Photo AI
The core of a thermal nuclear reactor contains a number of components that are exposed to moving neutrons - AQA - A-Level Physics - Question 4 - 2017 - Paper 2
Question 4
The core of a thermal nuclear reactor contains a number of components that are exposed to moving neutrons. 0 4.1 State what happens to a neutron that is incident on... show full transcript
Worked Solution & Example Answer:The core of a thermal nuclear reactor contains a number of components that are exposed to moving neutrons - AQA - A-Level Physics - Question 4 - 2017 - Paper 2
Step 1
State what happens to a neutron that is incident on the moderator.
Answer
When a neutron interacts with the moderator, it undergoes elastic collisions. During these collisions, the neutron loses energy to the moderator atoms while conserving momentum, which results in the neutron being slowed down, facilitating further nuclear reactions.
Step 2
State what happens to a neutron that is incident on a control rod.
Answer
When a neutron interacts with a control rod, it is absorbed. Control rods are made of materials that are efficient at capturing neutrons, thereby reducing the number of neutrons available to sustain the nuclear reaction.
Step 3
Describe what happens in the process.
Answer
In the fission process, a slow-moving neutron collides with the nucleus of an atom of the fuel, such as uranium-235. This collision can cause the nucleus to become unstable, leading to its immediate splitting into two smaller nuclei, releasing additional neutrons and a significant amount of energy in the form of heat. This released energy contributes to maintaining the ongoing nuclear chain reaction as the newly released neutrons can collide with nearby fuel nuclei to induce further fission events.
Step 4
State the source of the waste and discuss some of the problems faced in dealing with the waste at various stages of its treatment.
Answer
The primary source of radioactive waste in thermal nuclear reactors comes from spent fuel rods after they have undergone fission processes.
Outline of How Waste is Treated: Radioactive waste is initially stored in spent fuel pools where it is cooled and shielded from radiation. This is followed by a process of reprocessing where some of the materials are recovered, and the remaining waste is solidified in glass or concrete.
Problems Faced in Dealing with the Waste:
- Long-Term Storage: The long half-lives of some radioactive isotopes necessitate safe storage solutions for thousands of years, posing challenges for geological disposal sites which must be geologically stable to prevent leakage.
- Public Perception and Safety Concerns: Communities often oppose waste facilities due to fears of potential accidents or health risks, necessitating transparent communication and robust safety science.
- Decommissioning Costs: The costs associated with decommissioning nuclear facilities and managing waste are significant, necessitating comprehensive planning and funding to ensure environmental protection and accountability.
Suggestions for Overcoming These Problems:
- Increase community engagement to build trust and understanding about waste management techniques.
- Invest in advanced technologies for waste treatment and storage solutions to enhance safety and efficiency.