Nuclear Physics 🥼

Question 1

Describe the process of fission in a nuclear reactor

Answer 1

• A large nucleus absorbs a neutron and becomes unstable
• e.g. U-235 becomes U-236
• Larger nucleus then decays by fission
• Releasing and energy and fast moving neutrons

Question 2

Describe how fission reactions are controlled in a nuclear reactor

Answer 2

• Moderator slows down neutrons so they can collide with more nuclei and cause more fission reactions
• Control rods are lowered into or raised out of reactor
• Control rods absorb neutrons, only one neutron escapes per fission reaction

Question 3

Describe what is meant by a ‘chain reaction’

Answer 3

Each fission reaction produces more neutrons which go on to cause more fission reactions

Question 4

Why is energy released in both fission and fusion reactions?

Answer 4

total binding energy of products > total binding energy of reactants (the difference in energy is released)

Question 5

How does the moderator slow fast moving neutrons down?

Answer 5

Interacting with the moderator nuclei causes the neutrons to lose a large amount of kinetic energy

Question 6

Suggest a suitable material to be used as a moderator in a nuclear fission reactor

Answer 6

Water or carbon/graphite

Question 7

In what form is energy released from a fission reaction?

Answer 7

Kinetic energy