These are my comments following March 31, 2021's "India's future 6 SSNs over 3rd Carrier: Internal Leverage."
India has been discussing the development of 6 x SSNs, now dubbed "Project 75 Alpha" since the 1990s. There has been endless talk and breathless Indian media reporting that these Indian SSNs (lets call them Alphas) will be built "very soon" for the last 15 years.
India, like most nuclear submarine-nuclear weapon powers, has had to juggle needs to fill out all 3 "legs" of the nuclear triad. That means India has simultaneously developed nuclear weapons dropped by aircraft and mounted on long range land based missiles. SSBNs with their SLBMs, are the last, hardest and longest to develop, leg of the Triad. Meanwhile India has been talking about developing Alpha concepts before it can get around to "cutting steel" - noting the highest priority of Alpha SSNs is to protect SSBNs.
INS Chakra II and eventually III
India already has been transferring technology from its 30 year old design Russian built Akula SSN known as INS Chakra II (ex Nerpa) (see artwork below). Chakra II has been under 10 year lease since 2012 from Russia - so lease expiration may be in 2022. The lease may be extended if Russia is unable to supply a later model Akula (unofficially named “Chakra III”) by about 2025. Chakra II and then III hulls were designed in the early 1980s may not be carrying torpedoes or anti-ship missiles permitting them to be truly operational in defending Arihant-class SSBNs. I'm aware of no reports of Chakra II regularly pulling out of its base at India's Eastern Naval Command HQ - Visakhapatnam or returning to "Visak". So Chakra II's main value may be limited Indian crew training and/or Russian transfer of technology (ToT) to India.
Training and ToT would include Chakra II's 190MW OK-650 reactor which may be running in place while not actually moving the sub. An Indian variant of the full 190MW power of the OK-650 reactor will be more than adequate to power India's future 13,500 tonne (surfaced) S5-class full size SSBNs (see artwork below). Significant updated variants of the OK-650 already power Russia's latest Borei/Borey class SSBNs (see right sidebar).
Meanwhile Indian nuclear crew training continues on INS Arihant and soon Arihant's sister-sub INS Arighat.
French Barracuda SSN and K15 Reactor Value
India’s 6 x Alphas may have some features of India’s 8,140 tonne Chakra “II”. But India talks more of a 6,000 tonne Alpha that would, of course, have many design differences to a 8,140 tonne Chakra II. India understandably has an interest in French Naval Goup ToT from its 5,300 tonne (submerged) French Barracuda class very modern SSN which is likely to be much quieter than 38 year old hull technology Chakra-Akulas. Naval Group may be enticed to release more Barracuda details if this is packaged with India purchasing 6 x Scorpene (AIP) SSKs under the endlessly discussed and delayed Project-75I.
While a Russian OK-650 reactor would be too large for a 6,000 tonne Alpha Russia and India may want to investigate the Barracuda’s K15 reactor. Obtaining K15 details from France via India would constitute an intelligence coup for Russia. For India an enlarged, more powerful, variant of the K15 may be sought. The K15’s main limitation being its need to refuel every 7-10 years. India would value a fuel core more at 15 years or even better, 35 years (whole of submarine life).
Alternatively India may rely on a highly modified variant capable of 100MW derived from the 83MW reactor used for INS Arihant (more see) .
Alpha SSN Protection of SSBNs
The Indian government support for building 6 Alphas in India is not only a navy matter. A (or the) major task of the Alphas will be to protect India’s growing force of SSBNs. See this generalised and very useful description of India's future nuclear subs. These SSBNs (so far only the 2 small Arihant class) will form the most secure and potent second strike arm of India’s nuclear triad. Two more slightly larger Arihants are planned - making 4 Arihant small SSBNs (aka "Baby Boomers"). The Arihants however cannot accommodate SLBMs large enough to hit the capital, Beijing, of India’s (likely) enemy China.
A more effective second strike SSBN arm will come with the full size “S5” SSBNs (see artwork below). These S5s, which may be launched from the late 2020s/early 2030s, will be able to accommodate 12 to 16 larger, longer range, desirably "K6" SLBMs capable of hitting Beijing.
