Article – India’s S-5 Nuclear Submarines Get 200 MW Reactor – INS Arihant Power Will Be Double

Jai Siya Ram

What is Reported / What Looks Real

BARC Developing a More Powerful Reactor
- The Bhabha Atomic Research Centre (BARC) is reported to be working on a new submarine-nuclear reactor of ~200 MWe (megawatt electrical) for India’s next-generation nuclear submarines.
- This is a significant boost from the ~83 MWe reactor used in the Arihant-class (INS Arihant and INS Arighaat).
S-5 Class SSBNs
- The S-5 submarines are planned as a future class of large ballistic missile submarines (SSBNs). Their displacement is expected to be much larger (~13,500-15,000 tonnes) compared to Arihant-class (~6,000 tonnes) to accommodate greater fuel, missile capacity, crew, and endurance.
- These subs will likely carry long-range SLBMs, including the newer K-5 and K-6 series missiles, possibly with MIRV (Multiple Independently Targetable Re-entry Vehicle) capabilities.
Performance Improvements Expected
- With the higher power reactor, the S-5 will be able to stay submerged longer, have greater submerged speed, better endurance, and more capability for stealth operations.
- It’s part of strengthening India’s sea-based nuclear deterrent (the “sea leg” of the nuclear triad) by enhancing survivability and second-strike potential.

The exact rating (“200 MW”) is reported in some media, but also in others the figure is ~190 MW for the BARC reactor under development. There’s ambiguity about whether some reports are rounding up or using projected numbers.
It is not confirmed whether the “200 MW” reactor is fully tested, has gone into sea trials, or is merely in design or prototype stage. Media reports suggest development is ongoing.
Details like refuelling interval, reactor safety under operational conditions (shock, pressure, etc.), and how much additional displacement / cost this adds are not fully public.

Deterrence Strengthened: Higher power submarines with longer underwater endurance improve India’s second-strike capability; harder to detect and counter.
Maritime Balance: In response to growing Chinese naval strength (including more SSBNs/SSNs), this helps balance regional naval power in the Indian Ocean and Indo-Pacific.
Technical Sovereignty: BARC making indigenous reactors shows growing domestic capability in nuclear submarine reactor technology. Less dependency on foreign designs increases strategic autonomy.
Cost, Time & Risk: Bigger reactors mean more cost, heavier submarine hulls, greater engineering complexity (pressure, cooling, safety). Time to build, test, deploy will be longer.

Official confirmation from Indian Navy / BARC about the reactor’s specifications (power, trial results, safety certifications).
Timeline for S-5’s commissioning: when the first boat is expected to enter service. Some reports suggest 2027 for production start.
What missile payload (SLBMs) the S-5 will officially carry, and their range / MIRV status.
Any statements on stealth / propulsion improvements (e.g. pump-jet propulsors rather than classical propellers).
International responses — neighboring powers, strategic analysts’ takes on whether this alters deterrence in the region.