The Rosyth Shipyard in the UK is carrying out the world’s first complete dismantling of a nuclear submarine. The conning tower of the demonstration vessel HMS Swiftsure was cut open in June 2025, and the vessel is expected to be fully dismantled by the end of 2026. This nuclear-powered attack submarine, which entered service in 1972, has already had over 500 tons of conventional waste removed during the dismantling process. According to the plan, 90% of its structures and components will be recycled or reused. Babcock has secured a three-year contract worth £114 million (approximately $155 million) to prepare for the unloading of nuclear fuel from subsequent Trafalgar-class submarines. The high-quality steel recovered during the dismantling process has been confirmed for use in manufacturing components for future Royal Navy submarines. This “ship-to-ship recycling” model marks the first time a closed-loop economic chain has been established for the recycling of decommissioned nuclear submarines. From reactor pressure vessels and primary coolant piping to outboard heat exchangers, the technical challenges of decommissioned nuclear submarine recycling center on the identification, dismantling, and sorting of special alloys—welded joints involving dissimilar metals such as titanium alloys, copper-nickel alloys, and stainless steel must be clearly marked during the dismantling phase; otherwise, impurities will contaminate the melt during smelting, rendering the entire batch unusable. The Rossis facility currently employs 200 technical staff dedicated to the recycling of decommissioned nuclear submarines, and the dismantling process they have established will be directly applied to the remaining 26 decommissioned nuclear submarines of the Royal Navy.
The U.S. Navy’s EF(N) series heat exchangers are manufactured in accordance with MIL-C-15730 standards, with the Class 4 model specifically designed for submarine freshwater cooling applications. For this type of non-conventional heat exchanger, the connection between titanium tubes and copper-nickel alloy tube sheets employs a “swell-first, weld-later” process—the titanium tubes are embedded into 90/10 copper-nickel outer tube sheets via roller swelling, followed by full-length swelling of the inner tubes to ensure a seal. A technical assessment report by the International Atomic Energy Agency (IAEA) notes that if expansion is the sole method used to join titanium tubes to dissimilar tube sheets, crevice corrosion cannot be completely eliminated; sealing welds are the most effective means of preventing coolant infiltration into the joints. Copper-nickel alloy tube sheets are typically selected in 70/30 or 90/10 grades; the former offers higher strength to withstand greater flow rates, while the latter provides superior thermal conductivity for enhanced heat transfer efficiency. In non-conventional heat exchanger applications involving titanium tubes, a key advantage of copper-nickel alloy tube sheets is that a protective surface film forms naturally in seawater, preventing chloride pitting or stress corrosion cracking unlike stainless steel. Operational data from desalination plants indicate that thin-walled titanium tubes with a wall thickness of 0.5 mm, when expanded into copper-nickel alloy tube sheets, pass hydrostatic pressure tests without leakage, and their pull-out strength is positively correlated with the ratio of tube wall thickness to outer diameter. For recycling lines processing decommissioned nuclear submarines, the copper-nickel alloy tube sheets from such heat exchangers can be directly returned to the furnace for remelting after removal, while the titanium tubes from non-conventional heat exchangers are stripped and classified as titanium scrap. It is worth noting that if copper-nickel alloy tube sheet piping is exposed to sulfide-contaminated seawater for extended periods during service, the connection points with titanium may experience accelerated corrosion due to galvanic effects. However, this corrosion does not affect the value of the copper-nickel alloy itself as high-purity remelting material during the actual recycling of decommissioned nuclear submarines. Experience from multiple shipbreaking yards along the Pacific coast indicates that titanium tubes from non-standard heat exchangers also exhibit the aforementioned galvanic corrosion marks; during sorting, it is sufficient to simply cut off the connecting sections. On the spot market, intact copper-nickel alloy tube sheets can be priced within the range of Goodfellow’s 70/30 copper-nickel tubing—laboratory-grade tubing fetches approximately several dozen dollars per thousand millimeters, while industrial-grade material is settled at a discount based on the London Metal Exchange’s copper-nickel spot index.
The connection between a submarine propeller hub and a steel tail shaft is, in essence, a head-to-head clash of materials science. If a titanium alloy propeller hub were simply bolted onto an ultra-high-strength steel shaft, seawater would act as an electrolyte, and the galvanic potential difference between the two metals would be sufficient to corrode pitting into the contact surface within a matter of months. During the decommissioning and dismantling of decommissioned nuclear submarines, the British Navy discovered that early Trafalgar-class submarines employed an explosive bonding process to pre-bond titanium and steel into a transition joint, followed by welding with the same metal at both ends of the joint. When shipbreakers cut the propulsion shaft system, this transition section is a critical sorting point—the steel side goes into the ferrous metal stream, the titanium side into the non-ferrous metal batch, and the explosive-bonded layer in the middle is marked separately due to residual trace amounts of precious metal brazing material. For dissimilar metal connections in the rudder drive mechanism, the approach is more straightforward: a layer of silver-based dry film lubricant is applied between the titanium alloy connecting rod and the stainless steel pin, preventing seizing while also reducing galvanic corrosion. When applied to the recycling process for decommissioned nuclear submarines, this information means that whenever threaded fasteners of a different material are encountered during rudder disassembly, the drawings must first be checked to confirm the presence of any coatings; otherwise, mixing materials in the furnace will introduce silver contamination. Currently, the practice at the Rosis dismantling line is to scan the joints with a handheld X-ray fluorescence analyzer before cutting the piping, yielding composition results in two seconds.
The primary circuit is the lifeline of a nuclear submarine and the area where material compatibility issues are most concentrated. The reactor pressure vessel and main piping are made of austenitic stainless steel or nickel-based alloys, but some auxiliary piping connected to them uses titanium alloys to meet weight reduction and non-magnetic requirements. These two materials cannot be directly fusion-welded; welding them causes immediate cracking. The early approach involved using palladium- or gold-based brazing alloys to create a capillary-penetration joint at temperatures below the base material’s melting point, forming a ductile buffer layer while simultaneously blocking the migration path of hydrogen isotopes. When the British “Fast” decommissioning team cut the primary circuit boundary piping, they prioritized cutting straight pipe sections far from the joints, leaving the sections containing the joints intact to be sent to the post-processing workshop for disassembly. The goal was to recover those few grams of palladium or gold separately. When recycling decommissioned nuclear submarines, speed is not a priority for these components—a single misplaced cut would result in the precious metal brazing material becoming mixed with the stainless steel scrap, making it impossible to separate them later. Primary circuit joints also utilize platinum-coated titanium anodes as electrochemical protection components. The platinum layer is only micrometers thick; if melted down directly, the platinum would be diluted in the molten titanium to the point of having no recoverable value. Therefore, decommissioned nuclear submarine recycling standards require that, when dismantling the cathodic protection system, the platinum-coated titanium anodes be removed as a whole first, followed by chemical stripping to recover the platinum coating. The Babcock team revealed that while the total surface area of these coated auxiliary anodes on a single submarine is not large, with the international spot price of platinum exceeding $2201 per ounce (Data Source: 2026/05/11, DONGSHENG precious metal price page), the cumulative value represents a recovery effort that warrants serious consideration.
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