Naval Ship & Submarine Propulsion Systems

[StobieWan]

Again, from Capt. Skinners paper;
“Most current SSNs employ a Pressurised Water Reactor (PWR) for reasons of simplicity......and steam technology is well understood.
More recent interest is growing in the employment of advanced reactors such as the liquid fuelled molten salt reactor (MSR) which has the potential for refuelling while in service...MSRs also operate at ambient pressures and possess a high safety margin on temperature limits. They also provide the option of using thorium based fuel.”

Nuclear reactor fuel contains mainly U238 as well as small quantities of U235 but enrichment is low compared with nuclear weapons.

MRS's are gaining a bit of traction in civilian circles (there's a Brit company called Moltex that's just flogged an experimental reactor for instance) - the plus points look interesting and it could get around the proliferation regs using the right fuels for instance. Plus, the phrase "Oh my God, the core has melted" isn't quite as scary...

 

[Redlands18]

I did speak with an RN submariner at a social do in the Mess at Northwood and he introduced himself as being normally aboard a nuclear attack boat "nuclear powered, not armed" he hastily added. Turned out he does a lot of PR trips to schools etc and that was almost a by-rote disclaimer regarding the job.

Even the nuclear powered aspect is contentious - nuclear power generation has a very looming image problem after Chernobyl and Fukushima - somewhat unfairly I feel, given the numbers involved but it is what it is.

The TV Miniseries Chernobyl would not have helped things either(recommend it to anyone who hasn’t seen it), though its a demonstration on how not to run a Nuclear Power industry.

 

[StobieWan]

The TV Miniseries Chernobyl would not have helped things either(recommend it to anyone who hasn’t seen it), though its a demonstration on how not to run a Nuclear Power industry.

Indeed - that series was a monster hit in the UK and it was very gripping - I've since gone on to collect a small library of books on the incident and the aftermath. It's just slightly ironic that the total death toll seems to be around 40 from acute radiation sickness and around 9000 cases of thyroid cancer that were "avoidable" - meanwhile, in any given year, the death toll from fossil fuels on a "death per kw/hr" basis is around 2 million per year.

Touching on Australian nuclear ambitions, the supply chain just doesn't exist so some extraordinary arrangements would be required, such as building a power section remotely and having the host nation complete the rest of the boat - this is pretty much how the UK acquired it's first nuclear subs, using a US core mated with UK constructed vessel - I believe at least one defpro on this board wrote a very detailed analysis of why this was all unlikely.

 

[alexsa]

I did speak with an RN submariner at a social do in the Mess at Northwood and he introduced himself as being normally aboard a nuclear attack boat "nuclear powered, not armed" he hastily added. Turned out he does a lot of PR trips to schools etc and that was almost a by-rote disclaimer regarding the job.

Even the nuclear powered aspect is contentious - nuclear power generation has a very looming image problem after Chernobyl and Fukushima - somewhat unfairly I feel, given the numbers involved but it is what it is.

Chernobyl was a shocker and is a salient lesson. Fukushima also presented some telling lesions (noting the explosions were hydrogen explosions generated by the heat after the water in the cooling ponds for the spent rods drained away and the rods were exposed). However, we should not ignore the new technologies being considered for Gen IV SMR some of which include design features that make them inherently safer and less prone to events such as Chernobyl (in some cases it is claimed this risk is addressed altogether).

I know it is a hard sell be we do need to have a mature conversation about nuclear power in this country ...... but political game play make this unlikely.

Anyway .... I digress and this is off topic

 

[StingrayOZ]

Again, from Capt. Skinners paper;
“Most current SSNs employ a Pressurised Water Reactor (PWR) for reasons of simplicity......and steam technology is well understood.
More recent interest is growing in the employment of advanced reactors such as the liquid fuelled molten salt reactor (MSR) which has the potential for refuelling while in service...MSRs also operate at ambient pressures and possess a high safety margin on temperature limits. They also provide the option of using thorium based fuel.”

Nuclear reactor fuel contains mainly U238 as well as small quantities of U235 but enrichment is low compared with nuclear weapons.

Frances Barracuda reactor was delayed as they are trying to build a low enriched uranium reactor. A tricky endeavor never tried before. There were many problems to over come, however, using Low enriched Uranium means commercial uranium can be used. Brazil looks like going with highly enriched uranium but possibly much lower than highly enriched.

There is certainly a spectrum of options available. Smaller or low enrichment "teakettle" type reactors which could be far smaller, and provide basically hotel + low speed propulsion load only.

