Navy to axe 'Fukushima type' nuclear reactors from submarines

Reactors sharing similar design to ones at Japanese plant to be dropped because they fail to meet safety standards

guardian.co.uk, Severin Carrell, Scotland correspondent, Wednesday 23 March 2011

Trident submarines based at Faslane, Scotland, and six Trafalgar-class
subs have reactors similar to the ones involved in Japan's nuclear
crisis. Photograph: Corbis

The Royal Navy is to drop a dangerous type of reactor used in its existing nuclear submarines because it fails to meet modern safety standards, defence ministers have disclosed.

A safer type of reactor is expected to be used in the submarines that will replace the Trident fleet, as the existing design shares very similar features to the nuclear reactors involved in the Fukushima Daiichi disaster in Japan.

Liam Fox, the defence secretary, told MPs there was a "very clear-cut" case to use the new type of reactor because it has "improved nuclear safety" and would give "a better safety outlook".

A heavily censored Ministry of Defence report disclosed earlier this month by the Guardian and Channel 4 News said the current reactors are "potentially vulnerable" to fatal accidents, which could cause "multiple fatalities" among submarine crews.

The report, written by a senior MoD nuclear safety expert, Commodore Andrew McFarlane, said the existing type compared "poorly" with those in the most modern nuclear power stations because it relied on a vulnerable type of cooling system, falling "significantly short" of modern best practice for nuclear reactors.

McFarlane warned that the naval reactors are "potentially vulnerable to a structural failure of the primary circuit". An accident could release "highly radioactive fission products", posing "a significant risk to life to those in close proximity and a public safety hazard out to 1.5km [1 mile] from the submarine".

Known as the PWR2, this type is used in the four Trident submarines based at Faslane, near Glasgow, and six Trafalgar-class ones now being taken out of service. Like the Fukushima power station north of Tokyo, the PWR2 relies entirely on back-up power supplies to provide emergency cooling in the event of an accident.

Despite the anxieties about its safety, PWR2s are also being fitted in the seven Astute-class submarines being built. These vessels will also be based at Faslane.

There have been debates within the MoD and the navy about whether the PWR2 should be used if a replacement to Trident is finally approved – or if a safer type, PWR3, should replace it. The PWR3 uses "passive" cooling, which makes it far less reliant on back-up power, and has additional methods of injecting coolant into a reactor.

The PWR3 is widely used in modern US nuclear submarines. The debate has delayed a decision on what type of reactor to install by 18 months, McFarlane's report disclosed, and has cost a further £261m.

Fox was questioned in the Commons on the reactor's safety by Angus Robertson, the Scottish National party's defence spokesman, after the disclosure of the report. Fox said: "The government's view is that that is the preferred option, because those reactors give us a better safety outlook. That is a debate on both sides of the Atlantic, but we believe that in terms of safety, the case is very clear-cut."

Robertson said: "This still raises concerns about the currently operational and incoming nuclear submarines, which don't satisfy acceptable safety standards. The UK should give up its nuclear obsession."

John Ainslie, from the Scottish Campaign for Nuclear Disarmament, who uncovered the original McFarlane report, said the new reactor would push up costs for the Trident replacement fleet by billions of pounds, since it would need designing and testing.

"There is another option: they should completely abandon their plan to squander billions on new nuclear submarines," he said.