me165 1_week 10.1 nuclear energy

8/17/2019 ME165 1_Week 10.1 Nuclear Energy

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ME165-

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ALTERNATIVE ENERGY RESOURCES

Engr

Week-10.1 Nuclear Energy2015-2016 / 3T


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NUCLEAR ENERGY

Nuclear power, is it renewable?

Nuclear power is renewable as it doesn't use fossil fue

non-renewable resources in the production of energy; h

isn't as renewable as some of the alternatives, such as

solar power, which rely solely on natural phenomena to

their power. In the short term it is unlikely that uranium will run out

eventually it will.

Therefore we can say that nuclear power is only renew

short term.


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NUCLEAR ENERGY

Nuclear Energy

Nuclear energy comes from the energy stored inside th

of an atom.

Atoms are tiny - much too small to be seen even under

powerful microscope – but they make up everything in

around us.Nuclear energy is produced when an atomic nucleus is

when two light atomic nuclei are joined.

The energy released from either process – is so enorm

is the the soure of nuclear power.


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NUCLEAR ENERGY

Brief History

The pursuit of nuclear energy for electricity generation began s

discovery in the early 20th century that radioactive elements, s

radium, released immense amounts of energy, according to th

mass–energy equivalence. However, means of harnessing suc

impractical, because intensely radioactive elements were, by t

nature, short-lived (high energy release is correlated with short This situation changed in the late 1930s, with the discovery of

fission.

In 1932, James Chadwick discovered the neutron, which was i

recognized as a potential tool for nuclear experimentation beca

lack of an electric charge.


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NUCLEAR ENERGY

Brief History (cont’d.)

In 1934, Frédéric and Irène Joliot-Curie discovered induced radio

bombarding materials with neutrons.

Further work by Enrico Fermi in the 1930s focused on using slow

increase the effectiveness of induced radioactivity. Bombarding u

neutrons in his experiments, led Fermi to believe he had created

transuranic element, which was dubbed hesperium.

But in 1938, German chemists Otto Hahn and Fritz Strassmann, Austrian physicist Lise Meitner and Otto Robert Frisch, conducted

with the products of neutron-bombarded uranium, as a means of

investigating Fermi's claims. They determined that the relatively t

the nucleus of the massive uranium atoms into two roughly equa

contradicting Fermi. The process was dubbed "fission" — involved

rupture of the nucleus.


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NUCLEAR ENERGY


In 1939, Frédéric Joliot-Curie experimentally confirmed and annoprevious finding that if fission reactions released additional neut

sustaining nuclear chain reaction could result. Many countries (i

United States, the United Kingdom, France, Germany, and the So

petitioned their governments for support of nuclear fission resea

the cusp of World War II, for the development of a nuclear weapo

In the United States, the first man-made reactor, known as Chicag

achieved criticality on December 2, 1942. This work became par

Manhattan Project, which made enriched uranium and built large

breed plutonium for use in the first nuclear weapons, which were

cities of Hiroshima and Nagasaki.


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NUCLEAR ENERGY


After WWII, work in the United States, United Kingdom, Canada, aproceeded over the course of the late 1940s and early 1950s.

Electricity was generated for the first time by a nuclear reactor in 1

EBR-I experimental station in Idaho, which initially produced abou

Work was also strongly researched in the US on nuclear marine pr

eventually, the USS Nautilus, the first nuclear-powered submarinein 1955.

In 1953, US President Dwight Eisenhower gave his "Atoms for Pea

the United Nations, emphasizing the need to develop "peaceful" u

power quickly.

http://www.youtube.com/watch?v=VJfIbBDR3

http://www.youtube.com/watch?v=VJfIbBDR3e8http://www.youtube.com/watch?v=VJfIbBDR3e8


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NUCLEAR ENERGY


This was followed by the 1954 Amendments to the Atomic Energyallowed rapid declassification of U.S. reactor technology and enco

development by the private sector.


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NUCLEAR ENERGY

Processes

Nuclear energy is produced naturally and in man-made ounder human control.

Naturally :

Some nuclear energy is produced naturally.

For example, the Sun and other stars make heat and light by nuclear re

Man-Made: Nuclear energy can be man-made too.

Machines called nuclear reactors, parts of nuclear power plants, provi

many cities.

Man-made nuclear reactions also occur in the explosion of atomic and

bombs.


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NUCLEAR ENERGY

Processes (cont’d.)

