A Royal Navy Nuclear Submarine Is Being Scrapped For The First Time

Yahoo

06-06-2025

The former U.K. Royal Navy nuclear-powered attack submarine HMS Swiftsure has begun to be cut up as part of its scrapping process. Remarkably, this is the first British nuclear-powered submarine of any kind to be fully dismantled and decommissioned. This means that all the rest of the Royal Navy's out-of-commission nuclear-powered subs are currently sitting in docks awaiting disposal, a process that is only now starting to happen, after years of stasis.
Babcock International Group, a British aerospace, defense, and nuclear engineering services company, recently announced that the first major cut had been made on the exterior of Swiftsure. This involved the removal of the submarine's fin (or sail), after which it was lowered to the bottom of the dry dock, a process seen in the photo at the top of this story.
HMS Swiftsure was the lead ship of a class of nuclear fleet submarines built for the Royal Navy. Entering service in 1973, the submarine served until 1992. A highly notable episode in its service came in 1977, when Swiftsure penetrated undetected through layered escort screens of destroyers and frigates and approached the Soviet Navy aircraft carrier Kiev. The submarine recorded extremely valuable acoustic signatures and took detailed underwater periscope pictures of the Soviet carrier's hull and propellers, something you can read about in more detail here.
Swiftsure is being disposed of at Rosyth in Scotland, under the Submarine Dismantling Project (SDP). The submarine is serving as a demonstrator for the broader SDP, which will eventually dispose of the Royal Navy's other out-of-commission nuclear subs, which include both attack submarine (SSN) and ballistic missile submarine (SSBN) classes.
The work on Swiftsure is being carried out by Babcock in collaboration with the Ministry of Defense's Defense Nuclear Enterprise, contractor KDC Veolia Decommissioning Services UK Ltd, and Rolls-Royce. Up to 90 percent of Swiftsure (by total weight) is being recycled, with at least some of the high-grade steel being repurposed into components for future Royal Navy submarines.
'The project showcases our commitment to sustainable disposal practices,' explained Lorraine Russell, Senior Responsible Owner for the Submarine Disposals Program. 'By recycling materials wherever possible, we're ensuring these vessels that served the nation so well continue to provide value even after decommissioning.'
The plan calls for Swiftsure to be fully dismantled by the end of 2026, making it the first U.K. nuclear-powered submarine to be fully disposed of.
After the process has been proven out, Babcock will then lead work on the long-term dismantling of the backlog of other nuclear-powered subs, which are laid up in Rosyth and in Devonport, in southwest England.
According to Navy Lookout, a website providing independent Royal Navy news and analysis, there are currently 16 decommissioned nuclear-powered subs in Devonport and seven more in Rosyth (including Swiftsure). The other boats in Rosyth include HMS Dreadnought, which was the U.K.'s first nuclear-powered submarine, commissioned into service in 1963 and finally withdrawn in 1980. This means the boat has been in storage longer than it was in service.
At Devonport, notably, the naval base has a regular capacity for a maximum of 14 submarines. This means that special permission had to be granted to add another two subs (HMS Talent and Triumph, which arrived in 2023 and 2024). This provides further evidence of the urgency in starting the long-term disposal of these boats.
Of the boats in Devonport, 12 still have their nuclear fuel on board. The submarines are stored afloat in a non-tidal basin. Every 15 years, each boat goes into dry dock for an inspection and preservation work, where necessary.
At Rosyth, there is even less available space, especially bearing in mind the need for the base to accommodate the Queen Elizabeth class aircraft carriers when they go into dry dock.
That the United Kingdom has such a big backlog of nuclear-powered subs awaiting disposal reflects the fact that so many of these boats were withdrawn from service relatively rapidly with the end of the Cold War. During these times of tension, the priority was to build up underwater capabilities, with less thought given to what would be done with the nuclear-powered submarines once they were no longer needed. At one point, it was even suggested that the boats should be filled with ballast and sunk in deep water, but such at-sea disposal of nuclear material was banned in 1983.
Not only does the long-term storage of nuclear-powered submarines present very serious safety and security challenges, but keeping storing and maintaining the boats is also a considerable economic investment.
This is in stark contrast to the United States. The U.S. Navy has always had a bigger fleet of nuclear-powered submarines than the Royal Navy and its construction program is coupled with a decommissioning effort to deal with the boats once they are removed from service. The U.S. Department of Defense explains the decommissioning process — specifically at the Puget Sound Naval Shipyard & Intermediate Maintenance Facility in Bremerton, Washington — as follows:
Currently, the shipyard receives a steady flow of decommissioned Los Angeles class attack submarines that are brought in for the recycling process, which can take up to two years to complete.
Dismantling starts along the pier, where the subs remain afloat. Ladders used by sailors are removed, stairs are added to give workers easier access, and holes are punched into the sub's hull so cranes can be lowered to pull out scrap metal. The crews bring in their own electrical power and ventilation piping because the vessels are no longer functional.
The forward and aft ends of each submarine are then separated from the already defueled reactor compartment, which is then closed at each end with massive steel encasements.
