Nuclear power in Russian ships

Batteries are not good in terms off energy density compared to fuel. You would not carry as much fuel as a conventional ship, maybe 1/3 or 1/4. That can also cover helo operations and backup genset power.

You are quite right but if large sections of the ship can be closed off and filled with hydrogen gas then fuel cells can act as batteries with better fuel efficiency than a motor... a cryogenic section could be used to liquefy the hydrogen... the pure oxygen could be vented or burned with LNG for cooking or heating the ship in cold places...

It just seems so weird that the russians would cancel all plans to build a nuclear cruiser when they have enough reactors, state of the art off the shelf weapons and sensors, as well as near future free spots in shipyards.

Who said anything about cancelling plans?

They have access to rather more information than we have available to us... for all we know in 10 years time they might have plans for a totally new type of power system that is powerful and compact and reliable and not as expensive as current options...

There might be radar technologies that are on the way that will make current radars and stealth technology redundant and silly.

They are at the start of developing an all electric drive ship... some of the technologies involved might make serious changes to the way ships are designed and built... what they really need to do is start producing corvettes and frigates in useful numbers so older model vessels can be retired, and they need to start on a destroyer class to support the new helicopter carriers that are on the way.

They currently have a few cruisers... ex Kirov and ex Slava class ships that are not amazing... are not best of class in the world... but can sail around the world and do things cruisers are supposed to do...

Hydrogen would not be a great fuel for naval ships due to is low energy/volume ratio and the need for cryo/high pressure storage. If they can solve the problem for planes and cars then it may work...but until then.... The reality is all ships will be electric centric. Most warships cruise around at 10-15 knots tops. So building a small nuclear plant with 10-15 knots plus hotel load would make the most sense. For high speed, gas turbines will be up in 30 sec or less.

If they can develop a reversable way of using and storing Hydrogen it could be rather efficient and fully recyclable and clean fuel...

I am sure they could come up with some chemical way of storing hydrogen without needing to freeze or compress it... perhaps some nano technology that binds large numbers of hydrogen atoms to something inert like nitrogen where some catalyst can release the hydrogen as a gas when needed while the inert component could be recovered and used for storing newly created hydrogen.

This would allow fuel cell technology to be used to both generate electricity and create hydrogen storage...

GarryB wrote:If they can develop a reversable way of using and storing Hydrogen it could be rather efficient and fully recyclable and clean fuel...

I am sure they could come up with some chemical way of storing hydrogen without needing to freeze or compress it...  perhaps some nano technology that binds large numbers of hydrogen atoms to something inert like nitrogen where some catalyst can release the hydrogen as a gas when needed while the inert component could be recovered and used for storing newly created hydrogen.

This would allow fuel cell technology to be used to both generate electricity and create hydrogen storage...

Perhaps, but once they perfect that ...it will be 20-30 years min.

Ideally they could create some super molecule with something like Nitrogen and Carbon with large numbers of Hydrogen atoms all locked together... it is not my field but something like N6C6H36 or something, where they create a process where the Nitrogen is released as Nitrogen gas and the Carbon is released as a solid and the Hydrogen is release in enormous volumes as a gas.

Store the Carbon, release the Nitrogen, and use the Hydrogen... the size of the molecule will mean it will be some sort of fluid that is reasonably dense that contains the necessary Hydrogen in high concentrations but can be released cleanly... in fact the creation of the molecule locks up carbon... which is a good thing, and Nitrogen... which is the most abundant gas in Earths atmosphere... something like 70% is nitrogen which it cheap and available and inert.

From Wiki so not 100% accurate, but:

The average chemical formula for common diesel fuel is C12H23, ranging approximately from C10H20 to C15H28

So that explains Russian attempts at AIP using fuel cell technology that uses diesel instead of pure hydrogen.

Using diesel to run an AIP sounds counter productive on the face of it, but actually it is smart. Ports around the world already have the facilities to deliver diesel to ships for fuel... the infrastructure is all there and working already, while hydrogen fuel would need all new equipment an setups... which would cost money... the lack of fuel cell powered vessels means most ports will never get hydrogen fuel handling systems and infrastructure.

Also handling and storing diesel on submarines and ships is already present too... it is normal and already in place.

The only issue is that it will create a lot of carbon... but as there is no combustion involved that carbon could actually be in solid form which makes it much more useful than burning as it should create no CO or CO2.

The ideal would be all nitrogen binding atoms and lots of hydrogen atoms... N12H128 or something in a liquid form... as long as it is stable it would be quite heavy, and it would contain enormous volumes of Hydrogen atoms, but when the Hydrogen is released the only by product would be a small amount of Nitrogen gas... now that would be a useful technology... especially if the binding is strong and the molecule is therefore not flammable or combustable... you could store it as a liquid in enormous fuel tanks like a sort of heavy water that is not volatile or potentially dangerous like Hydrogen peroxide (H2O2)...

