GK
NUCLEAR SCIENCE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Candu reactor
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Fast breeder reactor
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Homogeneous reactor
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Pressurised water reactor
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Detailed explanation-1: -In a fast reactor, there is no moderator, only fuel and coolant. The moderation of neutrons is undesirable in fast reactors. Commonly used moderators include regular (light) water (roughly 75% of the world’s reactors), solid graphite (20% of reactors) and heavy water (5% of reactors).
Detailed explanation-2: -3. Which of the following reactors does not need moderator? Explanation: In fast reactors fission is caused by fast neutrons, so there is no need of moderator to slow down the neutrons.
Detailed explanation-3: -No moderator is used in the breeder reactor since fast neutrons are more efficient in transmuting U-238 to Pu-239. At this concentration of U-235, the cross-section for fission with fast neutrons is sufficient to sustain the chain-reaction.
Detailed explanation-4: -Heavy water is used as moderator in these reactors. 3. They breed more fissile material than they consume.