Which of the following are true about moderator used in nuclear reactors?

1.Moderators slow down neutrons to sustain the chain reaction

2.Moderators stops the neutrons to control chain reaction

3.Without a moderator chain reaction would stop

4.Example of moderator is Graphite Rod

A1 & 3 only

B2 & 4 only

C1, 3 & 4 only ✓ Correct

D2, 3 & 4 only

Correct answer: (C) 1, 3 & 4 only

Explanation

Moderators slow neutrons to keep the chain reaction going, are needed for it to continue, and graphite rods are an example.

Statement 1 is true, as moderators slow fast neutrons so they can trigger more fission.

Statement 2 is false, because stopping neutrons to control the reaction is the job of control rods, not moderators.

Statement 3 is true, since without a moderator the chain reaction in a thermal reactor would stop.

Statement 4 is true, as graphite is a common moderator along with heavy water.

Slow, thermal neutrons split uranium-235 far more readily than fast neutrons.

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