09III/09IV (093/094) Nuclear Submarine Thread


Blitzo

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A pump-jet usually translates to 5-10dB reduction in noise. It also offers a flatter and smoother gradient of noise due to speed variance.

PLAN will have to adopt it sooner or later because of that even if now there are other considerations that make it impractical.

I never said it was impossible that 09IIIB doesn't feature any improvements to its propulsion system, in fact I personally think it is quite likely and there is a decent chance they may have implemented a pumpjet on it as well.
 

Blitzo

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Thank you for your reply. I agree there are general pitfalls of inductive reasoning which we should stay away from. In particular it's difficult to judge what are in the space of possibilities and what prior probability we should assign to each of them. Credible rumors/indications are certainly helpful in this regard.

But in this particular case, we have more than just credible rumor/indication that PLAN is considering using PMM in its nuclear submarines. Recall the official news release I was referring to
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I hadn't fully grasped what this news implied until now. Why would a group of engineers from CSSC 712th Institute, which is located in Wuhan, go to Sanya to test their new motor? Couldn't they test it on some submarine test platform right next door? The only explanation is they went to Sanya to retrofit it onto a submarine in the Yulin naval base. Indeed, the news release stated it was a case of "实艇安装", i.e. installation on a submarine that the motor was designed to be installed on. I had thought until now that the testing had to do with China's conventional submarine program. But of course no, the test of the PMM was done in Sanya! Yulin submarine base is a nuclear submarine base, which means that (drumroll) in 2017 a permanent magnet motor was retrofitted onto a in service PLAN nuclear submarine!

Now the report didn't give any specs of the PMM that was successfully tested. It could be some tiny 800kW emergency motor. But the only permanent magnet motor listed on CSSC 712th Institute website's product page is the 5MW propulsion PM motor. So it's reasonable to infer that the PMM retrofitted onto a nuclear submarine at Yulin naval base was a 5MW motor. The retrofit plan either turns the submarine's propulsion system into to a hybrid system or an IEPS, depending whether additional PMM would be installed to completely replace the propulsion turbine. I have already listed what I took to be the pros and cons of hybrid vs IEPS. We know from the news release that the PMM was used to drive a propeller, so no pump-jet. According to my layman's analysis, due to space constraint IEPS will likely require using small turbogenerators with significantly lower total power output and thus significantly lower top speed. Hybrid or IEPS depends on PLAN's performance requirements.

This new evidence (or corrected reading of old evidence) significantly increased my credence that 09IIIB features a hybrid propulsion system.

I don't think this changes anything.

Ultimately, the final arbiter for us to be able to start speculating about 09IIIB implementing a hybrid propulsion system is through credible rumours/indicators.

We don't get the freedom to openly speculate about things without guidance from credible rumours.
 

OppositeDay

Junior Member
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I don't think this changes anything.

Ultimately, the final arbiter for us to be able to start speculating about 09IIIB implementing a hybrid propulsion system is through credible rumours/indicators.

We don't get the freedom to openly speculate about things without guidance from credible rumours.

I see our disagreement is over norms of posting for this community. But what exactly is this community? At SFD there's a mix of PLA fanboys, Chinese nationalists with marginal interests in military, PLA enthusiasts, general military enthusiasts, professional defense analysts, professional or unprofessional OSINT people. If each type of people here are to form their own separate communities, those communities are going to have very different norms. Even within in this mixed community, norms already differ in the world affairs forum and various defense forums.

What norms should govern activities on SDF's defense forums proper? Certainly not PLA fanboy norms. People don't get to quote YouTube videos claiming PLAN is equipping super railguns. Should the governing norms be like OSINT norms where you only get to claim X if you have some photo, video or official document evidence for X? Probably not that either.

My suggestion is to have a two tracks system. People can choose to have a "professional" tag or badge to indicate that they operate within more demanding norms. Non-professional members get a choice to follow less demanding norms. Posting fanboy videos from YouTube is still not okay, but I think some speculations make for very interesting discussions. Should we refrain from discussing whether the next Chinese aircraft carrier will be conventional or nuclear until some big shrimps with proven track records make their pronouncements on the matter? I don't know about professional analysts, but I would have no qualms in engaging in such speculation as long as it is supported by credible information on Chinese technological/industrial capacities, pros and cons of nuclear aircraft carriers and PLA's operational needs and doctrine. I see values in speculating as long as basic standards for evidence and inference are observed, because such speculation can encourage people to seek out information. If I haven't speculated on 09IIIB's propulsion system, then we wouldn't have this discussion, I won't have reexamined the news reports about the Sanya PMM test and I won't have learnt that a PLAN nuclear submarine was retrofitted with PMM. This piece of information might be new to some other reader of this thread as well. The point of speculation is not to necessarily to convince other people about what will happen, it's a process in which people discover and exchange evidence and ideas.

