The Indian Navy is reported to have secretly commissioned into service nuclear submarine INS Arihant.

The defence ministry and the navy did not confirm or deny reports that the submarine was inducted in August this year to complete the nuclear weapons triad that gives India capability to launch nukes from land, air and sea.

INS Arihant is India’s first indigenous nuclear submarine, and the lead ship of the Arihant-class of nuclear-powered ballistic missile submarines, which was launched in 2009 and is based on the Russian Akula-1 class submarine.

Controller of warship production and acquisition in the Indian Navy vice-admiral GS Pabby refused to answer questions about the submarine at a function here. He, however, said an interaction will soon be held to answer all questions on the submarine.

“There will soon be an opportunity to talk about it,” Pabby said.

Other officials too declined to comment on the matter. However, a few indicated that the vessel was now part of the naval fleet, without divulging the exact date of induction.

Former navy chief admiral Arun Prakash (retired) said the secrecy around the induction of the vessel was “customary” for a nuclear submarine.

 “Arihant is an achievement technology wise, but otherwise it is a top secret,” admiral Prakash told IANS.

“Its mission is to be a nuclear deterrent. Everything to do with the submarine will be a secret. Its movement, position and location will not even be known to the navy,” he said. “It is not a normal ship, though we would like to show it off, we cannot.”

The 60,000-tonne submarine was also not included in the International Fleet Review (IFR) hosted by the Indian Navy earlier this year. It was initially expected to start sea trials by 2012, but the production was delayed and sea trials began in December last year.

In 2013, the miniaturised nuclear reactor of Arihant, built with Russian help, became critical, causing delays.

The project was part of the advanced technology vessel programme and operated under the supervision of the Prime Minister’s Office and involved agencies such as the DRDO, the Department of Atomic Energy, the Submarine Design Group of the Directorate of Naval Design, besides companies such as L&T.

Its 100-member crew has been trained by Russian specialists, and Indian scientists at the Bhabha Atomic Research Centre have received significant expertise in reducing the size of the reactor to help it fit into the 10-metre diameter hull of the nuclear submarine.

India currently operates Russian-origin nuclear-powered submarine INS Chakra, which it leased for 10 years from Russia in 2012.

Nuclear submarines have the capability to stay out in sea for longer, and don’t need to surface for a long duration.