NAO publishes investigation into defueling and dismantling UK nuclear submarines

By agency reporter
April 4, 2019

Despite a government commitment from over 20 years ago to dispose of its radioactive waste as soon as reasonably practicable, the Ministry of Defence (the Department) has not yet disposed of any of the 20 submarines it has decommissioned since 1980.

The National Audit Office (NAO) finds the Department now stores twice as many submarines as it operates, with seven having been in storage for longer than they were in service. It first aimed to have a disposal process that would operate  by 2011 but now estimates to roll-out its dismantling approach by 2026. The Department has spent an estimated £0.5 billion since 1980 on storing and maintaining its retired submarines.

To dispose of submarines, the Department must undertake a complex series of inter-related tasks to remove the fuel, take out radioactive parts (dismantling) and then recycle the boat. At each stage the Department needs the necessary space, infrastructure, skills and regulatory approvals. Its approach involves several inter-dependent projects including defueling-related projects at Devonport and submarine dismantling covering Rosyth and Devonport.

Since 2004, the Department has not defueled any submarines and does not have a fully funded plan to re-start the work, says the NAO. Nine of the Department’s 20 out-of-service submarines contain nuclear fuel which needs to be removed using nuclear-regulator approved dock infrastructure and facilities. In 2004, the Office for Nuclear Regulation found facilities in Devonport did not meet the latest regulatory standards and the Department stopped defueling submarines. Following delays its latest planning estimate, subject to ongoing scrutiny and departmental approval, is to start defueling from 2023, an 11-year delay. Overall, the project budget has increased by 57 per cent (£100 million), from £175 million to £275 million in June 2018.  

Delays to defueling have wider consequences for costs, risk and dock space. The Department pays an estimated £12 million a year to maintain and store the nine fuelled submarines currently held in Devonport. Maintaining fuelled submarines presents additional technical uncertainties and affects dock availability, particularly in Devonport which is expected to run out of space for retired submarines in the mid-2020s. Space constraints have meant the Department does not have a dock to prepare its most recently retired submarine for long-term storage and is developing other ways of doing this. Until submarines are placed in storage, they need to be kept partially crewed, potentially affecting the Department’s ability to redeploy its personnel.   

The Department has started to dismantle two submarines, Swiftsure and Resolution, but does not yet have a fully funded process to remove, transport and store all types of radioactive parts.  The dismantling project has been delayed by 15 years, with the whole-life cost increasing by £0.8 billion (50 per cent). The Department’s latest planning estimate, which is yet to be approved, is to roll-out its approach by 2026. 

Delays create cost, capacity and reputational risks beyond the project. Alongside annual maintenance, the Department has committed to removing submarines from the water every 15 years for more detailed maintenance in dock, recognising a £2.2 billion liability for this within the overall £7.5 billion submarine disposal related liability included in its 2017-18 accounts. If this work took 24 months, rather than the assumed 18 months, and there was a two-year delay to dismantling, it could increase its liabilities by an estimated £0.9 billion.

Delays have provided the Department with an opportunity to re-assess its dismantling approach. To meet its commitments to Parliament, the Department has set itself a series of milestones. In particular, to dismantle its first submarine by 2023 for which it needs to have decided its approach to removing and transporting intermediate-level waste by December 2019. It will then design the process, demonstrate it can work, contract for the transport and ensure it has the budget in place.

In the last two years, the Department has revised its governance arrangements which it is continuing to develop. From April 2019, the Defence Nuclear Organisation will have responsibility for all disposal-related projects, including those previously within the Royal Navy’s remit. It recognises as high risk its failure to manage its nuclear liabilities coherently and has assessed itself as not yet having fully developed plans in place to meet 67 per cent of its submarine defueling and dismantling objectives.  

Looking further ahead, the Department does not have a fully-developed plan to dispose of Vanguard and Astute submarines, which are currently in service, or its future Dreadnought-class submarines, which have different types of nuclear reactor. For the Vanguard and Astute-class it has identified suitable dock space which, if used, will need to be maintained. Within the civil nuclear sector, organisations are required to consider nuclear waste disposal during the design stage of power stations and nuclear infrastructure. The Department does not have a similar obligation.

* Read Investigation into submarine defueling and dismantling here

* National Audit Office


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