|Demonstrators head to the Tamil Nadu Assembly on the roof of a bus to protest against the Kudankulam nuke plant on Monday. (PTI)
New Delhi, Oct. 29: India’s department of atomic energy is working on a nuclear power reactor with novel safety features that will, in principle, make it possible to build it in the heart of a city.
The Advanced Heavy Water Reactor (AHWR), on the drawing board for a decade, is also designed for the large-scale use of India’s vast reserves of thorium locked in its southern coastal sands.
The department of atomic energy has finalised the design for an AHWR intended to deliver 300MW electricity and hopes to start building the first reactor in the next three to five years, a senior official said.
“We believe the AHWR will be the world’s first commercial thorium-based nuclear reactor and, in principle, it could be located even in a densely populated area,” the department of atomic energy official said.
Under regulatory and safety requirements, all present-day nuclear reactors in India need to be girdled by an “exclusion zone” of 1.6km, an area of land where no human activity is allowed.
“The concept of an exclusion zone will go away with the AHWR,” the official told The Telegraph.
While the site for the first AHWR is yet to be finalised, department of atomic energy officials and nuclear reactor engineers say it will not be placed in any populated area.
The AHWR will have novel safety features that will use natural circulation to remove heat from the reactor after an emergency shutdown, eliminating the need for pumps.
A key design goal for the AHWR has been to ensure that in an emergency situation called “loss of coolant accident”, the safety features of the reactor will spontaneously make the power drop.
“To achieve this... is a nightmare for the designer but a delight for the operator,” Amit Thakur, a reactor design scientist at the Bhabha Atomic Research Centre, said in a presentation on the AHWR design.
A research paper co-authored six years ago by current department of atomic energy chairman R.K. Sinha had described the AHWR as a reactor with several passive safety systems for removal of decay heat from the reactor during an emergency shutdown.
The core of a nuclear reactor continues to generate “decay heat” that needs to be cooled continuously for weeks to prevent overheating and the type of accident that occurred after the tsunami struck the Fukushima reactor in Japan last year.
The safety analysis of the AHWR has covered “an exhaustive list of 55 postulated initial events”, according to the paper by Sinha and former department of atomic energy chairman Anil Kakodkar in the journal Nuclear Engineering and Design.
“The main objective has been to establish a case for elimination of a need for evacuation planning, following any credible accident scenario in the plant,” the atomic energy chiefs wrote in their paper.
India has 20 operating nuclear power plants with an installed capacity of about 4,700MW electricity, but hopes to raise this to 20,000MW by 2022. The AHWR will represent the next generation of reactors that drives India into using thorium.