India Navy Nuclear Submarines (SSBN & SSN)

[Nilgiri]

@Nilgiri I almost know nothing about SSN propulsion technology.
But how much refueling LEU reactor cost on avarage? Does it require hull cutting?

Also I am wondering if india's first generation indigenous SSN would be as quiet ( in terms of hull and propulsion system ) and advanced ( in sensors and CMC package ) as Astute or Virginia boats.

Reactor costs are pretty much the same (given enrichment of fuel and reactor design difference accommodating for that is very small portion of the final lifetime cost, if its even any different in the end).

As to what those costs are like, I am unsure (given what gets allocated in funding to their RnD "backdrop" versus actual unit production costs leveraging those and how you would split that up in the economies of scale etc....though I have heard figures in the 100 million - 500 million range depending how you do this). Maybe @Anmdt or others know more about that.

If by hull cutting, you mean what needs to happen during say French reactor replenishment, then no as they have accommodated that need in the hull design itself:

https://uploads.fas.org/2016/12/Frances-Choice-for-Naval-Nuclear-Propulsion.pdf

i.e they already had certain requirements (by law regarding nuclear reactors and materials) to have their boats come in every 10 years, so they went with LEU to make maximum use of the time spent anyway along with harnessing LEU long term advantages (foresight largely tied into leveraging from what exists in commercial reactors long term given dedicated HEU RnD from joint-service weapons program was ended in the 90s).

If India collaborates with French and the West in general regarding everything else on the sub (and the various non-nuclear related mitigations for the reactor area itself concerning pumps and so on)...one would expect the end product to be among western acoustic profile in the end too. Depends on degree of cooperation in the end there I guess.

 

[Gessler]

Hydrodynamic model of the 13,500-ton future SSBN class, commonly known as "S-5". Picture via Manjira Machine Builders' website

View attachment 54477

Some more pics of the models, via AlphaDefence

It's now more or less certain that the S-5 class SSBN will be having no less than 12 x ballistic missile tubes.

 

[JOYDEEPGHOSH]

After #AUKUS Deal How Many #SSNs Will #IndianNavy Need Afterall

After AUKUS Deal How Many SSNs Will Indian Navy Need Afterall

AUKUS Deal France and Australia were about to sign a US$ 65 billion (AU$ 90 billion) deal to build 12 conventional AIP-powered version...

rbt-defense.blogspot.com

 

[Nilgiri]

Updates from Vizag, Bhuj & Naliya

Construction of SBC-2, the second final-assembly line for the Indian Navy's six-boat SSN project, should be completed by the end of 2024. Th...

trishul-trident.blogspot.com

 

[Gessler]

So apparently, NSTL is testing this design, lack of a missile hump implies this is an SSN:

It does not necessarily mean that the upcoming Project-75A/76 SSN will have a pumpjet, or that this is indeed the indigenous SSN design (could just be a case-study of a generic modern SSN boat). But it's definitely interesting.

 

[Gessler]

Interesting...

https://twitter.com/i/web/status/1678784625223798784

Again, no comments from me. Could be the real deal, or could be just a representative model put together just so they have some commemorative token to give.

 

[Marlii]

https://twitter.com/i/web/status/1725113325074170303

 

[Marlii]

https://twitter.com/i/web/status/1750988254864929021

 

[dronie]

 

[Gessler]

View attachment 66370

This is pretty surprising...the missile hump on this test model is much more streamlined with the hull compared to the older model:

Considering the size of the hump depends on the size of the SLBM you plan to use from it, unless our intended SLBM specifications have changed (read: better propulsion tech resulting in a shorter missile with the same range as before), I don't see how they can redesign the hump to be more blended without changing the Sub's beam diameter itself (which essentially means going back to the drawing board and starting from square one). Which I don't think they're doing.

Additionally, the models seen previously had the dive planes on the hull (like on Vanguard-class) and not on the tower. It seems we're testing various different configurations, as we should. Don't know which one we will eventually settle on (or maybe we already have?).

 

[Gessler]

View attachment 66370

This is pretty surprising...the missile hump on this test model is much more streamlined with the hull compared to the older model:

View attachment 66371

Considering the size of the hump depends on the size of the SLBM you plan to use from it, unless our intended SLBM specifications have changed (read: better propulsion tech resulting in a shorter missile with the same range as before), I don't see how they can redesign the hump to be more blended without changing the Sub's beam diameter itself (which essentially means going back to the drawing board and starting from square one). Which I don't think they're doing.

