Indian nuclear submarines

Aniruddha Mulay

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Correction - Roosi enrichment is actually roughly same as ours.

View attachment 110669
I had a question regarding Brazilian SSN programme, the lead boat of the class is to be outfitted with a 48MW PWR on a sub displacing 6000 tons.
Isn't that a bit underpowered since the French Rubis class which weigh only 2500tons are powered by the same reactor
 

Gessler

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I had a question regarding Brazilian SSN programme, the lead boat of the class is to be outfitted with a 48MW PWR on a sub displacing 6000 tons.
Isn't that a bit underpowered since the French Rubis class which weigh only 2500tons are powered by the same reactor
Brazilian program is not really driven by threat vectors.

Heck, if the rector manages to move the sub, that's probably good enough for them. Either way I have little faith in their program actually delivering results.
 

Gessler

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Personally, this is how I'd want the IN nuclear sub fleet to shape up:

12 x SSN (3+3, and then another batch of 6 'improved' models)
4 x SSBN (S-5)
4 x SSGN (2 x Arihant and 2 x Arihant Stretch converted to carry cruise missiles after S5 takes over SSBN role)

Total 20 nuclear submarines.
 

FactsPlease

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Personally, this is how I'd want the IN nuclear sub fleet to shape up:

12 x SSN (3+3, and then another batch of 6 'improved' models)
4 x SSBN (S-5)
4 x SSGN (2 x Arihant and 2 x Arihant Stretch converted to carry cruise missiles after S5 takes over SSBN role)

Total 20 nuclear submarines.
That will be a force even larger than combine of France and UK (incl SSBN+SSGN).
Then my guess is you are hinting (or explicitly) for IN to switch under water forces to all nuclear. (Manned ones, of course).
Do-able? Of course, as long as one step at a time.
 

piKacHHu

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- Is barc naval reactor a heu design. If so, does that mean it didn't need to be refueled for its whole operational life. If it does need to be refueled than what's the point of heu.
French use LEU which of course requires to refuel at least twice in lifetime, which makes them the most inefficient & expensive to maintain. But they have the benefit of requiring less upfront cost thanks to avoiding of fuel enrichment, plus lot more commonality with civilian reactor designs. AFAIK China also uses LEU...or relatively low-grade HEU (not up to a 100% on that, know very little about chinese sub programs).
Adding my observations in this ongoing high quality discussion:

1. From design point of view, you always want a HEU core which could last for entire service life of the boat; however, considering the constraints w.r.t enrichment (if not part of P5) and the so called "Proliferation Risks" (Read: RERTR program), countries around the world are going for LEU cores. Even in the US, public pressure ( Senate committees on Non-proliferation) are being mounted to consider LEU fuels for upcoming Virginia class replacements.


2. It does affect the design in a way that you need to design a RPV which could be opened 2-3 times in its service life; meaning qualification of proper sealing of the vessel needs to be done again while in the dock. Also, it would increase the radioactive doses to the maintenance personnel.

3. Moreover, if there is any increase in the size of the core ( while scaling up the thermal power throughput), the RPV and Hull design will be impacted; increase in the dia. means increase in thickness of vessel for the rated pressure. That means complicating the already difficult part of vessel forging.

4. Enrichment process is still required for LEU albeit not up to extent of HEU; however, considering the SSBN operator countries are already having nukes; it's not a big issue for them w.r.t enrichment. Maybe, the big powers have already envisaged that other countries will eventually opt for SSNs in the future, they have started pitching LEU based SSNs to those countries who are not having nukes or capability to enrich uranium lets say Australia.

But if a country with stockpile nukes and have a reasonably good enrichment capability, HEU is the obvious choice for their SSBNs.
 

Gessler

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Adding my observations in this ongoing high quality discussion:

1. From design point of view, you always want a HEU core which could last for entire service life of the boat; however, considering the constraints w.r.t enrichment (if not part of P5) and the so called "Proliferation Risks" (Read: RERTR program), countries around the world are going for LEU cores. Even in the US, public pressure ( Senate committees on Non-proliferation) are being mounted to consider LEU fuels for upcoming Virginia class replacements.


2. It does affect the design in a way that you need to design a RPV which could be opened 2-3 times in its service life; meaning qualification of proper sealing of the vessel needs to be done again while in the dock. Also, it would increase the radioactive doses to the maintenance personnel.

3. Moreover, if there is any increase in the size of the core ( while scaling up the thermal power throughput), the RPV and Hull design will be impacted; increase in the dia. means increase in thickness of vessel for the rated pressure. That means complicating the already difficult part of vessel forging.

4. Enrichment process is still required for LEU albeit not up to extent of HEU; however, considering the SSBN operator countries are already having nukes; it's not a big issue for them w.r.t enrichment. Maybe, the big powers have already envisaged that other countries will eventually opt for SSNs in the future, they have started pitching LEU based SSNs to those countries who are not having nukes or capability to enrich uranium lets say Australia.

But if a country with stockpile nukes and have a reasonably good enrichment capability, HEU is the obvious choice for their SSBNs.
I doubt if countries like US (to include UK as they use same tech) will pay much heed to this proliferation nonsense (mostly coming from !diots who think nuclear = chernobyl). Australia is a prime example of a country which remained adamantly anti-nuclear, till push came to shove and now jumping straight to HEU.

