When nuclear energy is intended to be harnessed for generation of electricity, potentially destructive neutron released in a nuclear reactor are absorbed by

Options

A. Long rods of Cd
B. Heavy water
C. Cubical blocks of steel
D. Both (a) and (c)

Explanation

To solve the question regarding what absorbs potentially destructive neutrons in a nuclear reactor, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Neutron Absorption in Nuclear Reactors**:
- In a nuclear reactor, neutrons are released during the fission process. These neutrons can cause further fission reactions if not controlled.

2. **Identifying Neutron Absorbers**:
- Certain materials are known for their ability to absorb neutrons effectively. One of the most common materials used for this purpose is cadmium.

3. **Role of Cadmium Rods**:
- Cadmium rods are specifically used in nuclear reactors to absorb excess neutrons. This helps to control the fission chain reaction and prevents it from becoming uncontrollable, which could lead to catastrophic outcomes.

4. **Other Materials in a Nuclear Reactor**:
- While cadmium is a neutron absorber, other materials in a reactor serve different purposes. For example, heavy water is used as a coolant, and graphite can act as a moderator to slow down neutrons.

5. **Conclusion**:
- Therefore, the correct answer to the question is that the potentially destructive neutrons released in a nuclear reactor are absorbed by cadmium rods.

### Final Answer:
The potentially destructive neutrons released in a nuclear reactor are absorbed by **cadmium rods**.

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