Magazine Report: India’s Secret Undersea Weapon

THE SECRET UNDERSEA WEAPON
by Sandeep Unnithan

Located up the winding shipping channel in Visakhapatnam harbour is a secret, completely enclosed facility known only as the Shipbuilding Centre (SBC). Inside this dry dock, nearly 50m below ground level, is a cylindrical black shape, which is as tall as a two-storey building and at 104 m in length, is longer than the Qutub Minar lying on its side. Technicians working on it confess to a surge of national pride: India’s first nuclear-powered ballistic missile submarine or SSBN is arguably its greatest engineering project.

For over a quarter of a century, the Advanced Technology Vessel (ATV), smaller than the USS Alabama from Crimson Tide, has been among the most highly-classified government programmes, if not the most delayed. Officials still refuse to confirm the existence of the project or the sea-based ballistic missile. A decade after India came out of the nuclear closet in the sands of Pokhran, it has moved some tantalising steps closer to realising the third and possibly the toughest of the three legs of the triad enunciated in its nuclear doctrine: a sea-based deterrent
or a secure underwater platform for launching nuclear weapons.

“Things are developing as per schedule,” Defence Minister A.K. Antony recently said of ATV. Early last month, Chief of the Naval Staff Admiral Sureesh Mehta was the first government official to not only confirm its existence but also lay down a timeframe: “It is a DRDO project and a technology demonstrator. It is somewhere near completion and will be in the water in two years.” The admiral had reason to feel confident about the project. Just last month, an 80MW nuclear reactor, smaller than a bus, was pushed into the hull of the submarine and successfully
integrated—a milestone in the project approved by the then prime minister Indira Gandhi in 1970.

By April 2009, the submarine will be launched and will begin sea trials before it is inducted into
the navy. The goal is to field a fleet of three SSBNs by 2015, one in reserve and two on patrol, each carrying 12 nucleartipped ballistic missiles. Possibly the last “gift” to India from the now-extinct Soviet Union, it was designed with Russian assistance in the late ’80s. Based on an entirely new design, the 6,000 tonne submarine (not the elderly Charlie class N-sub as thought earlier) will make India the world’s sixth nation to operate a “boomer”.

Part of the acceleration in the programme has to do with the rapid buildup of Chinese nuclear forces. China operates 10 nuclear submarines, and in the past year, has fielded as many as three new Jin-class SSBNs, each carrying 12 submarine-launched ballistic missiles (SLBM). “Given the growing military asymmetry with China, India’s need for a reliable nuclear deterrent that can survive a first strike has never been greater,” says strategic expert Brahma Chellaney.

ATV is in line with India’s nuclear doctrine enunciated in 1999, which calls for its nuclear forces to be effective, enduring, diverse, flexible and responsive to the requirements in accordance with the concept of credible minimum deterrence. The doctrine calls for high survivability against surprise attacks and for a rapid punitive response. A nuclear submarine that can remain submerged almost indefinitely and cannot be detected underwater, therefore, meets all these criteria and offers an almost invulnerable launch platform for nuclear weapons. For a country like India with a no-first use policy, it is vital because it prevents a potential adversary from launching a crippling first strike that can knock out all nuclear weapons. It also allows India to inflict considerable damage to the aggressor.

“One submarine carries at least 12 missiles with Multiple Independently Targetable Reentry Vehicles, which could mean as many as 96 warheads. When such a submarine goes out to the sea, that many missiles are removed from our own territory. The enemy’s targeting of that many sites gets neutralised,” says Rear Admiral (retired) Raja Menon.

ATV, with its suitably muted acronym, was a euphemism for a longdelayed project. Shrouded in obsessive secrecy for decades, it has been under the direct supervision of the prime minister, who also chairs ATV’s apex committee. Nearly 200 naval officers and technicians are directly involved in the project that is managed by a vice-admiral who functions out of ATV headquarters in Delhi Cantonment. Funding was never a problem, even during the lean days of defence spending, like in the pre-1990s. An estimated Rs 2,000 crore was spent even before work on the submarine was started.

The excessive secrecy, say experts, was based on a misinterpretation of the Non-Proliferation Treaty (NPT)—that building a nuclear submarine would be a violation. There was, therefore, a lack of accountability, which harmed the project. Project officials in Vizag are now sealing the reactor with a special shield and plugging in the control systems, turbines and piping. The next few months are critical. After the reactor compartment is sealed, the tail sector— which includes the propeller and the shaft—will be welded in and the submarine will be ready.