But a fully electrical ship is going to take time too... I suspect some of the work on the Kuznetsov will be to improve the electrics in this regard too.

I don't think fully electrical ships are a big leap, the Russians already have a ton of experience with electric motors and power grids and controls of all kinds. Submarines have been largely electric for a very long time and they have made powerful electric drive ships before.

A great deal of commercial hydrogen actually comes from natural gas, its called grey hydrogen. You can catalyze hydrogen from alcohol as well. All fine for AIP subs but not currently worth the cost for surface warships. Much more effficient to go with a diesel genset.

I think the Russian AIP plan is to burn hydrogen in a turbine to generate electricity, low vibes, exhaust will be water etc etc.

Would it be possible to use molten salt reactors for submarines and smaller vessels in the 8000t range? I hear the Russians have lots of experience with develeoping them, and the alpha submarine had a reactor that worked on a similar concept but used molten lead I think, which prevented it from ever turning off the reactor, lest it solidify into a useless hunk of metal. I don't think that issue exists with molten salt reactors.

My understanding is that even diesel electric submarines use shaft driven screws and gearboxes and transmissions, while surface ships don't have any electric motors at all and are all shaft driven.

All electric drive means you can have a variety of power generation systems that are not linked directly into the screws or shafts and can therefore be located anywhere in the ship with no restriction. No enormous heavy shafts or gearboxes or transmissions... just an electric motor turning a propeller... perhaps in a pod or perhaps fixed.

Electric drive means the ability to store and transfer when needed large amounts of electrical energy... which is important for propulsion but also energy intensive systems like an EMALS catapult system, or an EM gun or DEW system, or even electric armour.

All sorts of technologies will have to be further improved, but are transferable to other areas like electric cars and trains and buses and armoured vehicles and aircraft.

An electric helicopter for example would be amazing... a coaxial helicopter design with no need for a big heavy gearbox and transmission for instance would save about 3 tons for a Helix or Hokum sized 10 ton class helicopter and would make even larger helicopters much more viable...

I think the Russian AIP plan is to burn hydrogen in a turbine to generate electricity, low vibes, exhaust will be water etc etc.

Would consume oxygen at a rapid rate so liquid oxygen would need to be stored onboard, which is dangerous.

Would it be possible to use molten salt reactors for submarines and smaller vessels in the 8000t range? I hear the Russians have lots of experience with develeoping them, and the alpha submarine had a reactor that worked on a similar concept but used molten lead I think, which prevented it from ever turning off the reactor, lest it solidify into a useless hunk of metal. I don't think that issue exists with molten salt reactors.

Actually their new high temperature metal alloys would become useful perhaps with ceramic pipes that allow absolutely enormously high temperatures to be used for reactor designs would be rather interesting...

The problem with pressurised water reactors (PWRs) is that even though they operate at very high temperatures the pressure the water is kept under means it is converted into steam efficiently... but if the temperature gets too high the hydrogen and oxygen separate and detonate like a bomb with the hydrogen being the fuel and of course the oxygen being the oxidiser... and extreme high temperature causing combustion.

Even using lead bismuth as a coolant there is no natural normal temperature the reactor could reasonably get to that would cause lead bismuth to explode... so it is an ideal coolant.

I am sure there are other secret projects and new designs they will be working on too.

limb wrote:Would it be possible to use molten salt reactors for submarines and smaller vessels in the 8000t range? I hear the Russians have lots of experience with develeoping them, and the alpha submarine had a reactor that worked on a similar concept but used molten lead I think, which prevented it from ever turning off the reactor, lest it solidify into a useless hunk of metal. I don't think that issue exists with molten salt reactors.

Problem with the Lead-bismuth eutectic reactor is not related to the base tehcnology , rather than the special design used in the given submarine.

Most likelly to avoid the problem with the solidification required few years worth of additional development, and the military just wanted the submarine as fast as possible, so they made the compromise about the control issue.

The molten salt reactor will be solid as well on room temperature,but the biggest issue with them is that the salt, that contain all fuel and fission product soluble in water.


The LBE is way better for submarines.

GarryB wrote:My understanding is that even diesel electric submarines use shaft driven screws and gearboxes and transmissions, while surface ships don't have any electric motors at all and are all shaft driven.

All electric drive means you can have a variety of power generation systems that are not linked directly into the screws or shafts and can therefore be located anywhere in the ship with no restriction. No enormous heavy shafts or gearboxes or transmissions... just an electric motor turning a propeller... perhaps in a pod or perhaps fixed.

