NEW DELHI, (PTI): The indigenously-built nuclear submarine INS Arihant will take another two years to be inducted in operational roles, a top military official said.

"Arihant, of course, will take about two years of trials before she is inducted in the Navy," Navy Chief Admiral Nirmal Verma said in an interview for the forthcoming issue of defence journal Indian Defence Review.

Verma said the Navy and the DRDO were looking into the challenges such as "proving of the new technology, getting the submarine fully operational, developing doctrines and procedures" for the induction of Arihant.

"We are actively working on all these issues, and more, to ensure that we have a credible deterrent in the form of Arihant and follow-on submarines," he said.

Verma said that India will learn a lot by operating the Arihant as it will "provide valuable inputs" for the indigenous nuclear submarine programme.

Terming the sea-based variant as "most survivable" and "least vulnerable" of the nuclear triad, the Navy Chief said the launch of the Arihant was a significant step towards achieving that capability.

India's nuclear doctrine calls for a minimum credible nuclear deterrent in form of a survivable triad, of land, sea and air based platforms that can deliver a second strike in case of nuclear attack by the enemy as it follows a 'no first strike' policy.