00X/004 future nuclear CATOBAR carrier thread

[taxiya]

The thorium reactor is still in its infancy far from practical usage. China is going to put it in the nuclear powered container ship before Navy.

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There's some pretty wild claims floating on the internet.
Supposedly China is currently building 2 Thorium powered super carriers. The proponents of this theory have failed to explain what military advantages would thorium have over uranium in regard to CVN's. Furthermore we do not have a good understanding of how much would it cost to convert thorium 232 into uranium 233. Is it any cheaper than just enriching uranium?....probably Not.

China's thorium reactor is LFTR (

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)

The advantage is 1. Inherent safety based on strong negative temperature coefficient of reactivity 2. refuling without shutting down the reactor and cut up the hull. It is almost like refuling conventional ship fuel. Thurium is disolved in liquid salt, burnt fuel will be constantly filterred out and new fertile fuel added while the reactor is running. Shutting down is easy by draining the liquid salt in a resvoir and the reactor will naturally stop.

USN went to highly enriched uranium to avoid refuling. A LFTR uses low enriched uranium to start the reactor, then it doesn't need uraium enrichment to run any more.

There is a possibility you could add driver fuel (enriched U-235 / Pu-239) to a fuel rod with thorium blanket for once through use. if I remember correctly, th-232 has a higher neutron absoprtion coefficient than U-238 and so more of it can be converted to U-233 than similar mass of U-238 to Pu-239. In a commercial reactor, 50% of the power comes from Pu-239 (that was transmuted from U-238 by neutron absorption) near end of fuel life. The advantage of using Th is that if you breed the fuel during operation, reactivity control could be easier (i.e., you don't have to load all of the fuel upfront that require activity suppression at beginning of life, but this is only a small gain in Th). This may more attractive for military use since they do not care about energy capture efficiency (lower operational temperature) and so metal Th (higher atomic density relative to oxide) blanket could be used in improve transmutation.

If you do two steps (i.e., irradiate Th and then separate U-233, tecnically can be done easily), the fuel during irradiation does not produce in highly active and long lived transuranics and the fuel could be safely disposed of after only a few hundreds years. I supposed you have a little more energy advantage as described above since more Th could be convereted than using U.

We are not looking at a large energy return advantages.

It's my observation that advocates of Thorium nuclear power always propose the Th being converted to U-233 at each power plant.
Technically it is the U-233 that gets fissioned not the Thorium.
I have an idea.
Why not build a large centralized Thorium-232 to U-233 converter factory on dry land and "produce" all the U-233 that will be needed?
The U-233 can be loaded into naval nuclear reactors directly. Wouldn't it make more sense to Convert the Thorium to U-233 on dry land where space is practically unlimited instead of on a ship where space is always in short supply?

You two are talking about how India uses its thorium for reactor (first breed thorium to U-233 in a breeder reactor, then take it out into another reactor to use it). It is a thorium circle but NOT a thorium reactor, and it has all the same challenges of a low enriched uranium reactor. That is certainly not feasible for a ship.

 

[hkky]

You two are talking about how India uses its thorium for reactor (first breed thorium to U-233 in a breeder reactor, then take it out into another reactor to use it). It is a thorium circle but NOT a thorium reactor, and it has all the same challenges of a low enriched uranium reactor. That is certainly not feasible for a ship.

There is no such thing as a thorium reactor. Thorium and uranium are just fuel, but thorium will need uranium or plutonium to breed fisile U-233 to start the process. Molten salt reactor can work with uranium just as well a thorium. Thorium has a small neutronic advantage , but not overhelming. The negative reactivity coefficient is a property of the salt and not of the fuel, just as water has a smaller negtiave activity coefficient with temperature. A big advantage of molten salt is that the salt allows high temperature opreation without a pressure vessel and so there is not need to worry about pipe breaks for the primary coolant or the need for a thick vessel wall. Some salt composition allow reasonably fast neutron that can breed fuel and so refuel is not needed for a long time, but the system will need to constantly remove active/neutron poison fission products.

Molten salt is very corrosive, I am not sure if the problem is worked out. I remember my advisor telling me how the solution dissolve couple inches of the reactor wall in short order in the 60s when R&D was more feverish.

