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News Extra: Delays in UK nuclear submarine dismantling programme raise leak threat

14 November 2014

In June another of the Royal Navy’s nuclear attack submarines, HMS Tireless, was taken out of service and laid up in Devonport naval dockyard, Plymouth. She joined seven other nuclear submarines at the base that have yet to have their nuclear fuel removed. Four previous-generation nuclear boats that have been defueled are also at Devonport, and seven others are laid up at Rosyth in Scotland. 

Devonport Naval Dockyard - Image: MOD
Devonport Naval Dockyard - Image: MOD

The main problems are that Devonport facilities do not meet sufficiently high standards for fuel disposal, according to the Office for Nuclear Regulation (ONR), and the UK does not yet have a suitable facility for disposing of the submarines' reactors, which means that those subs that have been defueled cannot yet be dismantled.

UK Defence Minister Philip Dunne said in April 2013 that submarine dismantling would be put to the test at Rosyth in 2016. If the process works, the remainder of the UK's retired nuclear fleet will be cut up in both Plymouth and Rosyth.

There are about 25 tonnes of radioactive waste in the reactors of each decommissioned submarine and dismantling cannot take place until there is an agreement on where to take the waste material.

Five possible storage sites have now been selected, at Aldermaston and Burghfield in Berkshire, which are owned by the MoD, Sellafield in Cumbria, Chapelcross in Dumfriesshire, and Capenhurst in Cheshire. Observers familiar with the matter think Sellafield will be the most likely destination, as the bulk of the country’s intermediate and high-level nuclear waste is already stored there.

The Ministry of Defence (MoD) has said it hopes to name a site for temporary reactor storage in 2015 and begin defuelling as soon as possible, but until that has been carried out the submarines are a significant risk to the local area.

There have been a number of relatively minor radioactive liquid leaks from operational submarines in Devonport, such as in March 2009 when radioactive water escaped from HMS Turbulent while the reactor's discharge system was being flushed out.

More serious was the failure of both the primary and secondary power sources of coolant for the laid up submarines’ fuelled nuclear reactors for a period of 90 minutes in July 2012, disclosed by the Independent on Sunday in a 2013 article and based on a report from the MoD's Site Event Report Committee (SERC).

The loss of coolant could have led to a major nuclear incident at the heart of the Plymouth agglomeration – causing a possible meltdown and radioactive release.

The IoS also said there had been two previous electrical failures at Devonport, both formally investigated. They were the loss of primary and alternative shore supply to the operational submarine HMS Talent in 2009 and the loss of AC shore supply to the now-decommissioned HMS Trafalgar in 2011, the SERC report said.

MoD contractor Babcock, which operates the dockyard, launched an internal investigation after the incident which blamed the complete loss of power on a defect in the central nuclear switchboard. It said the defect had resulted in an "event with potential nuclear implications".
Among a number of "areas of concern" uncovered by the Babcock investigation was what was described as an "inability to learn from previous incidents and to implement the recommendations from previous event reports".

A subsequent review from the Base Nuclear Safety Organisation revealed the "unsuccessful connection of diesel generators" and questioned the "effectiveness of the maintenance methodology and its management", while advising Babcock to "address the shortfalls in their current maintenance regime".

Its own stress test on Devonport safety, launched after the Fukushima disaster, said that in the event of the failure of both power supplies, heat levels in reactors could be controlled by emergency portable water pumps, and added that such a failure had occurred a "number of times" previously.

In September 2013 the ONR watchdog published details of an improvement notice it had served on Devonport on 16 July for three alleged breaches of health and safety legislation, and of Section 24 of the Nuclear Installations Act – regarding operating instructions.


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