Fission & Fusion Review

FISSION REACTION

A large nucleus (atom) splits into several small nuclei when impacted by a
neutron, and energy is produced.

Uranium-235 is
commonly used

Nuclear Fission: Chain Reactions

Free neutrons produced by fission can hit other
uranium nuclei emitting more neutrons
repeating the reaction over and over.

Multiple Choice

Which of the following enabled a chain reaction in fission?

• Free neutrons

• Beta particles

• Helium nuclei

• Hydrogen isotopes

This Photo by Unknown Author is licensed under CC BY-SA

Nuclear reactors use nuclear fission to generate electricity.

This Photo by Unknown Author is licensed under CC BY-SA

Nuclear power
A power station makes electricity. Fossil fuel (coal, oil and
gas) power stations and nuclear (uranium) power stations
both use the same processes to make electricity.
Nuclear power provides 20% of electricity in U.S.
Large amounts of thermal pollutant

Light Water Reactors
The nuclear reactor is designed to allow
a controlled chain reaction to take place.
Each time a uranium nucleus splits up it
releases energy and three neutrons. If all
the neutrons are allowed to be absorbed
by other uranium nuclei the chain
reaction will spiral out of control causing
an explosion. To control the energy
released in the reactor moveable control
rods are placed between the fuel rods.
These control rods are made
of boron/cadmium which absorbs some of
the neutrons so fewer neutrons are
available to split uranium nuclei. The
control rods are raised to increase and
lowered to decrease the number of free
neutrons.

Fusion Reactions: the combining of small nuclei
(atoms) into larger ones and releases energy.

MORE ENERGY THAN FISSION
Requires very high temperature and pressure

Small
atom

Small
atom

Large
atom

fuse

Only in: Sun

How do we get it to occur? Is there a container for it?

Hydrogen Bomb

´ What Is It?
´ First developed by the United States in the early 1950s, the

hydrogen or thermonuclear bomb is perhaps a thousand
times more powerful than a uranium- or plutonium-based
fission bomb

´ Only the five permanent United Nations Security Council

members — the United States, Russia, Britain, France and
China — are known to possess hydrogen bombs.

´ The difference between a hydrogen bomb and a regular

uranium or plutonium bomb is that a hydrogen bomb uses
fusion instead of fission to generate the main explosion

Multiple Choice

What kind of reaction is occurring?

_____ the type of reaction in the sun.

• Fission

• Fusion

Multiple Choice

What kind of reaction is occurring?

_____ the type of reaction in atomic bombs

• Fission

• Fusion

Multiple Choice

What kind of reaction is occurring?

_____ an atomic nucleus is split into 2 roughly equal parts

• Fission

• Fusion

Multiple Choice

What kind of reaction is occurring?

_____ requires incredibly high temperatures

• Fission

• Fusion

Multiple Choice

What kind of reaction is occurring?

_____ type of reaction in a nuclear power plant

• Fission

• Fusion

Multiple Choice

What kind of reaction is occurring?

_____ 2 very light isotopes come together to form a heavier

• Fission

• Fusion

Multiple Choice

What kind of reaction is occurring?

_____ principle reaction in a hydrogen bomb

• Fission

• Fusion

Multiple Choice

Which statement about nuclear fusion and fission is TRUE?

• Fission requires a high density and high temperature environment, while Fusion requires high speed neutrons to initiate

• Fission requires little energy to split atoms, while Fusion takes extremely high energy to bring two or more atoms together

• Fusion is the union of two or more lighter atoms into a larger one, while Fission is the splitting of a large atom into two or more smaller ones.

• Fission is the union of two or more lighter atoms into a larger one, while Fusion is the splitting of a large atom into two or more smaller ones.