CV-18 Fujian/003 CATOBAR carrier thread

[Anlsvrthng]

Could China’s ‘experimental’ ship be the world’s biggest nuclear-powered icebreaker?

• State-owned firm China General Nuclear Power Group invites bids to build vessel similar in size to Russian nuclear icebreakers
• Project could be stepping stone to building nuclear aircraft carriers

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The data doesn't make sense for a Chinese owned nuclear icebreaker.

So the data wrong or the analysis of the guys .

The Bering strait is 5000 km away from China mainland,so an icebreaker has to pass this distance as fast as possible. 11.6 seems like pathetically slow, even the Artika can go with 20.6 knots, and it has to operate in close proximity with the Russian ports.


The size /parameters of this ship can match another Russian nuclear complex, the floating nuclear power plant.

It can be a self propelled floating nuclear power plant.
In that case the slow speed not an issue, the 25 MW can be the power available for propulsion.

Can be very handy for offshore industrial projects ( like building islands) and as a tested for surface naval reactors.

 

[Anlsvrthng]

To catapult aircraft needs more power than to break ice. Carrier lose speed when catapulting aircraft. For 30 knots without ice you need more power than with 10 knots in the ice.

(the range with 30 knots is one fourth of the range with 15 knots or with other words: to double speed you need fourtimes more energie)

Icebreaker shape is not usable for fast speed.
Artika has 20 k displacement, and with 54 MW shaft power it can go wtih up to 20.6 knots.

De Gaulle has 42.5k displacement, 61MW shaft power, and can goes with 27 knots.

So the icebreaker shape needs at least 2-3 times more power for the same speed than the normal shape.

 

[taxiya]

The numbers talked about on the first paragraphs are kind off though. Typically a nuclear reactor has like half the MWe (electric) of its MWt (thermal) power rating. This is because of Carnot efficiency. Also the power comparison with regards to the carriers is kind of too simplistic.

For example. The Charles de Gaulle has 2x 150 MWt reactors.

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It also has like 42500 tonnes displacement. I think this is a better match to the Chinese nuclear carrier than a supercarrier. The Chinese nuclear carrier initially will allegedly only have a bit more displacement than the Type 001A. A carrier would need less power than an icebreaker of similar displacement because it does not need to break thick ice to move.

It is actually only 35% at best (A4W) regardless electric or mechanic power. Or the alleged >40% of A1B. 50% efficiency is only reachable at this time by super/ultra critical conventional fired steam plant.

Regarding the first paragraph, it is 25MW break power (output from turbine) per turbine, total thermal is 200MW, 100MWth per turbine input. So it is 25% efficiency. Considering this is a mobile and compact civilian application, 25% is alright and probably preferred (higher safety margin). However this low efficiency is another evidence that denied the possibility of connecting this project to a PLAN CVN because there is no way this reactor could be of any help to a Naval nuclear reactor.

icebreaker breaks ice at a very SLOW speed, the slower you go the more force you have to do the hard work. It is same as car running at first gear when climbing a steep slope because the engine now gives much higher torque. The proposed icebreaker's top speed is 11.5 knots, it's icebreaking speed will be much lower, when breaking 2 to 3 meters thick ice, it could be going like a snail at 5 knots.

A carrier has to run at top speed when launching aircraft, 25 to 30 knots. Power requirement increases at a much higher rate as speed increases. So a carrier would need much more power than an icebreaker in similar displacement.

 

[Anlsvrthng]

There is another explanation of this experimental ship.

China running a molten salt reactor program.

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This started in 2018.
This reactor type is superior compared to the water moderated , water cooled types, first it is smaller and lighter for the same power output, second it has higher thermal efficiency ( it can make superheated steam ).


Now, making an experimental surface ship with this reactor type would make a sense.

Maybe it can be a stretch to put it into a submarine , but a surface ship makes sense.

 

[gelgoog]

Molten salts have a lot of issues on naval applications. If you use sodium, it burns in contact with water. If you use fluoride, it is corrosive and toxic. If you use lead or lead-bismuth, you don't have those issues. But all the molten salt reactors use liquid fuel at high temperature, which solidifies when the reactor shuts down. So if for whatever reason the reactor stops then you are a sitting duck in the water. The reactor will need to be heated with thermal pads for significant amounts of time to melt the fuel and restart. That typically can only be done in a port. That is why no one uses them in naval applications.

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[ZeEa5KPul]

Molten salts have a lot of issues on naval applications. If you use sodium, it burns in contact with water. If you use fluoride, it is corrosive and toxic. If you use lead or lead-bismuth, you don't have those issues. But all the molten salt reactors use liquid fuel at high temperature, which solidifies when the reactor shuts down. So if for whatever reason the reactor stops then you are a sitting duck in the water. The reactor will need to be heated with thermal pads for significant amounts of time to melt the fuel and restart. That typically can only be done in a port. That is why no one uses them in naval applications.

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You're confusing liquid metal cooled reactors with molten salt reactors. There haven't been any electricity-producing molten salt reactors built, they're still experimental. And "the reactor might fail" is an invalid criticism of molten salt reactors - any reactor might fail. If the containment vessel of a ship-borne PWR is breached then you're in much worse shape than just being "a sitting duck in the water."

 

[taxiya]

I think it is time for us to drop the subject of this icebreaker reactor for now as it is certainly not related to 002. It is better to move to some other thread.

P.S. the suggestion of molten-salt reactor is strange as the bidding clearly says PWR.

 

[damitch300]

Yeah its kinda annoying to come here and read about icebreakers all the time. Can we please move on???

 

[Anlsvrthng]

No one in the Chinese government / industry said that it is an icebreaker, it is dreamed up by the journalists.

The Chinese tender named the ship as " experimental ship platform", not naming any specific purpose.

I think China needs nuclear powered naval ships more than icebreakers.
And the naval ship that really needs reactor is a carrier.

And the part that said it is a pressurised water reactor is this :

The ship will be able to be fitted with two 25 megawatt compact pressurised water reactors with thermal power output of 200MW, which could propel the ship to a maximum speed of 11.5 knots, according to CGN’s project description.

Considering that it give inconsistent MW numbers around ( a reactor has only thermal output, a power plant has electrical output/efficiency, and 25 MW what ?) maybe the original (Chinese ) version should give more information . I think many thing has been lost in translation.

All other English source gives the same text, so it must came from a single source.

Three 200 MWt reactor should be enough for a Type 001 sized carrier. ( at least by the wiki )

 

[Intrepid]

Wrong thread, stop that damn icebreaker nonsense.