France preference for LEU is mostly to do with overall cost considerations.

China is because of inability to enrich enough quantities of fuel to desired level, and/or to get the reactors to work with such fuel.

Of course arguments & counter-arguments will exist but security states like US will overrule all such nonsense in face of supreme national interest in blink of an eye.
 

swapcv

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Personally, this is how I'd want the IN nuclear sub fleet to shape up:

12 x SSN (3+3, and then another batch of 6 'improved' models)
4 x SSBN (S-5)
4 x SSGN (2 x Arihant and 2 x Arihant Stretch converted to carry cruise missiles after S5 takes over SSBN role)

Total 20 nuclear submarines.
I think the SSN and SSGN roles are nowadays combining into one given the proliferation of cruise missiles onto SSN's now, the Yasen is technically an SSGN, so is Virginia Block IV and above. So, merging the designations, I think we'll have 16 SSGN's and 4 SSBN's initially but we should increase that to atleast 8, it would be nice to park one or two SSBN's off the coast of Hostile nations as a reminder not to screw around with us.
 

Gessler

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I think the SSN and SSGN roles are nowadays combining into one given the proliferation of cruise missiles onto SSN's now, the Yasen is technically an SSGN, so is Virginia Block IV and above. So, merging the designations, I think we'll have 16 SSGN's and 4 SSBN's initially but we should increase that to atleast 8,
I can't call any sub an SSGN unless it has dedicated VLS cells for cruise missiles. And there's nothing solid yet to suggest our future SSNs will, regardless of what Sandeep Unnithan says.

With a >100mwt reactor of >50% enrichment, our SSNs will not have as much power surplus as Virginia or even Yasen. Adding the additional weight & power burden of a VLS module will complicate things further, which is why I think we won't. A sub somewhere between Barracuda & Astute (neither have VLS) is what I'm expecting from our SSN - both in terms of displacement & armament.

We wouldn't need to make them SSGNs anyway - converted Arihants should be able to carry up to 24 SLCMs and Arihant Stretch (last 2) up to 48 SLCMs per boat @ 6 per silo (just like Virginia Payload Module).

Unless we pull a rabbit out of the hat and it turns out the 190mwt CLWR-B2 would be ready to be used on SSNs. That would give us enough room to play with VLS add-on modules.

it would be nice to park one or two SSBN's off the coast of Hostile nations as a reminder not to screw around with us.
On the contrary SSBNs should not be anywhere near hostile waters. That's why they have long-range missiles.

Our SSBNs should never leave IOR. What we CAN & should park off Chinese/Pak coasts are SSNs and/or SSGNs.
 

pipebomb

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I can't call any sub an SSGN unless it has dedicated VLS cells for cruise missiles. And there's nothing solid yet to suggest our future SSNs will, regardless of what Sandeep Unnithan says.

With a >100mwt reactor of >50% enrichment, our SSNs will not have as much power surplus as Virginia or even Yasen. Adding the additional weight & power burden of a VLS module will complicate things further, which is why I think we won't. A sub somewhere between Barracuda & Astute (neither have VLS) is what I'm expecting from our SSN - both in terms of displacement & armament.

We wouldn't need to make them SSGNs anyway - converted Arihants should be able to carry up to 24 SLCMs and Arihant Stretch (last 2) up to 48 SLCMs per boat @ 6 per silo (just like Virginia Payload Module).

Unless we pull a rabbit out of the hat and it turns out the 190mwt CLWR-B2 would be ready to be used on SSNs. That would give us enough room to play with VLS add-on modules.
Exactly, this whole obsession with vls is also complicating our p75i acquisition and increasing cost.
 

hawwk

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Thanks for your response, it was very enlightening. I completely overlooked thermal power vs electrical power. Also i mistakenly consider heu close to weapons grade. I agree with you that we should continue with heu, maybe our next class of naval reactors doesn't need to be refueled during life time. LEU seems like a dead end.

Do you think double hull design is expensive or does it worth the hassle ?

Also why do you think our previous naval chief was showing interest in French leu ?
fbi is looking for you...
 

piKacHHu

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I doubt if countries like US (to include UK as they use same tech) will pay much heed to this proliferation nonsense (mostly coming from !diots who think nuclear = chernobyl). Australia is a prime example of a country which remained adamantly anti-nuclear, till push came to shove and now jumping straight to HEU.
I believe that Australia's decision to go for HEU/USA tech for their SSN program was more driven by geo-political (so called "QUAD" security umbrella) compulsions rather than the technical one. Opting for French LEU based subs would have made more sense but since Uncle Sam is now convincing its spooked allies, given what happened in Afghanistan, by offering sweetened deals in the form of sensitive nuclear technology; it might have played important role on Australia's decision making.

