00X/004 future nuclear CATOBAR carrier thread


taxiya

Brigadier
Registered Member
When did this onshore boiler testing facility commence construction? Looks like 2020 written on the back?
Yes. There was a procurement notation from JN shipyard about it long time ago, as early as maybe 2019. You can search this forum. It was in the 003 thread.

On a side note, seeing the establishments of cooperation between Jiangnan and Dalian on nuclear propulsion system technology, I believe we can be confident that China will be capable of building not one, but TWO nuclear-powered supercarriers - BOTH at the same time in the coming future.

This is a very excellent development for the PLAN and China.
Yes that is the idea of redundancy. 055 is another evidence.
 

taxiya

Brigadier
Registered Member
this is why I think SMR+combustion combo might be the way to go for 004, with SMR for base load and a combustion engine for peak load.

there is a theoretical basis for this in civil electrical engineering.
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Thus these plants usually runs at 100% of capacity. That means that the most efficient nuclear power capacity is to build as much as the lowest constant demand - the base load.

Why don't all countries with the capability simply have 100% reactors then? Not only because of expense, but because demand varies throughout the day. Electrical power in general cannot be stored at scale, demand must be kept up with supply instantaneously.
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especially over long periods of time. Likewise, demand varies throughout the course of carrier operations. Sometimes the ship is at cruise and reactor power is overgenerating. At other times it needs massive power for flight ops to work.

Why has this not been a problem in the past? EMALs is very different in terms of power requirement than steam catapult. Steam catapult uses gas expansion principle. It requires a reservoir of steam, which is generated by constant heat from the boilers, which reactors can provide. Nimitz has a huge steam reservoir and this is why steam catapults are so reliable and successful. It does not require electricity, because the steam reservoir is actually an energy storage device - the energy is stored in the enthalpy of vaporization of water.

EMALS uses electricity. The peak electrical demand during flight ops is much higher than the baseload electrical demand. That means complicated long term storage schemes must be used. These have reliability issues, especially in a shooting war. Large batteries, capacitors and flywheels do not like being shot. They tend to explode or light on fire when shot. They also have relatively low energy density.

The alternative to energy storage is to just generate it on the spot. In civil electrical engineering, the fastest starting generation stations are gas turbines. A civilian gas turbine can go from stationary to full power at 150+ MW within 10 minutes. A naval gas turbine which is smaller and optimized for very fast startup can probably go from stationary to full power within 5 minutes.
The issues that I see in the combo are:

Cruising mode uses about 30% of the max power. This means that your SMR is complemented by 70% of conventional steam boilers. It doesn't really give any advantage. Steam from nuclear reactor is lower in pressure and temperature. The turbines used are different. SMR steam can not be easily used for most of the turbines. SMR is not smaller than conventional boilers either. So you are adding more complications and volumes for no advantages.

If you use GTs instead of conventional steam engines, 70% of the max power is by GTs. That makes the ship a GT ship like QE class. Then why not a full GT ship? At least a full GT ship is simpler. Also the air duct and exhaust demands are different, that add another complication.

The key point is that SMR serving for the low load situation isn't saving space but adding more maintenance and operation work, therefor more risk.
 

FairAndUnbiased

Captain
Registered Member
The issues that I see in the combo are:

Cruising mode uses about 30% of the max power. This means that your SMR is complemented by 70% of conventional steam boilers. It doesn't really give any advantage. Steam from nuclear reactor is lower in pressure and temperature. The turbines used are different. SMR steam can not be easily used for most of the turbines. SMR is not smaller than conventional boilers either. So you are adding more complications and volumes for no advantages.

If you use GTs instead of conventional steam engines, 70% of the max power is by GTs. That makes the ship a GT ship like QE class. Then why not a full GT ship? At least a full GT ship is simpler. Also the air duct and exhaust demands are different, that add another complication.

The key point is that SMR serving for the low load situation isn't saving space but adding more maintenance and operation work, therefor more risk.
A full conventional EMALS ship wouldn't even be too bad IMO, but this is for a CVN thread. Not sure how Kirov gets around these problems. Compared to nuclear the advantage is 2 fold: 1. Higher uptime and deployment frequency 2. Removing the complication of long term storage of large amounts of electrical power for EMALS.

I think that steam catapult + nuclear is a natural combo because the steam is generated anyways, and is a vast and easy energy storage despite its inefficiency. EMALS + conventional is also a natural combo because you can change generation capability very quickly to match demand and you only need very short term energy storage. I think that Ford class is going to be looked upon as a Zumwalt style mistake and US might even go back to steam catapult in the future just like they went back to Burke.