Anyway I have reformulated my argument a bit, and I'm very curious at which step the argument becomes too speculative for you. Inferences certainly has to be drawn during a discussion, otherwise all we can do is to repost photos, videos, news reports and credible rumors, but when inferences become speculations differ for each individual.

My reformulated argument:

1. There's an 2017 official SASTIND press release stating a PMM designed by CSSC 712th Institute was installed and tested on a submarine in Sanya.

2. PMM was tested on a PLAN nuclear submarine, because 1) it's a SASTIND press release, so it's military related and 2) The naval base at Sanya hosts only nuclear submarines.

3. The retrofitted motor was part of a PLAN project to upgrade one of their existing nuclear submarine models and/or part of the testing/validation process for a new nuclear submarine design, because PLAN was unlikely to allow 712th Institute to retrofit a new motor on one of their nuclear submarines just for R&D when China has dedicated submarine testing platforms.

4. The motor tested at Sanya was likely a 5MW motor because that's the only PMM listed on 712th Institute website's product page. The same website lists 1MW and 2MW superconducting motors, so it does not omit all smaller motors.

5. A 5MW motor is way too big for an emergency only motor. It is part of the submarine's main propulsion system. Therefore, the upgraded propulsion system is either hybrid or full electric.

6. The retrofitting was done at a time (late 2017) when Type 9IIIB was at an early stage of construction at most. Nuclear submarines are expensive and and long-serving systems, it would be a serious case of project mismanagement if China keeps producing newest model submarines with the old propulsion system when what they're already retrofitting a more advanced system to older models. Therefore it's likely that either the first Type 9IIIB features a new propulsion system, or that design will be modified for subsequent batches to incorporate the new propulsion system if its performance is satisfactory.

7. Nuclear submarine are built in small numbers, commonalities in subsystems are desirable to reduce costs. So Type 9IIIB (either first or at latest the second batch) will receive the same system or a system that's built upon what's being test at Sanya. Going back to full mechanic transmission is unlikely both for developmental path reasons and pure performance reasons (given the many benefits of hybrid/IEPS I listed in my earlier posts). It will likely be either hybrid or IEPS.

Do you think this reformulated agreement is still too speculative? I would rank official SASTIND press release as being more credible than any credible rumors, so at least Step 1 cannot be too speculative. Where in the chain do you think admissible inference ends and inadmissible speculation begins?
 

Blitzo

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Staff member
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Registered Member
I see our disagreement is over norms of posting for this community. But what exactly is this community? At SFD there's a mix of PLA fanboys, Chinese nationalists with marginal interests in military, PLA enthusiasts, general military enthusiasts, professional defense analysts, professional or unprofessional OSINT people. If each type of people here are to form their own separate communities, those communities are going to have very different norms. Even within in this mixed community, norms already differ in the world affairs forum and various defense forums.

What norms should govern activities on SDF's defense forums proper? Certainly not PLA fanboy norms. People don't get to quote YouTube videos claiming PLAN is equipping super railguns. Should the governing norms be like OSINT norms where you only get to claim X if you have some photo, video or official document evidence for X? Probably not that either.

My suggestion is to have a two tracks system. People can choose to have a "professional" tag or badge to indicate that they operate within more demanding norms. Non-professional members get a choice to follow less demanding norms. Posting fanboy videos from YouTube is still not okay, but I think some speculations make for very interesting discussions. Should we refrain from discussing whether the next Chinese aircraft carrier will be conventional or nuclear until some big shrimps with proven track records make their pronouncements on the matter? I don't know about professional analysts, but I would have no qualms in engaging in such speculation as long as it is supported by credible information on Chinese technological/industrial capacities, pros and cons of nuclear aircraft carriers and PLA's operational needs and doctrine. I see values in speculating as long as basic standards for evidence and inference are observed, because such speculation can encourage people to seek out information. If I haven't speculated on 09IIIB's propulsion system, then we wouldn't have this discussion, I won't have reexamined the news reports about the Sanya PMM test and I won't have learnt that a PLAN nuclear submarine was retrofitted with PMM. This piece of information might be new to some other reader of this thread as well. The point of speculation is not to necessarily to convince other people about what will happen, it's a process in which people discover and exchange evidence and ideas.

