Chapter 8.1.7-8: Induced Fission and Safety Aspects

15 flashcards · Physics · by TheoTyson

1. What is the function of a thermal nuclear reactor?

   To harness the energy released during nuclear fission.

2. What happens in a thermal nuclear reactor?

   Rods of uranium that are rich in 235U^{235}\text{U}235U ready for fission are placed in a moderator. The fission reactions produce neutrons that then induce other nuclei to fission, a chain reaction.

3. What is the critical mass?

   The amount of 235U^{235}\text{U}235U \ fuel needed to keep the chain reaction going at a steady rate.

4. What is the function of the control rods?

   To control the chain reaction by limiting the number of neutrons in the reactor and absorbing them.

5. What can control rods do?

   They can be inserted by varying amounts, and in an emergency, they are dropped down to stop the reaction.

6. What is important about the material of control rods, and what is an example?

   They need to be good at absorbing neutrons, for example, Boron.

7. What is the function of the coolant?

   It is sent around the reactor to remove the heat produced in the fission.

8. What is important about the material of the coolant and what is an example?

   It needs to be a good insulator to best remove the heat, for example, water.

9. What is the function of the moderator?

   It slows down the neutrons released from fission so that they can be capture by the uranium nuclei.

10. What is important about the material of the moderator and what is an example?

    Collisions with particles of a similar mass are best at slowing down the neutrons, water is an example.

11. What is the nuclear reactor surrounded by?

    A thick concrete case that acts as shielding and prevents radiation escaping.

12. What is an extra safety precaution related to handling?

    In order to avoid handling, the radioactive material is handled remotely to minimise contact.

13. What is the problem with the waste of nuclear fission?

    The waste has high numbers of neutrons and so are unstable and radioactive.

14. What can the radioactive material be used for?

    Medical tracers that emit gamma radiation.

15. What happens to the nuclear waste?

    It is stored in sealed containers until the activity has fallen and it is stored away from people and animals.