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

[tphuang]

More Shilao chatter on this general topic

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tune in to maybe 1 hour 20 minutes through and just listen. People in Chinese military know there are just space limitation to 093 right now that cannot be solved with better technology. Whatever they do, type 095 will have more pressure hull space. I've made my own estimation on what that number needs to be. We probably won't find out for a while. And there is also no guarantee that what they end up producing will be as quiet as Virginia class now.

 

[taxiya]

From an engineering perspective, I see nuclear submarine stealth as being primarily about:

1. rafting (and therefore isolating) the internals from the outer pressure hull
2. having a natural flow reactor without noisy pumps
3. reducing any other discrete harmonics or noise sources that travel well in water

So submarine stealth isn't about a single magical technology, but simply heavy engineering graft and design experience.

It also seems that having a larger diameter pressure hull doesn't particularly increase quietness, assuming you have to have rafting anyway and if this is combined with a single pressure hull.

2. having a natural flow reactor without noisy pumps
Natural circulation (flow) reactor is taller than its equivalent counterpart, so larger diameter pressure hull is a necessity. One alternative instead of larger diameter hull was to make the reactor compartment vertical. It was a study by China long time ago. We don't know the outcome, but it just demonstrates the importance of the size. If this solution isn't practical, then diameter is the only solution.

 

[taxiya]

But if the goal for 09V is a Virginia/Astute category peer, I think a 09III family 11m-ish pressure hull diameter should be sufficient, even in a hybrid single/double hull configuration.

See my answer to ZeEa5KPul below. If 09V is to use natural circulation reactor, its diameter has to be larger than 09III, unless the reactor core of 09V is shorter than 09III leaving some extra space overhead.

Why is the Virginia as small as it is? If larger submarines have advantages like improved stealth and more room for everything from provisions to munitions, why did the US shrink its SSN size from Seawolf to Virginia?

My understanding is that the diameter difference is because of the "natural circulation" capability. Seawolf can, Virginia can not. As I understand, in theory all reactor can natural circulate, but the true natural circulating reactor can run in such mode for a very large power range, while others can only run on a very low power output. To do true natural circulation, the reactor has to have lots of water above the core. This demands a larger hull diameter. This explains why Seawolf's reactor is truly natural circulation.

 

[zavve]

Virginia can not

Source?

 

[Blitzo]

See my answer to ZeEa5KPul below. If 09V is to use natural circulation reactor, its diameter has to be larger than 09III, unless the reactor core of 09V is shorter than 09III leaving some extra space overhead.

The fact that 09V should have a larger pressure hull diameter than 09III is something that is already agreed upon between everyone, including myself.

The question is about whether 09V will need an overall larger hull diameter compared to 09III, because 09V is expected to adopt a single hull or hybrid hull configuration, meaning that it can have a larger pressure hull diameter will retaining the same overall hull diameter as 09III (given 09III is a double hull of course).



As for natural circulation, well 09III variants subsequent to the original vanilla pair should already be using natural circulation reactors.

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

Kyle also made the mistake of conflating "lprobable performance floor" of the Type 095 SSGN with the likely general performance of said submarine.

www.sinodefenceforum.com

The original text of the relevant part:
在第二代核潜艇研制工程项目中，涌现出了无数个大大小小的创新。面对数十载的心血结晶，张锦岚将之总结为三大跨越：一是核打击技术实现了重大跨越，二是核安全领域实现了重大跨越，三是系统集成技术实现了重大跨越。

“在核打击技术中存在两大难点，一个是针对大尺寸、大深度、密集大排孔的单双结构研究，另一个则是水下潜射，这也是我们和一代艇的区别，一代艇只能单发，我们实现了连发。”张锦岚介绍，连续发射既不在水面进行，也不在大深度进行，而是在离水面有一定深度的地方。这样一来，核潜艇既要承受水面波浪带来的干扰，又要在低速下掌握艇的操作，并且还要平衡导弹发射后带来的重量差，其艰难之处可以想见。

在经过大量的复杂性计算和试验后，张锦岚团队领导研制的新型核潜艇实现了在近水面波浪干扰复杂，大质量导弹发射冲击力强、载荷变化大，极低发射航速舵效差的情况下保证艇的姿态和深度的经典环境，首次实现了战略导弹水下连续发射，并使核打击距离大幅度提高。