For US the advantage of nuclear is huge, does it matter if they use steam? US already has to build all its carrier capable aircraft around steam. But for China the advantage of EMALS is huge for flexible launch.
 

taxiya

Brigadier
Registered Member
So we are talking about a hybrid power system onboard? A relatively small reactor for normal power supply & an addition for extreme scenarios?
Hybrid (SMR + something) is his personal suggestion, not what is known or said about CV-18.
To be honest hybrid never works well in one system. Check the hybrid car (HEV), it's more expensive and less reliable. It is a very innovative idea though but not sure if the PLAN is going to take that path.
HEV is a "I have to get into EV but I have no better choice". People are not buying it, but waiting for Full EV to drop price. HEV adds dead weight in both low and high speed, a waste of money. At low speed, the ICE is dead weight, in high speed the battery and Electric motors are dead weights. I wouldn't take that trouble if I were PLAN.

If it is only brought to my attention in one of the CV-18 introduction and I quote: "福建舰采用舰船综合电力系统..." which literally means CV-18 equipped with a "Ship Integrated Power System" (not sure if the translation is accurate).
I don't know where you heard it, I only heard this 福建舰采用舰船综合电力系统 from Xi Yazhou's video about CV-18. Here is the link
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at 3:10, he said 综合电站动力系统
1655927458285.png


However, at 6:39 he said CV-18 utilizes the similar design of integrated electric power station as Ford class.
1655927655776.png
at 6:42 he said the design take part of power to generate electricity (for EM launcher).
1655927754532.png

We know that Ford class is NOT IEPS, its propellers are driven mechanically by the steam turbines. Diverting part of the power to generate electricity means that the other part of power is not electricity but steam/mechanical power.

It was his mistake to put up 综合电站动力系统 (Integrated Electrical Power Station Propulsion System, ie IEPS) in his slide. It should have been 综合电站系统 (Integrated Electrical Power Station System).

I see many people here has taken that error as fact to call CV-18 being IEPS in this forum, in including another post I have responded to. I hope this will clarify things.
 

caudaceus

Junior Member
Registered Member
A full conventional EMALS ship wouldn't even be too bad IMO, but this is for a CVN thread. Not sure how Kirov gets around these problems. Compared to nuclear the advantage is 2 fold: 1. Higher uptime and deployment frequency 2. Removing the complication of long term storage of large amounts of electrical power for EMALS.

I think that steam catapult + nuclear is a natural combo because the steam is generated anyways, and is a vast and easy energy storage despite its inefficiency. EMALS + conventional is also a natural combo because you can change generation capability very quickly to match demand and you only need very short term energy storage. I think that Ford class is going to be looked upon as a Zumwalt style mistake and US might even go back to steam catapult in the future just like they went back to Burke.

For US the advantage of nuclear is huge, does it matter if they use steam? US already has to build all its carrier capable aircraft around steam. But for China the advantage of EMALS is huge for flexible launch.
Arguments I read on Twitter are that EMALS + Non-nuclear is bad because EMALS is very power-hungry which leads to swift fuel consumption.
 

taxiya

Brigadier
Registered Member
I am bit confused as you seem to mix steam, nuclear and EMALS together.
A full conventional EMALS ship wouldn't even be too bad IMO, but this is for a CVN thread.
EMALS has nothing to do with nuclear or conventional steam. There is just difference in boiling the water.
Not sure how Kirov gets around these problems. Compared to nuclear the advantage is 2 fold: 1. Higher uptime and deployment frequency 2. Removing the complication of long term storage of large amounts of electrical power for EMALS.
What is the long term storage of large amounts of electricity? Both Ford and CV-18 use the same flywheel system to store electricity. Flywheel can store energy for longer than an hour without loosing much. The steam reservoir in a steam cat system will loose more heat energy in the same period of time. So steam has no advantage in terms of how long they can be kept ready for launch.

I think that steam catapult + nuclear is a natural combo because the steam is generated anyways, and is a vast and easy energy storage despite its inefficiency.
steam catapult uses steam reservoir to store energy, it does not store more energy necessary for launching, nor is it easy because of quick loss of heat. It only store "vast" energy because it wastes most of them. It isn't an advantage.

EMALS + conventional is also a natural combo because you can change generation capability very quickly to match demand and you only need very short term energy storage. I think that Ford class is going to be looked upon as a Zumwalt style mistake and US might even go back to steam catapult in the future just like they went back to Burke.
Both the steam reservoir and the flywheel are short term storage for the same duration of launching.

For US the advantage of nuclear is huge, does it matter if they use steam? US already has to build all its carrier capable aircraft around steam. But for China the advantage of EMALS is huge for flexible launch.
EMALS' advantage is same to US and China. China build EMALS is NOT because of lack in nuclear reactor tech. US going EMALS is for the same advantages that China sees. So even though US may be forced to go back to steam if they could not fix EMALS, it is not what they are easily willing to give up simply because they have mature steam catapult.
 

FairAndUnbiased

Captain
Registered Member
Arguments I read on Twitter are that EMALS + Non-nuclear is bad because EMALS is very power-hungry which leads to swift fuel consumption.
Weird because these are the same guys who claim Kitty Hawk and Forrestal were invincible despite steam catapults being far less energy efficient.