The Arihant class and INS Chakra are current. Third one down is a possible shape and comparative size of a future Indian Alpha SSN below that is the possible shape of a future, larger Indian SSBN class (known as S5). (Artwork and captions courtesy
H I Sutton's, Forbes article of Feb 23, 2020).
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Bastion Protection of India's SSBNs
India's Arihant SSBNs are believed to be noisier than Russian or Western ideal SSBN noise levels and there are no new Alphas to protect them. So India's Arihants may need to be Bastion Protected in the Bay of Bengal by India's P8 MPAs, other jet aircraft, helicopters, surface naval ships, undersea sensors and many other sensor and weapons platforms.
It remains unknown whether India's leased Chakra II is armed, and therefore able to provide credible protection to just one Arihant. Even if a "newer" Chakra III is leased these Akulas are early 1980s hull designs, so liable to be comparatively noisy. They would need to be able to detect far quieter Pakistani AIP-Agosta-90Bs and late model Pak-AIP-Yuan SSKs as well as Chinese AIP-Yuans and Chinese SSNs.
India's first Alpha may be delivered to the Navy in the late 2020s and will need around 3 years of testing/training/working up to be fully commissioned in the 2030s. India will then probably require 2 more Alphas to form a credible protection force of 3 Alphas (noting rule of thirds). This may need to coincide with full commissioning of the first S5 full size, and quiet, SSBN.
So India may only have a fully operational force of 3 Alphas and 3 S5s in the late 2030s.
Pete
Another great article, Pete!
ReplyDeleteRegarding the Project-75 Alpha SSNs, much will depend on what the design is actually going to be. The three likely options will be:
1) Basically, an Arihant without the missile silo compartment. Same double-hull construction using many of the same hull sections (mainly bow, aft & reactor compartment), with some improvements to noise reduction (it's logical to assume many of the mechanical systems underwent significant improvement in the decade-plus since Arihant's design was frozen) and possible inclusion of a pump-jet instead of a traditional screw. This is likely the most straightforward and affordable method (both from an economic & timeline perspective).
2) A new clean-sheet design of Western-type single-hull construction. This would only become likely if France cooperates heavily with Barracuda-based tech. The cooperation would need to be extensive enough that Indian decision-makers wouldn't peg the whole thing as a distant pipedream (i.e. they'd have to be confident that they can build off of a lot of existing engineering models readily supplied by France). Either way this would be the most expensive & time-consuming option. And therefore the least likely.
3) Basically a nuclear-powered Scorpene...much in league with what Brazil hopes to build with the Alvaro Alberto. This would entail India again working closely with Naval Group in order to mate an Indian pressurized water reactor with the Scorpene hull. This is more of a middle-ground option with regard to money & time, and by extension the likelihood of happening.
Personally my money is on Option #1. An Arihant without missile silos, and incorporating whatever improvements were made along the way. I believe you already covered that bit about pumpjet propulsor research undergoing in India since quite a while.
Either way, I doubt India would be interested in the K15 Reactor. Like you said, being an LEU-based model it would present India with the compounding issue of high refuel cycle frequency - and India is already not happy with where they are with regard to the Arihant's 83MWt PWR's refuel cycle. And the 83 PWR as far as I know is HEU-based (but not high enough).
So going forward India is likely to want incorporation of HEU that is enriched to a much higher percentile, and the preferred way to do that would be by improving on the 83 PWR's design rather than working with a totally new French reactor (which again has to be modified & up-enriched in order to refuel less frequently anyway). In conclusion that '100MW PWR' you theorized is likely to be the most practical way forward, with a higher enrichment of Uranium than Arihant's 83MW model.
As far as I know, development of a 190MWt PWR is underway in India by BARC (Dept of Atomic Energy), whether the future S-5 class SSBNs will use this or maybe use 2 x of the 83-100MWt PWRs remains to be seen.
As of the Chakra-II/III, besides the uses you've already mentioned (both at-sea & docked crew training in operation of on-board PWRs as well as training of dock workers in proper handling of nuclear-powered vessels), I'd venture to say the leased SSNs may also have a role in conducting deep-ocean high-resolution mapping of the sea floor, underwater trenches, ridges etc. using active & passive sonars. Preparing the way for the Arihant-class SSBNs so that they can comfortably navigate those waters using charts & maps prepared by the Akula-class boats.