Nuclear energy is produced in two different ways. In one method;are split to release energy, known as nuclear fission. In the othe

small or light nuclei are combined to release energy, known as nu

Nuclear Fission

In nuclear fission, the nucleus of an atom is split, causing

released. Inside the nucleus of an atom, some of the masform of “binding energy”, the energy needed to hold the nu

together.


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NUCLEAR ENERGY

Schematic Diagram of a

Nuclear Fission/Chain React

As shown in the diagram,

(1) if a slow-moving neutron strikes a

uranium atom, the atom’s nucleus

absorbs the neutron.

(2) The nucleus becomes so unstable that

it breaks apart. The result is two large

fission products, three neutrons and a

burst of energy.

(3) Also, once a uranium nucleus is split,the multiple neutrons that are

released are used to split other

uranium nuclei.

This phenomenon is known as a chain

reaction.


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NUCLEAR REACTION - FISSION

Uranium-235 (235U) Fission


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NUCLEAR ENERGY

Processes (cont’d.)

Nuclear FusionFusion, the exact opposite of fission, occurs by joining two lig

one heavier nucleus, and clean nuclear energy is given off w

Fusion could produce a self sustaining energy source. Howe

a thermonuclear reaction, can starts only at a very high tem

millions of degrees – even hotter than the sun.

Such intense heat destroys anything on earth that tries to ho

it, and a heat source that hot is hard to control.

The hydrogen bomb, a fusion reaction designed to explode,

atomic fission bomb to get it started. Clearly, that would not

trigger for a fusion power station.


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NUCLEAR ENERGY

Schematic Diagram

Nuclear FusionFusion of deuterium with tritium creating

helium-4, freeing a neutron, and

releasing 17.59 MeV of energy, as an

appropriate amount of mass changing

forms to appear as the kinetic energy of

the products, in agreement with kinetic E

= Δmc2, where Δm is the change in restmass of particles.


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NUCLEAR REACTION - FUSION

Hydrogen Fusion Reactions


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TECHNOLOGIES

Nuclear Reactorhttp://www.youtube.com/watch?v=VJfIbBDR3e8

http://www.youtube.com/watch?v=VJfIbBDR3e8http://www.youtube.com/watch?v=VJfIbBDR3e8


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TECHNOLOGIES

Nuclear Reactor

The central structure of a nuclear power plant is the rea

The reactor in a nuclear power plant does the same thin

boiler does in a fossil fuel plant - it produces heat.

The basic parts of a reactor are the core, a moderator , c

a coolant, and shielding .The core of a reactor contains the uranium fuel. For a

reactor with an output of 1,000 megawatts, the core

contain about 75 tons of uranium enclosed in approx

200 fuel assemblies.


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TECHNOLOGIES

Nuclear Reactor (cont’d.)

The neutrons produced by fission are travelling at greand in most reactors, are deliberately slowed down by

known as a moderator .

Slow neutrons are much more likely, when they co

the nuclei of U-235, to cause a fission and keep th

going.

A moderator is composed of light atoms and the m

most commonly used are carbon in the form of gra

water.


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TECHNOLOGIES


For more precise control of the chain reaction, contro

inserted into the core of the reactor. Pushed in, they a

neutrons and slow down the reaction - pulled out they

speed up again. In this way the chain reaction is cont

The rods are usually made of boron, which absorbs

A separate set of shutdown rods can be inserted in

to stop the reactions quickly if there is an emergen


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TECHNOLOGIES


Fissions occurring in the reactor generate an enormoof heat. A liquid or gas coolant carries this heat awa

reactor to a boiler where steam is made.

Shielding , typically made of steel and concrete about

thick, is an outer casing that prevents radiation from

into the environment.


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KINDS OF NUCLEAR REACTORS

There are several different kinds of nuclear reactors, altho

work in a similar way. Following are some of them: Pressurize Water Reactors

Boiling Water Reactors

Heavy Water Reactors

High-Temperature Gas-Cooled ReactorsOrganic-Cooled Reactors

Fast Breeder Reactors


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Pressurize Water Reactor (PWR)

PWR Schematic Diagram


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Pressurize Water Reactors operation

o The PWR has three water loops separated from one another that water in each loop never touch or sees the water in the

while the heat is transferred from one loop to another.

o In this kind of reactor, water in the first loop flows through th

core, where it is heated by nuclear fission.

The water in this first loop is kept under pressure so that itmuch like the water in a home pressure cooker.

When heated, this pressurized water is sent through a pipe

through a container, called a steam generator, where it hea

in the second loop.


