<P> In December 1971, during the Indo - Pakistani War of 1971, the US President Richard Nixon sent a carrier battle group named Task Force 74, led by the nuclear - powered USS Enterprise into the Bay of Bengal in an attempt to intimidate India . In response, the Soviet Union sent a submarine armed with nuclear missiles from Vladivostok to trail the US task force . The event demonstrated the significance of nuclear weapons and ballistic missile submarines to then Prime Minister Indira Gandhi . Following the 1974 Smiling Buddha nuclear test, the Director of Marine Engineering (DME) at Naval Headquarters initiated a technical feasibility study for an indigenous nuclear propulsion system (Project 932). </P> <P> The Indian Navy's Advanced Technology Vessel project to design and construct a nuclear submarine took shape in the 1990s . Then Defence Minister George Fernandes confirmed the project in 1998 . The initial intent of the project was to design nuclear - powered fast attack submarines, though following nuclear tests conducted by India in 1998 at Pokhran Test Range and the Indian pledge of no first use, the project was re-aligned towards the design of a ballistic missile submarine in order to complete India's nuclear triad . </P> <P> The Arihant - class submarines are nuclear powered ballistic missile submarines built under the Advanced Technology Vessel (ATV) project . They will be the first nuclear submarines designed and built by India . The submarines are 112 m (367 ft) long with a beam of 11 m (36 ft), a draught of 10 m (33 ft), displacement of 6,000 tonnes (5,900 long tons; 6,600 short tons) and a diving depth of 300 m (980 ft). The complement is about 95, including officers and sailors . The boats are powered by a single seven blade propeller powered by an 83 MW (111,000 hp) pressurised water reactor and can achieve a maximum speed of 12--15 knots (22--28 km / h) when surfaced and 24 knots (44 km / h) when submerged . </P> <P> The submarines have four launch tubes in their hump and can carry up to 12 K - 15 Sagarika missiles with one warhead each (with a range of 750 km or 470 mi) or 4 K - 4 missiles (with a range of 3,500 km or 2,200 mi). The submarines are similar to the Akula - class submarine of Russia . The Indian Navy will train on INS Chakra, an Akula - class submarine leased from Russia in 2012 . </P>

Which is the first nuclear submarine to be designed and built in india