The INS Arihant at the Shipbuilding Centre in Vizag The INS Arihant at the Shipbuilding Centre in Vizag

India's quest for a secure seaborne nuclear deterrent is set for a giant stride when its first indigenously constructed nuclear submarine the INS Arihant begins sea trials next week.

Naval sources indicated a casting-off date of Monday, December 15, and preparations are currently underway at the Shipbuilding Centre, Visakhapatnam to ensure a smooth sail out for the 6,000-tonne nuclear powered ballistic missile submarine (SSBN).

"It will be a surfaced sortie, but a great milestone nevertheless," naval officials told India Today.

It has been a slow crawl for the Arihant since she was launched at the shipbuilding centre in Vizag on July 26, 2009. It was four years before the next major milestone could be crossed, in August 2013 when the 83MW reactor onboard the submarine went critical.

Navy chief Admiral Robin Dhowan told mediapersons on December 3 that the submarine would commence its sea trials "very soon" and attributed the five-year time lag to the complexity of the platform and its equipment. Sources say the navy chief Admiral Dhowan wanted Prime Minister Narendra Modi to be present at the cast-off, but it failed to materialize because of scheduling reasons.

Naval officials say the sea sortie marks the first in a series of steps-submerged sea trials and weapon firing trials which the submarine will have to cover before she is ready for induction into the navy, a process which could take another year.

The navy plans a fleet of five SSBNs, all of them capable of firing nuclear-tipped ballistic missiles from under the sea. Two more Arihant class submairnes are being fabricated at the SBC in Vizag and are likely to be inducted over the next five years.

India currently operates one nuclear submarine, the INS Chakra (the ex Russian sub 'Nerpa') taken on a ten-year lease from Russia in 2012. One of the items on the agenda of recent summit-level talks between Russian President Putin and Prime Minister Narendra Modi is believed to have been the lease of a second SSN, the unfinished 'Iribis', left unfinished after the breakup of the Soviet Union.