This is not a matter of norms over posting in the community -- I have no issue with what you've written or what you've posted, I only contest the main argument that your premises are trying to support.

If you'd written all of your premises but made your final argument as one of "the hybrid nuclear propulsion arrangement may have been demonstrated, and thus be a potential application on future nuclear submarines, but at this stage we have no credible rumours or indicators it will be applied on any nuclear submarines including the recently launched 09IIIB," then I would fully agree with you.



Anyway I have reformulated my argument a bit, and I'm very curious at which step the argument becomes too speculative for you. Inferences certainly has to be drawn during a discussion, otherwise all we can do is to repost photos, videos, news reports and credible rumors, but when inferences become speculations differ for each individual.

My reformulated argument:

1. There's an 2017 official SASTIND press release stating a PMM designed by CSSC 712th Institute was installed and tested on a submarine in Sanya.

2. PMM was tested on a PLAN nuclear submarine, because 1) it's a SASTIND press release, so it's military related and 2) The naval base at Sanya hosts only nuclear submarines.

3. The retrofitted motor was part of a PLAN project to upgrade one of their existing nuclear submarine models and/or part of the testing/validation process for a new nuclear submarine design, because PLAN was unlikely to allow 712th Institute to retrofit a new motor on one of their nuclear submarines just for R&D when China has dedicated submarine testing platforms.

4. The motor tested at Sanya was likely a 5MW motor because that's the only PMM listed on 712th Institute website's product page. The same website lists 1MW and 2MW superconducting motors, so it does not omit all smaller motors.

5. A 5MW motor is way too big for an emergency only motor. It is part of the submarine's main propulsion system. Therefore, the upgraded propulsion system is either hybrid or full electric.

6. The retrofitting was done at a time (late 2017) when Type 9IIIB was at an early stage of construction at most. Nuclear submarines are expensive and and long-serving systems, it would be a serious case of project mismanagement if China keeps producing newest model submarines with the old propulsion system when what they're already retrofitting a more advanced system to older models. Therefore it's likely that either the first Type 9IIIB features a new propulsion system, or that design will be modified for subsequent batches to incorporate the new propulsion system if its performance is satisfactory.

7. Nuclear submarine are built in small numbers, commonalities in subsystems are desirable to reduce costs. So Type 9IIIB (either first or at latest the second batch) will receive the same system or a system that's built upon what's being test at Sanya. Going back to full mechanic transmission is unlikely both for developmental path reasons and pure performance reasons (given the many benefits of hybrid/IEPS I listed in my earlier posts). It will likely be either hybrid or IEPS.

Do you think this reformulated agreement is still too speculative? I would rank official SASTIND press release as being more credible than any credible rumors, so at least Step 1 cannot be too speculative. Where in the chain do you think admissible inference ends and inadmissible speculation begins?

At 6 and 7 it becomes too speculative to me.

Let's put it this way -- to me, it is simultaneously very possible that they can test a hybrid nuclear propulsion motor on an existing old nuclear submarine a few years ago at Sanya, and for the new 09IIIB (launched earlier this year) to not feature that same technology.

Even if a technology is demonstrated at a seemingly relatively advanced stage of development, it does not mean it will be present on "XYZ next platform".
For example, the PLAN has tested a rail gun on a 072 LST at sea -- but that doesn't mean we can argue that "XYZ next surface combatant" (whether it be "055A" or whatever) will likely feature a rail gun, because we don't have any credible rumours or indicators suggesting the rail gun will actually be applied and utilized on an upcoming surface combatant.