Hi Gessler
ReplyDeleteThanks for your very useful comments at Apr 7, 2021, 4:40:00 PM. I'll turn them into an article soon.
CALCULATIONS FOR AN INDIAN ALPHA SSN
I'll assume Project 75 Alpha SSN https://en.wikipedia.org/wiki/Project_75_Alpha 's
6,000 tonnes means surfaced tonnage?
Looking at Barracuda's https://en.wikipedia.org/wiki/Barracuda-class_submarine_(France) dimensions, from 4,650 tonne (surfaced), 99.5m long, 8.8m beam, 150MW reactor, 20-24 HWT shots,
Simultaneously paring back an Arihant class. It seems very possible that:
if the high missile hump were removed from Arihant class to yield a more streamlined Alpha that can still keep the Arihants 11m beam - important to jam in a decent power reactor.
The less than 5,000 tonne surfaced Barracuda has a 150MW (K15) reactor than a 6,000 tonne Alpha needs considerably more power.
The Soviets had a history of using a pair of reactors in the one SSN - see https://en.wikipedia.org/wiki/Soviet_naval_reactors.
2 x 83MW reactors for Alpha?
OR
The very similar weighted Mike https://en.wikipedia.org/wiki/Soviet_submarine_K-278_Komsomolets up to 5,750 tons surfaced, 117.7m long actually used a 190 MW OK-650 b-3 that fitted into Mike's 10.7m beam.
So maybe an Indian variant of the OK-650 is right for Indian Alpha?
AND
Somme reduction in Arihants 116m length may be necessary https://en.wikipedia.org/wiki/Arihant-class_submarine . Reducing length in the missile campartment to add some length for a larger reactor than Arihants. Maybe 2m additional for an Alpha pumpjet.
I'll assume the Alpha will carry 20 hwt horizonta torpedo tube launched shots (for Varunastra hwt torpedoes, Nirbhay conventional or nuclear tipped SLCMs and BrahMos land/anti-ship convntional SLCM). Like the Astute and Barracuda I'll asume no VLS.
Much to consider especially in reactor choices.
Regards Pete
Hello, Pete
ReplyDeleteFor Chakra II, the 10 years leasing is corresponding with period between major overhauls of Soviet subs (10 years).
For the French nuclear reacor, their life-span comes from France's decision to use "civilian" nuclear fuel, and not a spécific one whiwh is far more costly to produce... and huely costly to clean after use.
Best regards
Excellent writings from gessler and pete...thanks for the learning moment...
ReplyDeletePete, I think we discussed this way back in 2019, similar to the Type-91, The Indian SSN will likely (initially) use a slightly uprated Arihant 40% HEU PWR (uprated from 83 MWt to 100 MWt implying electrical power uprates to 16.7 MWe from a maximum of 13.8 MW presently) (the rule of 1/6 for naval reactors vs 1/3 for land based)
(the S-5 could see a OK-650 derivative as the bigger SSBN will need 25 MWe or more capacity to be available implying a 160-170 MWt OK-650 class reactor)
However, SSN reactor dynamics are likely to be different as the rapid 'power up power down' variation demand on the SSN reactor for 'sprint chases' will be much higher than an SSBN. Arihant class or even the S-5 likely speed requirement could stay between 22-24 knots while the SSN will need burst speed capability of 35 knots and the ability to do 28-30 knots frequently and consistently... (like the Type-93 Shang of the PLAN for instance)
Also I think Chakra elements with Arihant base is the most likely in SSN Alpha and not Barracuda or the Alvero Alberto Brazilian Scorpene SSN (though some learnings will cross over in welding, silencing, reduction gear design etc.)
I think a VLS combo with Horizontal launch capability could be better... 24 Tri-packed Nirbhay sub-sonic SLCMs in 8 VLS with 20+ combo of Varunastra Torpedo and Brahmos SLCM are the most likely combos..
Also while propulsor pumpjet is desirable and is being tried, I think a conventional 7 blade screw is likely for the first 2 boats at least. Like the Chinese in 1975, the focus first should be to get a couple of boats out and test...only then can real progress be made instead of what i think is an unhealthy obsession with 'perfect profile' product launches.