EMALS is 90% efficient electricity to motion. The generation from a gas turbine is 40-50% efficient. So it's overall 40% efficient. Steam is 5% efficient. Yet Kitty Hawk and Forrestal did just fine with steam.
 

FairAndUnbiased

Captain
Registered Member
I am bit confused as you seem to mix steam, nuclear and EMALS together.

EMALS has nothing to do with nuclear or conventional steam. There is just difference in boiling the water.

What is the long term storage of large amounts of electricity? Both Ford and CV-18 use the same flywheel system to store electricity.


steam catapult uses steam reservoir to store energy, it does not store more energy necessary for launching, nor is it easy because of quick loss of heat. It only store "vast" energy because it wastes most of them. It isn't an advantage.


Both the steam reservoir and the flywheel are short term storage for the same duration of launching.

Zumwalt's is IEPS, Ford is not IEPS but EMALS. There problems are due to the inherited problem of AC-AC architecture. Ford going back to steam catapult is due to its own problem, regardless Zumwalt being faulty or not.


EMALS' advantage is same to US and China. China build EMALS is NOT because of lack in nuclear reactor tech. US going EMALS is for the same advantages that China sees. So even though US may be forced to go back to steam if they could not fix EMALS, it is not what they are easily willing to give up simply because they have mature steam catapult.
EMALS requires high instantaneous power but not continuous high power. In general electricity is not storable and needs to match demand to generation. This is very well known in civil electrical power engineering. You either need storage sufficient for matching the difference between base load demand and peak demand, or you need variable generation.

Steam catapult does not require storage of electrical energy. The energy is stored in the enthalpy of vaporization of water and the pressure of the steam. There is no such demand-supply matching constraints on steam storage. So you can accumulate and store steam without constraints.

Nuclear is not easy to vary in generation capability. This is well known from electrical power engineering. This doesn't matter for steam, as you can indefinitely store steam. This does matter for EMALS.
 

taxiya

Brigadier
Registered Member
Arguments I read on Twitter are that EMALS + Non-nuclear is bad because EMALS is very power-hungry which leads to swift fuel consumption.
That is a idea out of the back end of people who has no idea in what they are talking about. :D

On the contrary EMALS consumes much less energy than steam catapult.

No offence intended to you, but I'd appreciate every new member doing some study through reading this forum, especially the dedicated EM launcher thread. Going through the same rubbish over and over again in this forum is not fun.
 

taxiya

Brigadier
Registered Member
It is getting more confusing. I don't even know what you are trying to say now.
EMALS requires high instantaneous power but not continuous high power.
EMALS release the high power during launch, it draws lower power over a longer time from the grid. So there is difference of powers.

Steam reservoir releases high power during launch, it draws steam over a longer time from the boilers. There is difference too.

Electrical energy is just like heat energy in steam. Steam reservoir acts exactly like flywheels in EMALS. The amount of heat energy released during launch is the high instantaneous power, the drawing of heat energy from the boilers over a longer time is the continuous power.

In general electricity is not storable and needs to match demand to generation. This is very well known in civil electrical power engineering. You either need storage sufficient for matching the difference between base load demand and peak demand, or you need variable generation.
Certainly storable, I think you wanted to say that electrical energy is worse to store than heat energy by steam. Electrical energy is stored in the flywheel, like heat energy in the steam in the reservoir. Steam looses energy faster than flywheel.

matching the load is the work of the flywheels which are energy storage. The steam system has the steam reservoir which is another type of energy storage.

As said above, in steam catapult the reservoir is doing the same job as matching different load.

Steam catapult does not require storage of electrical energy.
of course not, because there is no electrical energy to begin with.
The energy is stored in the enthalpy of vaporization of water and the pressure of the steam.
So there is still energy to store. What is the difference then? You store different type of energy by different means.
There is no such demand-supply matching constraints on steam storage. So you can accumulate and store steam without constraints.
There is in steam storage as explained above. Flywheel charging between launches is like you accumulate and store steam between launches. Both will draw portion of energy from the source.
Nuclear is not easy to vary in generation capability. This is well known from electrical power engineering. This doesn't matter for steam, as you can indefinitely store steam. This does matter for EMALS.
Neither is it any easier for any other type of power generation engines. This is actually proven by all types of power generation plant, include the GT powered Type 45. An example is “蓄能电站" to regulate the power peaks in a national power grid. It has been used since before nuclear power stations.

You can not indefinitely store steam. It will cool over time loosing energy. On the contrary, flywheel loose energy in a slower rate, therefor able to store energy for a longer time.

Steam is a physical media, it stores energy in the form of excited molecules. Flywheel is a physical media, it stores energy in the form of rotating momentum. Electricity is the movement of electrons. It is not energy but the phenomenon of energy transmission. I have a feeling that you equated Steam to Energy and Electricity to Energy, therefor the confusions.
 
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