Match each nuclear reactor component to its correct function and material.

1. Control rods
2. Moderator
3. Coolants
4. Shielding

Functions and Materials:

• W: Made of graphite or water; slows down fast neutrons so they can cause further fission.
• X: Made of thick concrete and steel; stops high-energy radiation (like gamma rays and neutrons) from escaping.
• Y: Made of boron or cadmium; absorbs excess neutrons to regulate the rate of the chain reaction.
• Z: Made of water or carbon dioxide; transfers thermal energy from the reactor core to spin a turbine.

Which of the following is required to initiate the fission of uranium-235?

• A a high-energy alpha particle
• B a slow-moving (thermal) neutron
• C a fast-moving proton
• D a positron

Describe the process of a nuclear fission reaction of uranium-235 once it has been initiated.

State three differences between nuclear fission and nuclear fusion.