A new system, subsystem or otherwise can be at an advanced stage of development and even demonstration, but yet ultimately still not be procured, because:
- its benefits are not worth the cost
- its performance was lower than expected
- it was judged to be insufficiently mature
- ad infinitum


If we want to make a credible argument to suggest that 09IIIB features/will feature a hybrid nuclear propulsion arrangement, there are a few example credible indicators I can describe:
- a rumour from a credible source/grapevine stating that 09IIIB will feature hybrid nuclear propulsion
- an official contract/subsystems list for 09IIIB that includes key equipment that can only be for hybrid nuclear propulsion
- some type of official CCTV "disclosure" alluding to a "recently launched new nuclear submarine" using hybrid nuclear propulsion or key equipment that can only be for hybrid nuclear propulsion
 

tphuang

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I see our disagreement is over norms of posting for this community. But what exactly is this community? At SFD there's a mix of PLA fanboys, Chinese nationalists with marginal interests in military, PLA enthusiasts, general military enthusiasts, professional defense analysts, professional or unprofessional OSINT people. If each type of people here are to form their own separate communities, those communities are going to have very different norms. Even within in this mixed community, norms already differ in the world affairs forum and various defense forums.

What norms should govern activities on SDF's defense forums proper? Certainly not PLA fanboy norms. People don't get to quote YouTube videos claiming PLAN is equipping super railguns. Should the governing norms be like OSINT norms where you only get to claim X if you have some photo, video or official document evidence for X? Probably not that either.

My suggestion is to have a two tracks system. People can choose to have a "professional" tag or badge to indicate that they operate within more demanding norms. Non-professional members get a choice to follow less demanding norms. Posting fanboy videos from YouTube is still not okay, but I think some speculations make for very interesting discussions. Should we refrain from discussing whether the next Chinese aircraft carrier will be conventional or nuclear until some big shrimps with proven track records make their pronouncements on the matter? I don't know about professional analysts, but I would have no qualms in engaging in such speculation as long as it is supported by credible information on Chinese technological/industrial capacities, pros and cons of nuclear aircraft carriers and PLA's operational needs and doctrine. I see values in speculating as long as basic standards for evidence and inference are observed, because such speculation can encourage people to seek out information. If I haven't speculated on 09IIIB's propulsion system, then we wouldn't have this discussion, I won't have reexamined the news reports about the Sanya PMM test and I won't have learnt that a PLAN nuclear submarine was retrofitted with PMM. This piece of information might be new to some other reader of this thread as well. The point of speculation is not to necessarily to convince other people about what will happen, it's a process in which people discover and exchange evidence and ideas.

Anyway I have reformulated my argument a bit, and I'm very curious at which step the argument becomes too speculative for you. Inferences certainly has to be drawn during a discussion, otherwise all we can do is to repost photos, videos, news reports and credible rumors, but when inferences become speculations differ for each individual.

My reformulated argument:

1. There's an 2017 official SASTIND press release stating a PMM designed by CSSC 712th Institute was installed and tested on a submarine in Sanya.

2. PMM was tested on a PLAN nuclear submarine, because 1) it's a SASTIND press release, so it's military related and 2) The naval base at Sanya hosts only nuclear submarines.

3. The retrofitted motor was part of a PLAN project to upgrade one of their existing nuclear submarine models and/or part of the testing/validation process for a new nuclear submarine design, because PLAN was unlikely to allow 712th Institute to retrofit a new motor on one of their nuclear submarines just for R&D when China has dedicated submarine testing platforms.

4. The motor tested at Sanya was likely a 5MW motor because that's the only PMM listed on 712th Institute website's product page. The same website lists 1MW and 2MW superconducting motors, so it does not omit all smaller motors.

5. A 5MW motor is way too big for an emergency only motor. It is part of the submarine's main propulsion system. Therefore, the upgraded propulsion system is either hybrid or full electric.

6. The retrofitting was done at a time (late 2017) when Type 9IIIB was at an early stage of construction at most. Nuclear submarines are expensive and and long-serving systems, it would be a serious case of project mismanagement if China keeps producing newest model submarines with the old propulsion system when what they're already retrofitting a more advanced system to older models. Therefore it's likely that either the first Type 9IIIB features a new propulsion system, or that design will be modified for subsequent batches to incorporate the new propulsion system if its performance is satisfactory.

7. Nuclear submarine are built in small numbers, commonalities in subsystems are desirable to reduce costs. So Type 9IIIB (either first or at latest the second batch) will receive the same system or a system that's built upon what's being test at Sanya. Going back to full mechanic transmission is unlikely both for developmental path reasons and pure performance reasons (given the many benefits of hybrid/IEPS I listed in my earlier posts). It will likely be either hybrid or IEPS.

