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 glow all 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
• Risk of nuclear accidents
• Expensive to commission and decommission the stations - which may be bad for a country’s economy

Question 3

What is nuclear fusion?

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 factor?

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 i started, 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 oh 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 two nuclei