The fast breeder reactor uses the following moderator
A
Demineralised water
B
Carbon dioxide
C
Heavy water
D
No moderator is used
Correct Answer: No moderator is used
No moderator is used in the breeder reactor since fast neutrons are more efficient in transmuting U238 to Pu239. At this concentration of U235, the cross-section for fission with fast neutrons is sufficient to sustain the chain-reaction.