Heavy Water Reactors : what are & Status in India

Date: February 08, 2017

nuclear energy renewable energy

Threat of climate change and importance of sustainable development has brought nuclear power in sharper focus in recent times. Growth of nuclear power worldwide, however, requires satisfactory technological response to challenges of very high level of safety and security assurance (as dictated by very large increase in number of reactors), ability to perform with lower level of technological infrastructure as it prevails in several developing countries, high degree of fuel use efficiency and superior waste disposal options.


At present, Pressurised Heavy Water Reactors (PHWRs) are under construction in the states of Gujarat, Rajasthan, and Haryana. More PHWRs are proposed to be set up in the states of Haryana, Rajasthan, Madhya Pradesh & Karnataka.

PHWRs are expected to contribute a significant portion of electricity to be generated from nuclear sources in the country.

The share of generation of electricity from PHWRs in the last three years is as follows:
(in million units)
Year                                          Total Generation                                Generation from PHWRs

2013-14                                         35333                                              32099

2014-15                                         37835                                              31491
2015-16                                         37456                                              33909


Commercial reactors around the world
There are six main reactor types in use around the world. The various designs use different concentrations of uranium for fuel, different moderators to slow down the fission process, and different coolants to transfer heat.
The most common reactor type is the pressurized water reactor (PWR), representing 290 of the world’s 447 reactors now operating.
Commercial reactor types around the world
1- Pressurized water reactor (PWR)
2-Boiling water reactor (BWR)
3-Pressurized heavy water reactor (PHWR)
4- Light water graphite reactor (LWGR)
5- Gas-cooled reactor (GCR)
6- Fast breeder reactor (FBR)

A pressurized heavy-water reactor (PHWR) is a nuclear reactor, commonly using unenriched natural uranium as its fuel, that uses heavy water (deuterium oxide D2O) as its coolant and neutron moderator. The heavy water coolant is kept under pressure, allowing it to be heated to higher temperatures without boiling, much as in a pressurized water reactor. While heavy water is significantly more expensive than ordinary light water, it creates greatly enhanced neutron economy, allowing the reactor to operate without fuel-enrichment facilities (offsetting the additional expense of the heavy water) and enhancing the ability of the reactor to make use of alternate fuel cycles.