Article
Please read https://www.yahoo.com/news/world/articles/navy-entire-fleet-submarines-while-131000399.html of June 7, 2026, first.
Pete Comments
The UK Royal Navy (RN) is again suffering, politicly embarrassing, defensively dangerous, nuclear attack submarine (SSN) unavailability. This means all five Astute-class SSN's (HMS Astute, Ambush, Artful, Audacious and Anson) are unavailable, awaiting maintenance and repairs. The sixth (HMS Agamemnon) commissioned September 2025, is not yet ready to deploy. Last of class, HMS Achilles, is due to be commissioned sometime in 2028-29.
Constant checking by the RN detects a fault familiar to the RN. That is weakened or frayed piping that works with each Astute's PWR2 Reactor. Hot Pressurised water/steam can stress the piping over time. Minute piping holes may cause a release of low level radioactive water. If left undetected or unrepaired this may cause the piping to burst.
While the piping contains hot water/steam this is not as hot as the fissioning U235 in the core of the reactor. However slowdowns or interruptions to the water/steam may cause an increase in temperature within the reactor which causes or triggers an automatic emergency shutdown of reactor function (called a reactor "trip" or "Scram").
So it is important that piping is intact and working efficiently. For the Astute's PWR2 reactor this is essential.
Put another way once the pipes split there can be loss of water based coolant demanding shutdown of the sub's reactor (at sea and especially in port). Any risk of release of coolant to civilian populated areas is, according to the UK Ministry of Defence (MoD), negligible, nothing to worry about. Although the dangers of this piping-to-reactor-risk has been examined and debated for many years. See this semi-paywalled 2011 Guardian article https://www.theguardian.com/world/2011/mar/10/royal-navy-nuclear-submarine-reactor-flaws . Failing that see this 2014 BBC article https://www.bbc.com/news/uk-politics-26463923 ).
This problem was earlier observed with the UK's post-collision HMS Vanguard nuclear missile submarine (SSBN).
Nuclear sub owning governments routinely assure publics how safe nuclear sub operations are. Here is the very long list of submarine mishaps, including an explosion and nuclear submarine collisions, since the year 2000.
During the Astute-classes availability failure the RN must rely on USN or French Navy SSNs to perform the highest priority tasks of escorting UK Vanguard-class SSBNs in and out of the UK SSBN base. The base is HMNB Clyde, near Glasgow, Scotland.
The mainly UK designed submarines, known as SSN-AUKUS, that Australia will buy/build, later than we're paying for, around 2045, will be heavily based on the Astutes. The PWR3+ reactor powering SSN-AUKUSes will owe much to the troubled PWR2 design.
french ano
ReplyDeletein june 2020 a fire broke out on the SSN Perle in Toulon wlhile in decennial, scheduled maintenance.Ths cost of the repair amounted to 120 million euros (50 paid by the insurancce) and lasted about 18 months (In the Fr LEU reactor system the reactor and the steam generator above in the pressure vessel is removed by a robot in a few weeks every 10 years and the empty vessel is inspected (visual and US).There was no fuel or reactor during the fire..
The Perle will be decommissioned this summer in Cherbourg and dismantling will start
The PWR 2 "leaks" point to the limit of the "sealed for life" concept ..An organized ,engineered, robotized as in civilian PWR,system for quick fuel exchange ,steam generator exchange, inspection , is an advantage built on the apparent shortcoming of LEU (replace fuel every 10 y)
Hi Anonymous from France at 6/09/2026 12:33 AM
ReplyDeleteYes such is the constant problem of pipes to reactor risks and even leaks, in UK SSSNs and SSBNs, it would be useful if the the UK developed robotic methods of detecting and repairing pipe problems. The UK could learn from France.
In the case of French submarine Perle there were actually 2 maintenance caused fires:
one in 2020 ( https://en.wikipedia.org/wiki/French_submarine_Perle_(S606)#2020_fire ) with no reported injuries
and the other in 2022 ( https://en.wikipedia.org/wiki/French_submarine_Perle_(S606)#2022_fire_and_return_to_operational_service ).
Also see Submarine Matters' details recorded shortly after the 2020 and 2022 Perle fires https://gentleseas.blogspot.com/search?q=perle
Regards Pete
Hi Anonymous from France at 6/09/2026 12:33 AM - a further comment:
ReplyDeleteThis time on your point:
"The PWR 2 "leaks" point to the limit of the "sealed for life" concept ..An organized ,engineered, robotized as in civilian PWR, system for quick fuel exchange ,steam generator exchange, inspection , is an advantage built on the apparent shortcoming of LEU (replace fuel every 10 y)"
Yes, robotic solutions, anticipating even low chance of leak risks, is a good idea.
Australia's planned east coast nuclear submarine base options are all ports next to middle to large cities. That is Wollongong/Port Kembla, maybe Newcastle, outside chance Brisbane.
As the UK only has the industrial capacity to modify (not totally reinvent) potentially unsafe high pressure hot water/steam piping of the type currently serving PWR2s we can expect similar piping for Australian SSN-AUKUS PWR3 reactors.