PS: Lobner got it right with his 100 MWt prediction I think
PPS: Good that Rawat, Doval and co were able to prevail on the SSNs after 3 years of wrangle at North Block
Part 2: some amendments and comments on INS Chakra
ReplyDeleteWhen I compared SSN Alpha to Type 91, I meant in the sense that, get the first 2 boats out first and then we can see. Type 91 used a 60 MWt inefficient PWR that delivered 8 MWe and was very radiation leak prone. The key difference being the PWR was a LEU (thanks to the Soviets screwing the chinese over and China left with minimal uranium and also expertise post cultural revolution)..India has been a HEU navy always
INS Chakra
No, INS Chakra cannot be used in war/offense, if that is what the question is. It cannot be armed with any missile ranging > 290 km i.e. original MTCR restrictions apply (unless I am gravely mistaken)...it can help in case of open war, but will be limited to defending with torpedoes and such short range missiles as to be of very limited utility indeed....plus the sonars and combat suites are very old as well....
I do hope India is able to leverage Thales and Rafael under water suites expertise to equip the SSN with good sonar suites and combat capabilities....
Hi Pete and Gessler
ReplyDeleteAgain back to the Feb 25 blog and my contribution of March 6(03 46 PM)
HEU vs LEU in nuclear propulsion is not a military /tactical issue.LEU is the natural solution when an existing civilian , sustainable N power industry exists.If HEU is in place moving to LEU does not make sens (Lobner article, invest to displace an existing performing assets..)
The changing of fuel"lost availability" is irrelevant. We are talkings in days here.All subs ,N or not, require over their 30 + life complete overhaul , meticulous dismantling/replacement/upgrades every 8 to 10 years lasting one to two years. No different than other complex miltary/civilan assets (aircraft?)
This is why the UKRN or the French Navy have 4 SSBM in order to maintain 2 at sea or the fact that yard deliver one sub every 2 years. Each sub has 2 crews in order to maintain 270 days at sea . The crew recruting , training and retaining is the biggest problem by far..
Whether brain surgery or plumbing (no insults to plumbers)you excell and improve on what you do every day and not forget for a year or two
The target availability of 60 % is very high but is much higher than , helicopters,jet figthers or even tanks.A modern tank (MBT)cost around 10 M euros/piece A bataillon with the infantry combat velhicles cost I billion Euros..And the salaries/pensions ect are for 800 people..Will it last 30 +years?
If Indian subs are built like my Indian 5Kva generator set, then they will be having to collect handfuls of coarse-thread nuts and bolts daily.
ReplyDelete@Pete
ReplyDeleteI'm skeptical about the figures of Alpha tonnage/displacement floating around in the media. I suspect those displacement figures (not only mentioned by Hindustan Times but many others as well) are from the same erroneous sources that also claimed that the S-3 boat (INS Arighat, the sister of S-2 INS Arihant) would be considerably bigger and carry 8 missile silos. But satellite images of the Ship Building Centre (SBC) harbour at Visakhapatnam (Visak, most commonly pronounced & spelled Vizag) prove that both Arihant & Arighat are the same length & size, and carry the same number of missile tubes - Four.
https://frontierindia.com/google-maps-show-indian-nuclear-submarines-berthed-alongside/
Now don't get me wrong - I still am inclined to believe the 4th nuclear boat to be built by SBC (known in the media as the S-4* or S-4 Star) would indeed be considerably bigger than the Arihant-class, satellite images of a new submarine dockyard shelter constructed at Vizag which is up to 40m longer than Arihant's shelter substantiate the theory that a new, bigger boat is around the corner - and it definitely can't be the S-5 yet. So it has to be the rumoured S-4* SSBN, with perhaps 8 silos.
Nuclear expert Hans M. Kristensen's observation of the same summarized in his tweet, though he speculates this to be intended for the S-4 itself (3rd nuclear boat), not the S-4*:
https://twitter.com/nukestrat/status/1370325335435309058
Personally, I would think all three Arihant-class SSBNs will be of the same dimensions, it would not make any sense to have the last boat in class to be substantially different than the others. The S-4* on the other hand might make sense as both a test platform for new, larger equipment that may eventually find use on the still larger S-5 class down the line, once the systems mature after at-sea testing on this boat. The Arihants would have to be at sea (or in refit), delivering on the deterrence role, you can't ask them to come off their vitally important duties to function as test platforms for new stuff - the S-4* might make a lot of sense in that respect.
