Nuclear Submarine Project – Arihant

INS Arihant is India’s first nuclear-powered submarine. The ship submersible ballistic, nuclear (SSBN) submarine was launched at the Indian Navy’s dockyard in Visakhapatnam, which is the headquarters of India’s Eastern Naval Command.

Indian Prime Minister Manmohan Singh, who has inaugurated the vessel into the Indian Navy, asserted that the indigenously built submarine would be used for self defence. The name Arihant derives from two words – Ari meaning enemy and Hanth meaning destroy.

Arihant, India’s first indigenously built nuclear submarine, cost $2.9bn. It was jointly developed by the Indian Navy, Bhabha Atomic Research Centre (BARC) and Defence Research and Development Organisation (DRDO) at the naval dockyard in Visakhapatnam. Russian designers assisted in building the vessel.

Other companies involved in the development of the submarine are Tata Power, a division of Tata Group and Larsen & Toubro (L&T), a technology, engineering, construction and manufacturing company.

The project, earlier known as the advanced technology vessel (ATV), has been under development since 1998. Construction of five more nuclear-powered submarines is also being planned. According to a report in the Indian Express, the hulls of the second and third submarines have already been constructed.

Arihant will be commissioned into the Indian Navy after extensive sea trials for at least two years. Initially harbour acceptance trials (HATs) would be conducted followed by sea acceptance trials (SATs).

Arihant has been developed as part of the military modernisation programme undertaken by India. The Indian Navy has a fleet of 16 diesel-electric submarines leased from Russia and Germany. However, the disadvantage with diesel electric submarines is that they cannot stay under water for an extended period.

“INS Arihant is India’s first nuclear-powered submarine.”

Conventional diesel-electric submarines have to ascend to the surface each day to eject carbon dioxide produced by the generator. Nuclear-powered submarines, on the other hand, can stay under water for long durations without being detected. Arihant is expected to enhance the Indian Navy’s capability of delivering nuclear weapons from all terrains.

Arihant’s design is based on the Russian Akula-1 Class submarine. It weighs 6,000t. At a length of 110m and breadth of 11m, Arihant is the longest in the Indian Navy’s fleet of submarines and can accommodate a crew of 95. It can reach a speed of 12kt-15kt on surface and up to 24kt when submerged.

Arihant will be able to stay under water for long periods undetected due to the nuclear-powered 80MW pressurised water reactor (PWR). The PWR was developed by the Bhabha Atomic Research Centre with assistance from a Russian design team.

The submarine’s exterior is uneven and the hull is placed on a mat covered with tiles. The tiles help in absorbing sound waves and provide stealth capability to the submarine. Compared to conventional submarines, the conning tower of Arihant is situated near the bow instead of the centre.

The central part of the submarine’s body consists of the outer hull and an inner pressurised hull. The starboard side consists of two rectangular vents that draw in water when the submarine submerges into sea.

The Indian Navy and the DRDO together designed the submarine. Once the design was finalised detailed engineering was implemented at L&T’s submarine design centre using 3D modelling and product data management software.

Tata Power designed the control systems for the submarine. Walchandnagar Industries, a company specialising in execution of heavy engineering projects, designed parts of the steam turbine.

Tests and delivery

The trials are being conducted at a concealed test area called ‘Site Bravo’. During harbour acceptance trials, the nuclear power plant and auxiliary systems of the submarine will be tested for stability.

“Arihant has been developed as part of the military modernisation programme undertaken by India.”

The most crucial part of the trials will be the firing of the reactor. Once the reactor is fired all systems on board are tested on the inherent power of the submarine.

Arihant will be taken for a series of high-speed runs during the sea acceptance trials and its various components will be tested at different depths, temperatures and pressure.

The final phase of the trials will include weapon trials. During these trials actual firing of submarine-launched ballistic missiles (SLBM) will take place from the platform.

The crew of Arihant will be trained on the 12,000t Akula-II submarine. The submarine will be taken on lease from Russia in 2010 for ten years. Apart from the Akula-II submarine, six Scorpene attack submarines will also be acquired by the Indian Navy between 2012 and 2017.

Arihant armament

Arihant will be capable of carrying all types of missiles and will have underwater ballistic missile launch capability. It will carry 12 K-15 SLBMs that can be launched even under ice caps.

Tested in 2008, the K-15 missiles are 10.4m long and have a diameter of 1m. The 6.3t missiles can carry a 5t nuclear warhead targeted 750km away. The K-15 missiles, however, will be replaced later by the 3,500km range K-X missiles.

Apart from the K-15s, the submarine will carry a range of anti-ship and land-attack cruise missiles and torpedoes.

Submarine propulsion

A significant progress in the development of Arihant took place when the land-based pressurised water reactor became operational in 2004 at the Indira Gandhi Centre for Atomic Research in Kalpakkam, Chennai. Following this, miniaturisation of the land-based PWR had to be carried out to enable it to fit into a confined space in the submarine. The reactor consists of 13 fuel assemblies each having 348 fuel pins.

Several companies supplied components of the reactor. High grade steel supplied by Heavy Engineering Corporation, Ranchi was used to build the reactor vessel. The steam generator was provided by Bharat Heavy Electricals Limited (BHEL); and Audco India, Chennai built the pressure valves.

