Step 1: Understanding the Concept:
This is a general knowledge question about the locations of major nuclear power plants in India.
Step 2: Detailed Explanation:
The Kalpakkam Nuclear Power Plant, officially known as the Madras Atomic Power Station (MAPS), is located in Kalpakkam, which is situated on the coast of the Bay of Bengal in the state of Tamil Nadu. It is about 80 kilometers south of Chennai.
For reference, other major nuclear plants are:
\[\begin{array}{rl} \bullet & \text{Kaiga Nuclear Power Plant is in Karnataka.} \\ \bullet & \text{Narora Atomic Power Station is in Uttar Pradesh.} \\ \bullet & \text{Kakrapar Atomic Power Station is in Gujarat.} \\ \end{array}\]
Step 3: Final Answer:
The Kalpakkam Nuclear Power Plant is located in Tamil Nadu.