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Pressurize Water Reactor operation (cont’d.)

o This water, at a lower pressure than the water in the first into steam which rushes against the turbine’s blades to p

electricity.

The high-pressure water is pumped back to the reactor,

heated again.

The steam in the second loop change back into water, a

cooled down by the cooling water in the third loop, and

back to the steam generator again.


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Boiling Water Reactor (BWR)

BWR Schematic Diagram


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Boiling Water Reactor (cont’d.)

In the boiling water reactor, one loop performs both funcfirst and second loops.


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Heavy Water Reactor (HWR)HWR Schematic Diagram


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Heavy Water Reactor operation

A Candu reactor is an example of a Pressurized Heavy W

Reactor (PHWR). Fuel assemblies are placed horizontall

called a calandria.

Heavy water coolant is pumped through tubes containin

assemblies to pick up the heat generated from the nuclreaction.

The coolant then moves to the steam generators to prod

from ordinary water and back to the reactor.


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Heavy Water Reactor operation (cont’d.)

Heavy water is a rare but natural form of water and iseffective moderator used in nuclear reactors to maint

continuous fissioning.

Ordinary water is a combination of one oxygen and tw

atoms (H2O). Heavy water is virtually identical, except

hydrogen atoms have an extra neutron.

This hydrogen isotope is called deuterium (D). Since h

(D2O) has almost all the extra neutrons it wants, it slo

in the reactor without significantly absorbing them.


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Heavy Water Reactor operation (cont’d.)

The advantage of heavy water is that it permits the usunenriched uranium as fuel. This means two less ste

required in the conversion process resulting in a more

economical fuel source.


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High-Temperature Gas-Cooled Reactor


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High-Temperature Gas-Cooled Reactor operation

In high-temperature gas-cooled reactor (HTGR), the coousually helium or carbon dioxide, and graphite is used

moderator.

Both helium and carbon dioxide allow the reactor core

higher temperatures than water (or heavy water) coole

so HTGR can make electricity more efficiently than wat

and doesn’t depend on a water source.


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Organic-Cooled Reactor

Organic cooled reactor (OCR) combines the advantage which can use unenriched uranium for fuel, and HTGR,

reach high temperature.

OCR uses an organic liquid (a liquid that must have at l

and hydrogen as components) as a coolant, which is ch

heavy water, but it is flamable, so the danger of fire or

greater than with other reactors.


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Fast Breeder Reactor

The Fast Breeder Reactor (FBR) has a core of plutonium surroundU-238.

The U-238 nuclei absorb neutrons from the core and are transfor

plutonium (P-239).

For every four atoms of plutonium that are used up in the core of

five new plutonium atoms are made from the U-238. Therefore, F

plutonium.

Fast breeder reactors work at such a high temperature that they

coolant such as liquid sodium.

In addition, they are not equipped with a moderator to slow down

for this reason are called "fast" breeders.


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Fast Breeder Reactor


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NUCLEAR ENERGY

REACTOR TYPES IN USE WORLDWIDE


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NUCLEAR ENERGY

Nuclear Power Reactors: Typical Characteristics

Type of Reactor Fuel Form Coolant Mod

BWR Enriched Uranium Dioxide Water W

PWR Enriched Uranium Dioxide Water W

PHWR Candu) Natural Uranium Dioxide Heavy Water Heav

GCR Natural Uranium Carbon Dioxide Gra

AGR Enriched Uranium Dioxide Carbon Dioxide Gra

LWGR Enriched Uranium Dioxide Water Gra

FBR Plutonium Oxide and

Uranium Dioxide

Liquid Sodium N


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NUCLEAR ENERGY

Uses and applications

Making Electricity. Nuclear energy can be used to makeThis happens at nuclear power stations.

Sterilization of medical equipment (e.g., bandages)

Foods. Stop food from going stale (e.g., dired spices)

Smoke detectorsNuclear Energy in Medicine. X-rays, Radiation theraphy

with cancer.


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NUCLEAR ENERGY

Uses and applications (cont’d.)

Nuclear-powered Transportation. Some ships and submuse nuclear energy to run their engines. Submarines c

under water longer when they use nuclear energy to ru

engines.

Nuclear Energy in Space. Some unmanned spacecraft

away from the sun use nuclear energy


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ADVANTAGES AND DISADVANTAGES

Advantages

The Earth has limited supplies of coal and oil. Nuclear plants could still produce electricity after coal and oil b

scarce.

