India's Third Nuclear-Powered Ballistic Missile Submarine, INS Aridhaman, to Incorporate BARC's Upgraded 83 MW Reactor

India's strategic nuclear capabilities are poised for further enhancement with the imminent commissioning of its third nuclear-powered ballistic missile submarine (SSBN), the INS Aridhaman (S4). This development follows the recent induction of INS Arighaat (S3) into active service in August 2024, signifying the continued progress of India's indigenous SSBN program.

The program, initiated with the commissioning of INS Arihant (S2) in August 2016, represents a cornerstone of India's strategic deterrence posture. The Arihant, the country's first indigenously built SSBN, displaces 6,000 tonnes and is powered by an 83 MW pressurized light-water reactor (PLWR) developed by the Bhabha Atomic Research Centre (BARC) using enriched uranium fuel.

This marked a critical step in establishing a credible sea-based nuclear deterrent, forming the third leg of India's nuclear triad, complementing its land-based ballistic missiles and strategic bomber aircraft.

The INS Arighaat, commissioned recently, builds upon the foundation laid by the Arihant. While maintaining the same reactor and overall dimensions, it incorporates significant technological advancements.

These are believed to include improved sonar systems for enhanced underwater detection capabilities, upgraded navigation systems for precise positioning, enhanced stealth features to reduce detectability, and advanced fire control systems for improved targeting accuracy.

These upgrades mark the maturation of India's SSBN development and underscore the country's commitment to bolstering its strategic assets. The Arighaat is expected to be armed with the K-15 Sagarika submarine launched ballistic missiles which have a range of 750 km.

The forthcoming INS Aridhaman, nearing completion, will further enhance the Indian Navy's underwater strategic capabilities. While details remain limited, sources suggests it will continue to utilize an upgraded version of the 83 MW reactor, the heart of its predecessors, now incorporating design changes based on operational feedback for the reactors of previous submarines of the class. These enhancements are reported to focus on improved maintenance features and enhanced safety measures for the crew.

This continuous improvement reflects the iterative approach adopted by BARC, the primary developer of the reactor, in refining the technology over time. The Aridhaman is expected to be armed with the under-development K-4 submarine launched ballistic missiles which have a reported range of 3500 km.

The development of India's SSBN fleet is part of a broader strategic vision that emphasizes a "No First Use" (NFU) nuclear doctrine. India's nuclear doctrine emphasizes a posture of credible minimum deterrence, relying on a survivable second-strike capability. SSBNs, with their ability to remain submerged for extended periods, provide an essential element of survivability against potential adversaries.

The ongoing development of India's SSBN fleet, including the INS Aridhaman, signifies a significant step in the country's pursuit of a robust and credible sea-based nuclear deterrent. While details on specific capabilities remain classified, the continuous improvements being made highlight India's commitment to technological advancement and its determination to maintain a secure and reliable strategic deterrent in an evolving geopolitical landscape.

It is also believed that India is working on a new class of nuclear-powered ballistic missile submarines dubbed the S5-class which will be larger than the Arihant class and capable of carrying 12-16 nuclear ballistic missiles.

 

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[sanket]

INS Arighaat second SSBN commissioned in August 2024 while third SSBN INS Aridhaman is nearing completion & soon join the fleet that means only First INS Arihant SSBN & Second INS Arighaat took time for Induction betwwen two time duration was 8 years

 

[WarTech]

All of this is cool and all, but what about missiles. Our ordinance are still short ranged when compared to other countries. We need more long ranged weapons.

 

[Rajesh]

When is 180 mw reactor going to be ready?

 

[PKPRS]

Need 190MW reactor soon to have higher displacement submarines.

 

[swatkats_razor]

83 MW is anemic even for a 6000 tonne nuclear submarine.
This should have been upscaled to at least 100 MW for Arihant class itself.

Peoblem is we lack technology to miniaturize nuclear reactors which in turn could be because of low enrichment figures of nuclear fuel used in our reactors.

Government needs to look into this area as well. Role of private sector will be important. The government should come up with policy and liberalize entry of private sector into nuclear power generation and research.

 

[Sandeep]

Any performance upgrade is a bonus but they need to start developing the S5 and 190MW reactor and also the longer range MIRV SLBM with a range of at least 10000km. These are the critical requirements that we urgently need to keep China in check.

 

[beencensured]

When is 180 mw reactor going to be ready?

It is probably ready, but the sub to house is not yet built.

 

[beencensured]

All of this is cool and all, but what about missiles. Our ordinance are still short ranged when compared to other countries. We need more long ranged weapons.

We need the sub to house it too.

 

[Rational Guy]

All of this is cool and all, but what about missiles. Our ordinance are still short ranged when compared to other countries. We need more long ranged weapons.

3,500 KM K4 with 2,000 KG payload is more than enough to hit China and Pakistan. Our nuke warheads weigh around 50-250 KG depending on yield which means with our nuclear warhead payload K4 can probably reach 4-5,000 KM even. Anything more than 5000 KM is overkill imo.

 

[Rational Guy]

83 MW is anemic even for a 6000 tonne nuclear submarine.
This should have been upscaled to at least 100 MW for Arihant class itself.

Peoblem is we lack technology to miniaturize nuclear reactors which in turn could be because of low enrichment figures of nuclear fuel used in our reactors.

Government needs to look into this area as well. Role of private sector will be important. The government should come up with policy and liberalize entry of private sector into nuclear power generation and research.

According to most reports we use 40% enriched uranium which even China doesn't use (they use 5-10% enriched uranium for their reactors). Only USA and UK use weapons grade uranium for their nuclear reactors and even then USA has to scavenge that uranium from old nuclear weapons apparently. 40% is also the figure of Russian nuclear reactors.

Likely we copied Russian nuclear reactors for both 83 MW and 190 MW as the energy capacity is weirdly similar to the nuclear subs we leased from Russia in 1990s and 2000s.

 

[desigandu]

Good, now let us get the 190mw reactors going for our SSNs and S5!

 

[swatkats_razor]

According to most reports we use 40% enriched uranium which even China doesn't use (they use 5-10% enriched uranium for their reactors).

This was true for their initial submarines. The level of enrichment in their new submarines, honestly nobody knows. But since the Chineae have made a lot if progress on nuclear front, I would be surprised if they haven't reached 40% enrichment in their reactors yet.

The only western country which uses low enrichment reactors is France. French are known to have used 7% LEU reactors in their submarines.

 

[WarTech]

3,500 KM K4 with 2,000 KG payload is more than enough to hit China and Pakistan. Our nuke warheads weigh around 50-250 KG depending on yield which means with our nuclear warhead payload K4 can probably reach 4-5,000 KM even. Anything more than 5000 KM is overkill imo.

Nah, having 5000 km with full yield would be lot better than having 3500 km with reduced yield. 3500 km is max range of K4. Range will reduce if we modify payload.

 

[WarTech]

We need the sub to house it too.

Yes, but we are atleast focusing on subs. Missiles, not so much.

 

[WarTech]

Any performance upgrade is a bonus but they need to start developing the S5 and 190MW reactor and also the longer range MIRV SLBM with a range of at least 10000km. These are the critical requirements that we urgently need to keep China in check.

10000 km would be practically useless. 5000 km with full load would be the best SLBM for us.

 

[Sandeep]

10000 km would be practically useless. 5000 km with full load would be the best SLBM for us.

No you can still achieve a major strike with a 10000km missile as we just need to make sure the nuclear warhead is large and powerful enough that can destroy a city. We already have a hydrogen powered weapon so it can wipe out more than a city.