KCET2021PhysicsNuclear Physics
In a nuclear reactor heavy nuclei is not used as moderators because
Options
- Athey will break up
- Belastic collision of neutrons with heavy nuclei will not slow them down
- Cthe net weight of the reactor would be unbearably high
- Dsubstance with heavy nuclei do not occur in liquid or gaseous state at room temperature
Correct answer
B. elastic collision of neutrons with heavy nuclei will not slow them down
Step-by-step solution
The moderator used in nuclear reactor, have light nuclei (like proton). When protons undergo perfectly elastic collision with the neutrons emitted, their velocities are exchanged i.e. neutrons. Heavy nuclei will not serve the purpose because elastic collision of neutrons with heavy nuclei will not slow them down.