n atomic reacotrs, graphite is used as a

Options

A. Lubricant
B. Moderator to show down neutrons
C. Fuel
D. Liner of the reactor

Explanation

**Step-by-Step Solution:**

1. **Understanding the Role of Graphite in Atomic Reactors:**
- In atomic reactors, graphite is primarily used as a moderator. A moderator is a substance that slows down fast neutrons produced during nuclear fission.

2. **Function of Neutrons in Nuclear Reactions:**
- When a nucleus undergoes fission, it releases fast-moving neutrons. These neutrons need to be slowed down to increase the probability of further fission reactions.

3. **How Graphite Works as a Moderator:**
- Graphite is effective in slowing down neutrons because it has a structure that allows for elastic collisions with neutrons. When neutrons collide with the carbon atoms in graphite, they lose energy and slow down.

4. **Importance of Slowing Down Neutrons:**
- Slower neutrons (thermal neutrons) are more likely to be captured by fissile materials (like Uranium-235 or Plutonium-239), leading to a sustained nuclear chain reaction.

5. **Conclusion:**
- Therefore, in atomic reactors, graphite is used as a moderator to slow down neutrons, which is essential for maintaining the nuclear fission process.

**Final Answer:**
In atomic reactors, graphite is used as a moderator to slow down neutrons.

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