INS Arihant SSBN


INS Arihant SSBN


INS Arihant SSBN is the first of India's nuclear powered missile submarine developed under the Advanced Technology Vessel (ATV) project initiated in 1974. The ATV project became a serious endeavor in 1985 after Mazagaon docks began construction of two German HDW 209 class submarines in 1984. Over Rs 30,000 crore have been spent on the project so far.

INS Arihant was launched by Gursharan Kaur, wife of Prime Minister Manmohan Singh on July 26, 2010, at Eastern Naval Command headquarters in Visakhapatnam.

The SSBN will be commissioned into the Navy in two years after completion of harbor and sea trials; and then weapon trials.

Harbor and Sea Trials

During harbor trials the submarine will be operated using external steam and power, instead of the steam and power generated using the onboard nuclear PWR. The crew will perform trim dives by pumping water in and out of its ballast tanks.

Following successful completion of harbor trials, the submarine's nuclear reactor will be made critical for sea trials and the submarine sailing under its own power. The initial focus will be on surface sailing and maneuvering at progressively increased speeds. Shallow dives will follow with diving depth being progressively increased.

The submarine will return to harbor following each dive to enable inspection of its hull.

The reactor will be powered up to its full 83 MWe capacity in phases and the submarine will be tested to its maximum depth.

Weapon trials will start on completion of the sea trials.

At a glance

Displacement: 6,000 tons
Length: 112m
Beam: 10m
Powerplant: 83 MWe PWR
Crew: 95
Surface Speed: 12-15 kts
Submerged Speed: 24 kts
Armament: 12 K-15 Sagarika missile, Torpedos, Torpedo launched cruise missiles


The Arihant is essentially a Navy project with BARC providing the reactor. The Navy designed the vessel, built its power plant, and did all the welding. Larsen and Toubro fabricated the hull. Various parts were built at Visakhapatnam, Mumbai and Kalpakkam, and assembled at Visakhapatnam.

The project is led by Vice Admiral D S P Verma (retd).

The boat's hull, made of titanium steel with a beam of 10m, is built at Hazira, Gujarat. The submarine was assembled in a completely-enclosed dry-dock called the Shipbuilding Centre (SBC) in Visakhapatnam. 

Operational Status

Addressing a press conference in New Delhi on December 2, 2011 Navy Chief Admiral Nirmal Verma said sea trials of Arihant will begin "some months from now" and operational patrols by sub before the end of 2012. 

"I had said that we will do so in 2012 and by and large we are on track. A firm date can be given only when we have the sea trials which will happen from some months from now," he said.

In November 2011, Srikumar Banerjee, Chairman, Atomic Energy Commission, and Secretary, Department of Atomic Energy told Frontline magazinethat the reactor on INS Arihant was likely to go critical in January or February 2012.

"I was actually hoping that it would be started up by the end of this year, but I am told now that it will be commissioned in January or February 2012. Some things are yet to be settled," he said.

On December 2, 2010, speaking at his annual press conference in New Delhi, Naval Chief Nirmal Verma indicated that there were some hiccups with commissioning the sub.

The delays were on account of the indigenous equipment that would be fitted on the submarine. "But I think we will be within time and commission the vessel by 2012," he added. 

As of September 6, 2010, the submarine had not completed its harbor trials and its nuclear reactor was yet to be fueled.

At the time of its launch, the submarine reactor was expected to be fueled and started in early 2010 following completion of harbor trials.

In an interview with The Hindu on September 2, 2010 Srikumar Banerjee, Chairman, Atomic Energy Commission (AEC) and Secretary, Department of Atomic Energy (DAE), said:

"Our nuclear steam supply system is ready 100 per cent. From our (DAE) side, everything is ready. We are only waiting for other systems to become operational so that we can start the commissioning activity of the reactor. I really do not know when the harbour trials will be done."

Banerjee also confirmed that DAE is already building more reactors for the additional submarines.