Do you think this reformulated agreement is still too speculative? I would rank official SASTIND press release as being more credible than any credible rumors, so at least Step 1 cannot be too speculative. Where in the chain do you think admissible inference ends and inadmissible speculation begins?
It seems like a few of these are quite speculative. I'm also not sure why you are this passionate about PMM? This is really not where the loudest source of noise comes from for nuclear submarine. There is a lot of complexity involved with IEPS or a hybrid design. We really haven't seen PLAN use that type of propulsion anywhere else.
 

OppositeDay

Junior Member
Registered Member
It seems like a few of these are quite speculative. I'm also not sure why you are this passionate about PMM? This is really not where the loudest source of noise comes from for nuclear submarine. There is a lot of complexity involved with IEPS or a hybrid design. We really haven't seen PLAN use that type of propulsion anywhere else.

PMMs are very torque dense - super important for if you want to speed up your propellers quickly. It's common for PMM to have 70% of the size and weight and produce 150% of the torque of an induction motor of the same power rating. Normally you don't gain torque and lose size/weight at the same time. PMM is black magic.

Electric motor's regenerative braking function might save the submarine from underwater collision.

Reduction gears can be very noisy.

IEPS is far simpler for submarines than for surface combatants. There is no submarine equivalent of turning on multiple high power radars at a moment's notice. All modern SSKs use IEPS.
 
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tphuang

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PMMs are very torque dense - super important for if you want to speed up your propellers quickly. It's common for PMM to have 70% of the size and weight and produce 150% of the torque of an induction motor of the same power rating. Normally you don't gain torque and lose size/weight at the same time. PMM is black magic.

Electric motor's regenerative braking function might save the submarine from underwater collision.

Reduction gears can be very noisy.

IEPS is far simpler for submarines than for surface combatants. There is no submarine equivalent of turning on multiple high power radars at a moment's notice. All modern SSKs use IEPS.
Sure, there are advantages to IEPS and hybrid. That applies to surface combatants too, but we haven't seen any 055 using IEPS yet. I wouldn't consider a hybrid propulsion with electric and nuclear to be less complicated than IEPS from gas turbines.

The propulsion in nuclear submarine is significantly more complicated than SSKs. You are never turning off your nuclear reactor on your SSN. There are so many things going on in the engine room. On diesel subs, you have them running on battery modes when you are not charging them. I'm not really sure how they can be compared.

Anyways, I will take the wait and see approach until reliable sources come out about 093B.
 

OppositeDay

Junior Member
Registered Member
At 6 and 7 it becomes too speculative to me.

Let's put it this way -- to me, it is simultaneously very possible that they can test a hybrid nuclear propulsion motor on an existing old nuclear submarine a few years ago at Sanya, and for the new 09IIIB (launched earlier this year) to not feature that same technology.

Even if a technology is demonstrated at a seemingly relatively advanced stage of development, it does not mean it will be present on "XYZ next platform".
For example, the PLAN has tested a rail gun on a 072 LST at sea -- but that doesn't mean we can argue that "XYZ next surface combatant" (whether it be "055A" or whatever) will likely feature a rail gun, because we don't have any credible rumours or indicators suggesting the rail gun will actually be applied and utilized on an upcoming surface combatant.

A new system, subsystem or otherwise can be at an advanced stage of development and even demonstration, but yet ultimately still not be procured, because:
- its benefits are not worth the cost
- its performance was lower than expected
- it was judged to be insufficiently mature
- ad infinitum


If we want to make a credible argument to suggest that 09IIIB features/will feature a hybrid nuclear propulsion arrangement, there are a few example credible indicators I can describe:
- a rumour from a credible source/grapevine stating that 09IIIB will feature hybrid nuclear propulsion
- an official contract/subsystems list for 09IIIB that includes key equipment that can only be for hybrid nuclear propulsion
- some type of official CCTV "disclosure" alluding to a "recently launched new nuclear submarine" using hybrid nuclear propulsion or key equipment that can only be for hybrid nuclear propulsion

Yes it's certainly a possibility that the system could performed below expectation, even though according to the report the performance in the initial test was good.