Nuclear power plants need less fuel than ones which b

fuels. One ton of uranium produces more energy than i

by several million tons of coal or several million barrels

Coal and oil burning plants pollute the air. Well-operate

power plants do not release contaminants into the env


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Disadvantages

One possible type of reactor disaster is known as a meltsuch an accident, the fission reaction goes out of contro

to a nuclear explosion and the emission of great amoun

radiation.

In 1979, the cooling system failed at the Three Mile I

nuclear reactor near Harrisburg, Pennsylvania. Radia

forcing tens of thousands of people to flee. The probl

solved minutes before a total meltdown would have o

Fortunately, there were no deaths.


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Disadvantages (cont’d.)

In 1986, a much worse disaster struck Russia's Cher

nuclear power plant. In this incident, a large amount

escaped from the reactor. Hundreds of thousands of

were exposed to the radiation. Several dozen died wi

days. In the years to come, thousands more may die

induced by the radiation.

In 2011, another nuclear disaster in Japan’s Fukush

facilities has resulted to radiation leaked, forcing tho

people living within 50 mile radius from the plant to f

Fortunately, no deaths reported that can be tied dire

the incident


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Nuclear reactors also have waste disposal problems. Reactors pr

waste products which emit dangerous radiation. Because they co

who touch them, they cannot be thrown away like ordinary garbag

many nuclear wastes are stored in special cooling pools at the nu

reactors.

The United States plans to move its nuclear waste to a remote

dump by the year 2010. In 1957, at a dump site in Russia's Ural Mountains, several hu

from Moscow, buried nuclear wastes mysteriously exploded, k

of people.

Nuclear reactors only last for about forty to fifty years.


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The nations of the world now have more than enough nuclear boevery person on Earth. The two most powerful nations -- Russia a

United States -- have about 50,000 nuclear weapons between th

What if there were to be a nuclear war?

What if terrorists got their hands on nuclear weapons?

Or what if nuclear weapons were launched by accident?

Nuclear explosions produce radiation. The nuclear radiation harm

of the body which can make people sick or even kill them. Illness

people years after their exposure to nuclear radiation.


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FUTURE OF NUCLEAR ENERGY

Some people think that nuclear energy is here to

we must learn to live with it. Others say that we should get rid of all nuclear we

and power plants.

Both sides have their cases as there are advantag

disadvantages to nuclear energy. Still others have opinions that fall somewhere in b

REFERENCES


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Textbooks

Renewable Energy Technologies, Jean-Claude Sabonnadiere, 2009 Energy Conversion, D. Yogi Goswami, Frank Kreith, 2008

Power Plant Engineering, 3rd Edition, PK Nag, 2008, Tata McGraw Hill

Web http://en.wikipedia.org/wiki/Nuclear_power

http://library.thinkquest.org/06aug/01335/welcome.htm

http://www.cameco.com/uranium_101/uranium_science/nuclear_reactors/

Youtube Videos http://www.youtube.com/watch?v=VJfIbBDR3e8

http://www.youtube.com/watch?v=BdbitRlbLDc

http://www.youtube.com/watch?v=2Vua6uuJO_c

REFERENCES
http://en.wikipedia.org/wiki/Nuclear_powerhttp://en.wikipedia.org/wiki/Nuclear_powerhttp://library.thinkquest.org/06aug/01335/welcome.htmhttp://library.thinkquest.org/06aug/01335/welcome.htmhttp://www.cameco.com/uranium_101/uranium_science/nuclear_reactors/http://www.cameco.com/uranium_101/uranium_science/nuclear_reactors/http://www.youtube.com/watch?v=VJfIbBDR3e8http://www.youtube.com/watch?v=VJfIbBDR3e8http://www.youtube.com/watch?v=BdbitRlbLDchttp://www.youtube.com/watch?v=BdbitRlbLDchttp://www.youtube.com/watch?v=2Vua6uuJO_chttp://www.youtube.com/watch?v=2Vua6uuJO_chttp://www.youtube.com/watch?v=2Vua6uuJO_chttp://www.youtube.com/watch?v=BdbitRlbLDchttp://www.youtube.com/watch?v=VJfIbBDR3e8http://www.cameco.com/uranium_101/uranium_science/nuclear_reactors/http://library.thinkquest.org/06aug/01335/welcome.htmhttp://en.wikipedia.org/wiki/Nuclear_power

me165 1_week 10.1 nuclear energy

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