The CLWR-B1’s submarine specific land-based prototype nuclear reactor

Bhabha Atomic Research Centre (BARC) is developing an advanced 200 MWe nuclear reactor to power the Indian Navy’s next-generation nuclear submarines, notably the larger S-5 class ballistic missile submarines (SSBNs) and future nuclear-powered attack submarines (SSNs).

This represents a dramatic leap from the current 83 MWe reactors fitted in India’s first-generation SSBNs—INS Arihant and INS Arighaat, with a third boat INS Aridhman still under trials.

By more than doubling reactor output, the new design will provide submarines with significantly greater endurance, operational range, and submerged stealth time, strengthening the survivability of India’s sea-based nuclear deterrent, a critical leg of the nuclear triad.

With China rapidly expanding its SSBN fleet and deploying advanced Type 094 and developing Type 096 boats, India’s effort reflects strategic necessity to maintain credible retaliatory capability in the Indo-Pacific maritime domain.

The S-5 class, estimated at 13,500–15,000 tons displacement compared to Arihant’s ~6,000 tons, will be able to carry more K-5/K-6 SLBMs and potentially incorporate MIRV-capable ballistic missiles, giving India a formidable second-strike ability.

Parallelly, beyond military applications, BARC has announced the development of next-generation civilian nuclear technologies, including the 200 MWe Bharat Small Modular Reactor (SMR) for flexible deployment, a 555 MWe SMR for scalable grid-level power, and a High Temperature Gas-Cooled Reactor integrated with thermochemical plants to enable clean hydrogen production, linking nuclear technology with India’s wider energy transition goals.

Together, these initiatives underscore India’s dual-track strategy: fortifying its strategic deterrence architecture while leveraging nuclear science to achieve energy security and decarbonization targets.

Agencies