True. However there needs to be technological innovation for the mini-nuke concept to be viable, otherwise it would be like the French Rubis with the price tag of SSN but half the capabilities, PLAN won't even contemplate it
Rumoured "mini-nuke/diesel" Submarine SSK-N(?) thread
- Thread starter ACuriousPLAFan
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True. However there needs to be technological innovation for the mini-nuke concept to be viable, otherwise it would be like the French Rubis with the price tag of SSN but half the capabilities, PLAN won't even contemplate it
No.
1. The speed of this "mini-nuke" will be higher than a SSK, but not comparable to a true SSN. Furthermore, as I said you have no right to compare the cost between this "mini-nuke" and a proper SSN because a proper SSN has much greater crew facilities and stores for endurance, much greater weapons and sensor loads.
2. Having comparable noise to a conventional submarine does not mean it is stealthier than a modern nuclear submarine, especially if it is under equivalent operational environments and speed demands.
3. Again, that's not logical. That is like saying that we should expect the PLA to have procured more J-10s throughout than Flanker family aircraft through its lifetime because the J-10 is smaller, single engined and logically cheaper, however the scale of procurement entirely depends on the actual fleet/service requirements.
For the PLAN, a large fleet of "mini-nukes" would be appropriate if the PLAN were focused mostly on missions in the 1st island chain, with a degree of venturing out to 2nd island chain, but unable to properly compete in the 2nd island chain or beyond.
However, as we can see from the Bohai expansion, we can see that they intend to have significant capacity to build a large number of proper sized nuclear submarines, with the sort of high end blue water capability that offers.
The final fleet composition is yet to be determined, so it is very much early days, but it is certainly far too early and overly excitable to suggest that such a "mini-nuke" could perform the role of proper nuclear submarines in an "exponentially better" way.
If you want to say "Again, it is not a nuclear attack sub, it dont carry VLS. I made it very clear in previous post. But the fact these "nuclear-like SSK" will help China own the ocean means 'proper nuclear sub' can be freed to do its job in less quantity." -- that is fine, then you are conceding that this "mini-nuke" is not and will not take on the role that proper nuclear submarines do.
In which case, you are agreeing that the "mini nuke" will not be able to do the role of proper nuclear submarines "exponentially better" but that they are instead different in role and capability profile.
Edit, to make it clear for everyone, the "mini nuke" (if it is real) will almost certainly be vastly inferior to a proper nuclear submarine in terms of:
- speed (both maximum/transit speed, and tactical speed)
- sensor capability and processing
- weapons load and variety (both underwater as well as VLS; the "mini-nuke is unlikely to have VLS anyhow)
- onboard/perishable endurance (which is determined by crew facilities and stores of consumables on the boat)
What this means is that the "mini-nuke" will be vastly outcompeted in the open ocean and at greater distances from home ports, by proper nuclear submarines, as well as much more vulnerable to enemy ASW forces (surface ships as well as MPAs and helicopters) in said open oceans/long distances from home as well.
What the "mini-nuke" can offer is a SSK-esque capability profile, but with greater endurance and slightly better speed, meaning they can do better in the short range and more littoral and green water environments, but to at proper blue water, open ocean distances they would be vastly inferior to a proper nuclear submarine, and if they are applied for that mission profile it would be due to not having other appropriate proper nuclear submarines available.
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modernized reactor + Stirling engine + high capacity modern battery has far more off-the-shelf components than the French turboelectric configuration which still have the full turbine set, and only 50 km battery life.
basically the more off-the-shelf components you can use the better and cheaper, the more custom built components the more expensive not only to build, but to develop, design and validate.
stacking Li batteries that already had crash and water immersion tests done on them for cars is FAR cheaper than a custom turboelectric drive train. Even today, a gas or steam turbine is basically custom built and costs millions of dollars, regardless of power source. it is a construction project, not a product. Avoiding that alone is worth millions per unit.
With a nuclear reactor, the limiting factor for endurance becomes the crew and their needs. With the nuclear reactor, sterling engine and battery bank taking up significant space is there much room for the crew?
take a look at what actually takes up room.
Let me point a few things out:
1. the reactor space is not the only space taken up by the propulsion system. Notice that the reactor is connected to a steam generator, which connects to a turbine, which turns a shaft. The shaft is connected both to a generator and drives the propellers.
2. The problem is, a generator shaft spins fast, but a propeller spins slow. That means you need a transmission gearbox to turn the fast spinning low torque generator shaft to the slow but high torque propeller speed. You also need the transmission gearbox to be able to change gears for different speed conditions.
3. The shaft is straight. You can't bend it or change its direction. All that takes up room. You need significant clearance around the moving shaft and gearboxes for maintenance, as they're moving parts. Thus, a direct drive engine actually takes up a huge amount of space with the heat exchanger, steam generator, turbine, generator, turbine, etc and their associated engineering spaces.
Let me point out how big and complicated a steam generator is. Diagram to show complexity, then a photo to show size.
It's probably more apt to refer to a similarly sized class of submarine such as the type 39 with a crew complement of 36 rather than the los Angeles which is big enough to house 110 crew.take a look at what actually takes up room.
Let me point a few things out:
1. the reactor space is not the only space taken up by the propulsion system. Notice that the reactor is connected to a steam generator, which connects to a turbine, which turns a shaft. The shaft is connected both to a generator and drives the propellers.
2. The problem is, a generator shaft spins fast, but a propeller spins slow. That means you need a transmission gearbox to turn the fast spinning low torque generator shaft to the slow but high torque propeller speed. You also need the transmission gearbox to be able to change gears for different speed conditions.
3. The shaft is straight. You can't bend it or change its direction. All that takes up room. You need significant clearance around the moving shaft and gearboxes for maintenance, as they're moving parts. Thus, a direct drive engine actually takes up a huge amount of space with the heat exchanger, steam generator, turbine, generator, turbine, etc and their associated engineering spaces.
Let me point out how big and complicated a steam generator is. Diagram to show complexity, then a photo to show size.
I won't speak to the accuracy of the diagram, but compared to a 110m nuclear submarine, a Diesel attack sub is a lot more cramped. While you're saving space from not having bulky gearboxes and shaft, you may also need extra crew to maintain the reactor.
FriedRiceNSpice
Captain
How much more expensive (both to produce and to operate) can we expect this new sub to be relative to a conventional SSK? Would the cost model be more akin to a scaled down SSN or more closely follow that of a traditional SSK?
I agree with most of what you said, but 4th reactor is not as far away as you think, gas cooled reactor for example has been in demonstration run in China for a decade already and it does have self regulation feature.
It is possible to just hook up sterling engines to PWR however I think it would be a waste because PWR operates at lower temperature arround 300 degrees C. If paring sterling engines to much higher temperature heat source we can have much higher thermal efficiency and power density, which is where 4th gen reactor come into play, gas cooled reactor for example can operates at 900 degrees C.
While it is not definitive, the use of sterling engine does scream 4th gen reactor to me, otherwise sticking with turbine makes more sense as it provides higher power density in that case
The world just had the first ever 4th-gen nuclear reactor put into commercial service not even a year ago at Shandong, China.
If anything, that means 4th-gen reactors are still very much a WIP technology across the world. Rushing to put next-gen systems that are not yet fully mature and reliable-proven into platforms that are meant for active service and deployment is not how the PLAN typically does things.
Compared to conventional you can cut the diesel and fuel tanks entirely, and even cut the backup diesel since you'll have battery reserves as backup. That also means no need for a snorkel or hull penetrating intake, yet more space savings.
You also can lower crew because you don't need mechanics for the transmission or any combustion engines. More savings.