The PWR consists of a huge pressure hull, a tank containing water and a reactor. It also consists of a pressure vessel built from unique steel, a control room as well as an auxiliary control room.

The propulsion plant housing the reactor is 42m long and 8m in diameter. The complete propulsion plant along with the primary, secondary, electrical and propulsion systems occupy half of the submarine. To reduce the weight of the plant, light water and enriched uranium was used as opposed to non-enriched uranium used in land-based reactors.

Control and communication systems

Arihant is fitted with a combination of two sonar systems – Ushus and Panchendriya. Ushus is state-of-the-art sonar meant for Kilo Class submarines. Panchendriya is a unified submarine sonar and tactical control system, which includes all types of sonar (passive, surveillance, ranging, intercept and active). It also features an underwater communications system.

A new submarine promises to give the world’s most populous democratic nation a powerful second-strike nuclear capability. The INS Arihant, India’s first nuclear ballistic-missile submarine, will finally give the country nuclear weapons that could survive a surprise first strike and go on to deal a crushing retaliatory blow to the enemy. The new sub will complete India’s triad of air, land and sea nuclear forces.

India tested its first weapon, an eight-kiloton device nicknamed Smiling Buddha, in 1974. Although small in yield, the device was a remarkable technological achievement that thrust the young country into the exclusive, so-called “nuclear club” that had until then consisted of the United States, Soviet Union, United Kingdom, France and China.

India is believed to have 520 kilograms of plutonium—enough for, according to the Arms Control Association, “100 to 130 warheads.” New Delhi describes this a “credible minimum deterrent” against neighboring nuclear powers China and Pakistan. India has a firm No First Use policy with regard to nuclear weapons, vowing to never be the first to use them in any conflict and only use them to retaliate in kind.

Nuclear-armed submarines are an ideal basing solution for a country such as India. While less accurate than land-based missiles and less flexible than air-launched weapons, ballistic-missile submarines are the most difficult to destroy in a first strike. Hiding in the vastness of the oceans, a nuclear-armed submarine is nearly invulnerable. And, in the logic of nuclear deterrence strategy, an invulnerable nuclear arsenal makes for an invulnerable country.

The Arihant program goes back more than three decades, to the vaguely named Advanced Technology Vessel. Begun in 1974, ATV was broadly conceived as a project to research nuclear propulsion and, down the road, field a indigenously developed and constructed nuclear-powered submarine. The program was a collaboration between the Bhabha Atomic Research Centre, the Indian Navy and the Indian government’s Defence Research Development Centre.

By 1995, ship-sized reactor trials were underway at the Bhabha Centre in Mumbai. According to Combat Ships of the World, the reactor had been under development since 1985, weighed 600 tons and was “entirely unsuccessful.” By 1989, Russian nuclear scientists and engineers joined the project, and yet the program still failed to yield a viable reactor. In 1998, the Indian government threw in the towel and purchased a reactor design outright from Russia, and by 2004, a working eighty-megawatt prototype reactor had been built, tested and achieved criticality.

Hull began construction in 1998 at Visakhapatnam, but could not be completed due to the lack of a working reactor. The hull itself is variously reported as based on the Russian Akula/Project 971–class nuclear attack submarine or the ex-Soviet Charlie II class. Combat Fleets of the World claims it is based on the Akula, and lengthened an additional thirty feet to accommodate a missile compartment. Other sources claim it is based on the Charlie II class, one of which was leased to India from 1988 to 1991 and served as INS Chakra. At either rate, the submarine is estimated to be 330 to 360 feet long, with submerged displacement of 6,500 tons. It is the smallest ballistic-missile submarine in the world, with the possible exception of the North Korean Gorae class.

Thanks to nuclear propulsion, Arihant can do twelve to fifteen knots on the surface and twenty-four knots underwater. Maximum diving depth is unknown, and probably a closely held secret, but the Akula class is known to dive to six hundred meters. The submarine is manned by a crew of ninety-five to one hundred.

Arihant was officially launched in 2009. The onboard reactor reached criticality in 2013, and the ship began sea trials in late 2014. It was officially commissioned into service in August 2016. According to Naval Technology, the total price tag was $2.9 billion.

Arihant’s name literally translates to “Slayer of Enemies,” and the ship’s armament makes it the greatest concentration of firepower in Indian history. The submarine was built with four missile tubes mounted in a hump behind the conning tower. The four can carry twelve K-15 Sagarika (“Oceanic”) short-range ballistic missiles. K-15 has a maximum range of just 434 miles, making it capable of hitting just the southern half of Pakistan.

Alternately, the sub can carry four K-4 medium-range ballistic missiles with a 2,174-mile range, capable of hitting targets as far away as Beijing. Both the K-4 and the K-15 are nuclear capable, but the warhead yield is unknown. India has yet to master multiple independently targetable reentry vehicle (MIRV) technology, so whatever the yield of the warhead, K-4 and K-15 carry just one of them.

In order to be credible, a seagoing nuclear deterrent must have at least one submarine on patrol at all times. The second ship in class, Aridhaman, is under construction in Visakhapatnam, and India plans to have as many as four boomers by 2020—the same number as the United Kingdom and France. With the four nuclear-armed boats completed, India may finally achieve its goal of strategic invulnerability.

Covert Shores

1 thought on “Nuclear Submarine Project – Arihant

  1. Pingback: Nuclear Submarine Project – Arihant – faujibratsden

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