You may use a calculator. You should show all your working and use appropriate units. Take the weight of 1.0 kg to be 9.8 N (acceleration of free fall = 9.8 m/s²).
(a)Read question and case materials as text
Text can be resized with your browser. Refer to the original figures below for diagrams and their layout.
Fig. 9.1 shows a nuclear reactor containing uranium-235 fuel, control rods, a moderator and a coolant.
Describe the fission of a uranium-235 nucleus. Include the role of neutrons in your answer.
Fig. 9.1 shows the main parts of a nuclear reactor.
The fuel rod contains uranium-235, which can undergo nuclear fission.
Describe the process of nuclear fission that occurs in the fuel rod.
Your description should include the role of neutrons in the process.
Answer guidance
Describe Say what happens, in order. Reasons are not required unless the question also asks why.
[3 marks]
(b)
Explain what happens as a control rod is moved out of the reactor core.
Answer guidance
Explain Give reasons, not just what happens. Each distinct reason is usually worth a mark.
[2 marks]
(c)
The nuclear reactor releases energy at a steady rate.
By referring to neutrons, describe what is happening to achieve this steady rate.
Answer guidance
Explain Give reasons, not just what happens. Each distinct reason is usually worth a mark.
[1 mark]
(d)
Explain the purpose of the moderator in the nuclear reactor.
Answer guidance
Explain Give reasons, not just what happens. Each distinct reason is usually worth a mark.
[2 marks]
5054/02/SP/23Cambridge O Level Physics 5054 · Specimen 2023 · Paper 2 · Question 9