Vivek Dhattarwal asked: What is the role of nuclear submarines for the Indian Navy?

Abhay Kumar Singh replies: A nuclear submarine is a submarine powered by a nuclear reactor. Since nuclear propulsion does not require atmospheric oxygen, it frees the submarine from the need to surface frequently, as is necessary for conventional submarines. Due to the long interval between refuelling of the reactor, the sortie duration of nuclear submarine remains limited by food embarked and crew fatigue. Simply put, a nuclear submarine has a nearly limitless range and superior manoeuvrability.

There are basically two types of nuclear submarines. The ballistic missile capable nuclear submarines (SSBNs) are nuclear-propelled submarines designed to carry nuclear-tipped ballistic missiles. Due to stealth characteristics enabling its discrete and prolonged deployment, SSBN provides a credible, effective and survivable capability, and contributes to nuclear deterrence through an assurance of punitive retaliation against a nuclear attack. The nuclear attack submarines (SSNs) are nuclear-propelled submarines with conventional weapons, viz. torpedoes and cruise missiles. The operational roles of SSN are similar to tasks assigned to conventional submarines which include gathering surveillance data, communicating tactical information, controlling the surface and undersea battlespace, and delivering strike weapons or special operations forces ashore in contingencies. Roles of nuclear submarines, both SSBN and SSN, in the Indian Navy broadly follows these doctrinal prescripts of naval warfare.

Since ‘no first use’ (NFU) policy amply illustrates India's intentions of using the nuclear deterrent only as a retaliatory measure of last resort, the sea-based leg of the nuclear triad enables a survivable second-strike capability and is, therefore, a critical enabler for the NFU doctrine to attain credibility. Indian Navy’s Maritime Security Strategy (2015) states that “the three principles central to India’s nuclear deterrence, viz. credibility, effectiveness and survivability, are imbibed in the sea-based segment of the nuclear triad, primarily the nuclear-powered submarine carrying ballistic missiles (SSBN).” It further states that “the Indian Navy will operate the SSBN to reinforce nuclear deterrence, supported by corresponding operational capabilities and procedures for optimal deployment, in keeping with national policy.”

Posted on December 04, 2019

Views expressed are of the expert and do not necessarily reflect the views of the IDSA or of the Government of India.