Another reason to be skeptical about the Alpha's displacement figures would be that pretty much all available sources (unless I'm misremembering) quote the Arihant-class boats' surfaced displacement as approx. 6,000 tons. So if the Alpha indeed turns out to 'Arihant without silos' then there's no way it'll also be 6,000 tons surfaced. Has to be 5,000 or so, but even that is speculation.
So personally I'll hold my horses for now regarding the displacement figures.
@GhalibKabir at 5:43 PM on April 8
ReplyDeleteRegarding the use of VLS system to launch SLCMs from the Alphas - I don't think they will go down that way. Allow me to explain my point of view.
In the 2030s, when the S-5 SSBNs start becoming available for carrying forward the role of what the Royal Navy calls Continuous At-Sea Deterrence or CASD... (I'm using that expression because the hydrodynamic testing model of S-5 has it's bow planes attached to the hull roughly at the same spot where the Vanguard-class SSBN has them, instead of on the conning tower like Arihant...though the similarities are likely to end there)
...anyway, as each new S-5 becomes available to take over the CASD role, a corresponding Arihant-class boat would in all likelihood be retired from performing any form of deterrence role***, after which it would probably be subjected to a scheduled refit & refueling of the reactor. So what will the Indian Navy do with these boats then? They would still have at least 10-15 more years of service life left.
My guess: they will convert them into performing a role that is somewhat less demanding (on the part of keeping at least one boat operational at all times) - into an SSGN role. When the Arihants are subjected to refit & refueling, the nuclear armed K-4 intermediate-range ballistic missiles can be swapped out and replaced with up to 5 or 6 Nirbhay-type SLCMs per silo. The Arihant's silos were designed to accept either one K-4 or three smaller K-15 per tube so we know it is designed to support the multi-round ejection systems needed for such 'pack' VLS.
The K-15 missile has a diameter of 0.74m compared to 0.52m for the Nirbhay, so it can potentially pack 5 or 6 (more?) Nirbhays in those tubes I'm guessing, for a total of 20-24 vertically-launched cruise missiles per boat (someone needs to do the math on that diameter, either way very similar to the 7-round Tomahawk VLUs on some Virginia-class boats).
So, better to not encumber the Alphas with the additional weight & power requirements needed to fulfill an SSGN role - better to let them be as light & sleek as possible for reasons of speed, stealth as well as reactor efficiency, all critical for a hunter-killer SSN.
( Will explain my view on the subject I've marked with '***' in a separate post )
@GhalibKabir
ReplyDeleteHere you go regarding '***'
Considering India does not have stockpiles of hundreds & hundreds of nukes, we might not even have the number it would be needed to simultaneously arm Three or Four S-5 class as well as Three Arihant-class (discounting the S-4*). So it would have to be an inevitability to bring the Arihants off the line as deterrence platforms once the S-5s start coming in...
...keeping in mind the fact that the S-5 class will probably have 12 missile tubes storing K-5 or K-6 intercontinental SLBMs (which will most definitely have Multiple Independently-targeted Re-entry Vehicles or MIRVs). Each S-5 boat, even if we assume a relatively modest MIRV capacity of 3 RVs per missile, would be carrying 36 nuclear warheads. Three such boats, if we assume each has it's own permanently assigned load of missiles, would require 108 warheads. If we're talking four boats (following the UK & France pattern of SSBN numbers) that goes to 144 warheads. That's close to the total stockpile that most experts assume India to have currently (~150 warheads).
If we assume 4 MIRVs per SLBM (like the slide I've linked below, shown by DRDO's then-chairman Dr. VK Saraswat at IIT-Bombay university) then it would be 48 warheads per sub, and 144 for Three boats and 192 for Four boats. With a quoted throwaway weight of 2 tons, likelihood is high for there to be indeed 4 x 500kg MIRVs per K-5/K-6.
https://ibb.co/bb4xms4
Personally I'd definitely assume India has more than 150 nukes even currently, the delays of Plutonium deliveries to the PFBR prototype also point at the possibility of the Pu going to fill other, more pressing & strategically important requirements, like perhaps building more bombs. By the time the S-5s come online, I'd certainly expect us to have more than 150.