Nuclear Power Plant

The submarine is powered by a miniature 83 MWe pressurized water reactor (PWR) fueled by highly enriched uranium. The reactor was reportedly developed with Russian assistance. 

This enriched uranium for the reactor comes from the Rare Materials Project, an undertaking of the Department of Atomic Energy (DAE), situated at Ratnahallai, near Mysore.

In the past BARC has built Pressurized Heavy Water Reactors (PHWR) which use natural uranium as fuel and heavy water as coolant and moderator. PWR reactors use highly enriched uranium as fuel and light water as coolant and reactor.

Interestingly, the nuclear reactors that India imports in the future under the recently concluded Indo-US nuclear deal will be PWR reactors. By developing the submarine reactor BARC demonstrated that it had independently acquired PWR technology.

The challenge before BARC was to compact the reactor enough to fit it into the 10m diameter hull of the submarine.

"We have so far developed reactors built on the shore. But the submarine is a moving platform. It is rolling and pitching, and undergoes other kinds of motion. Against these, we have designed and developed this compact reactor. This is a major achievement," Dr. Srikumar Banerjee, BARC Director, told The Hindu.

Asked if the Russians helped in miniaturizing the reactor, Banerjee said:

"No, no. They were consultants...Consultancy was done for the whole submarine, not for the power plant alone."

A miniaturized PWR reactor, like the one on the Arihant, became critical inside a simulated submarine pressure hull at Kalpakkum on 11 November 2003. It was declared operational on 22 September 2006
has been running successfully since then.

The test reactor is fitted on a 42-meter-long land-based prototype submarine with eight compartments housing complex electrical and control systems and simulating ocean conditions.

Propulsion Reactor Project  director and Anil Kakodkar, chairman of the Atomic Energy Commission (AEC), showed the test reactor to media person a week after the launch of Arihant.

Speaking on the occasion Dr. Banerjee put Russian assistance in developing the reactor in perspective.

“We have used the Russians as consultants. As far as efforts in designing, developing and maintaining the reactor are concerned, they are entirely ours,” the BARC Director said.

S. Basu, Director, BARC Facilities at Kalpakkam, also asserted that “everything is totally indigenous” about the PWR developed at Kalpakkam. “It has been developed by us. It is 100 per cent our reactor,” he said. 

Enough Enriched Uranium for the Submarine Reactors

In an interview with The Hindu on September 2, Srikumar Banerjee, Chairman, Atomic Energy Commission (AEC) and Secretary, Department of Atomic Energy (DAE), confirmed that DAE will have enough enriched uranium to fuel the reactors of INS Arihant, as well as the follow-up submarines. 

"Our Ratnahalli plant capacity has been enhanced. But more than that, there is significant improvement in our technology. Usually, a term called Separating Work Units (SWUs) defines the technology level that we have achieved in this, and I can assure you that there has been considerable improvement in SWUs of our next generation caskets of centrifuges. The separating capacity of our centrifuges has improved. So total capacity enhancement at Ratnahalli has been done. We are confident of supplying the entire fuel for the set of….

"You cannot say anymore that India does not have enrichment technology. India has its own technology and we can produce [enriched uranium]. We have not started doing it for large-scale commercial nuclear power stations, which require a much larger quantity of enriched uranium. We will be able to do that once we go to Chitradurga.(Special Material Enrichment Facility in Chitradurga district in Karnataka)."

Based on Russian Charlie II subs

India is reported to have acquired design of the Charlie II class nuclear submarines from Russia and the ATV was based on those designs. Along the way, in January 1988, India leased a Charlie class nuclear powered submarines from Russia to help the Navy familiarize itself with operating a nuclear submarine. The leased submarine was christened Chakra in the Indian Navy which operated it for three years. After the term of the lease ran out, the sub was returned to Russia.

The Arihant is 112m long as compared to 103m Charlie class subs, probably because of a section was added in the middle to accommodate its four missile tubes.

Its 10m beam is the same size as a Charlie class sub.

