Step 1: Understanding India's Nuclear Power Journey.
India's first atomic power station, the Tarapore Atomic Power Station (TAPS), was established in 1969 and is located in Tarapur, Maharashtra. It was the first nuclear power station to be commissioned in India.
Step 2: Explanation of other options. - Narora, Kalpakkam, and Rana Pratap Sagar are significant nuclear sites, but they were established after the commissioning of the Tarapore power station.
Step 3: Conclusion.
Thus, Tarapore is the correct answer as the location of India's first atomic power station.
\[
\boxed{\text{The correct answer is Tarapore.}}
\]