09V/09VI (095/096) Nuclear Submarine Thread

[Blitzo]

Having 2x 38MW steam turbines per boat seems way too much for a SSN.

Both Akula and Yasen SSNs with 12000+ tons of submerged displacement only has one ~32-35 MW steam turbine per boat.

Even the Borei SSBNs with 24000+ tons of submerged displacement has one ~38MW steam turbine per boat. The Ohio SSBNs with 18000+ tons of submerged displacement has one ~26MW steam turbine per boat.

I'm reading back on the last page or so, where did the idea of 2x 38MW steam turbines arise from?

As I understand, the 2x steam turbine matter only arose in #1479 when @gelgoog was saying that US SSNs use 2x steam turbines, and then @Maikeru specified Seawolf having 2x steam turbines as well producing a total of 43MW.

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Ultimately what's important is the total output (or shaft horsepower) produced by the steam turbines, and from what I understand, it basically sums up as so:
Seawolf: 43MW total, from 2x steam turbines
Virginia: 30MW total, from 2x steam turbines
Yasen: 37ishMW total, from 1x steam turbine

For 09V, a single 38MW (total) steam turbine will be sufficient to power it, for what we would expect for a 10,000t submerged, single or hybrid hull design which is what 09V has been said to be.


Also, the output versus displacement relationship of other SSNs should be considered in context of what the desired form factor and hydrodynamic performance you want your SSN to have.
If you aren't massively lengthening your base SSN hull to fit a disproportionate number of VLS (like Block V Virginia), and if you are wanting to attain quiet but high performance in terms of speed and maneuverability (which dictates certain form factors), then a 38MW steam turbine would be quite appropriate for a 9,000-10,000t submerged SSN rather than something bigger like 12,000-13,000t submerged... and doubly so if your SSN is single or hybrid hulled versus double hulled.




Edit: 2x 38MW for a total of 76MW wouldn't be a SSN anymore but a Typhoon/Pr 941 sized SSBN (which has 2x 37MW steam turbines), so I assume @Maikeru was just throwing random stuff at the wall

 

[ACuriousPLAFan]

How about Type 093B ?

Given that the 093 family's submerged displacement is roughly in the same category as the Los Angeles SSNs (~6000-7000 tons submerged displacement), I'd wager about 25-26MW, i.e. similar to the Los Angeles SSN (and <30MW at maximum) from one steam turbine per boat for the 093B SSNs.

Of course, there are various other factors at play that would determine how much propulsive power is needed for each boat (e.g. form factor and hydrodynamic performance), hence my figure is more of a rough guess.

 

[Aspide]

According to wikipedia Yasen has similar steam turbine power as Akula, 32MW.

Only on Severodvinsk, the first one.

 

[ACuriousPLAFan]

maybe its for two units. 38MW for each submarine.

Well, turns out there are indeed two of the aforementioned 38MW steam turbines stated in the tender document, with handover stipulated in June and August 2026 respectively. Posted by @星依樱未 on Bilibili.



Considering the claims of one 095 SSN (if not two) already under construction for quite some time by now (and purported launch by the end of this year if not early-2026), I would suspect that these steam turbines are meant for the 2nd and 3rd boats (if not the 3rd and 4th boats). Though, this is just my own speculation on the matter.

 

[sunnymaxi]

Well, turns out there are indeed two of the aforementioned 38MW steam turbines stated in the tender document, with handover stipulated in June and August 2026 respectively. Posted by @星依樱未 on Bilibili.

View attachment 162331

Considering the claims of one 095 SSN (if not two) already under construction for quite some time by now (and purported launch by the end of this year if not early-2026), I would suspect that these steam turbines are meant for the 2nd and 3rd boats (if not the 3rd and 4th boats). Though, this is just my own speculation on the matter.

great.

this is likely for further 095 units beyond just first and second boat.

 

[tphuang]

The Akula submarine's steam turbine has 32MW power for a 190MWt nuclear reactor.

