Kaiga 5 and 6 will be the first of ten Indian-designed 700 MWe pressurised heavy water reactors (PHWRs) to be built using a fleet mode of construction to bring economies of scale as well as maximising efficiency, which have been given administrative approval and financial sanction by the Indian government. Excavation works for the units began in May 2022. Two 700 MWe PHWR units have already been built at Kakrapar, in Gujurat, and are already in commercial operation, and fuel loading is under way in another, Rajasthan unit 7, which is expected to begin commercial operation before the end of the year.
Steam generators are heat exchangers used to convert water into steam from heat produced in a nuclear reactor core. In PHWRs, the coolant is pumped, at high pressure to prevent boiling, from the reactor coolant pump, through the nuclear reactor core, and through the tube side of the steam generators before returning to the pump.
The component weighs over 200 tonnes and is about 24 metres in length, with a diameter of about 4 metres.
Nuclear Power Corporation of India Ltd currently operates four 202 MWe PHWRs at Kaiga.
