The 'Arihant' was launched on July 26, 2009, exactly 10 years after the end of the Kargil conflict, which means it has taken four years for its nuclear reactor to achieve criticality. Its design is based on the Russian Akula-1 class submarines, of which the best-known example is the INS Chakra, a nuclear submarine first leased by India from the Soviet Union for three years in January 1988, and leased again from the Russians in 2011. The 100-member Indian crew for the Arihant, besides training at the School for Advanced Underwater Warfare at Vishakapatnam, is also training on the INS Chakra.

The Arihant's 83Mw pressurised water reactor (PWR) has also been built with considerable assistance from the Russians, who are said to have helped scientists at the Bhabha Atomic Research Centre (BARC) in miniaturising the reactor to fit into the 10m diameter hull of the nuclear submarine. Read More