That is a pretty big submarine if it has a 38MW steam turbine. Bigger than anything the US has. The US uses two smaller turbines with less power combined than this single one.

Keep in mind that 095 will probably be using a nuclear electric propulsion which means 38MWe might only require a 190MWt reactor. Since it can generate energy separately from when it’s actually used. Even 20% efficiency is quite poor compared to a modern 3rd gen reactor.

so I would imagine China full propulsion actually require less space than Akula’s propulsion system but generate more power.

the additional power is needed for the latest sonar and onboard electronics.

 

[qwerty3173]

Keep in mind that 095 will probably be using a nuclear electric propulsion which means 38MWe might only require a 190MWt reactor. Since it can generate energy separately from when it’s actually used. Even 20% efficiency is quite poor compared to a modern 3rd gen reactor.

so I would imagine China full propulsion actually require less space than Akula’s propulsion system but generate more power.

the additional power is needed for the latest sonar and onboard electronics.

With how batteries are improving now storing extra energy into banks will eventually become the norm rather than the exception. Although energy densities of batteries are still far from ideal (Actually good compared with other underwater solutions though), the power density that they can provide in short time periods is already phenomenal.

 

[ACuriousPLAFan]

Keep in mind that 095 will probably be using a nuclear electric propulsion which means 38MWe might only require a 190MWt reactor. Since it can generate energy separately from when it’s actually used. Even 20% efficiency is quite poor compared to a modern 3rd gen reactor.

so I would imagine China full propulsion actually require less space than Akula’s propulsion system but generate more power.

the additional power is needed for the latest sonar and onboard electronics.

Speaking of which, the designation of the steam turbine is listed in the tender document as HN38-2.7A汽轮发电机组, which translates to "HN38-7.2A steam turbine generator set".

Could this be sufficient indication (if not evidence) of the 095 SSN using turbo-electric propulsion system (if not outright IEPS)?

As of present, only the Triomphant SSBN and the upcoming Columbia SSBN are known to be using turbo-electric propulsion systems.

 

[tphuang]

Speaking of which, the designation of the steam turbine is listed in the tender document as HN38-2.7A汽轮发电机组, which translates to "HN38-7.2A steam turbine generator set".

Could this be sufficient indication (if not evidence) of the 095 SSN using turbo-electric propulsion system (if not outright IEPS)?

As of present, only the Triomphant SSBN and the upcoming Columbia SSBN are known to be using turbo-electric propulsion systems.

I would think so since normally generator is a term used for the auxiliary power generator that provides power to the submarine rather than the propulsion. of course, 38MWe would be for the entire submarine.

I think the optimistic theory here is that if this is anything like ACPR50S

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which has 30% efficiency (200MWt to 60MWe). Then 38MWe would indicate around 130MWt. That actually should not be a particularly large reactor. Even if we are being optimistic here and the reactor is closer to 150-160MWt (let's say 25% efficiency), that would still be far more space efficient than any other active nuclear subs.

 

[ACuriousPLAFan]

As of present, only the Triomphant SSBN and the upcoming Columbia SSBN are known to be using turbo-electric propulsion systems.

Slight correction - The Rubis and Suffren SSNs are using turbo-electric propulsion systems as well, not just the Triomphant (and future Columbia) SSBNs.

I would think so since normally generator is a term used for the auxiliary power generator that provides power to the submarine rather than the propulsion. of course, 38MWe would be for the entire submarine.

I think the optimistic theory here is that if this is anything like ACPR50S

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which has 30% efficiency (200MWt to 60MWe). Then 38MWe would indicate around 130MWt. That actually should not be a particularly large reactor. Even if we are being optimistic here and the reactor is closer to 150-160MWt (let's say 25% efficiency), that would still be far more space efficient than any other active nuclear subs.

In that case, the 095 SSN should become the 1st in China (and 3rd worldwide) to have turbo-electric propulsion system on serial-production SSNs.