Anyway to further the argument between HEU-LEU, one may look for Pros- Cons associated with each of them;

Pros-HEU
1. No refueling needed in service life; Low maintenance and better turnaround time.
2. Since refueling is not there, there is no need of the Hatch Opening. No welds/openings are present on the submarine hull (single hull in case of US/UK boomers) due to absence of the Hatch; which in turn makes the subs more stealthier due to low acoustic signature (Low turbulence/noise on the seamless surface) . Also, there will be no requirement of qualifying the hatch connections/welds again during refueling.
3. Utilisation of excessive HEU stockpile gathered during Cold-war (Valid for the USA, UK, Russia)

Cons-HEU
1. High Cost-Enrichment is a costly business due to technologies involved.
2. Heavy maintenance cost, if there occurs any serious issue with the core/propulsion systems; it like doing an open heart surgery of the sub with complete cutting of the hull to resolve the issue.
3. Perceived proliferation risk; an HEU core even at the end of life cycle may provide enough fissile material for low yield or "dirty" devices.

Pros-LEU
1. Low cost of production; suitable for countries don't having legacy stockpiles of nukes.
2. Low proliferation risk
3. Ease in maintenance of propulsion system due to presence of Hatch

Cons-LEU
1. Prolonged refueling time; leading up to months
2. Presence of Hatches compromises with acoustic characteristics; Argument valid only for Attack SSNs.
3. Increase in Core volume; subject to design changes / low power density

Considering all that w.r.t LEU, France has demonstrated its prowess in designing stealthier subs even with the hatches; No wonder the French always excel once it comes to design whether its aircrafts like Mirage/Rafale, Submarines- Barracuda class, or Haute Couture 😜 ;)

Proliferation is indeed an issue in the US political spectrum; it continues to evoke strong response in the woke/liberal camps within Democrats so much so that President Obama has ordered a task force to layout road map for HEU-LEU conversion.

Reference: Open source info from internet
 
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Gessler

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I believe that Australia's decision to go for HEU/USA tech for their SSN program was more driven by geo-political (so called "QUAD" security umbrella) compulsions rather than the technical one. Opting for French LEU based subs would have made more sense but since Uncle Sam is now convincing its spooked allies, given what happened in Afghanistan, by offering sweetened deals in the form of sensitive nuclear technology; it might have played important role on Australia's decision making.

Anyway to further the argument between HEU-LEU, one may look for Pros- Cons associated with each of them;

Pros-HEU
1. No refueling needed in service life; Low maintenance and better turnaround time.
2. Since refueling is not there, there is no need of the Hatch Opening. No welds/openings are present on the submarine hull (single hull in case of US/UK boomers) due to absence of the Hatch; which in turn makes the subs more stealthier due to low acoustic signature (Low turbulence/noise on the seamless surface) . Also, there will be no requirement of qualifying the hatch connections/welds again during refueling.
3. Utilisation of excessive HEU stockpile gathered during Cold-war (Valid for the USA, UK, Russia)

Cons-HEU
1. High Cost-Enrichment is a costly business due to technologies involved.
2. Heavy maintenance cost, if there occurs any serious issue with the core/propulsion systems; it like doing an open heart surgery of the sub with complete cutting of the hull to resolve the issue.
3. Perceived proliferation risk; an HEU core even at the end of life cycle may provide enough fissile material for low yield or "dirty" devices.

Pros-LEU
1. Low cost of production; suitable for countries don't having legacy stockpiles of nukes.
2. Low proliferation risk
3. Ease in maintenance of propulsion system due to presence of Hatch

Cons-LEU
1. Prolonged refueling time; leading up to months
2. Presence of Hatches compromises with acoustic characteristics; Argument valid only for Attack SSNs.
3. Increase in Core volume; subject to design changes / low power density

Considering all that w.r.t LEU, France has demonstrated its prowess in designing stealthier subs even with the hatches; No wonder the French always excel once it comes to design whether its aircrafts like Mirage/Rafale, Submarines- Barracuda class, or Haute Couture 😜 ;)

Proliferation is indeed an issue in the US political spectrum; it continues to evoke strong response in the woke/liberal camps within Democrats so much so that President Obama has ordered a task force to layout road map for HEU-LEU conversion.

Reference: Open source info from internet
Yet Columbia-class SSBN will have a 'sealed' HEU reactor - no refuel needed.
 

THESIS THORON

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any guesses how much enrichment have we able to achive??
i have read an article, very informative link---


but 1 imp point that struck my eyes

January 1987: India’s AEC chairman, Dr. Raja Ramanna, says that India can enrich uranium to any desired level and that BARC has already been enriching uranium on a pilot scale. BARC Director, Dr. P. K. Iyengar notes that India is also developing laser enrichment technologies.
 

pipebomb

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⬆ is there any truth to this, or were the russian deliberately escalating to de-escalate. I am also appalled by gaul of russians telling us how to use our own ship(ins vikky).

Also heard a rumor that russian are always present at chakra's operational patrol, can anyone confirm whether they heard similar rumor themselves.
 

Rajaraja Chola

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What makes you say that? I was thinking 2025 looked possible. 6 more years after they have basically finished design work already?
Don't think so. GoI sanctioned 100 crores in 2019 for preliminary design work for SSN. And then there is turf war btw Navy and DAE on who should be funding the reactor development. Not sure if it's resolved.
 

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