The submarine's exterior is uneven and the hull is placed on a mat covered with tiles. The tiles help in absorbing sound waves and provide stealth capability to the submarine. Compared to conventional submarines, the conning tower of Arihant is situated near the bow instead of the centre.

Naval technology has a page on the Arihant.
http://www.naval-technology.com/projects/arihant-class/

Nice to see NT guys using Gagan's impression of Arihant.

with your image to boot ! congrats ji !

May or may not be... but who want to see India in the same position as UK, Germany, South Korea and Japan. They have one thing in common, good economy but is that all?

I remember one story I studied in school. A dog who ran away from a bunglow to forest, all he wanted was freedom.

BARC designed, developed and built the steam generating unit of Arihant by facing many technical challenges

“The compact Pressurized Water Reactor was designed for this purpose with several features; such as very quick response for power ramping, extremely stable undership motions and resistance against exposure to very high acceleration resulting from eventual depth charges”, Dr Sukumar Banerjee, Director, BARC said in his Founder’s Day Address

“Since the nuclear reactor is fuelled with high fissile containing fuel, it can supply energy in the submerged condition for an extended period without refuelling”, he clarified. Details about the reactor are classified.

Generally, Pressurized Water Reactors (PWR) power nuclear submarines. A PWR has a core of highly enriched uranium. When uranium nuclei undergo fission, the fission fragments carry enormous energy. They dissipate the energy in the core which gets heated up. The high pressure primary system with water as coolant removes the heat from the core continuously.

Water at high temperature enters the steam generators. In the steam generators, the heat from the water in the primary system is transferred to the secondary system to create steam. In the secondary system, the steam flows from the steam generators to drive the turbine generators, which supply the ship with electricity, and to the main propulsion turbines, which drive the propeller. After passing through the turbines, the steam condenses into water which is fed back to the steam generators by the feed pumps.

Naval reactors pitch and roll. Demands of power change rapidly. The manufacturing and quality assurance of reactor components must be of exceptionally high standard.

The reactor internals remain inaccessible for inspection or replacement throughout the long life of their core. They must be rugged and resilient. Reactor components and systems must withstand, harsh and hostile environment, long term effects of radiation, corrosion, high temperature and pressure.

As the reactor operates radiation level increases. Appropriate shields are built around the reactors to ensure radiation safety. A reactor may use over 100 tons of lead as shielding.

“Many systems and equipment designed and built were first of its kind in the country. The entire steam generating plant has been designed to give highly reliable offshore operation in a completely isolated environment”, Dr Banerjee noted.

“Control and instrumentation design is fault tolerant and requires minimum operator interventions. An elaborate diagnostic system enables a very high availability factor. Many new materials and technologies have been developed and new infrastructure has been created for this project”, he revealed.

The development of the steam generating plant of Arihant was preceded by setting up of the land based prototype system at Kalpakkam. The reactor which has been working for the past three years has served as a technology demonstrator.

“The entire plant with primary, secondary, electrical and propulsion system along with its integrated control was packed in the aft end of a land based submarine hull designed and built specifically for the purpose.

This protoype is serving as a training centre for the crew for the nuclear submarine”, Dr Banerjee said. The crew gets training with the help of an indigenously designed and built full scope simulator.

The nuclear reactor installed on the S-2, according to open source information, is understood to be based on first or second generation Soviet era technology with a short re-fuelling cycle.

Srikumar Banerjee, BARC Director, also stressed that “the event marks the beginning of PWR technology in India.” The BARC made many design features to make this reactor compact. “There are novelties not only in the reactor’s design but in its manufacturing,” he said. For instance, the steam generator which drove the turbine to generate electricity, was compacted in a novel manner. The heart of the reactor is the steam generator.

Second generation reactors
Experience from the first generation reactors showed that the main operational problem was leakage of water from the primary to the secondary circuit. This occurred mainly through the steam generators. There were also problems of leaks in the pumping systems and the gaskets of the steam generators. The pumps and steam generators were intended to cool the reactor in the event of a power failure.

These experiences formed the basis for modifications introduced in the second generation reactors. Nevertheless, the loop pattern (i.e., a system of spiralling cooling pipes) was retained. The volume and distribution of the primary circuit was sharply reduced, and a system of pipes within pipes was used for the steam generators, especially for the newest pumps leading to the primary circuit.

Third generation reactors
A new block system was developed to protect the cooling circuits from leakage. By replacing the old system of pipes with a block system, in which the reactor and the cooling system were treated as one block, the dimensions of the pipes and other components could be reduced because the cooling efficiency of the system could be increased.

From a safety point of view, this solved number of problems. First of all, this system permitted a natural circulation of coolant within the primary circuit, even at high power. This was important for the flow of coolant into the reactor core at complete or partial power failure. With the block system, pipes to the primary circuit were replaced with short, wide diameter pipes which connected the main components (reactor, steam generators, and pumps).

Fourth generation reactors
The reactor for the first submarine was finished in 1995. Fourth generation nuclear reactors are formed into a single block. The monoblock design has the advantages of localising the coolant in the primary circuit into one volume of fluid and eliminates the need for pipes of wide diameter. The fourth generation reactors are constructed consistent with modern requirements for radiation safety.

http://www.bharat-rakshak.com/NEWS/news ... wsid=11822 A reactor may use over 100 tons of lead as shielding.

the reactor should have gone critical by now and harbour acceptance trials ongoing.

btw, nothing about noise factors.. , that I thought the author would

AHWR goes online the same will be miniaturised to go onto subs and surface ships which is supposed to be on the long term wishlist of BARC and IN.(which is what I said a way back that the future subs/ships will use a mixed fuel)

It is obvious. The clip which shows the journos trip to Kalpakam, PRP center, registered the S1 noise in the background. You may check that with Kilo sub. Anyone had gone in the Kilo can throw the light. As i aware, the db level is less comparative to Kilo (just a wild guess).

The statement, "For instance, the steam generator which drove the turbine to generate electricity, was compacted in a novel manner. The heart of the reactor is the steam generator." from BARC director give some indication about the quietness of the reactor.

I don't know about the noise but it definitely confirms BARC's capability in designing a compact PWR for naval applications and yes this should lay to rest stories about the Akula's reactor being used by the Arihant