而在备受关注的核安全方面，张锦岚团队也在新型核潜艇中实现了重大跨越。首先就是实现了核反应堆自然循环。众所周知，潜艇核动力装置的自然循环能力是衡量其安全可靠性能的重要标志之一，所以各国都在竭尽全力提高自然循环能力，也就是指不用冷却剂泵推动，仅靠冷却水的自流就能带走核反应堆堆芯热量的能力。而反应堆的冷却剂泵又正好是核潜艇发出噪声的主要来源之一，因此，一旦实现了核反应堆自然循环，不仅保证了潜艇的安全性，即停电的时候也能保障核潜艇正常工作，而且使潜艇在不开启冷却剂泵的情况下也能向推送装置输出能量，极大地降低了潜艇的噪声。

“在核安全领域另一大创新点就是完成了非能动性的余热导出。一般而言核潜艇有两个回路，第一个回路就是把核反应堆的热量带出来，作为原动力将水加热成为蒸汽；第二个回路就是将蒸汽用来给艇上的发电机等装置供电。我们发明的余热导出实际上实现了第三个回路，即将第二回路的热量最终通过第三回路导出艇外，这样核潜艇就实现了完全意义上的核安全。”张锦岚介绍。

至于系统集成技术方面的创新更是多如繁星。实现了复杂武器系统网络化，发明了新型减振器、消声瓦，保障了潜艇优良的空气，实现了鱼雷大深度发射，完成了从一个目标到同时跟踪多个目标的转变……

 

[taxiya]

The fact that 09V should have a larger pressure hull diameter than 09III is something that is already agreed upon between everyone, including myself.

The question is about whether 09V will need an overall larger hull diameter compared to 09III, because 09V is expected to adopt a single hull or hybrid hull configuration, meaning that it can have a larger pressure hull diameter will retaining the same overall hull diameter as 09III (given 09III is a double hull of course).



As for natural circulation, well 09III variants subsequent to the original vanilla pair should already be using natural circulation reactors.

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

Kyle also made the mistake of conflating "lprobable performance floor" of the Type 095 SSGN with the likely general performance of said submarine.

www.sinodefenceforum.com

The original text of the relevant part:
在第二代核潜艇研制工程项目中，涌现出了无数个大大小小的创新。面对数十载的心血结晶，张锦岚将之总结为三大跨越：一是核打击技术实现了重大跨越，二是核安全领域实现了重大跨越，三是系统集成技术实现了重大跨越。

“在核打击技术中存在两大难点，一个是针对大尺寸、大深度、密集大排孔的单双结构研究，另一个则是水下潜射，这也是我们和一代艇的区别，一代艇只能单发，我们实现了连发。”张锦岚介绍，连续发射既不在水面进行，也不在大深度进行，而是在离水面有一定深度的地方。这样一来，核潜艇既要承受水面波浪带来的干扰，又要在低速下掌握艇的操作，并且还要平衡导弹发射后带来的重量差，其艰难之处可以想见。

在经过大量的复杂性计算和试验后，张锦岚团队领导研制的新型核潜艇实现了在近水面波浪干扰复杂，大质量导弹发射冲击力强、载荷变化大，极低发射航速舵效差的情况下保证艇的姿态和深度的经典环境，首次实现了战略导弹水下连续发射，并使核打击距离大幅度提高。

而在备受关注的核安全方面，张锦岚团队也在新型核潜艇中实现了重大跨越。首先就是实现了核反应堆自然循环。众所周知，潜艇核动力装置的自然循环能力是衡量其安全可靠性能的重要标志之一，所以各国都在竭尽全力提高自然循环能力，也就是指不用冷却剂泵推动，仅靠冷却水的自流就能带走核反应堆堆芯热量的能力。而反应堆的冷却剂泵又正好是核潜艇发出噪声的主要来源之一，因此，一旦实现了核反应堆自然循环，不仅保证了潜艇的安全性，即停电的时候也能保障核潜艇正常工作，而且使潜艇在不开启冷却剂泵的情况下也能向推送装置输出能量，极大地降低了潜艇的噪声。

