The control rod in a nuclear reactor is made of

Options

A. Graphite
B. Plutonium
C. Cadmium
D. Uranium

Answer

To solve the question regarding the material used for control rods in a nuclear reactor, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Purpose of Control Rods**:
- Control rods are used in nuclear reactors to manage the rate of the nuclear fission reaction. Their primary function is to absorb neutrons.

2. **Identify the Materials Used for Control Rods**:
- Control rods must be made from materials that can effectively absorb neutrons without undergoing fission themselves. Common materials used for this purpose include cadmium, boron, and graphite.

3. **Evaluate the Given Options**:
- The options provided are:
- Graphite
- Plutonium
- Cadmium
- Uranium
- Among these, we need to determine which material is best suited for neutron absorption.

4. **Analyze Each Option**:
- **Graphite**: While it is used as a moderator in some reactors, it does not absorb neutrons as effectively as other materials.
- **Plutonium**: This is a fissile material and is not used for neutron absorption in control rods.
- **Cadmium**: This is known for its ability to absorb neutrons effectively without undergoing fission.
- **Uranium**: This is also a fissile material and is not suitable for use in control rods.

5. **Select the Correct Answer**:
- Based on the analysis, the correct answer is **Cadmium**, as it is specifically used in control rods due to its neutron-absorbing properties.

### Final Answer:
The control rod in a nuclear reactor is made of **Cadmium**.

---