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

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

Functions and Materials:

• A: Made of carbon dioxide gas or liquid sodium; transfers thermal energy away from the reactor core.
• B: Made of boron or cadmium; absorbs excess neutrons to regulate the rate of the chain reaction.
• C: Made of thick concrete and steel; stops high-energy radiation (such as gamma rays and neutrons) from escaping.
• D: Made of graphite or water; slows down fast-moving neutrons so they can cause further fission reactions.

Which of the following particles must be absorbed by a uranium-235 nucleus to initiate a fission reaction?

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

Describe the sequence of physical events that occurs during the induced fission of a uranium-235 nucleus, starting from the absorption of a neutron.

State three fundamental differences between nuclear fission and nuclear fusion.