But with lithium batteries rapidly moving ahead as a technology, the may soon be no need for nuclear submarines as advanced battery tech will effectively close the gap on most mission profiles easily with in the next generation. A nuclear submarine produces power effectively for 7 years or in modern subs, the entire life of the submarine. Missions typically sit in the 45-80 day profile, so nuclear is massively over capable in this realm. Even SSNs approach the surface, ventilate, communicate, periscope etc. So we are already pretty much at the juncture of designing advanced conventional subs exceeding the capabilities of nuclear in most conops. If your SSN is running loud and fast then it might as well be running a diesel engine as well.

USS Albacore (AGSS-569) - Wikipedia was a diesel electric submarine that could operate up to 33 kts and do things that basically setup the future of nuclear submarines. Its silver and zinc batteries were not practical for submarines long term, but we now have alternatives.

Ultimately new technology batteries will probably increase the cost of conventional submarine production, but also its performance. A nuclear powered submarine may perhaps seem as silly as a Ford Nucleon - Wikipedia. Even with this increased cost of say lithium ion batteries, it won't cost as much as nuclear submarines. Of which we would basically be starting from scratch for countries like Canada and Australia.

 

[Hazdog]

If the source is a personal conversation then state it as so and name the participants in the conversation. If you don't want to name the sources, state that it as an off the record conversation with an anonymous 1 star etc., at such and such, so that people can assess the validity of the info for themselves.

Thank you for the advice.

I shall add this to the original post too: The off-record conversation as indicated by my direct statement that it was "unofficial" was with a retired 2-star within the RAN submarine community. I do not wish to give their name as I wish not to have their name or reputation slandered or brought into question.

Now back to the 24 submarines:

The main objectives of the RAN Submarine fleet are

• intelligence collection and surveillance;
• maritime strike and interdiction;
• barrier operations;
• advanced force operations;
• layered defence;
• interdiction of shipping;
• containment by distraction; and
• support to operations on land

According to the Seapower Centre - Australia Publication: Navy Contribution to Australian Maritime Operations - Royal Australian Navy.

Such roles indicate the number of deployed submarines to be at roughly 8 submarines as these aforementioned roles are almost all achieved best at maritime chokepoints within our region. As such, I suggest whoever doubts the choke points of the South China Sea should open google maps and have a quick count of the number of potential choke points or pass-throughs that they can see.
- I myself did a quick check of the number of potential choke points and regions that submarines would be well suited too and found many more than 8.

I do acknowledge @Takao and his points which are almost all valid and true, I am not suggesting that we revolutionize for 24 submarines tomorrow; but I am suggesting that cutting or reducing or underestimating the number of submarines needed/available would not enable the RAN and ADF a reasonable deterrent and/or capability to respond with, to a high-intensity maritime conflict in our region.

I response to Takao's point regarding people. The current authorized force strength is roughly 500 sailors (please correct me if I am wrong as my latest source is from 2007 - Walters, Patrick. "Higher pay for sailors in subs". The Australian). Thus that new number for 24 submarines (assuming a linear manning model, which I doubt, as the efficiency of training and manning would increase as the force increases in size) is 2000 sailors or roughly 11% of the current RAN.

I hope this clarifies my stance and hope for a genuine conversation on this issue.

EDIT: I am unable to edit the earlier post, as such if a mod wishes to add "The off-record conversation as indicated by my direct statement that it was "unofficial" was with a retired 2-star within the RAN submarine community. I do not wish to give their name as I wish not to have their name or reputation slandered or brought into question." they are free to do so with my thanks.

 

[Preceptor]

This is a reminder for everyone. DT isn't the correct place to discuss topics like climate change as DT is a defense forum, not an environmental forum, same goes for topics like the Australian energy industry or potential for an Australian nuclear industry. Also, while this is the RAN thread and therefore the topic of RAN subs and power generation and storage for them is relevant, discussion of nuclear-powered subs for the RAN isn't. Continuing to bring these topics up degrades the quality of discussion, which will trigger further action by the Mod team.
-Preceptor

 

[Volkodav]

The only OTS solution I can think of would be if Australia were to consider shorter range submarines. By the 2030s Australia may well find itself in a position where they are countering Chinese submarines and surface ships in our own waters. Maybe then range won't be as big an issue. Perhaps a mix of shorter-range and longer-range boats might be an acceptable compromise. We could have around three overseas builds now instead of a LOTE program for the Collins and hopefully, they will hold the line until the Attacks start entering service from the mid 30s.