By April next year, the dry dock will be flooded andthe vessel will be officially launched. After it hits the water, the nuclear reactor will be jump-started and the submarine’s propellers — seven highlyskewed brass blades—will be tested. After the reactor and all its associated control systems are successively proven, the submarine will be towed out of the harbour for extensive sea trials lasting over a year before it is inducted into the navy around 2010. While the impending launch of ATV is reason for cheer, the actual fielding of a secure second-strike capability is still three years away. This is the time it will take to integrate and successfully test fire the missile from the submarine. Without its nuclear missiles, the submarine is just a platform.

The missile is being concurrently developed under an equally-classified programme. Announcing its successful test in April last year, DRDO chief M. Natarajan called it “a strategic system which I cannot talk about”. The enigmatic two-stage missile—dubbed K-15 under the Defence Research and Development Organisation’s (DRDO) Sagarika (oceanic) project — is a technological breakthrough. Rapidly ejected from the submarine’s launcher by igniting an underwater gas booster, it rises nearly 5 km above the ocean. When it reaches a pre-determined
height, it ignites a solid booster and travels to a range of nearly 750 km. Tested three times from a specially-designed submersible pontoon, the yet to-be-named “naval missile” is another feather in India’s cap. The 100-member crew, which will man the submarine, is being trained at
an indigenously-developed simulator in the School for Advanced Underwater Warfare (SAUW) at the naval base in Vizag. Hands-on training will be done on the INS Chakra, a 12,000-tonne
Akula-II class nuclear-powered attack submarine being taken on a 10-year lease from Russia next year.

SBC in Vizag is to become the assembly line for three ATVs, costing a little over Rs 3,000 crore each or the cost of a 37,000 tonne indigenous aircraft carrier built at the Cochin Shipyard. Larsen and Toubro (L&T) has begun building the hull of the second ATV at its facility in Hazira, to be inducted into the navy by 2012. The SSBN fleet will be housed on the east coast at a new naval base in Rambilli, a few kilometres south of Visakhapatnam, where nearly 3,000 acre of land has been acquired for India’s first strategic base, to be manned entirely by military personnel. Unlike the narrow single channel in Visakhapatnam, it will offer the nuclear fleet direct access into the sea. The first phase of the project, costing approximately Rs 1,500 crore, will be ready by 2011.

Why has the project taken so long? For a country that built only two conventional submarines of the Germandesigned HDW Type 1500 class in the early ’90s, building a nuclear submarine was the ultimate challenge: a DRDO official sees the learning curve to be the equivalent of a scooter mechanic building a Mercedes. The key challenge, however, was not in designing or fabricating the hull, but the reactor and containment vessel, which consumes one-tenth (nearly 600 tonne) of the vessel’s total displacement. The hydrodynamics of a vessel with one-tenth of its weight concentrated in one place is a formidable naval engineering challenge, but miniaturising a nuclear reactor the size of a football field to fit inside an 8m enclosure is an even bigger hurdle. This was among the reasons for the decade-long delay in the project. The nuclear reactor in a submarine
generates heat to convert water into saturated steam to turn the submarine’s turbines. Unlike an oilfired boiler, it does not require air to operate. All other parts of the submarine are the same as any steam-powered turbine plant’s. The reactor operates on uranium enriched to nearly 45 per cent (uranium used in civilian nuclear reactors is less than 5 per cent and bombs use uranium enriched to over 90 per cent).

In 1998, L&T began fabricating the hull of ATV but the struggle with the reactor continued. After BARC designs failed, India bought reactor designs from Russia. By 2004 the reactor had been built, tested on land at the IGCAR and had gone critical. Its modest size, around 6,000 tonne (the Ohio class SSBN in the movie Crimson Tide weighs over 14,000 tonne), has led experts to call it a “baby boomer”.

While the present project ends at three units, defence officials have not ruled out building larger submarines on the basis of national strategic imperatives. These have changed since the conception of the project. The plan, until late ’80s, was to build an SSN—a fast-moving deep-diving nuclear-powered attack submarine, which would hunt surface ships. Around the time India leased a Charlie-I class nuclear-powered attack submarine from the Soviet Union, it had
already veered towards building a submarine carrying ballistic missiles. The hull design was lengthened and the SSN quietly transformed into an SSBN. There are, however, some key challenges to be overcome. ATV’s SLBMs have a range of only 750 km, a big leap from its start of 250 km a decade ago, but still smaller than the SLBMs deployed by the Big Five, which boast ranges in excess of 5,000 km. DRDO is working on fielding a submarine launched variant of the 5,000-km Agni III missile, which will give the submarine true striking power and flexibility.

cientists believe the submarine’s present reactor output of around 80 MW is limited because it imposes operational restrictions on the submarine’s speed and will mean that the reactor will have to function near peak power at most times. The reactor would also need constant refuelling — a fairly expensive process where the hull is cut open and the nuclear cores replaced every decade.

For the moment, however, the immediate challenge lies in successfully sending the submarine out to the sea.