No UK Astutes Available Again! Safety Fears Demand Lengthy Repairs

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. 

The main detected foreseen, only temporarily rectified, fault, needing constant checking, detection and extra maintenance, has been extra wear of pipes working to each Astute SSN's PWR2 Reactor. 

Once the pipes split there can be loss of 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). 

Above is the US Los Angeles-class nuclear submarine, USS San Francisco, in drydock following its collision with the seafloor northeast of Australia in 2005. 98 (most) crewmen were injured, one died. Her nuclear reactor was not damaged.

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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.