Indian Prime Minister Manmohan Singh with other dignitaries at the launch ceremony of Arihant. PIB 
India's air force and army are already capable of delivering nuclear warheads. A third delivery platform will be in place once Arihant joins the Navy and is christened INS Arihant. This could take more than two years if all goes well.
With Arihant's birth, India now becomes part of an exclusive club of countries that build and operate nuclear submarines. Russia, China, France, the US and UK are the other nations. The Americans have close to 70 such vessels and the Chinese 10.
India is committed to a no first-strike policy. So, in the event of an adversary attacking the country, it's quite likely that the army and air force will take a major hit first. A nuclear-propelled submarine will provide India the capability to retaliate in such a scenario.
Lurking deep under water, a nuclear submarine can last long stretches there and rarely has the need to surface, unlike submarines that are diesel and battery powered. But then, even a nuclear submarine has to deal with the endurance limitations of its crew. Similarly, even boomers — Naval lexicon for nuke subs — need upkeep and maintenance.
So, for the nuclear submarine arm of a Navy to be effective, it would need a minimum fleet strength of at least three to four vessels—which the Indian defence establishment is acutely conscious of. Nuclear submarines need to rotate their voyages. While some are berthed, others are on the prey. This is why no time was wasted in starting work on the second Arihant-class vessel at Visakhapatnam's Ship Building Centre dry docks the moment the first vessel slipped out and headed for the steam turbine test facility which is part of the same Visakhapatnam facility.
As of now, the Arihant is armed with only medium-range (250km-350 km) Sagarika K-15 missile systems. In order to be real killers, these subs will need to be loaded with Inter-continental Ballistic Missiles (ICBMs) with ranges of 5,000 to 7,000 km. Scientists at the Defense Research and Development Organisation (DRDO) are working on these.
Till Sunday (July 26, 2009), the 112-metre-long Arihant, based on a Russian Charlie-II class model, was sitting in a half-km long, 50 metre deep covered dry dock at the Ship Building Centre. It saw the light of the day after a gestation that lasted close to a quarter of a century.
An 85-MW nuclear reactor powers the Arihant. The beast would need a 95-member crew to man it. Though its technical specifications are classified, reports suggest its seven-blade skewed propeller is fuelled by a steam-driven turbine and generators. The nuclear reactor generates heat to convert water into steam, which in turn drives the turbines providing the submarine propulsion and thrust.
Other than the Sagarika K-15s, the Arihant is also armed with torpedoes and land attack missiles. A product of cutting-edge engineering that leaves no margin of error, the Arihant has been in the works since 1967, when the Indian Navy and Bhabha Atomic Research Centre (BARC) mooted the concept of nuclear propulsion for naval systems. In 1976, Raja Ramanna and BARC scientists devised a nuclear submarine reactor design. But the project failed to make much headway.
In 1984, the Advanced Technology Vessel project was launched. Meantime, India leased a Charlie-II class nuclear submarine on a three-year deal from the Russians. India had to wait until 1998 for the hull of its own ATV to be laid. Larsen Toubro, a private sector giant, was roped in. Nine years later, the 85 MW nuclear reactor was fused into the hull.
The next big step now would be to ensure the nuclear reactor attains criticality. A painstaking series of trials would follow. These are all the more important because even a minor slip-up with a nuclear submarine could result in catastrophic consequences. The recent Kursk accident was a case in point. This Oscar-II class Russian nuclear cruise-missile submarine sank in the Barents Sea on August 12, 2000 with all crew.