When you look at the distance from Fleet base East or Fleet Base West to our northern approaches you are already talking longer distances than pretty much anyone elses subs need to cover. Short range subs just don't make sense in the Australian context

 

[John Fedup]

Is a Northern sub base(s) deemed unviable due to economics or military feasibility (perhaps both)?

 

[Calculus]

When you look at the distance from Fleet base East or Fleet Base West to our northern approaches you are already talking longer distances than pretty much anyone elses subs need to cover. Short range subs just don't make sense in the Australian context

So what kind of range are we talking here? Most of the new designs I've seen (such as A26 (Blekinge) Oceanic ER (H I Sutton - Covert Shores) and Type 216 (Type 216 submarine - Wikipedia) have 10,000nm ranges. Even our relatively small Victorias have 8000 nm ranges. Would those still fall short?

 

[John Fedup]

So what kind of range are we talking here? Most of the new designs I've seen (such as A26 (Blekinge) Oceanic ER (H I Sutton - Covert Shores) and Type 216 (Type 216 submarine - Wikipedia) have 10,000nm ranges. Even our relatively small Victorias have 8000 nm ranges. Would those still fall short?

I think the range issue is largely due to the large transit distances to the patrol areas they need to be at. By the time they reach these areas from their southern bases, there isn’t a lot of endurance left plus they have to get back to base. The RCN would have the same issues for far north patrols but let’s face it, they don’t really bother as the only players in the Arctic at present are US and Russian SSNs.

 

[Calculus]

I think the range issue is largely due to the large transit distances to the patrol areas they need to be at. By the time they reach these areas from their southern bases, there isn’t a lot of endurance left plus they have to get back to base. The RCN would have the same issues for far north patrols but let’s face it, they don’t really bother as the only players in the Arctic at present are US and Russian SSNs.

Ah, OK. Understood. So is that an issue with the Collins class now?

 

[John Fedup]

Ah, OK. Understood. So is that an issue with the Collins class now?

Our Australian cousins could better answer this but the Collins program was an attempt to address this as other SSKs at the time were deemed limited wrt range.

 

[ASSAIL]

Is a Northern sub base(s) deemed unviable due to economics or military feasibility (perhaps both)?

There are multiple problems with permanent bases in the north.
It’s hard enough to maintain retention levels with them based in the west, remember being a submariner limits your seagoing posting to one place only and if that was away from the main population areas, from family and friends there’s hurdles aplenty.
Lack of industrial support including docking facilities is also a problem. To give you some idea of the remoteness of the N/NW coast, if you combine the population of all coastal towns between Darwin and Perth there are less than 250,000 and half of those are in Darwin.
The biggest problem though is strategic. Submarines departing from say Darwin have to transit over 500nms in shallow water before they can become invisible and by that time Red Force can take counter measures and has a fair idea of intent.
Sailing from Fleet Base West or East a boat can disappear 5miles from the coast not to be seen again until it reappears in the same place.
This also explains the transit/endurance/indiscretion ratio equation.

 

[John Fedup]

Canada has a nuclear industry so the Barracuda SSN would be a suitable solution and would be Arctic capable as a future replacement assuming the French it right. Building subs in Canada would be a serious commitment and would only be feasible if 8-10 boats were planned. If the number is smaller, forget it and just buy off shore.

 

[ngatimozart]

Canada has a nuclear industry so the Barracuda SSN would be a suitable solution and would be Arctic capable as a future replacement assuming the French it right. Building subs in Canada would be a serious commitment and would only be feasible if 8-10 boats were planned. If the number is smaller, forget it and just buy off shore.

Well it would make sense to have SSNs for under the ice, if it's still there, but the big question really is would a Canadian government be willing to stump up the cash for such subs, and like you say, build 8 - 10. I can't really see them agreeing to an offshore build for such a large and costly project because it goes against everything in their DNA.

 

[StingrayOZ]

Canada's nuclear industry is specifically not a lot in common with nuclear power plants in subs and its nuclear industry is a heck of a lot weaker than it was even a decade ago. Canada's nuclear industry is based around large CANDU reactor which specifically don't run enriched fuel, where as every SSN/SSBN is running highly enriched except for Suffern, after much effort and delay, which is running LEU which is still very different from CANDU. Canada looked this in the 70's and 80's. It went no where even with cold war threats and budgets.

