Guidance

Submarine Dismantling Project (SDP)

Delivering on the UK Government’s commitment to provide a safe, environmentally responsible and cost-effective solution for the dismantling and disposal of the UK’s decommissioned nuclear submarines.

From:
Ministry of Defence and Submarine Delivery Agency
Published
20 May 2021
Last updated
23 August 2024 — See all updates

The Ministry of Defence’s (MOD) SDP is delivered by the Submarine Delivery Agency (SDA) on behalf of the Defence Nuclear Enterprise (DNE).

The SDP was approved in 2013 with the objective of delivering a dismantling and disposal solution for 27 decommissioned nuclear submarines.

The project will incorporate lessons learnt from dismantling and disposing of the submarine Swiftsure to improve the process for all future submarines, including those not contained within the current scope of the SDP.  

While awaiting dismantling, the 22 submarines that have already left service are stored safely and securely: seven at Rosyth Dockyard in Fife, Scotland and 15 at Devonport Royal Dockyard, Plymouth. The submarines undergo regular essential maintenance to comply with the required safety, environmental and security standards.

How submarines are dismantled

UK submarines are powered by nuclear reactors. During a submarine’s life cycle, normal nuclear operations cause radioactive substances to be deposited in the pipework and components within the reactor compartment. This can cause some parts of the nuclear reactor itself to become radioactive.  

This radioactivity is in addition to the nuclear fuel which powers the reactor. The radioactive parts of the submarine remain radioactive, even after the fuel is removed. This means that safe management is required even after the submarine leaves service and the fuel has been removed.  

Decommissioned submarines that are being stored and are waiting to be defueled and dismantled pose no safety risk to workers or members of the public. They undergo a regular programme of survey and maintenance, including in-water inspections to preserve and test the systems and ensure the integrity of their hull.  

The MOD adopts a three-stage approach to dismantling which meets both safety and environmental regulatory standards and is in line with government policy for managing radioactive waste safely and in a timely manner. This approach was supported by the results of two public consultations in 2012 and 2015.

The three-stage dismantling method allows the less radioactive parts of a submarine’s nuclear reactor, containing only Low Level Radioactive Waste (LLW) to be removed first.  

This is followed by the second stage which is the removal of the Reactor Pressure Vessel at the heart of the reactor. This is classed as Intermediate Level Radioactive Waste, and is the component that remains radioactive for the longest period.  

The process also involves ensuring the submarine has been completely cleared of all radioactivity and radioactive material associated with its nuclear operational life before it is released for the final stage, which is undergoing recycling.

A circular economy is important and the SDP looks to re-use components that can be safely and appropriately re-purposed in our operational fleet. The remainder of the metals and other non-hazardous waste materials will be recycled wherever possible 

Our experience has identified that once all the radioactive waste has been removed, around 90% of the remaining materials on the submarines, mainly steel and other metals, can either be re-purposed or undergo conventional recycling. This forms the third and final stage of the dismantling process.

The process of dismantling a submarine is highly complex. The UK’s chosen approach to dismantle submarines is one that safely and securely manages and disposes of as much of the radioactive waste as practicably possible.

Latest news

Acting as a demonstrator project for dismantling, Swiftsure was docked down in Rosyth on 27 July 2023 to undergo final dismantling and recycling.  

Work is ongoing to identify the remaining classified items as well as analysis to determine areas of the boat that can be confirmed as free of all radioactive material.   This will support removal of the remaining security-implicated items and non-radioactive materials.

We’re continuing the process of removing the stage 1 LLW which is on schedule for completion. 

The bulk of accessible LLW has been safely removed from the following decommissioned submarines:  

  • Swiftsure  

  • Resolution 

  • Revenge 

  • Repulse  

With each submarine that is processed, more waste has been managed to final disposal, at a faster rate and at lower cost as techniques have been refined and optimised. For example, on Resolution, 50% greater tonnage of waste was removed in three quarters of the time that Swiftsure had taken. This work has to date been successfully completed safely, on time, within budget and minimising any environmental impact. 

This demonstrator project serves as a proof of concept and a benchmark against which market testing of future dismantling proposals can be assessed to improve future submarine dismantling.

Scrutiny reports and studies

The NAO and PAC reports both recognised the progress made, however, significant challenges remain. All the agreed recommendations from the PAC’s report were implemented by 31 March 2020.

Guidance

Consultations

News

Updates to this page

Published 20 May 2021
Last updated 23 August 2024 + show all updates

  1. Page updated with most recent information about the Submarine Dismantling Project.

  2. Added a 'Related documents' section and updated latest updates.

  3. First published.

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