Royal Australian Navy Discussions and Updates 2.0
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iambuzzard
Well-Known Member
Some people can't be educated. Dullness seems to be in epidemic proportions at the moment.
I am not seeing any major differences between the Australian and UK versions of the AUKUS submarines. They seem to be basically the same boat down to the AN/BYG-1 combat system.
If that's the case surely we should be able to start construction, perhaps as early as this decade.
If that's the case surely we should be able to start construction, perhaps as early as this decade.
I think the current program sees first construction in 2029. It's just a long slow build for the first hull.
I note in the same article they describe how...
Seems odd to me that the construction of the reactor doesn't count towards building the submarine, only the first cutting of steel for the hull. In any event, some real progress has apparently been made.
Going Boeing
Well-Known Member
I briefly spoke to a guy who’s involved with the reactors for the SSN AUKUS and he was very guarded about what he could say but did indicate that the reactors will have 40 years of fuel life and the reactor version is known internally as PWR3+ which is because of design changes from the PWR3 being fitted to the Dreadnought class.
iambuzzard
Well-Known Member
If that's the case, and with the Mogamis having a similar lifespan, If the powers that be have any common sense we should have a continuous production line with updates as required. The Japanese do it very well.
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Fairly certain Peter Garret had a large part in writing the anti USA midnight oil song as far back as 1982. Regardless of their opinion or motivation the whole, project is too far down the road to revisit.
For what it's worth the Barracuda design is about a decade younger than Virginia, so age wasn't a concern. IMHO their main advantage vs Virginia would have been the smaller crew and high availability which allow for dual crewing. This in turn would have enabled a more rapid capability ramp up with the first 3 subs in the 2030s (and ultimately more sea time and forward presence given the target fleet size of 5-6 SSNs). A proper analysis of alternatives instead of Morrison's captain's call might have found that strategically and operationally relevant.
Virginia vs Suffren dates below:
Preliminary design started: October 1993 | Mid 2002
Construction started: October 1997 | December 2007
Alpha sea trials: July 2004 | May 2020
Both designs have been upgraded, with the RAN aiming to get Virginia Block IVs (Alpha sea trials starting March 2020), though there's a risk that the USN might try to dump older Block IIIs (Alpha sea trials starting July 2014). Both Block IV and III are therefore somewhat older than the current Barracuda Block II (Alpha sea trials starting March 2026).
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Good question. Apparently refueling is a non-event with the right access hatches.
A typical refueling overhaul lasts 16-18 months on a 10 year cycle, which is not too dissimilar to other navies' overhaul cycles without refueling. The French use a mobile Reactor Access House (the UK has one at Faslane too) that can be rolled over the submarine; this provides a secure sealed maintenance area and greatly simplifies opening the hatches and replacing fuel rods or containment vessels. It's not quite drop-in/drop-out, but almost (simplifying somewhat of course).
With 6 subs on a 10 year cycle, that means 5 operational subs (10 crews) with the 6th sub in overhaul/refueling. Each operational sub spends 160-170 days per year at sea (80-85 sea days per crew), with 70 days/year for routine maintenance.
Sounds almost too simple to be true, but we know from the Rubis class decommissioning ceremonies that they are being retired with an average of 120,000+ diving hours (almost 14 years at sea). That's 37-38% operational sea time over a 35+ year service life. We also know that they hit 1,000 sea days in peak years (45% sea time). Apparently the Barracudas are doing better than that thanks to longer operating cycles between overhaul and refueling.
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iambuzzard
Well-Known Member
Going Boeing
Well-Known Member
The RN submarine maintenance base at Devonport also has an overhead Reactor Access House (recently installed).
One thing that became public during the refueling of HMS Vanguard is that, because it was planned to have sufficient fuel for the life of the submarine, the design had made no allowance for the refueling process. This resulted in a lot more work and a much longer period that the submarine was out of service (circa 7 years). The refueling was done as a precaution in case the Dreadnought class was not operational in time to replace the Vanguards. The other 3 in the class are not expected to require refueling.
I’ve read that in past refuelings of US submarines, the first 18 months involve the reactor slowly stopping the fission process and cooling down to a level where the fuel cell can be removed and replaced (continuous monitoring crew required). Obviously, other maintenance work is done during this period but it shows why they were normally out of service for about 3 years. Being able to fuel submarines for their entire service life has significant savings as shown by the fact that 12 Columbia class will have the same “at sea availability” as 14 Ohio class.
All USN reactors are routinely shutdown to “cold iron” status prior to any maintenance period in dock. So stopping the fission process and cooling is not a big deal, and not unique to refueling overhauls.
For the French SSNs I recall reading that the Barracuda refuelings were designed to take only 3 months, typically as part of a longer overhaul and with non-nuke maintenance continuing in parallel. Apparently this involves doing some of the defueling/refueling steps at night so as not to interfere with daytime maintenance shifts.
For the French SSNs I recall reading that the Barracuda refuelings were designed to take only 3 months, typically as part of a longer overhaul and with non-nuke maintenance continuing in parallel. Apparently this involves doing some of the defueling/refueling steps at night so as not to interfere with daytime maintenance shifts.
iambuzzard
Well-Known Member
OldTex
Well-Known Member
The information in the public domain all points to no refuelling for the life of the boat. There is also reportedly information from RR that the PWR3+ reactors for the boats have a life of approximately 40 years.
AndyinOz
Active Member
No refueling of the reactor material was from what I understand seemingly a reason the project was allowed to proceed. We were able to give assurances to the IAEA etc that the reactors would remain welded shut just as we'd receive them. That way we would not require a fully fledged nuclear industry and our partners could not be accused of proliferation of nuclear technology used for something other than civilian power generation.
iambuzzard
Well-Known Member
Don't the French boats require refueling? That's the major reason for not going down that path.
OldTex
Well-Known Member
According to recent information the French Barracuda/Suffren class SSN needs refuelling after 7-10 years, but that only requires approximately 3 months to achieve, usually as part of a longer major maintenance docking.
Refueling is only an issue due to the US and UK’s use of HEU, with its proliferation and infrastructure concerns (long term storage of spent fuel). Luckily Virginia and Aukus SSN have life of type reactors which allowed for a fudge by keeping the reactor sealed.
There are 30+ countries with LEU reactors, some of them as small as Slovenia, others being emergent countries like Bangladesh. So no proliferation or infrastructure concerns… you can even send spent fuel rods by ship back to Europe for reprocessing. That’s what the French subs use.
IIRC when Canada was considering buying SSNs in the late 80s, those would have been LEU fueled (Rubis class). Some pros and cons to each approach obviously, but bottom line is that HEU vs LEU should not be a deciding factor.