May 10, 2018

Launch of French Barracuda SSN delayed by Reactor

Might this be the first almost externally complete Barracuda submarine (the Suffren) at Cherbourg? Note the X-plane tail, which no other French submarines have. Photo recorded May 7, 2018 courtesy le marin.

See the latest and partly corrective article on the Barracuda K15 reactor issue at Submarine Matter's France's Barracuda Delay - Existing K15 Reactor Too Big To Fit in It, dated November 15, 2018.

Following the previous article - the main reason for the delay in launching France’s new Barracuda SSN is the delay in developing an adequate reactor for Barracuda. On the Barracuda is English wiki but see French article with important added content. France does not have the advantages of Britain in relying on some US technology transfer to develop world's best practice reactors for submarine. The first Barracuda submarine, Suffren, was laid down in 2007 and hasn't been launched yet.  

If the testing on the not yet launched Barracuda has not been completed by 2020 it will be difficult for Naval Group to adequately design and "cut steel" on a settled Australia's Future Submarine prototype by Australia's 2022 milestone.  

France's current K-15 reactor (fitted to the Triomphant class SSBN - see sidebar) is reportedly 42 years old (see page 54 at [1] below). The K-15's old age may be a pointer to how slowly a new reactor (project started in 2003? [1]) adequate for Barracuda may be developed.

This slow development of a new submarine reactor may have been limited by France's policy of using money saving dual (civilian-military) use nuclear facilities reliant on low enriched Uranium (LEU) for propulsion.

Instead of the K15's 7-10 year till Uranium refueling cycle (which means lower submarine availability), France may be aiming for at least 15 years between refuels. This is still short of the full and modern 33 year life of submarine reactor core solution being used in US and UK submarines which require Highly Enriched Uranium of around 90% U235. Under the 1958 US–UK Mutual [Nuclear] Defense Agreement (see 3rd paragraphBritain has drawn heavily from US submarine reactor technology from the beginning

France does not want to repeat some UK reactor deficiences. France would have observed Britain's problems using Vanguard SSBN's PWR2 reactor in the Astute SSN (launched in 2007). More specifically the mismatch between the powerful PWR2 and Astute's undersized steam turbine has prevented Astute reaching full power [2]. That British PWR2 will only drive the Astutes at a deficient speed of 29-30 knots when around 35 knots would fulfil Astute's mission requirements. The opposition, Russia's Akula (see sidebar) and Yasen can travel at 35 knots.

French Submarine Reactor Table Based on [1] page 54.
Class using reactor
Reactor on French Nuclear Submarine
Redoutable class SSBN
Called Pressurised Water Reactor “PWR” in English. 110 MW source (no K name)

Rubis class SSN
CAS48 = K48) Rated at 48 MW giving just 7 MW propulsion (confirmed here). For submerged speed of 25 knots). K48 must be recharged every 6 to 7 years

Triomphant class SSBN
Resulting fleet reactor: K15.
The K15 design may go back to 1976 that is 42 years by 2018. [see page 54 [1] Lobner]. K15 rated at 150 MW.

Barracuda /
Suffren class SSN
Reactor construction started in 2003, with land test module completed in 2005Intended to replace K15.

[1]  Information on French SSBNs and SLBMs are on pages 49-83 of Peter Lobner’s 60 Years of Marine Nuclear Power: 1955-2015 - Part 4 - Other Nuclear Marine Nations, August 2015. large PDF (around 20MB) Information on K15 is mainly on page 54.

[2]  see page 203 of David Ross'sThe World's Greatest SUBMARINES: An Illustrated History, Amber Books Ltd, London, UK 2016.



Peter Coates said...

Zachary Keck writing for National Interest May 12, 2018 has subsequently written article
: "Paris announced that it was purchasing a fifth Barracuda nuclear attack submarine.."

And more important

"...The lead boat of the [Barracuda] class, Suffren, is scheduled to be delivered to the French Navy sometime in 2020, three years after it was initially slated to be ready."

[So it seems there will still be a lengthy period of testing AFTER the French Navy receives Suffren in 2020. So Australia's Barracuda based Shortfin might not cut steel until 2024...]

[relevant to Australia and South Korea Keck continues] "Despite not being in operation yet, the Barracuda has already been generating interest abroad. First, Australia selected a conventionally powered version of the submarine called the Shortfin Barracuda as the replacement for its Collins-class subs. In doing so, it beat out the much more established German Type 216 and Japanese Soryu-class subs.

More recently, South Korea has been eyeing as the Barracuda as a model to follow should it decide to build nuclear-powered submarines. One advantage of the Barracuda for South Korea is that, as noted above, it will not require highly enriched uranium."

Anonymous said...

Hi Pete

Alfa-class submarine used high-power liquid-metal-cooled nuclear reactor. But control of liquid metal medium was so troublesome for futher application in suceeding submarine [1].

Molten salt [2], which is liquid at room temperature and is not well researched in the era of Alfa-class, attracts interest in various applications. If a molten salt reactor (MSR) [3], a class of generation IV nuclear fission reactor using the molten salt as cooling medium is applied in Barracuda, high performance submarine like Alfa-claa can be realized.



Tri-ring said...

Anonymous said...

Molten salt [2], which is liquid at room temperature

Check your own link you provided, it states;
"Molten salt is salt which is solid at standard temperature and pressure"

That is why they call it MOLTEN salt.

Anonymous said...

Hi Pete & Tri-ring (16/5/18 12:34 AM)

Thanks for pointing out my mistake.