Indian context: the nuclear power reactor at Tarapur (Maharashtra) is of which reactor type?

Introduction / Context:
Recognising reactor types at specific Indian sites is a frequent exam theme. Tarapur Nuclear Power Station (the earliest commercial nuclear station in India) began with imported boiling water reactor units, distinct from later indigenous heavy-water moderated designs deployed elsewhere.

Given Data / Assumptions:

• Historical identification of Tarapur Unit-1 and Unit-2 technology.
• Question asks only for the reactor type label.

Concept / Approach:
BWRs generate steam directly in the reactor core; the steam is dried and sent to the turbine. This contrasts with PWRs, which use a steam generator to isolate the primary loop, and PHWRs (pressurised heavy-water reactors), which use D2O moderator and pressure tubes. Fast breeders are a separate class using liquid-metal coolants.

Step-by-Step Solution:
Recall Tarapur’s earliest commercial units were BWRs.Match with the options.Select “boiling water.”

Verification / Alternative check:
Site overviews consistently refer to Tarapur’s original units as BWRs, with later Indian fleets dominated by PHWRs elsewhere.

Why Other Options Are Wrong:

• PWR: different coolant/steam separation concept.
• Fast breeder: different spectrum and coolant (e.g., sodium).
• Gas cooled: not applicable to Tarapur’s early units.
• Heavy-water pressure tubes: characteristic of PHWR/CANDU, not Tarapur BWRs.

Common Pitfalls:
Mixing Tarapur with PHWR-heavy sites; confusing BWR and PWR characteristics.

Final Answer:
boiling water