Electric drive means the ability to store and transfer when needed large amounts of electrical energy... which is important for propulsion but also energy intensive systems like an EMALS catapult system, or an EM gun or DEW system, or even electric armour.

All sorts of technologies will have to be further improved, but are transferable to other areas like electric cars and trains and buses and armoured vehicles and aircraft.

An electric helicopter for example would be amazing... a coaxial helicopter design with no need for a big heavy gearbox and transmission for instance would save about 3 tons for a Helix or Hokum sized 10 ton class helicopter and would make even larger helicopters much more viable...

I think the Russian AIP plan is to burn hydrogen in a turbine to generate electricity, low vibes, exhaust will be water etc etc.

Would consume oxygen at a rapid rate so liquid oxygen would need to be stored onboard, which is dangerous.

Would it be possible to use molten salt reactors for submarines and smaller vessels in the 8000t range? I hear the Russians have lots of experience with develeoping them, and the alpha submarine had a reactor that worked on a similar concept but used molten lead I think, which prevented it from ever turning off the reactor, lest it solidify into a useless hunk of metal. I don't think that issue exists with molten salt reactors.

Actually their new high temperature metal alloys would become useful perhaps with ceramic pipes that allow absolutely enormously high temperatures to be used for reactor designs would be rather interesting...

The problem with pressurised water reactors (PWRs) is that even though they operate at very high temperatures the pressure the water is kept under means it is converted into steam efficiently... but if the temperature gets too high the hydrogen and oxygen separate and detonate like a bomb with the hydrogen being the fuel and of course the oxygen being the oxidiser... and extreme high temperature causing combustion.

Even using lead bismuth as a coolant there is no natural normal temperature the reactor could reasonably get to that would cause lead bismuth to explode... so it is an ideal coolant.

I am sure there are other secret projects and new designs they will be working on too.

The diesel submarines doesn't have gearbox between the motor and screw.
The battery gives so little energy using oversized power on screw doesn't bring any benefit.


The nuclear submarine is a different kind of issue however.


Advantage with the LBE or molten salt is they operate on room temperature, so there is no heavy/constrained shape pressure vessel, making the reactor more compact and light.

The Ford class with EMALS uses steam turbines to drive the screws, the Artika uses electric drive on the screws and nuclear/steam to generate electricity. Type 45 uses gas turbine/diesel genset for electric and pure electric drive. Integrated electric has a whole range of definitions. The 20386 will use gas turbines to for speeds and electric motor/diesel genset for cruise. This is a very intersting option. The Kirov class looked kinda crazy with nuclear/oil but when you think of it, 100% rational. 20 knots nuclear and 1000KM with oil superheaters at 30+ knots.

A great deal of commercial hydrogen actually comes from natural gas, its called grey hydrogen.

In an article in the technology section they were talking about yellow hydrogen and blue hydrogen too... each will have different ramifications I suspect and the different processes to release the hydrogen will have different ecological effects.

The Ford class with EMALS uses steam turbines to drive the screws,

The Ford class was never intended to be an all electric drive ship... I think that is what the Zumwalt was supposed to achieve... but both have plenty of problems of their own ...

The Kirov class looked kinda crazy with nuclear/oil but when you think of it, 100% rational. 20 knots nuclear and 1000KM with oil superheaters at 30+ knots.

Kirov was clunky and was necessary because they didn't have a powerful enough reactor for a large ship.

GarryB wrote:
Kirov was clunky and was necessary because they didn't have a powerful enough reactor for a large ship.

don't really think that is the reason for it, they had 600 MW of nuclear power between 2 reactors. I think the superheating was for quick response in tactical situations and they needed fuel for helo ops and diesel generators anyway.

mnztr wrote:

GarryB wrote:
Kirov was clunky and was necessary because they didn't have a powerful enough reactor for a large ship.

don't really think that is the reason for it, they had 600 MW of nuclear power between 2 reactors. I think the superheating was for quick response in tactical situations and they needed fuel for helo ops and diesel generators anyway.

CONAS system was above all more fuel efficient than a conventional one as heaters acted on an already pre-heated vapor instead to lose hours of idle time to put it under pressure and in the same time also more power efficient than a purely nuclear one as they acted directly on the secondary fluid.

I think the superheating was for quick response in tactical situations and they needed fuel for helo ops and diesel generators anyway.

I doubt the helicopters operated on the same fuel the ships engines ran on....

GarryB wrote:

I think the superheating was for quick response in tactical situations and they needed fuel for helo ops and diesel generators anyway.

I doubt the helicopters operated on the same fuel the ships engines ran on....

Maybe not, but it is very easy and not very expensive to use kerosene in the boilers and diesel engines, especially since the boilers are only occasionally used. Even the diesel gensets would only be used when not under way.