PHWR technology was introduced in India in the late 1960s with the construction of RAPS-1, a CANDU reactor in Rajasthan.

In 1974, after India conducted Smiling Buddha, its first nuclear weapons test, Canada stopped their support of the project.

India took help of Soviet Union whose VVER(Pressurised Water Reactor type) technology was used as a design for indigenization.

Improvements were made in the original VVER design to reduce construction time and cost.

[3] Like other pressurized heavy-water reactors, IPHWR-700 uses heavy water (deuterium oxide, D2O) as its coolant and neutron moderator.

These designs handle the case of a loss of coolant accident such as occurred in the Fukushima Daiichi nuclear disaster.