This may put the residents hosting future bases at Wollongong/Port Kembla, OR maybe Newcastle OR maybe Brisbane at risk.
A base at a lower population port at Twofold Bay, very far from cities may be preferable. See https://gentleseas.blogspot.com/2025/03/australian-sub-depot-ship-twofold-bay.html
This is the same principle as placing nuclear waste dumps in low population density, desert locations. Like Western Australia's in operation, semi-secret Sandy Ridge nuclear waste dump, discovered by Submarine Matters here https://gentleseas.blogspot.com/2024/11/pop-up-sandy-ridge-nuclear-waste-dump.html
Pete
Hi Pete,
ReplyDeleteWith every nation, sustainment of military assets is as important as maintaining a product life-cycle, and this is a fact that is sadly ignored by almost every politician on this planet.
Spending AUD10 billion on LOTE for Collins to stretch their life by 15 years in a case in point, so to is a proper maintanence and training cycle for naval ships - both the USN and RN have boasted about record deployments - 326 days for USS Gerald R. Ford and 205 days for HMS Vanguard - but they have ignored the health and mental issues of the crew (the Ford's toilet issues come down to a sewage system NOT designed to handle waste of 4,000 humans for 326 days, plus crew flushing rope and clothing as they wanted to get off the boat).
Vanguard had to stay out as it was the only operational boomer the RN had..
https://ukdefencejournal.org.uk/why-are-all-of-britains-attack-submarines-in-port/
Hi Shawn
ReplyDeleteIt seemed odd indeed that the UK politicians and top brass were almost cheering that Vanguard had done 205 days - some strange test of Positive UK RN "efficiency" implying manliness when its a Negative potentially dangerous organisational failure.
The Australian LOTE has last been estimated at A$11 Billion - but we know Osborne and Aussie efficiency generally suggests double the time period and triple the price. A project taking until 2042 and costing A$30 Billion.
Yes the Swedes, with their recent Gotland-class Mid Life Upgrade (MLU) could do it (all up) for A$6 Billion in Sweden by 2035 but its not about the money or Australia or rendering each Collins unavailable for 3 years (if not longer.
Highlight the large AI string down below - then right-click it - then scroll down and click on "Go to..."
https://www.google.com/search?q=gotland+submarine+mid+life+upgrades&sca_esv=99fd30d500723c13&sxsrf=ANbL-n5fzt9SV8arJDtWZkCUMJiSdqWx6w%3A1781264422758&source=hp&ei=JvArauvkKorBrfcP-frqqA4&iflsig=AFdpzrgAAAAAaiv-Nm03LtwwUpP7RdJwwy7exxwIFYr7&ved=0ahUKEwjrj6qJz4GVAxWKYOsIHXm9GuUQ4dUDCDs&uact=5&oq=gotland+submarine+mid+life+upgrades&gs_lp=Egdnd3Mtd2l6IiNnb3RsYW5kIHN1Ym1hcmluZSBtaWQgbGlmZSB1cGdyYWRlczIFEAAY7wUyCBAAGIAEGKIEMggQABiABBiiBDIFEAAY7wUyCBAAGIAEGKIESI-ZAlDKDVjHkwJwAXgAkAEAmAHbAaABpjWqAQYwLjI5Lje4AQPIAQD4AQGYAiWgArs2qAIKwgIHECMY6gIYJ8ICDRAuGMcBGK8BGOoCGCfCAgcQLhjqAhgnwgIKECMYgAQYigUYJ8ICCxAAGIAEGIoFGJECwgILEAAYgAQYsQMYgwHCAhEQLhiABBixAxiDARjHARjRA8ICERAuGIAEGIoFGJECGMcBGK8BwgIREAAYgAQYigUYkQIYsQMYgwHCAgUQABiABMICCBAuGIAEGLEDwgIFEC4YgATCAg4QLhiDARixAxiABBiKBcICDBAAGIAEGAoYCxixA8ICDRAuGIAEGMcBGNEDGArCAgcQABiABBgKwgILEC4YgAQYxwEY0QPCAgsQLhiABBjHARivAcICBhAAGBYYHsICCxAAGIAEGIoFGIYDwgIFECEYoAHCAgUQIRifBcICBxAhGAoYoAHCAgQQIRgVwgIEECEYCpgDBvEFOOWEhEcV1GaSBwcxLjI0LjEyoAeVtgGyBwcwLjI0LjEyuAe0NsIHBzguMTkuMTDIB1CACAE&sclient=gws-wiz
Its about Federal money for South and Western? Australia, for management, Australian supply chain firms, union politics and especially for buying votes in Federal Elections.
"until 2042 and costing A$30 Billion. " will also distract the public from much larger amounts wasted on non, or very late, delivery of Block II and III Virginias for the RAN for AUKUS in the 2040s and only variants of Astutes with slightly improved PRW2s relabelled "SSN-AUKUSes"
Cheers Pete