- A nuclear submarine is fuelled by an onboard nuclear reactor, which allows it to operate underwater for long periods of time. In contrast, a conventional diesel submarine uses batteries to operate underwater, but is forced to surface periodically to recharge its batteries using diesel-combustion engines that require oxygen.
- SSBNs were first deployed during the Cold War and justified as a tool of last resort. If an adversary were to launch a devastating first-strike on a country, destroying its land-based missiles and paralysing its air force, the submarine — undetected at sea — could still deliver a counter-strike, assuring the “mutual destruction” of both countries.
- India’s first indigenous ballistic-missile armed nuclear submarine (SSBN), Arihant, had “successfully completed its first deterrence patrol” and claimed that this “accomplishment” would “always be remembered in our history”.