France's future SSN, the Barracuda (first laid down 200
7) has been delayed for years due to French delays in developing a new reactor known as the "Improved K15". Of course large existing K15s power the French carrier
Charles de Gaulle and France's Triomphant class SSBNs. Put succinctly as France's existing K15 reactor is 10m tall it is too large to fit in the Barracuda's 8.8m diameter hull.
The smaller developing "Improved K15" can be described as a new reactor that will differ not only in size (to fit in the smaller Barracuda hull), but requires other characteristics, including longer periods between refueling, improved natural circulation performance and quietness of operation, improved safety and lower life-cycle costs.
MANY SILENT ON WHY BARRACUDA ARE DELAYEDSo this developing-a-smaller-reactor problem has caused an overall delay in the Barracuda Program. The first Barracuda, the Suffren, was laid down in late 2007 and still hasn't been launched in late 2018.
Delays in the Barracuda SSN Program will (or have) caused delays in Australia's Future Submarine Program. This is important because France's DCNS (now Naval Group) itself identified the Barracuda SSN as the reference design (pumpjet, hydroplanes and all)
for Australia's Future Submarine. A crucial area is the hydrodynamic waterflow over the not yet launched submarine's hull and the associated noise the flow makes. With no water flow results from a full scale Barracuda SSN Australia cannot be sure that Australia's Future Submarine will move efficiently and quietly in the water.
The Asia-Pacific Defence Reporter's (APDR's) Editor, Kym Bergmann in SEA 1000 - The future submarine project in trouble – and the ‘Barracuda’ reference design, of October 29, 2018 raises the issue that as Australia’s Future Submarine was advertised by DCNS, now Naval Group, as the “
Shortfin Barracuda Block 1A.” then:
“...it would be helpful for Australian readers to have an update about what has been happening on the [Barracuda SSN] parent program. [When French representatives were asked about progress] The result was silence so complete as to be a metaphor for the supposed stealth characteristics of the submarine itself.”
Later in the article Kym commented:
“Speaking of which, when another small group of Australian journalists were on a French Government media tour a year ago, one of them asked about delays to the Barracuda program and received the answer from Naval Group that – improbably – it was all the fault of the reactor supplier, the majority Government-owned Orano (previously Areva). French military reactors are unusual because they use commercial grade uranium, unlike enriched uranium favoured by all other navies. Having said that, Orano has a huge amount of experience and since the K15 50 MW reactor for the Barracuda is a derivative of the ones powering the aircraft carrier Charles de Gaulle – themselves a version of the nuclear reactors developed for the Triomphant class SSBNs – so it seems unlikely that this is the real cause of the delay.”
Nuclear reactor on a French submarine. Note how the reactor, which is on the right, takes up the whole height/diameter of the submarine - so miniaturising the reactor is essential. (See diagram on page 200 of Peter Lobner's Marine Nuclear Power 1939 – 2018_Part 4_Europe & Canada (PDF 20 MB).)
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BUT NEED FOR SMALL, IMPROVED K15, IS THE MAIN CAUSE FOR DELAY
Fortunately GhalibKabir has pointed me to a July 2018 body of work by submarine reactor expert Peter Lobner which reveals the K15 reactor issue is still valid. Basically the problem with the existing K15s in the French carrier
Charles de Gaulle and in French
Triomphant class SSBNs are that they are too large to fit in the smaller Barracuda SSN hulls. Put succinctly France's existing K15 reactor, at 10m tall, its too large to fit in the Barracudas' 8.8m diameter hulls.
Peter Lobner's Marine Nuclear Power: 1939 - 2018, at https://lynceans.org/all-posts/marine-nuclear-power-1939-2018/, runs to 1,000s of pages. But the relevent section on France's latest naval reactors is in Marine Nuclear Power 1939 – 2018_Part 4_Europe & Canada (PDF 20 MB). Don't be downhearted when you see that Part 4 alone is 364 pages. The relevent pages I focus on concentrate on the Improved K15 on page 179 and then 189 to 208.
As well as smaller size there are other improvements to the K15 which make it (or more correctly will make it) a new reactor. It is known for public relations, political and defence program cost saving reasons as the "Improved K15". Lobner explains that the prototype of the Improved K15 has not even gone critical as at mid-2018 in the French naval reactor prototype test center at Cadarache. As there is no operating Improved K15 actually in a Barracuda (these subs are still in a shed) we need to rely on land based prototype reactor reports . Lobner Page
207 explains the existing K15 vessel is about 10m tall. So, yes, it does fit into the Triomphant class SSBN's 12.5m diameter hull and of course two K15s fit into the much larger French carrier Charles de Gaulle.
Page 208 states the need to
"Reduce the physical size of the [Improved K15 reactor] so it can fit on a Barracuda-class SSNs which has an outer hull diameter of 8.8 m..." DETAILED INFORMATION ON NEED TO CREATE THE IMPROVED K15
The detail, in context, in Marine Nuclear Power 1939 – 2018_Part 4_Europe & Canada (PDF 20 MB) is important.
Page 179 with table "Naval reactor [land] prototypes" when put fully into English the:- "RNG" the "K15" drives the Triomphant class SSBN and carrier Charles de Gaulle, and- "RES" land prototype for the "improved K15""Originally intended to replace [the K15] in about 2009. Not yet operational in 2018." then
Page 189:
"The
RES test reactor is an upgraded version of the K15 [reactor] that currently is operating on four Le Triomphant-class SSBNs and the aircraft carrier Charles de Gaulle. The upgraded [ie Improved] K15 will be the [reactor] for the new Barracuda-class SSNs."Page 190: "RES [land reactor] prototype...Key milestones...As of mid-2018: No report yet of initial criticality."
Page 197: "French naval nuclear reactors...Improved K15 integral PWR for the Barracuda-class SSNs, expected to use LEU fuel."
Page 207: "K15 integral PWR...The complete K15 vessel is about
10 m (32.8 ft.) tall and 4 m (13.1 ft.) in diameter. Le Triomphant-class SSBN hull outer diameter is
12.5 m (41 ft.)."
Page 208: "
Improved K15 integral PWR...The design is based on the K15 integral PWR [reactor]. This reactor was expected to be tested in the RES prototype facility at Cadarache.
However, significant delays have been encountered in the completion of RES,
and, as of mid-2018, initial criticality of the reactor prototype has not yet occurred."
Page 208 continues:
Objectives for the improved K15 include:-
Reduce the physical size of the [improved K15 reactor] so it can fit on a Barracuda-class SSNs, which has an outer hull diameter of 8.8 m (28.9 ft). The complete K15 vessel is about 10m (32.8 ft.) tall.
- Improve the [reactor's] natural circulation performance and quietness of operation.
- Operate with LEU fuel and deliver thermal power comparable to the K15.
- Achieve 10 years of operational activity between refueling.
- Reduced the time needed for refueling (target 3 months vs. 5 months currently).
- Improve the human-machine interfaces with the instrumentation, control and protection systems.
- Reduce life-cycle costs (construction + operation).
- Improve safety.
- Improve availability.
The first Barracuda-class SSN is expected be launched in the 2018 –2019 timeframe."
COMMENT
Note that even if the Improved K15 prototype at Cadarache goes critical in late 2018 that does not make an Improved K15 instantly ready to be placed in a Barracuda hull and then go critical. It may take years longer to propel this first Barracuda with subsequent design, building and testing delays for Australia's Future Submarine Program. Pete
