`Pu^(239)` is artificial nuclear fuel.It is obtained from fertile material. `………………………..`.

Answer

To solve the question regarding the source of plutonium-239, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Understanding Fertile Material**:
- Fertile materials are substances that are not fissile themselves but can be converted into fissile materials through neutron bombardment.

2. **Identifying the Fertile Material for Plutonium-239**:
- The primary fertile material used to produce plutonium-239 is Uranium-238 (U-238).

3. **Nuclear Reaction**:
- When Uranium-238 is bombarded with neutrons, it undergoes a nuclear reaction. The reaction can be summarized as follows:
\[ \text{Uranium-238} + \text{neutron} \rightarrow \text{Uranium-239} \]

4. **Beta Decay of Uranium-239**:
- Uranium-239 is unstable and undergoes beta decay, emitting a beta particle (electron) and transforming into Neptunium-239 (Np-239):
\[ \text{Uranium-239} \rightarrow \text{Neptunium-239} + \beta^- \]

5. **Further Beta Decay to Plutonium-239**:
- Neptunium-239 is also unstable and undergoes another beta decay to become Plutonium-239 (Pu-239):
\[ \text{Neptunium-239} \rightarrow \text{Plutonium-239} + \beta^- \]

6. **Final Conclusion**:
- Therefore, Plutonium-239 is produced from Uranium-238 through a series of neutron bombardment and beta decay processes.

### Final Answer:
Plutonium-239 is obtained from the fertile material Uranium-238.

---