Context

Nuclear submarines are back in the news post the announcement of AUKUS (Australia, the UK and the US) forming a military alliance.

• Under this alliance, the US and the UK have offered Australia their expertise to build nuclear submarines.

About

What is a nuclear weapon?

• A nuclear-powered submarine is powered by a nuclear reactor.
• But it is not a nuclear weapon.
• Every nuclear-powered submarine draws from its own miniature nuclear reactor onboard, which is typically fuelled with uranium.
• For such a reactor to work, uranium has to be ‘enriched’ to contain 50 per cent of a key isotope, uranium-235.
  • Natural uranium consists of approximately 99.3 per cent of the isotope uranium-238 and only 0.7 per cent of uranium-235.
  • The process of enrichment can be carried outthrough gaseous diffusion, gas centrifuges or laser isotope separation.
• Only six nations own and operate these submarines currently: China, France, India, Russia, the UK and the US.

Types of nuclear-powered submarines

• Nuclear-powered submarines can be divided into three broad categories:
  • the nuclear-powered fast-attack submarines or SSNs
  • the nuclear-powered ballistic submarines or SSBNs
  • the nuclear-powered cruise missile submarines or SSGNs
• SSNs are the oldest type of nuclear-powered submarines and the first of these, the American-made Nautilus, was deployedin 1954 by the US.

India and the nuclear submarine industry

• The Navy currently has 15 conventional submarines-
  • eight Russian Kilo class ones
  • four German HDWs
  • three Scorpenes and nuclear ballistic missile submarine (SSBN) INS Arihant.
• Second indigenous SSBN Arighat,now in advanced stages of sea trials, is expected to be commissioned next year along with indigenous aircraft carrier Vikrant, which recently began sea trials, the two officials remarked.
• Akula class SSN Chakra, on a decade-long lease from Russia, has been returned recently, slightly ahead of schedule.
• India has already signed a deal for the lease of another such submarine and the project is underway.
• Given the delays, India is also considering leasing one more Akula class SSN.
• It does not have a nuclear-powered conventional attack submarine.