Like the Charlie II subs, Arihant has a single nuclear power plant which gives it a rather limited underwater speed of 24 kts. Not enough to chase warships or get away from them when it is detected.

During the launch of INS Arihant on Sunday, July 26, Prime Minister Manmohan Singh did not mince words while acknowledging Russia's role in the fruition of the challenging project.

"I would also like to express our appreciation to our Russian friends for their consistent and invaluable cooperation, which symbolizes the close strategic partnership that we enjoy with Russia," he said.

Additional project details

A total of three submarines of the Arihant class are proposed to be built over the next five years. Hulls for two additional Arihant class subs are currently being built at Hazira, 

The launch of the submarine was initially planned for January 26, 2009.

"Things are in the final stage now in the ATV (advanced technology vessel) project. There were bottlenecks earlier...they are over now," minister A K Antony on Wednesday, February 11, during Aero India-2009.

The ATVs 100-member crew has undergone training in a locally developed simulator and at the School for Advanced Underwater Warfare, also at Visakhapatnam.

The launch date marks the tenth anniversary of the conclusion of the Kargil War.

The launch involved floating the submarine in SBC by flooding the drydock. Later the submarine will be towed out to an enclosed pier for its Harbor Acceptance Trials (HATs), which will be followed by Sea Acceptance Trials (SATs).

The HATs and SATs are expected to last one-and-a-half year, after which the submarine will undergo weapon trials.

The boomer submarines is expected to be commissioned into the Indian Navy within 2-3 years.

Weapon fit

The ATV will reportedly be equipped with 12 launch tubes of 2.4m diameter each. Initially, each missile tube will likely accommodate 3 0.74m diameter K-15 Sagarika missile. Later the tubes could accommodate the 2.0m diameter Agni IIISL (The submarine launched version of the Agni V / Agni 3+) missiles with MIRV capability.

Sagarika has a range of approximately 700 km (435 miles). It was last tested on February 26, 2008, off the coast of Visakhapatnam from a pontoon simulating the conditions of a submarine.
In addition to ballistic missiles, Arihant will eventually also have the capability to launch curise missiles through its torpedo tubes.

The Navy hopes to induct the first ATV by 2012.

Nuclear Submarine Base

India is reported to be constructing a nuclear submarine base on its eastern coast that will be named INS Varsha on commissioning. The Indian Navy spent about Rs 18 crore on the project in 2009 and 2010.

According to the Deccan Herald, the government sanction close to Rs 160 crore in the 2011-12 budget for the project, of which Rs 58 crore has been allocated for civil works and the the rest for setting up a VLF communication system.

The new base will berth the INS Arihant as well as INS Chakra, the Akula - 2 nuclear attack submarine being leased by India from Russia.

Two indigenous nuclear subs that are believed to be under construction are likely to be ready by 2020.


Though the Arihant is based on the Charlie II class, it likely incorporates a lot of advancements in propulsion, noise suppression, command and control, communication and sonar that the Russians learnt since they built the Charlie II subs, as well as what the Indians learnt while building German HDW 209 1500 submarines – INS Shalki and INS Shankul - in the late eighties to early nineties.

Unofficial illustrations of the boat show elements of Akula design like the towed sonar at the aft. However, Arihant is unlikely to be based on the Akula II or the more modern Graney class Russian subs, as reported in some sections of the press, since these subs use a twin hull design and are therefore considerably heavier. Not surprisingly the Akula is powered by a 190 MW reactor.

It is likely India has sourced components like propellers and shafts from Russia for the boat to minimize risks. 

The focus must have been on building a safe nuclear propulsion unit and adding ballistic missile launching capability to the submarine. 

A lot of recent speculation in the press has focused on the nuclear propulsion of the Arihant with many analysts saying that the success of the project depended on its reactor reaching criticality. BARC has an excellent track record and the reactor is likely to have been tested before being fitted. Nuclear subs routinely power up and down. There is good reason to believe that problems with the reactor have long been sorted out.