IMO nuclear subs are not a great option for Canada. Tremendously expensive. Canada doesn't really need or seem interested the high transit speeds for global power projection, so more affordable energy options are going to make a lot more sense. AIP like Stirling engines are going to work quite well for Canada's purposes, as are other technologies. Canada already has extensive experience with diesel boats, that seems like a more realistic goal. Operating around ice doesn't mean requires nuclear power. The Russians have been doing it for decades with diesels.

I think given the previous experience with Canada and defence submarine procurement and the 1980's-90 experience, no SSN builder would be interested in wasting their time with a Canadian tender. While not exactly fresh in everyones minds, would be very cautious. A sensible realistic conventional program is warranted.

The history behind this is very lengthy. Through a Canadian Periscope: The Story of the Canadian Submarine Service is a good book that explores some of the issues.

 

[John Fedup]

Well it would make sense to have SSNs for under the ice, if it's still there, but the big question really is would a Canadian government be willing to stump up the cash for such subs, and like you say, build 8 - 10. I can't really see them agreeing to an offshore build for such a large and costly project because it goes against everything in their DNA.

If the geopolitical situation continues to deteriorate, a larger submarine fleet may be in the cards assuming Canada isn’t bankrupt after COVID19. Building either SSKs or SSNs in Canada with a partner nation would be problematic and the absolute minimum is 8 boats to consider this option. Five to ten years from now, the Arctic ice cap condition will be known and it is likely going to be ice free negating the SSN advantage.

 

[John Fedup]

Canada's nuclear industry is specifically not a lot in common with nuclear power plants in subs and its nuclear industry is a heck of a lot weaker than it was even a decade ago. Canada's nuclear industry is based around large CANDU reactor which specifically don't run enriched fuel, where as every SSN/SSBN is running highly enriched except for Suffern, after much effort and delay, which is running LEU which is still very different from CANDU. Canada looked this in the 70's and 80's. It went no where even with cold war threats and budgets.

IMO nuclear subs are not a great option for Canada. Tremendously expensive. Canada doesn't really need or seem interested the high transit speeds for global power projection, so more affordable energy options are going to make a lot more sense. AIP like Stirling engines are going to work quite well for Canada's purposes, as are other technologies. Canada already has extensive experience with diesel boats, that seems like a more realistic goal. Operating around ice doesn't mean requires nuclear power. The Russians have been doing it for decades with diesels.

I think given the previous experience with Canada and defence submarine procurement and the 1980's-90 experience, no SSN builder would be interested in wasting their time with a Canadian tender. While not exactly fresh in everyones minds, would be very cautious. A sensible realistic conventional program is warranted.

The history behind this is very lengthy. Through a Canadian Periscope: The Story of the Canadian Submarine Service is a good book that explores some of the issues.

The SSN requirement will fade as the Arctic ice cap does so. As for builder, the French are the only possible builder as the US won’t allow a sale and hence the UK can’t offer to build as they use US nuclear technology. It will be interesting in the years to come to evaluate the cost of an Australian future SSK based on a derivative of the Barracuda SSN sub versus just buying the actual SSN. I appreciate the requirement for building subs in Australia makes the latter option impossible.

 

[StingrayOZ]

The SSN requirement will fade as the Arctic ice cap does so

Its likely within the next 20 years there will be no multi year ice left in the northern hemisphere. While there will be an ice cap in winter, it will mostly only be ~<1m and its coverage will be much smaller. Really if Canada started a design and build process now, by the time the first sub hits the water it isn't going to be much of an issue as there won't be any ice that troubles any submarine.

Far more of a issue is patrolling all this new non-ice territory.

Much is made of the Australian sub project price. People talk about unit price which really has nothing to do with anything going on. Nuclear subs are tied to nuclear weapons programs, as they basically run off weapons grade fuel. You basically cannot divorce them. The sale of them is problematic because of it. If you have a nuclear sub program, you have a nuclear weapons program.

Diesel subs are cheaper, by an order of magnitude. French sub production has basically been continuous for 75+ years, and tied into SSN, SSK and SSBN production. Australia built one class of 6 conventionals, once. Australia had also torched their heavy industrial and ship building capability, France has a significant and continuous military ship building tradition going back hundreds of years and as a function of a much bigger economy. So on rebuilding all of that, Australia is also building 12 conventional submarines as a first batch of a continuous sub building, forever. There will not be any future tenders for new submarine designs as the design will now evolve with Australia's needs and technology and sovereign capability.

However they will be interesting programs to benchmark against each other. Particularly as the project continues. In terms of cost, capability and km patrolled.