£9.75bn nuclear sub fleet slow, rusty and leaking

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  By a Newsnet reporter  

The United Kingdom’s replacement nuclear submarine fleet, already overdue and over-budget, is suffering from serious design flaws which mean that it is unable to fulfil the purposes for which it was obstensibly designed. 

HMS Astute, the first submarine in the fleet, suffers serious problems of corrosion, is slow, and suffers from serious leaks.

The £9.75bn programme, over six times the cost of sending the Curiosity probe to Mars, has been beset by construction and design flaws.  According to an internal MoD memo leaked to the Guardian newspaper, the flaws are so bad that they will lead to “severe problems” in the fleet’s operation, and the corrosion in the subs is a “cause of major concern”.  The budget for the replacement subs has already ballooned by more than £2 bn over the initial cost estimates, and the fleet is four years overdue.

The newspaper also revealed that HMS Astute is unable to reach its planned top speed due to a mismatch between its nuclear reactor and the turbines providing motive power.  The problem means that the submarine is unable to react promptly to emergency situations and cannot sprint away from any attack – essential requirements for “hunter-killer” submarines.  

Although one of the main roles of the new submarines is to act as a protection for the UK’s new aircraft carriers, the submarines are unable maintain enough speed to keep up with the aircraft carriers.  Engineers on the project have claimed that the submarines have a “V8 engine with a Morris Minor gearbox”.

The Rolls-Royce Pressurised Water Reactor 2 (PWR2) used on HMS Astute is reportedly powering steam turbines based on those developed for the older Trafalgar class submarine.

A source told the newspaper: “The PWR2 was meant for a much bigger boat, and Astute had to be designed around it. That may have cut costs, but it has caused problems. The power from the reactor does not translate into forward movement.”

The submarine also suffers from a flawed periscope, meaning commanders are unable to view the surface in realtime, and is fitted with the wrong type of nuclear monitoring instruments.  HMS Astute has experienced corrosion on valves and pipework fittings.  HMS Ambush, which was launched for sea trials two months ago, has reported corrosion on the “internal surfaces of … pipe work running through the reactor compartment”.  

A more serious flaw was revealed during recent exercises in the North Atlantic off the east coast of the United States when a pipe supposed to take seawater from the back of the submarine to its nuclear reactor sprang a leak, flooding a compartment.  The submarine was forced to surface immediately.  An investigation discovered that a cap on the pipe was made of the wrong metal, despite construction records saying that the correct alloy had been used.

Alarmingly, this piece was supposed to have been subject to “level one quality assurance”, the highest scrutiny level.  Sources in the MoD have said that there is no way of knowing whether other pieces of vital equipment on the submarine are also substandard.

Speaking to the Guardian, an MoD source said: “The fact the cap failed is bad enough, but the most worrying thing is that there is no way of knowing whether the submarine has other pieces of equipment like this on board.

“The quality assurance tests are there to make sure this kind of thing doesn’t happen, but it did. So what else has been installed that we don’t know about? It is impossible to know. They fitted the wrong cap but it was still signed off.”

Speaking to the Guardian, John Large, a special engineer who is an expert in nuclear safety, said: “These problems are much more significant than the niggles and glitches expected to arise during working up of a new class of nuclear-powered submarine. Particularly disturbing is the apparent mismatch between the nuclear reactor plant and the steam turbine sets, putting the submarine speed below par and making her susceptible in the anti-submarine warfare theatre.”

In addition to its many design faults, HMS Astute has suffered other problems since coming into operation.  In an embarrassing incident in 2010, the submarine grounded itself off the Isle of Skye, leading to the removal and replacement of the sub’s commander.  In 2011, a senior officer was killed in when a crew member went on a shooting rampage, leading to accusations that the Royal Navy was not adequately screening submarine crews for possible psychological problems.