Nuclear Power

Question 1

Describe the advantages of nuclear power for

generating electricity.

Answer 1

● Nuclear fuels do not produce carbon dioxide
● The fuel is readily available, so would reduce strain on the
fossil fuel supplies
● Less nuclear fuel has to be used to produce the same
amount of energy as burning fossil fuel
● Does not contribute to global warming

Question 2

Explain some disadvantages of using nuclear power

to generate electricity.

Answer 2

● Unpopular - the public perceive nuclear power as very dangerous
● Security risks as the radioactive substances can be useful for
terrorists
● Expensive to commission and decommission the stations - which may
be bad for a country’s economy
● The radioactive waste can be difficult to dispose of and will remain
radioactive for many years - which can be dangerous to humans and
the environment
● Risk of nuclear accidents

Question 3

What is nuclear fission?

Answer 3

The splitting of large, unstable nuclei to
form smaller more stable nuclei (+ the
emission of spare neutrons)

Question 4

What usually needs to happen to induce fission?

Answer 4

● The unstable nuclei must absorb a
neutron
● Spontaneous fission (where no
neutron absorption occurs) is rare

Question 5

Alongside two smaller nuclei, what else is emitted in

a fission reaction?

Answer 5

● Two or three neutrons
● Gamma rays
● Energy

Question 6

Name a common fissile nuclei.

Answer 6

Uranium-235

Question 7

What are the three main components of the core a

nuclear reactor?

Answer 7

1. Fuel rods
2. Control rods
3. Moderator

Question 8

What takes place during a chain reaction in a

nuclear reactor?

Answer 8

● An unstable nucleus absorbs a neutron
● The nucleus undergoes fission and
releases 2 or 3 further neutrons
● These induce more fission, which results
in a chain reaction

Question 9

What is the consequence of an uncontrolled chain

reaction?

Answer 9

● The rate of fission events becomes to
high and results in the production of
too much energy
● This can lead to a nuclear explosion

Question 10

How is the chain reaction in a fission reactor kept

under control?

Answer 10

● Control rods are positioned in between the fuel
rods
● The rate of fission is controlled by moving
these rods up and down
● The lower the rods are inserted, the slower the
rate of fission

Question 11

What is the role of the moderator in a nuclear

reactor?

Answer 11

To slow down the neutrons so they are
travelling at speeds which allow them to
be absorbed by fissile nuclei and cause
fission

Question 12

How is electricity is produced in a nuclear power

station?

Answer 12

● The reactions release thermal energy
● The thermal energy is used to boil water and
then produce steam.
● This steam is then used to turn a turbine which
starts the generator

Question 13

What is nuclear fusion?

Answer 13

When two light nuclei join to produce a

heavier nucleus and release energy

Question 14

Name two isotopes of hydrogen which are commonly

used in nuclear fusion

Answer 14

Deuterium and Tritium

Question 15

Which releases more energy, nuclear fission or

nuclear fusion?

Answer 15

Nuclear fusion

Question 16

Explain the difficulty of generating

energy through nuclear fusion

Answer 16

Fusion requires very high temperatures
which in itself requires large quantities of
energy. Currently, the production of
fusion results in a net loss of energy

Question 17

Give an example of where fusion

occurs?

Answer 17

In the sun - stars use fusion as their

energy source

Question 18

Why does nuclear fusion require so much energy?

Answer 18

This is because both nuclei are positive
therefore a lot of energy is required to
overcome the electrostatic repulsion
between the two nuclei.