“在核安全领域另一大创新点就是完成了非能动性的余热导出。一般而言核潜艇有两个回路，第一个回路就是把核反应堆的热量带出来，作为原动力将水加热成为蒸汽；第二个回路就是将蒸汽用来给艇上的发电机等装置供电。我们发明的余热导出实际上实现了第三个回路，即将第二回路的热量最终通过第三回路导出艇外，这样核潜艇就实现了完全意义上的核安全。”张锦岚介绍。

至于系统集成技术方面的创新更是多如繁星。实现了复杂武器系统网络化，发明了新型减振器、消声瓦，保障了潜艇优良的空气，实现了鱼雷大深度发射，完成了从一个目标到同时跟踪多个目标的转变……

That is an old news (2017) but new to me. I wasn't paying much attention to the thread. However, I did hear argument that the hump in the later 09III was for the enlarged (natural circulation) reactor compartment, and I quoted this argument in this forum. Do you think that the hump is for the reactor?

 

[Maikeru]

That is an old news (2017) but new to me. I wasn't paying much attention to the thread. However, I did hear argument that the hump in the later 09III was for the enlarged (natural circulation) reactor compartment, and I quoted this argument in this forum. Do you think that the hump is for the reactor?

That would make a lot of sense. Question is whether it is a full on multi-power level natural circulation reactor like Seawolf or one that can only do natural circulation at very low power levels as essentially a safety function.

 

[taxiya]

Source?

You should have read and quoted my whole post. See the bold and underlined texts below.

My understanding is that the diameter difference is because of the "natural circulation" capability. Seawolf can, Virginia can not. As I understand, in theory all reactor can natural circulate, but the true natural circulating reactor can run in such mode for a very large power range, while others can only run on a very low power output. To do true natural circulation, the reactor has to have lots of water above the core. This demands a larger hull diameter. This explains why Seawolf's reactor is truly natural circulation.

I was saying that:
Seawolf's S6W is true natural circulating reactor running a large power range without pump.
Virginia's S9G can run a smaller range without pump, but like other earlier classes it is not regarded as true natural circulation reactor.

Here is a source that I can find.

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The paper classifies S5G and S8G as true natural circulating reactors. S8G is for Ohio class. S6W is developed from S8G.

 

[Blitzo]

That is an old news (2017) but new to me. I wasn't paying much attention to the thread. However, I did hear argument that the hump in the later 09III was for the enlarged (natural circulation) reactor compartment, and I quoted this argument in this forum. Do you think that the hump is for the reactor?

I've heard that argument before as well -- I personally am not sure how seriously to take it. It might be plausible.

Anyway, in regards to application of natural circulation reactors, I read somewhere that the 09IV SSBN was the first application of a generation one natural circulation reactor (vanilla 09III lacked it), then a modded 09III that also applied it. Gen two and gen two-improved natural circulation reactors were applied on the 09IIIA and last couple of 09IV SSBNs.
I'm not sure how seriously to take it, but the timing would work out in regards to when the award to Mr Zhang was unveiled, and would explain partially why the original 09IV SSBN took a bit longer to enter service than we expected (along with its SLBM and deterrence mission of course).


Gen three natural circulation reactors naturally would be expected about now, and we don't really know if it will be first applied on 09V or 09IIIB.

 

[taxiya]

That would make a lot of sense. Question is whether it is a full on multi-power level natural circulation reactor like Seawolf or one that can only do natural circulation at very low power levels as essentially a safety function.

Seawolf can not run its full power range without using the pump. No reactor can. It is only that Seawolf can run a very high percentage of its full power without the pump.

On the other hand, as I said in theory all reactor can run without pump on a very low power level. So long as there is enough volume of coolant placed over the reactor core and that volume of coolant can remove the heat without pump you can run the corresponding power which is a percentage of the full power. The larger room you have, the higher percentage. There is no clear cut boundary to distinguish the two.

This means that all reactors can somehow natural circulate. But when the designer of 09III said that it is natural circulating, I believe that he as a professional was talking about the "true" natural circulation in the sense of Seawolf.