India's First Nuclear Sub Undergoes Sea Trials

India's First Nuclear Sub Undergoes Sea Trials
NEW DELHI, July 26 -- India on Sunday launched its first indigenously built nuclear-powered submarine for sea trials, making it the sixth nation in the world to possess such sea attack capabilities.

The dream of over a quarter of a century will be fulfilled today when Ms Gursharan Kaur, wife of Prime Minister Manmohan Singh, breaks the coconut on the hull of India’s first indigenously constructed nuclear- ,ballistic missile submarine — called a boomer in popular parlance — at a super- secret Naval base in Visakhapatnam.

At that moment, the 112- metre long black marine monster, now named Arihant ( destroyer of the enemy), will be pulled out of its lair — a covered dry dock, nearly halfa- kilometre long and 50 metre deep — where it has been conceived and grown. The building, called the Ship Building Centre at INS Virbhau, the Navy’s base in Vizag, is at the very end of the harbour.

The Indian Navy and the Defence Research and Development Organisation ( DRDO) have expended a great deal of treasure and sweat to reach this point. A year from now, after harbour and sea trials, the Arihant, with a complement of 23 officers and 72 sailors, will join the naval fleet.

What is so special about a boomer? Everything, if you see it from the point of view of the country’s nuclear deterrent.

Because of India’s “ no first use” pledge, our weapons must survive a first strike for retaliation.

So the Arihant’s primary weapon is stealth. It can lurk in ocean depths of half a kilometre and more and fire the Sagarika from under the sea. The key lies in its nuclear propulsion. The nuclear reactor of the sub generates heat to turn water into steam in a generator which, in turn, drives the turbine generators which supply the ship with electricity and drive the main propulsion turbines and propeller. There is no stage which requires air or oxygen.

SUBMARINES can be detected by sonar, or sound ranging, and so not only has the Arihant’s propulsion system given a double shield, its outer hull is covered by thick rubber tiles studded with conical gaps that trap sound.

After the first trial of the steam cycle and turbines, the Arihant will be hooked up to the nuclear reactor. The reactor’s fuel rods are currently locked and sealed.

They will be unlocked and neutrons will be introduced to start up the 85 MW pressurised water reactor. The reactor will work continuously for anything up to 10 years till the fuel runs out.

Then it will be brought back to the dock, the reactor compartment will be cut open, new fuel rods inserted and resealed.

Arihant’s construction got underway in 1998 with Larsen & Toubro machining 13 sections of the hull at its plant in Hazira to a design provided by the Malakit design bureau of Russia. These were then taken in a barge to Vizag and outfitted with their respective equipment — missile launchers, combat information systems, torpedo tubes, ballast tanks, living spaces, sonars, steam generator and turbine and so on. Then they were welded into three distinct sections.

The first contained the sonar equipment, torpedo tubes and control systems. The second section comprised of the combat information systems and an array of electronic equipment, accommodation as well as the ballistic missile launchers. The third section, distinct and specially shielded, comprised of the reactor and the steam turbine and gearings.

Considering that India began its first project for the sub in the late 1970s, you could well ask why it has taken so much time.

The short answer is that we are not as advanced as we think we are when it comes to engineering, metallurgy, and nuclear science.

The first glimmer of this was visible when in the early 1980s the first project ran aground after spending some $ 4 million ( Rs 20 crore). The second project under the auspices of the DRDO worked on different assumptions, but even it has had a rocky ride.

The plan was for India to acquire the drawings of the Russian Charlie II submarine and fabricate it, and at the same time design its own 100 MW reactor. A new Advanced Technology Vessel programme was created. At the same time, in 1988, a Charlie II, renamed Chakra, was leased from the Soviet Union. The idea was to run it till we had made our own.

UNFORTUNATELY, the Soviet Union collapsed and there was no extension of the lease. By then we had created a number of facilities which included a special pier with a 60- tonne crane, radiation safety services, swimming dock, slipway and workshop, but the project remained in the doldrums.

This was the time, in the mid- 1990s, when the ATV organisation realised how much of a long haul it would be. Components and assemblies for nuclear- propelled submarines had to have a very high quality requirement, something the country lacked.

For obvious reasons, precision welding is one of the most important aspects of submarine construction.

More troubling was the fact that the reactor made by the Indira Gandhi Atomic Research Centre, Kalpakkam could not make grade. Once again the Russians helped, quietly.

They provided equipment for two VM- 5 pressurised water reactors, one of which was assembled and tested at Kalpakkam’s Prototype Testing Centre in 2004. The Russians have also been helping with the design of the Sagarika, the ballistic missile that will be the main weapon of the Arihant.

The big challenge for the engineers was to use the Charlie II design and modify it by adding one more compartment, the one that carried the ballistic missile tubes which increased its length by 10 m or so. But they managed this and earlier this year the reactor and propulsion unit was finally welded to the other two units. Many Indian companies have been involved. The uranium, enriched at around 20 per cent, has been provided by the Indian uranium enrichment facility at Ratnehalli, near Mysore.

India has another nuclear- propelled submarine en route in 2010, an Akula- class Russian attack submarine which differs from the Arihant which is a ballistic missile sub. Such subs are used to hunt down enemy submarines and ships. Curiously, no one seems to know who wants the Akula. The Navy brass insists it is not them. But the country is expected to spend $ 700 million ( Rs 350 crore) to lease it for a period of 10 years. But then this is what keeps the country’s defence purchases booming.