Once Arihant's nuclear propulsion is proven the focus will shift to weapon testing. 

Operational Capability

The Sagarika's limited range of 700km makes it inadequate even as a deterrent against Pakistan, let alone China. 

There have been misleading press reports that as a vital component of the India's credible minimum deterrent strategy, Arihant is designed to lurk in littoral waters of Pakistan and China to fire its very limited range nuclear missiles in case India comes under a nuclear attack. Nothing could be further from the truth.

It will be years, more likely decades, before the Navy acquires the confidence to send an Arihant class nuclear submarine close to the Chinese or even Pakistani mainland. At the very least the sub would need to repeatedly demonstrate its ability to operate under the sea for months without returning to base. 

Arihant's limited underwater speed of 24 kts makes it incapable of running away from modern warships once detected. Nuclear subs tend to be noisy when operating at max speeds, Arihant will in all probability be very noisy.

As soon as the submarine is deployed on patrol its movement will be tracked by the Americans and possibly by the Chinese. 

There isn't a boomer armed with nuclear missiles in the open oceans that isn't being tracked by America. Russian boomers that threaten America are essentially those that are lurking under the ice in the Arctic circle or in Russian coastal waters.

China has operated nuclear submarines for over 25 years now, but none of their submarines have ventured too far away from the Chinese mainland. Their subs are, however, equipped with missiles that can be launched at the US mainland from within Chinese waters.

The acknowledged range of the Sagarika missile, 700 km, is likely its range with a 500 kg warhead. With a lighter nuclear warhead it could conceivably go as far as 1500 km. Deployed in Indian territorial waters the Arihant can threaten Pakistan but not China.

Hopefully, DRDO will be ready with the Agni IIISL within a year or two which will give Indian Strategic Command the option to launch counter value nuclear strikes on mainland China from within Indian waters.

It could well be another 5 years before that capability is reached. 

It could probably be a decade before an Arihant nuclear submarine leaves the Indian ocean. 

It is likely that followup nuclear subs will accommodate more sections to carry at least 12 launch tubes insteade of the four that the sub currently carries. They will need more powerful nuclear power plants to propel their greater weight and achieve speeds in excess of 30 kts 

The ATV project appears to be well conceived and carefully calibrated. It has a good chance of succeeding despite past delays. Indian nuclear and missile technology is well developed and reasonably advanced, though DRDO's past record has not always been stellar.

Arihant Followup Submarines

The Arihant submarine is a technology demonstrator. 

A second submarine of its class is already under construction.

In July 2011 a high ranking sources told Deccan Chronicle that the keel of the project has been laid and the initial work is on full swing at a classified facility in Visakhapatnam.. The submarine is expected to be ready for sea trials by 2015.

The laying of the keel with 24 months of the launch of the first nuclear submarine, INS Arihant, reflected the growing maturity of the program, the sources said.

“The second program took far lesser time than Arihant to reach the shipyard from the drawing board. This time we had a clear plan and we had learned a lot from our mistakes,” sources said.

It was earlier reported that the reactors for the two follow-up nuclear submarines is already under construction.

Though exact details of the project's progress are not available, it is learnt that fabrication of the hull and body has begun. The reactor has been fabricated with the help of Russia.

Three submarines are being built under the ATV project, with the third being of a much larger size.

Indian Navy's long term acquisition plans include three SSBN and six SSN submarines.


Outgoing Russian ambassador, Vyacheslav Trubnikov, claimed in an interview in July 2010 that India's recently launched nuclear powered submarine – INS Arihant – is an Akula class submarine.

Speaking to the press on Wednesday, December 2, 2009, Naval Chief Admiral Nirmal Verma indicated that INS Arihant will be commissioned into the Navy with its full complement of ballistic missiles within two years.

"Work is going on apace. We will put it through sea trials. The timeframes will be done and closely monitored," he said.

The Naval Chief also indicated that India will continue to build nuclear submarines in the future to optimally utilize its huge investments in the project.


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