Powering the deep: India's next-gen submarines to get a massive 200 MWe boost

India’s main nuclear research centre, the Bhabha Atomic Research Centre (BARC) in Mumbai, is building a new reactor. This reactor is expected to produce 200 MWe (megawatt electric) and will be used in the next generation of Navy submarines. With this, submarines will be able to stay longer at sea without needing to return to base.

According to a Times of India report (September 21), a BARC scientist confirmed this “top-secret” project. The new reactor will be fitted on India’s upcoming S5 Nuclear Submarine and the six planned Nuclear Attack Submarines (Project 77).

Nuclear Submarines Explained

A nuclear submarine uses a nuclear reactor for power, which lets it stay underwater for months without refuelling. It is mainly about long endurance and silent movement. Such submarines may or may not carry nuclear weapons—some only carry torpedoes or conventional missiles for defence.

How the New Reactor Works

The new reactor is a pressurised light-water type that uses enriched uranium as fuel. Here, ordinary water is used to cool the reactor and control the heat, but it is kept under very high pressure so it does not boil, even at high temperatures. This matters because liquid water is much better than steam at carrying away heat. Using enriched uranium makes the reactor produce more energy than normal uranium, which helps the submarine remain powerful, efficient, safe, and stable while operating underwater for long periods.

Enriched uranium means uranium that has been specially treated to increase the amount of a substance called U-235. Normal uranium found in nature has only a small amount of U-235, which is the part that gives energy in a reactor. By increasing (enriching) the U-235 level, the fuel becomes much more powerful and efficient, making it suitable for nuclear submarines and power plants.

Reactor Design Ready for Production

The reactor’s design and computer testing are finished, and now it is ready for production, according to a report by Defence.in.

The new reactor is highly fuel-efficient and can run for up to ten years before it needs refuelling. Here, the nuclear fuel is enriched uranium. So, refuelling means taking out the used enriched uranium from the reactor and putting in fresh enriched uranium to keep producing power. This process is rare because enriched uranium lasts for many years before it runs out.

This technological upgrade is a strategic step to strengthen India’s defences as China’s nuclear naval power continues to grow. India’s submarines INS Arihant and INS Arighaat use a small 83 MWe nuclear reactor. This limits how long they can stay underwater and also reduces mission duration. The 83 MWe nuclear reactors on INS Arihant and INS Arighaat were built by BARC.

The first design came with Russian help, and then BARC developed the small reactor under India’s Advanced Technology Vessel (ATV) project for nuclear submarines. The third submarine, INS Aridhaman, is now undergoing trials, and it also uses the same reactor type.

The new reactor will produce 200 MWe, making it almost twice as powerful and expected to double the submarine’s capabilities. This upgrade will let India’s next-generation submarines stay in the deep oceans for longer, with better operational strength and the ability to take on long, sustained missions.

The S5-class submarine is India’s next-generation ballistic missile submarine (SSBN) with a huge size of 13,000 tons. An SSBN is a nuclear-powered submarine that carries ballistic missiles with nuclear warheads. The letters mean: Ship, Submersible, Ballistic, Nuclear. These submarines can stay hidden deep underwater for long periods and are mainly used to give a country a strong second-strike ability in case of a nuclear attack. These powerful submarines will carry 12 to 16 K-5 submarine-launched ballistic missiles (SLBMs), each with a range of 5,000 km (3,106 miles), reports online publication Interesting Engineering.

India wants to protect its interests in the highly contested Indo-Pacific region. This development is a big step for India to match and counter China’s growing submarine fleet, which now has more advanced technologies. China’s submarine force is expected to become the largest in the world by 2030, even surpassing the United States in numbers.

The Indian government focuses on nuclear submarines because they are part of the nuclear triad. The nuclear triad means three ways to launch nuclear weapons — from the land (missiles), from the air (bombers), and from the sea (submarines). These submarines provide a survivable and mobile platform to launch a retaliatory or second-strike attack, which is a key part of nuclear deterrence. This sea-based part of the triad works along with the land-based missiles of the Army and the air-based weapons of the Air Force. It ensures a nuclear response can still be made even if one or two parts of the triad are destroyed in a first strike.

According to Atomic Energy Commission Chairman A. K. Mohanty at the 69th IAEA conference in Vienna, BARC is designing several other reactors, according to reports. This includes a larger 555 MWe nuclear reactor and a High Temperature Gas Cooled Reactor that can make clean hydrogen when linked to a thermochemical plant.

The Indian Navy plans to buy four large Landing Platform Dock (LPD) warships. These ships can launch fixed-wing naval drones and act as command-and-control centres for long offshore operations.