However I would say proper analogy is not with a railgun being retrofitted on a Type-072, but a H-6 retrofitted with turbofans in the early 2000s. PMM is to naval propulsion what turbofan was to jet propulsion.

If you think I'm being overenthusiastic about PMMs, here's another 2017 news article about the same trial that I just dug up. This time straight from ST Daily 科技日报
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"...永磁推进电机具有体积小、重量轻、噪声低、效率高、操作简单和维护简便等优点,有助于舰船性能的提升。永磁推进电机已成为舰船标志性技术之一,是今后时期内舰船推进技术发展的主要方向。

七一二所“十二五”期间完成了永磁推进系统的工程科研,并进行了长期可靠性试验和实爆抗冲击试验,充分释放了设备装艇应用风险。据该所负责人介绍,未来几年永磁电机推进系统将得到推广应用,实现我国舰船推进技术的跨越式发展。"

"...permanent magnet propulsion electric motor has advantages in size, weight, noise, efficiency, operability and maintainability. It contributes to the improvement of naval vessels performance. Permanent magnet propulsion electric motor has become one of the landmark naval technologies, it is the main direction of technological advancements in naval propulsion at present and in the foreseeable future.

During the 12th Five Year Plan, the 712th Institute has completed the engineering development of permanent magnet propulsion system, and performed long-term reliability trials and live explosion anti-shock trials to sufficiently control the system's risks in submarine application. According to the head of the 712th Institute, in the next few years permanent magnet propulsion system will see wide applications, and enable China to leapfrog in naval propulsion technology."

So Ke Ji Ri Bao called PMM a "landmark naval technology" and "the main direction of technological advancements in naval propulsion at present and in the foreseeable future". Not "one of the" but "the" main direction. Not the direction of "electric naval propulsion" but "naval propulsion" period. Coming from the most authoritative Chinese media on science and technology (Ke Ji Ri Bao is a vice-ministerial level organ), it's safe to say this reflects PMM's place in future (circ 2017) Chinese naval propulsion.

Oh the phrase "leapfrog". I think this implies Ma Weiming's earlier research on advanced induction motors will not see much applications. Chinese AIM joins Chinese steam catapult. But I'm sure Ma is happy.

The article didn't mention Type 09IIIB specifically, but here's a PMM
1. specifically engineered for submarine reliability requirements
2. had been tested on a (mostly likely nuclear) PLAN submarine in 2017
3. the engineering development of which was part of the 12th Five Year Plan (2011-2015)
4. the technology of which was hailed by official media as THE future of naval propulsion
5. an official newspaper (actually official, not Global Times official), quoting an official source, stated in 2017 that the PMM would see applications "in the next few years" to help PLAN leapfrog in naval propulsion.

Different people obviously have different standards for evidence, but I'll just state that for my standard of evidence, at this stage I would assume that Type 09IIIB would feature PMM (hence either hybrid propulsion or IEPS) until I receive new information to the contrary.
 

banjex

Junior Member
Registered Member
I'm curious why it seems to be more difficult to develop quiet nuclear subs than other tech. China's clearly done quite well when it comes to other complicated items such as AESA, em cats, low observability and fifth gen, SSKs, drones, etc.

Can't the skills and advances in those fields be applied in sub R&D? I assume much of it is transferrable. Or are submarines more of a black art than other equipment?
 

FairAndUnbiased

Major
Registered Member
I'm curious why it seems to be more difficult to develop quiet nuclear subs than other tech. China's clearly done quite well when it comes to other complicated items such as AESA, em cats, low observability and fifth gen, SSKs, drones, etc.

Can't the skills and advances in those fields be applied in sub R&D? I assume much of it is transferrable. Or are submarines more of a black art than other equipment?
Not SME but from what I understand there is little civil demand for the technologies used in SSNs anywhere except SSNs. For example, there's no civil demand for small, quiet reactors that don't need refueling, because civil reactors don't care about size and noise constraints. The noise isn't too high for humans and they can just make a bigger building to both dampen the noise and house bigger reactors. They can also easily refuel.

On the other hand SSKs benefit from civil fuel cell, battery, motor and heat engine research. The only part of a SSK that doesn't benefit from civil research is hull construction and engine quieting. But even here, quieting isn't as hard because an ICE engine can be run at a low speed, it is much lighter than a reactor, and only runs for a short period of time to charge batteries.
 

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