chapter 30 nuclear energy

7/31/2019 Chapter 30 Nuclear Energy

1/14

Nuclear energy is released when anunstable element breaks up intosimpler forms or when light elementsfuse together to form a larger

element.

In either case, the energy released ishuge and the potential that nuclearenergy presents in terms of analternative source of energy, to

generate electricity, is tremendous.However, issues such as the dangersof uncontrolled use of nuclear energyas well as industrial accidents andradiation caused by nuclear wastesare matters of concern.

30Chapte

rNuclear energy


2/14

Chapter 30: Nuclear Energy


3/14

1 10 7 4

0 5 3 2n B Li He+ +

Nuclear reactions take place when a nuclide is bombarded byanother nuclide or a particle.

This results in :1) A change to the nuclear structure of the nuclide2) Release of energy (due to the change in mass).

An example of a nuclear reaction:A slow moving

neutron bombards astationary

boron atom. Thisresults in a nuclear

change to form

lithium and helium.

In any nuclear reaction, mass number and proton numberare conserved but mass is not. Energy and momentum arealso conserved during a nuclear reaction.


Neutrons are effective as bombarding particles as they

are uncharged.They are not repelled by the atoms that they bombard.


4/14


Einsteins Mass-Energy Equation

E = mc2

whereE is the energy released or required in anuclear reaction;m is the change in mass; andc is speed of light in vacuum (3108 ms1).

1 u is the equivalentof 1.661027 kg of

mass.


5/14

There are two main types of nuclear reactions

Nuclear Fission and Nuclear Fusion

Nuclear fission

occurs when alargeunstable nuclidebreaks up into

smaller nuclideswhen it is collided bya neutron or anotherelement.

Nuclear fusion

occurs whensmallunstable nuclides

fuse together toform a heaviernuclide coupledwith the release ofsome particles.

th nuclear reactions result in the release of huge amounts of ener



6/14

Chain Reactions


The neutrons from the first fission bombard two orthree other uranium atoms and process goes on.

The fission of uranium results in the emission of at

least two neutrons.

The neutrons that are produced in the first emissionhave enough energy to bombard other uranium

atoms.

A chain reaction can occur if there are sufficienturanium atoms.


7/14

Nuclear Reactors

Nuclear power plants consist of nuclear reactors in whichnuclear reactions take place.

Nuclear reactors make use of the fission of uranium togenerate electricity. The chain reaction during the fission of

uranium means that large amounts of energy is produced.

The energy generated is used to heat up water to producesteam.

The steam is channelled to a secondary section where itdrives a turbine which results in the production of electricity.



8/14



9/14

Nuclear Power

Nuclear energy is an alternative source of energy.

The main source of energy now is fossil fuels. However, oursupply of fossil fuel is limited and exhaustive. As such, thecost of fossil fuels increase with increasing demand.Nuclear plants produce energy using nuclear reactors.

The advantage of producing nuclear energy is that onlysmall amounts of uranium-235 is needed to produce thesame amount of electricity that is produced by burninglots of coal and oil.

Nuclear energy can help conserve theamount of fossil fuels used and it is able tomeet the increasing energy demands ofthe world.


Advantages


10/14

Environmental Impact

Coal-burning power stations and oil-burning power stationsrelease large amounts of pollutants to the environment. Thesepollutants are harmful and global warming is partly attributedto the pollutants from these power stations.

Nuclear reactors do not release as much pollutants to theenvironment and very little carbon dioxide is produced.Waste that is produced during nuclear reactions is mostlycontained within the reactors, thus, reducing harm to theenvironment.


Advantages


11/14

Nuclear Waste Storage

Nuclear waste cannot be disposed of easily as they containsubstances that emit harmful radiation.

Special containers need to be built to store nuclear wastesand even then, nuclear spillage and leakage have occurredthroughout history due to negligence and accidents.

Even if nuclear wastes are carefully stored, they stillneed to be disposed off. This may mean finding sitesfar away from any human existence or disposing ofthem underground.


Disadvantages


12/14

Nuclear Accidents

Nuclear reactions however well controlled, have thepossibility of having run-away reactions.

Explosions can occur if these reactions happen.

Explosions can result in the emission of dangerousradioactive chemicals into the environment.


One of the most disastrous nuclear accidents is theChernobyl nuclear power station accident in Russia in1986. It led to thousands of people being exposed toharmful radiation. Many people died a few days after theincident and thousands more were affected by theradiation in the years after. The surrounding

environment was also badly affected.

Disadvantages


13/14

Hiroshima Atomic Dome Memorial

Nuclear BombsThe destruction caused by nuclear bombs is devastating.This is evident from the after-effects of the atomic bombs

that were dropped on Hiroshima and Nagasaki during WorldWar II.

Hundreds of thousands of people were killed from theimpact of the bomb and the radiation affected the survivorsfor years to come.


Disadvantages


14/14

Nuclear energy promises cheaper and cleaner energy

using only small amounts of uranium.

However, the dangers of radiation leakage, accidentsand of course, nuclear weapons are a major concern.Moreover, uranium-235 is also exhaustive and limited.


Nuclear Choice

Are you for or against nuclear energy?

chapter 30 nuclear energy

Documents