radioactivity
produced in the process of electricity generation. There are
two distinct kinds of HLW:
1. used fuel itself in fuel rods, or separated waste from
2.reprocessing the used fuel
22. Alternative energy
Solar energy
• Solar energy is generating of electricity from the sun. It is split
up into two types, thermal and electric energy. These two
subgroups mean that they heat up homes (and water) and
generate electricity respectively.
Wind energy
• Wind energy is generating of electricity from the wind.
Geothermal energy
• Geothermal energy is using hot water or steam from the
Earth’s interior for heating buildings or electricity generation.
Biofuel and ethanol
• Biofuel and ethanol are plant-derived substitutes of gasoline
for powering vehicles.
24. The Future of Nuclear Energy
• Some people think that nuclear energy is here to
stay and we must learn to live with it.
• Others say that we should get rid of all nuclear
weapons and power plants. Both sides have their
cases as there are advantages and disadvantages
to nuclear energy.
• Still others have opinions that fall somewhere in
between.
• What do you think we should do? After reviewing
the pros and cons, it is up to you to formulate
your own opinion.