Additionally, the models seen previously had the dive planes on the hull (like on Vanguard-class) and not on the tower. It seems we're testing various different configurations, as we should. Don't know which one we will eventually settle on (or maybe we already have?).

Another thing I'm noticing just now...

The length of the missile compartment has significantly increased in the new model. This was the old one:

...compared to the new one, where the compartment is now going almost all the way to the tail section:

Assuming the old model had 12 x missile tubes (two rows of six, side-by-side), it seems we are looking at 16-20 tubes for the new model!

 

[Gessler]

"Arihant Stretch" class is indeed real.

View attachment 37818

That means either 8 x long-range SLBMs (K4/K5) or up to 24 x medium-range ones (K15).

S4 aka Arihant Stretch

 

[dronie]

https://twitter.com/i/web/status/1793600260821987799

 

[Nilgiri]

https://www.ndtv.com/india-news/ins...ow-about-indias-2nd-nuclear-submarine-6442561​

​

INS Arighaat: All About India's 2nd Nuclear Ballistic Submarine​

​

Made by the Shipbuilding Centre (SBC), Visakhapatnam, INS Arighaat, an upgraded version of INS Arihant, can travel at a maximum speed of up to 24 knots (44 km/h) when submerged and 12-15 knots (22-28 km/h) on a surface level. ​

India News

INS Arighaat, India's second nuclear-powered ballistic missile submarine, was commissioned on Thursday in Visakhapatnam. Defense Minister Rajnath Singh, head of Indian strategic command Vice Admiral Suraj Berry, Chief of Naval Staff Admiral Dinesh Tripathi and leading DRDO officials were present for the commissioning.

The Arihant class submarines are named after a Sanskrit word meaning the “Destroyer of the Enemy”. The name befits the strategic significance of a nuclear-powered submarine. The name "Arihant" was chosen from a wide range of choices and received approval on all fronts due to its suitability and subtlety in expressing the commitment.

Made by the Shipbuilding Centre (SBC), Visakhapatnam, INS Arighaat, an upgraded version of INS Arihant, can travel at a maximum speed of up to 24 knots (44 km/h) when submerged and 12–15 knots (22–28 km/h) on a surface level. It shares the same hump as the INS Arihant and has four launch tubes. It can carry twelve K-15 SLBMs with a range of about 750 kilometres, or up to four nuclear-armed K-4 SLBMs with a range of over 3,500 kilometres.

INS Arighaat has an advantage over conventional submarines, like its predecessor INS Arihant. It is propelled by 83 MW pressurised light-water reactors and can remain submerged for extended periods.

The Indian government has been planning to construct nuclear and conventional boats to acquire and develop its long-term submarine acquisition and capabilities plan. In addition to the six nuclear attack submarines that will be constructed in three blocks, India is working on five Arihant class boats. Six new Kalvari class boats have already been delivered to the Indian Navy and 15 more are scheduled to be delivered as part of Projects 75 AS, 76, and 75 India.

 

[Nilgiri]

Fuzziest of fuzziest pics released after the commissioning, just like with INS Arihant earlier.

https://twitter.com/i/web/status/1829158155869401570

 

[Nilgiri]

https://twitter.com/i/web/status/1829102185222664212

 

[Rajendra Chola]

https://twitter.com/i/web/status/1829102185222664212

I honestly don’t think Arighat has a better “nuclear” reactor than Arihant. Maybe some systems & safety improvements around the reactor, but not the reactor itself. Indian MoD cried about sanctioning money to make new reactor for SSN’s & kept the file pending since 2015, only to approve it in 2022.

S4 & S4* (the original INS Aridhaman) may feature a new reactor. Or they can continue with existing design to build everything new for S5, the big boomer

 

[Nilgiri]

I honestly don’t think Arighat has a better “nuclear” reactor than Arihant. Maybe some systems & safety improvements around the reactor, but not the reactor itself. Indian MoD cried about sanctioning money to make new reactor for SSN’s & kept the file pending since 2015, only to approve it in 2022.

S4 & S4* (the original INS Aridhaman) may feature a new reactor. Or they can continue with existing design to build everything new for S5, the big boomer

Depends. There could have been two iterations done with the original design.

This is all classified and specint anyway, so not really much to debate/analyse anyway.

 

[Nilgiri]

some grainy footage apparently:

https://twitter.com/i/web/status/1835252124080349267