Arihant-class submarine

The Arihant class (Sanskrit, for Slayer of Enemies) is a class of nuclear-powered ballistic missile submarines being built for the Indian Navy. The lead vessel of the class, INS Arihant, has been launched for sea trails by August 2013. Four vessels are being built and are expected to be in commission by 2023.

The Arihant-class vessels are India's first indigenously designed and built nuclear submarine. They were developed under the US$2.9 billion Advanced Technology Vessel (ATV) project to design and build nuclear-powered submarines. INS Arihant is the first ballistic missile submarine to have been built outside the five permanent members of the United Nations Security Council.

Description
The Arihant class submarines will be ballistic missile submarines that are nuclear powered. They are being built under the US$2.9 billion Advanced Technology Vessel (ATV) project to design and build nuclear-powered submarines. They will be the first nuclear submarines designed and built by India. INS Arihant is the first nuclear submarine built outside the five permanent members of the security council.

The Arihant-class submarines will have a length of 112 m overall, a beam of 15 m and a draft of 10 m. They displace 6000 t and have a diving depth of 300 m. The complement is about 95, including officers and sailors.

The boats will have one seven blade propeller powered by an 83 MW pressurized water reactor. They can achieve a maximum speed of 12 - 15 kn when on surface and 24 kn when submerged.

The submarines have four launch tubes in their hump. They can carry up to 12 K-15 Sagarika missiles with one warhead each (with a range of 750 km), or 4 of the under-development K-4 missiles (with a range of 3500 km).

The Arihant-class submarines are reported to be similar to the Akula I class submarines of Russia. The Indian Navy will have the opportunity to train on INS Chakra, an Akula-class submarine, which the Indian Navy leased from Russia in 2012.

The lead boat of the class, INS Arihant is fitted with a combination of two sonar systems – USHUS and Panchendriya. USHUS is a 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.The hull features twin flank-array sonars and Rafael broadband expendable anti-torpedo countermeasures. The UPA government's report card carried an image of the lead vessel, which provided the first public glimpse of the completed submarine.

History
India continued to harbour deep ambivalence about nuclear weapons and did not accord a priority to their production until the 1970s. In December 1971, during the Indo-Pakistani War of 1971, the U.S. President Richard Nixon sent a carrier battle group named Task Force 74, led by the nuclear-powered USS Enterprise, into the Bay of Bengal in an attempt to intimidate India. In response, the Soviet Union sent a submarine armed with nuclear missiles from Vladivostok to trail the US task force. The salutary effect of the Soviet response demonstrated the deterrent significance of nuclear weapons and ballistic missile submarines to then Prime Minister Indira Gandhi. Following the 1974 Smiling Buddha nuclear test, the Director of Marine Engineering (DME) at Naval Headquarters (NHQ) initiated a technical feasibility study for an indigenous nuclear propulsion system (Project 932).

The Indian Navy's Advanced Technology Vessel (ATV) Project to design and construct a nuclear submarine took shape in the 1990s. First confirmation of the project came in 1998 from then Defence Minister, George Fernandes. The initial intent of the project was to design nuclear-powered fast attack submarines, though following nuclear tests conducted by India in 1998 at Pokhran Test Range and the Indian pledge of no first use, the project was re-aligned towards the design of a ballistic missile submarine in order to complete India's nuclear triad.

The ATV project overcame many challenges, the primary one being the design and miniaturization of the nuclear reactor. The lead vessel was first floated from its dry dock at a symbolic launch ceremony on 26 July 2009.

Development
The Arihant-class submarines are powered by an 83 MW pressurized water reactor (PWR) with highly enriched uranium fuel. The miniaturized naval version of the reactor was designed and built by the Bhabha Atomic Research Centre (BARC) at the Indira Gandhi Centre for Atomic Research (IGCAR) in Kalpakkam. A land-based prototype of the marine PWR was first built at Kalpakkam. It included a 42-meter section of the submarine's pressure hull containing the shielding tank with water and the reactor, a control room, as well as an auxiliary control room for monitoring safety parameters. The prototype reactor became critical on 11 November 2003 and was declared operational on 22 September 2006. Successful operation of the prototype for three years yielded the data and the confidence that enabled the production version of the reactor for Arihant. 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 BHEL; and Audco India, Chennai built the pressure valves.

Separately, infrastructure for testing the reactor subsystems was set up at the Machinery Test Centre in Visakhapatnam. Facilities for loading and replacing the fuel cores of the naval reactors in berthed submarines were also established at the Ship Building Centre.

Once the design was finalized, detailed engineering was implemented at Larsen and Toubro's submarine design centre at their Hazira shipbuilding facility using 3D modelling and product data management software. Tata Power SED built the control systems for the submarine. The steam turbines and associated systems integrated with the PWR were supplied by Walchandnagar Industries.

The lead vessel underwent a long and extensive process of testing after its "launch" in July 2009. Every sub-system of the propulsion and power systems on board the submarine was repeatedly tested with high-pressure steam trials of all pipelines. This was followed by harbour-acceptance trials that included submersion tests by flooding its ballast tanks and controlled dives to limited depths. Data gathered from her acceptance trials is expected to aid the development of nuclear submarines to follow. INS Arihant reactor went critical for the first time on August 10th, 2013, with harbour acceptance trials completed and sea trials expected later that year.

Ships in class
India has decided to construct more nuclear-powered Arihant-class submarines and three more submarines of this class are under construction (dubbed S-2, S-3 and S-4),. One submarine is being constructed at Visakhapatnam and two at Vadodara. India plans to built six of these submarines in long term. The first four vessels are all expected to be in commission by 2023. As of 2013, the lead boat Arihant is undergoing sea-trails with its nuclear reactor active.

Video

 * http://www.ndtv.com/news/videos/video_player.php?id=1138779
 * http://indiatoday.intoday.in/index.php?option=com_magazine&opt=section&sectionid=86&secid=0&videoid=53438&ptype=video