PSNS & IMF is the only naval shipyard that can make robust steel encasements large enough and with the safety requirements needed to hold the empty reactor cores. The giant cases are pieced together by expert welders using submerged-arc welding, technology not used anywhere else in the Navy.
Part of the recycling team's work includes filling large bins with items such as insulation, circuit boards, electrical components, cabling, and other debris that is sent to different waste streams.
The contents of the bins are sent to contractors who will either melt down the scraps, reuse them, sell them, or send them out for environmentally safe disposal.
As parts are removed, the subs slowly rise out of the water. Visitors on the pier can see water lines on the subs from where they initially sat when they were at their operational weight.
Once in dry dock, it takes another 10 months to break down a sub to where all that's left is the empty reactor compartment. The dry dock is where that heavy recycling process takes place. Parts of the ship that are too big to remove along the pier, such as the diesel generator, are removed during this phase. Large chunks of the submarine's main structure are also ripped apart and deposited onto barges at the pier for disposal as scrap metal.
The shipyard itself also reuses some of the material.
The defueled nuclear reactor compartment is all that is left. They are placed in robust shipping packages consistent with federal and state regulations and shipped to the Department of Energy's Hanford Site in Hanford, Washington. The packages make the 700-mile journey by barge from the shipyard in Bremerton down the Washington coast and up the Columbia River before being transported on a multi-wheeled transporter to the site for safe, permanent disposal.
As of March 2025, more than 140 reactor compartment disposal packages had been transported by PSNS & IMF to the Hanford Site since 1986, reflecting the huge scale of the decommissioning effort.
It's only more recently that the United Kingdom started a similar kind of disposal project for its unwanted nuclear subs.
While Swiftsure will be the first Royal Navy submarine to be fully dismantled and decommissioned, Babcock is now also under contract to prepare for the nuclear defueling of four Trafalgar class SSNs. Nuclear defueling has been done before in the United Kingdom — all seven of the boats at Rosyth have had their fuel removed, and of the 16 boats at Devonport, four are also without fuel.
However, the work on the four Trafalgar class SSNs will be the first nuclear defueling of a decommissioned Royal Navy submarine in over 20 years.
According to Navy Lookout, until 2003, nuclear subs had their fuel removed soon after decommissioning, but this process was abandoned after it was determined that the facilities for doing this work were no longer safe enough. As an interim measure, these submarines had their primary circuit chemically treated to ensure it remains inert and were fitted with additional radiation-monitoring equipment.
'This meant fully fueled boats have been stored afloat for the last two decades while a solution was developed at a glacial pace,' Navy Lookout reported yesterday. 'The submarines that have not had fuel removed have their reactor primary circuit chemically treated to guarantee it remains inert, and additional radiation monitoring equipment is fitted.'
To make the defueling process safer, the previous cranes used to remove the fuel have been replaced with a so-called Reactor Access House. Moving on rails, this is an enclosure that is positioned over the submarine in a dry dock, after which the reactor pressure vessel (RPV) is hoisted into it. The largest and most radioactive element of the submarine, the RPV is then transported to the Sellafield nuclear site for above-ground storage. Longer-term, it's expected that the RPVs will be buried underground, but this plan has yet to be finalized.
Here again, there are differences with the U.S. approach, as Alex Luck, an analyst who closely follows submarine developments, told TWZ:
'[Decommissioned U.S. Navy submarines] get defuelled, and the remaining material goes to Idaho for processing and then storage. The reactors and all associated elements are cut up and put into special waste storage sites. Unlike the United Kingdom, the United States simply disposes of a lot of material by burying it. The United Kingdom, on the other hand, is reprocessing and recycling as much as possible due to their far more limited capacity/tighter regulations for 'buried,' i.e., long-term stored waste.'
Regardless, once the RPVs are removed, the submarines can start to be fully broken down, as is now happening with Swiftsure at Rosyth.
While there was already some urgency to develop a plan to finally dispose of decommissioned nuclear-powered submarines, the problem is only set to grow in the years to come.
The four Vanguard class SSBNs that entered service in the 1990s and currently comprise the United Kingdom's permanent at-sea deterrent are scheduled to be taken out of service between 2031 and 2040. These will be replaced by a similar number of new Dreadnought class SSBNs. The four Dreadnought boats represent one of the most important U.K. defense programs in many years, and you can read more about their design here.
Beyond that, starting in the late 2030s, the United Kingdom will have to dispose of seven Astute class SSNs. These will be replaced by an increased fleet of up to 12 SSNs, to be developed under the SSN-AUKUS in collaboration with Australia and the United States, in a plan that was outlined in the Strategic Defense Review earlier this week.
Despite these plans for expansion, the Royal Navy's submarine fleet will remain a shadow of its numerical strength back in its Cold War heyday. For many years, the growing backlog of retired nuclear-powered submarines stood testament to that period of naval power. Now, with the milestone cutting of the exterior of Swiftsure, this increasingly problematic and costly legacy is starting to be dealt with.
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