By Venkatachari Jagannathan, Chennai, Aug 10 IANS | 2 years ago

India's first indigenously-designed and built reactor for a submarine - INS Arihant - is functioning well but will be shut down sometime later to study reports of its functioning, top atomic energy establishment officials said.

According to the officials, the reactor for a second nuclear submarine has also been delivered to the Navy.

"The reactor in INS Arihant is functioning well. It will be shut down later to study the reports generated," Atomic Energy Commission (AEC) chairman R.K. Sinha told IANS over phone Saturday.

Speaking to IANS over phone, Bhabha Atomic Research Centre director Sekhar Basu said: "After a reactor goes critical (beginning of the nuclear fission process), it is shut down to check the reports. Then the reactor physics experiments will be done. Unlike land based power reactors, shutting down and restarting a submarine reactor is not a big problem."

The reactor on board INS Arihant was activated Friday night and its successful functioning was termed by Prime Minister Manmohan Singh as a "giant stride" in the progress of the country's indigenous capabilities.

The officials also lauded the scientists' achievement.

"It is a great moment for all of us. It is a great technological achievement for our scientists in designing and building the reactor," said Sinha, who is also secretary of the department of atomic energy.

"The design was unique as compared to a land-based reactor. The reactor was designed and manufactured in India," he added.

The submarine reactor was developed from a land-based prototype located in Kalpakkam, around 70km from here.

The scientists' team was given the mandate to develop a land-based prototype power pack for a submarine and development and construction of a nuclear steam generating system for the sea-going version.

There is a sea of difference between designing a nuclear power pack to propel a submarine and a land-based atomic power station. While a land-based atomic power plant gets support from the grid and others, a nuclear power pack in a submarine does not have such fallback systems.

The 82.5 MW nuclear reactor for submarine has been designed at Kalpakkam by PRP Centre - PRP originally stood for Plutonium Reprocessing Project - under the BARC.

Prior to his current position, Basu was heading the PRP.

According to Indian nuclear scientists the major challenges in designing the reactor for INS Arihant were miniaturisation of the land-based plant to fit into the confined space of a submarine and also making it lightweight but strong enough to endure the shock due to depth discharge.

The reactor, while withstanding the pitch and roll of a submarine should also be capable of accelerating and decelerating at a quick pace - unlike a land-based power plant which would ramp up speed in a gradual manner.

The reactor designed for a long fuelling cycle time, would also have to be capable of remaining under water for an extended period, the sortie time being essentially dictated by the endurance of the crew.

The land-based version kept at Kalpakkam was conceived and built as a technology demonstrator for the compact pressurised water reactor with a load following capability.

Also known as 'half boat', the entire propulsion plant with primary, secondary, electrical and propulsion systems along with its integrated control was packed in the aft end of the land-based submarine hull designed and built specifically for this purpose.

While in sea the reactor supplies super-heated steam to the propulsion plant to run the submarine, at the PRP Centre, the propulsion power is absorbed in the dynamometer which in turn is cooled by sea water.

(V. Jagannathan can be contacted at

(Posted on 10-08-2013)