However - it must be remembered that India, with two hostile neighbours who share land borders, certainly has no plans of giving up it's land-based rail & road-mobile nuclear deterrent like UK & France have done. This portion of the triad will continue to be armed in the form of Agni-4, 5 and the in-development Agni-6 with MIRVs. The Agni-6 is reportedly designed to have a throw weight of 3 tons, so we're again looking at a significant MIRV payload (again, refer to the slide I've linked below, from same source at IIT-Bombay presentation).
https://ibb.co/42DJB42
And we won't be giving up the Air-launched deterrent either (like UK has done), the presence of nuclear gravity bombs as well as the ongoing development of a nuclear-capable Liquid-Fuel Ramjet (LFRJ) ALCM intended for the Indian Rafales (very similar to the French ASMP-A missile) indicate that this leg of the triad is here to stay as well.
https://www.livefistdefence.com/revealed-indias-naval-anti-ship-missile-breaks-cover-at-defexpo2020/
https://twitter.com/Indrani1_Roy/status/1301312093795225607
What all this means is that we'll be needing a significant number of warheads (at least 100) outside of CASD as well. And this just goes to show that there's no way we can continue operating Arihants as nuclear-armed SSBNs even after S-5s come in. We just won't have enough nukes for them, and that's just part of the reason compelling us to convert the Arihants into conventionally-armed SSGNs in the 2030s - poised to be the ideal platform for cruise missile strikes on likes of Karachi's naval facilities/airbases or any Chinese naval presence at Gwadar in the event of open hostilities.
@Anonymous at 1:59AM on April 9
ReplyDeleteI would assume your 5KVa generator is not made by Larsen & Toubro (L&T) so I'll say no. Joking aside if you'd assume the quality of construction of an important national asset based on something made to generate the biggest margin of profit, you're gonna be wrong most of the time.
Speaking of L&T (the Private-sector company responsible for building the hulls of all Indian nuclear boats so far, as well as significant portions of India's land-based PHWR reactors), I'd indeed rate them very highly - among the Top 5 heavy engineering companies in the world in fact when it comes to building anything that involves Nuclear power & Heavy Engineering.
If the International Thermonuclear Experimental Reactor (ITER) taking shape at Cadarache, France trusts them to deliver the biggest & heaviest components of ITER (like the 3,850-ton Cryostat Assembly that contains & insulates the entire Fusion reactor), I'd definitely trust them to build India's nuclear submarines (including hulls & significant components of reactors) to a very good standard indeed.
https://youtu.be/S0ewQR2rJak
https://youtu.be/YOVYjKhUPp0
An overview of the very interesting project itself, for those interested in fusion power (the project is a joint collaboration between European Union, United States, India, China, Japan, South Korea & Russia):
https://youtu.be/2Y2CBJIp2j8
Hi @Anon,
ReplyDeleteI don't know how we compare generator with SSN construction.
It is same like questioning Chinese submarine construction capability because of defected Chinese Christmas lights. And I have no doubt in L&T capabilities to construct SSN's hull. And DAE's capabilities to provide much better reactor than in Arihant. I know the Adani effect in Australian mindset, but that has nothing to with nuclear submarine construction capability of India, including industrial capability and human resources.
On HEU part, refueling a marine reactor is not that simple as you suggesting, you have to cut the hull open after every 5-7 years in LEU. Further the HEU provide much better patrol hours per year than LEU, as proven during the cold war again & again.
Also, India investing hugely in HEU dedicated for fueling submarine, so I don't know why we reverse whole policy and adopt LEU marine reactor from France, when the all know how & know why of HEU PWR marine reactor exist in India.
https://isis-online.org/isis-reports/detail/indias-new-uranium-enrichment-plant-in-karnataka1/7
Hi Anonymous, GhalibKabir, Gessler and Arpit Kanodia
ReplyDeleteThanks for your veritable avalanche of great comments.
I'll begin to respond on the morrow.
Cheers
Pete