INS Arihant

The Indian Navy leased a Project 670A Skat (Charlie I Class) nuclear-powered submarine (INS Chakra in Indian Naval service) for three years - from 04 January 1988 to January 1991. The boat was was manned by a Russian crew who also had the task of training Indian submariners on how to operate the nuclear-powered vessel. In addition to becoming a training ground, INS Chakra also acted as a design laboratory for developing and testing indigenous nuclear submarine technologies. The lease was not extended after January 1991 and the submarine was returned back to Vladivostock, Russia where it was decommissioned from Russian naval service. The Russian crew that trained the Indian submariners have reportedly taken key posts, probably in the Indian Naval Design Organisation, to design India's first nuclear-powered submarine codenamed the Advanced Technology Vessel (ATV). This top secret project has facilities in New Delhi, at Visakhapatnam and Hyderabad in Andhra Pradesh and at Kalpakkam in Tamil Nadu. The plan is for a class of five submarines fitted with long-range, nuclear-tipped missiles. A nuclear-capable missile (Sagarika) is reportedly under development at the Aeronautical Development Establishment (ADE) at Bangalore, Karnataka.

The naval wing of DRDO (Defence Research & Development Organisation) manages the organization and since 1985 has always had a retired Vice Admiral in charge. Vice Admiral Bharat Bhushan is the first known Director General of the program. In late 2000, the project was given a new lease of life with the appointment of Vice Admiral R.N. Ganesh (Retd) to take charge. An experienced submariner, he was the first commander of INS Chakra. In early 2004, Vice Admiral P.C. Bhasin (Retd) was appointed as the head of the ATV program, as he was the former Chief of Material. As per a news article in domain-B, dated 19 May 2007, Vice Admiral Arun Kumar Singh (Retd) is to be appointed as the new Director General (DG) of the highly-classified ATV program. He too had commanded INS Chakra during her service with the Indian Navy. He also commanded submarine shore establishments, INS Virbahu and INS Satvahana and served as the Director of Submarine Operations. As the Assistant Chief of Naval Staff (Submarines), he authored the Indian Navy's 30 year submarine construction program and was also responsible for the modernisation of the submarine force, primarily the Sindhugosh Class boats.

Rahul Bedi in a news article in IndiaPRWire, dated 17 May 2007, stated the following;

The vessel will be based on the Charlie I Class boat and will be 124 meters long, have a displacement of 4000 tons and be fitted with a 100 MW nuclear reactor, developed jointly by DAE (Department of Atomic Energy) and DRDO (Defence Research & Development Organisation). Bharat Rakshak Note: Earlier reports indicated that the boat could likely resemble the Russian Navy's new Severodvinsk Class attack submarine and/or the Akula Class attack submarine, of which the Indian Navy reportedly plans to lease a pair.

The 100 MW nuclear reactor went critical in October 2004 at Kalpakkam and is now fully operational. A miniaturised version of the reactor is under construction for integration into the ATV at Visakhapatnam. In July 2006, then-incumbent Defence Minister Pranab Mukherjee inspected the ATV's reactor project while participating in the 20th anniversary celebrations of the commissioning of the Fast Breeder Test Reactor at the Indira Gandhi Centre for Atomic Research in Kalpakkam. Earlier, in October 2004, Prime Minister Manmohan Singh visited the ATV facility when he launched the construction of the Prototype Fast Breeder Reactor. The Prototype Testing Centre at Kalpakkam will be used to test the boat's turbines & propellers while a similar facility at Visakhapatnam will run trials on the vessel's main turbines & gearbox.

Officials familiar with the ATV project stated that the highly enriched uranium fuel for the reactor was supplied by the Rare Materials Project (RMP) in Ratnahalli near Mysore, Karnataka. The four to five years delay in the reactor reaching criticality, was due to the extended time taken by RMP to produce an adequate quantity of uranium, the officials added. While many components of the reactor like the steam-generator and the control rod mechanism have been indigenously developed within India itself, senior naval officers stated that Russia had helped Indian scientists overcome certain technical hurdles. This included assistance not only in designing the vessel's reactor, but also guidelines in eventually mating it with the boat's hull. The involvement of Larsen & Toubro, that began in 2001, helped kick-start the stalled ATV project. L&T was awarded the contract to build the hull (code named P 4102) at its Hazira dockyard facility in Gujarat and has already floated sections of it on a barge to Visakhapatnam.