Great news overnight: Its 83MW pressurized water reactor finally going critical, India’s first indigenous nuclear-powered ballistic missile submarine Arihant is finally ready to leave harbour and enter a phase of sea trials in the Bay of Bengal.

With ballistic missiles and air delivery in place, the Arihant and its sister boats (India plans to build three, with the second hull already ready) will form the final leg of India’s nuclear deterrent triad.