No Longer On Exam

Question 1

What is nuclear fission?

Answer 1

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

Question 2

Give an example of a fissionable isotope

Answer 2

Uranium - 235

Question 3

What usually needs to happen to induce fission?

Answer 3

• The unstable nuclei must absorb a neutron.

- Spontaneous fission (where no neutron absorption occurs) is rare.

Question 4

Alongside 2 smaller nuclei, what else is emitted in a fission reaction?

Answer 4

• 2 or 3 neutrons.
• Gamma rays.
• Energy.

Question 5

What form of energy do all fission products have?

Answer 5

Kinetic energy.

Question 6

What takes place during a chain reaction in a nuclear reactor?

Answer 6

• 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 7

What is the consequence of an uncontrolled chain reaction?

Answer 7

• 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 8

What are the 3 main components of the core in a nuclear reactor?

Answer 8

• Fuel rods.
• Control rods.
• Moderator.

Question 9

What is the role of the moderator in a nuclear reactor?

Answer 9

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

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 term is used to describe nuclei in which fission can be induced through the absorption of slow neutrons?

Answer 11

Fissile nuclei.

Question 12

What is nuclear fusion?

Answer 12

The joining of 2 light nuclei to produce a heavier nuclei and release energy.

Question 13

Name 2 isotopes of hydrogen which are commonly used in nuclear fusion

Answer 13

Deuterium and Tritium.

Question 14

Which releases more energy, nuclear fission or nuclear fusion?

Answer 14

Nuclear fusion.

Question 15

Explain the difficulty of generating energy through nuclear fusion

Answer 15

Fusion requires very high temperatures which in itself requires casing which can withstand them.

Question 16

Explain why nuclear fusion is currently not a viable way to produce energy on Earth

Answer 16

With current equipment/techniques, the energy required is greater than the energy produced, resulting in a net energy loss.