 

[taxiya]

There is no such thing as a thorium reactor. Thorium and uranium are just fuel, but thorium will need uranium or plutonium to breed fisile U-233 to start the process. Molten salt reactor can work with uranium just as well a thorium. Thorium has a small neutronic advantage , but not overhelming. The negative reactivity coefficient is a property of the salt and not of the fuel, just as water has a smaller negtiave activity coefficient with temperature. A big advantage of molten salt is that the salt allows high temperature opreation without a pressure vessel and so there is not need to worry about pipe breaks for the primary coolant or the need for a thick vessel wall. Some salt composition allow reasonably fast neutron that can breed fuel and so refuel is not needed for a long time, but the system will need to constantly remove active/neutron poison fission products.

Shall we not play the game of splitting hair? TMSR-LF1 (Thorium Molten Salt Reactor) is a name used by China and presented in reports to IAEA without objection, so I will stick to the convention accepted by IAEA.

Yeah, I know how thorium reactor works, breeding non-fisible thorium to fisible fuel to burn in a single loop. Other designs as you talked about involve two separate loops, first to breed, second to burn, in between you move the fissile fuel in between. It is this difference (single loop vs. duel loop) that defines a throium reactor by most people except you perhaps. I suggest we leave the dispute of naming and focus on the essense.

Molten salt is very corrosive, I am not sure if the problem is worked out. I remember my advisor telling me how the solution dissolve couple inches of the reactor wall in short order in the 60s when R&D was more feverish.

Everybody knows the challenge of molten salt in a reactor. Today is 2020s, not 1960s, US (your advisor) couldn't do it in 1960s means not much now. TMSR-LF1 has been connected to power grid for months, so by now somebody already know if they have solved that problem. It isn't something like fusion (another 50 years forever).

 

[OppositeDay]

Now the catapult on 076 is shaping up to be the same as the one on 003 (at least judging from the length), one may wonder if this means they're not in a hurry to build 004 and meanwhile putting catapults on LHDs partially to keep the supply chain working.

 

[henrik]

Now the catapult on 076 is shaping up to be the same as the one on 003 (at least judging from the length), one may wonder if this means they're not in a hurry to build 004 and meanwhile putting catapults on LHDs partially to keep the supply chain working.

They can build more 003 if they want to keep the catapults supply chain working.

 

[by78]

A

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on a control console for a certain twin-reactor marine nuclear power system.

This might or might not have anything to do with China's future nuclear carriers (could be for a nuclear icebreaker or an off-shore nuclear powerplant, for example), but nevertheless posting it here for documentary purposes.

 

[Alfa_Particle]

A

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on a control console for a certain twin-reactor marine nuclear power system.

This might or might not have anything to do with China's future nuclear carriers (could be for a nuclear icebreaker or an off-shore nuclear powerplant, for example), but nevertheless posting it here for documentary purposes.

Interesting to note that they're from 2018.

 

[Kalec]

The shipyard rumored to build CVN. Latest satellite image in Apr 2024, yet nothing seen here.

 

[ChinaWatcher1]

The shipyard rumored to build CVN. Latest satellite image in Apr 2024, yet nothing seen here.

View attachment 131689

When was it rumored to begin?

 

[gelgoog]

It is way too early. We have zero information on the naval nuclear reactor development program being finished.
Type 003 is also still not in service and no aircraft launches have been made with it with the new aircraft.
It is probably too early to make a proper evaluation of how to proceed for the Type 004.

I am skeptical on the use of thorium molten salt reactors on naval ships. You have several problems with using something like that on a ship. Sodium ignites in contact with water. And it will solidify if the reactor is shut down. You will then have to heat the reactor core to high temperature to make it liquid again. This is a common trait with lead-bismuth nuclear reactors. Which we know caused the Soviets no end of trouble in the Alfa submarine. These kinds of reactors do have the advantage of being more compact than LWRs which makes it possible to design ships with performance that would be impossible to do with LWRs.

Another nail in the coffin with regards to the thorium molten salt reactor being put into use in ships in the near future is that they only started the land based test reactor like two years ago. And this is like a 1MW reactor. It would need to be massively scaled up.