The British experience with nuclear submarines reveals a litany of public health risks as well as delays and cost blowouts, and it can confidently be predicted that problems will beset the AUKUS submarine programme ‒ the joint development of nuclear-powered submarines by the UK, the US and Australia.

My new report prepared for Friends of the Earth Australia demonstrates that the development of a nuclear-powered, conventionally-armed nuclear submarine (SSN) fleet entails multiple public health risks and would inevitably suffer from delays and cost-blowouts.

Operational risks of SSN deployment include radiological pollution of marine and coastal environments and wildlife; risks of radioactivity doses to coastal populations; and the serious risk of dangerous collisions between civilian vessels and SSNs, especially in the approaches to busy naval and civilian sea ways and fishing grounds.

Inconsistent

Ominously, the problems seem to be worsening. In May 2025, it was revealed that the number of ‘incidents’ at the Faslane naval base has been on the rise in recent years. 

The UK Ministry of Defence acknowledged that 12 incidents since 2023 had “actual or high potential for radioactive release to the environment” ‒ but refused to say what actually happened in any of the incidents, or exactly when they occurred. 

Navy Lookout reported on a major fire in October 2024 at the BAE system’s yard where nuclear submarines are built. After initial claims of no damage or delay to construction of Astute class attack subs, damage was later confirmed and delays are certain. 

Meanwhile, radioactive air emissions have been increasing year-on-year at Coulport, a nuclear submarine bases in Scotland. Emissions of radioactive tritiated water vapour doubled between 2018 and 2023.

Case studies of the first generation of British SSNs, fitted with PWR-1 reactors, reveal an inconsistent performance history of reactor cores. 

Malfunctions

All had to undergo extensive planned maintenance periods consisting of updating military equipment such as sonar and repair, refuelling and back refit of new reactor cores. A surprising number of boats required “unplanned maintenance”.

PWR-1 reactors were characterised by a marked tendency to develop “serious cracking in the primary cooling circuits” of the reactors leading to leaks of cooling water. In some cases, these problems were recurrent despite repair and were the cause of premature retirement of some boats.

Vanguard class SSNs fitted with PWR-2 reactors had to undergo extensive planned maintenance periods consisting of updating of military equipment and repair, refuelling and expensive back refit of new reactor cores. 

AUKUS SSNs will be the first UK designed and built nuclear powered submarines to be run without the benefit of the Naval Reactor Test Establishment input. 

'Unplanned' maintenance outages disrupted the programme of 'planned' maintenance and increased the wear-and-tear pressure on boats waiting for their planned maintenance.

The seven-year long maintenance outage of the ballistic missile submarine HMS Vanguard from 2015 to 2022 occurred in the wake of a series of reports of observed reactor malfunctions from the Naval Reactor Test Establishment (NRTE). 

At-sea

In 2009 the NRTE reported that such malfunctions posed a risk of “potential failure of the reactor primary coolant circuit”, the leaking of “highly radioactive fission products” and “significant risk to life in close proximity and a public safety hazard out to 1.5 km from the submarine".

In 2011, the NRTE discovered unexpected increases in radioactivity concentrations in the reactor cooling water attributed to microscopic cracking defects in the cladding of the nuclear fuel elements.

In 2015, in the aftermath of the NRTE reports of reactor and nuclear fuel malfunction, the UK Government and the Ministry of Defence (MoD) decided to close down the NRTE and to abandon empirical “lead” research on naval reactors in favour of computer modelling analysis of the performance of all new reactors and cores.

This also applies to AUKUS SSNs, which will be the first UK designed and built nuclear powered submarines to be run without the benefit of the NRTE input. 

All previous UK nuclear submarine reactors and core types have been built and put into operation at the NRTE at least two years before their deployment in nuclear submarines under operational conditions, thus enabling potential flaws in reactor, core and fuel performance to be identified in advance of at-sea operation and also informing core and fuel designers working towards the development of improved reactors, cores and fuels.

Deradiation

In November 2009, the UK House of Commons Defence Select Committee found that delays due to technical and programme issues meant that the Astute class SSN programme was 57 months late and 53 percent over-budget.

By March 2021, Astute SSNs were delivered between three to five years behind the original schedule. This necessitated the extension in service of HMS Trenchant, Talent and Triumph with the attendant costs of keeping aging boats running.

There are now growing indications from sources close to the government and MoD that the AUKUS successor to the Astute class may be delayed due to financial and technical issues. “It’s early days … but the first boat is unlikely to arrive before the mid-2040s,” Navy Lookout reported in 2023.

The UK experience is that the decommissioning, defueling, deradiation and scrapping of nuclear submarines is fraught with technical problems and delays. It is also clear that these issues give rise to ever increasing costs.

In 2019 the National Audit Office (NAO) published its report of an investigation, by the Public Accounts Committee of the UK House of Commons, into submarine defueling and dismantling. The investigation took place between 2017 and 2019. 

Repository

The NAO report noted that since 1980, the Ministry of Defence (MoD) had decommissioned 20 submarines from service and replaced them with updated boats and that the MoD had committed to handling the arising nuclear liabilities responsibly and disposing of submarines “as soon as reasonably practicable”.

The NAO reported that despite the 20-year-old MoD commitment to dispose of the 20 submarines it had decommissioned since 1980, none had been completely dismantled by 2019 and that as a result the MoD now stored twice as many nuclear submarines as it operated, with seven of them having been in storage for longer than they were in service. 

At the time of the NAO report in 2019, nine of the 20 decommissioned boats still contained irradiated (spent) nuclear fuel.

The long-term management, storage and disposal of radioactive waste streams from nuclear submarines remains unsolved in the UK after many decades. 

And radioactive waste management remains unsolved in Australia, which does not even have a national repository for low-level waste let alone a disposal option for long-lived intermediate-level waste and high-level waste.

Protocols

Between 1982 and 2015, UK civilian sources collated a dossier of information on 170 “interactions” between civilian vessels and nuclear submarines including net “snaggings”, collisions, near misses and at least 30 suspicious unexplained sinkings in UK waters. These incidents have led to loss of life, total loss of vessels and loss of fishing gear. 

In the UK it is evident that, despite not firing a shot in anger, UK nuclear submarines have been responsible for the death of a number of UK citizens as a result of such interactions. Wider research has uncovered a number of other incidents involving nuclear submarines across the world’s oceans.

A summary review of interactions between nuclear submarines and civilian vessels illustrates that submarine patrol routes, exercise and training areas, followed by maritime choke points and port approaches, present the greatest risks to the safety and operation of civilian vessels and their crew, ranging from small inshore commercial fishing boats up to super tankers.

Despite the best attempts of both civilian and Defence authorities, the secrecy surrounding nuclear submarine operations makes risk avoidance that much more complex, with notification of nuclear submarine movements not publicised and the details of patrol and training strategies not divulged to judicial or government agency inquiries.

On a number of occasions civilian stakeholder groups (fishers etc.), local authorities and citizens campaigns have attempted to initiate improved protocols for submarine activity by interacting with the International Maritime Authority (IMA). 

Flaws

However, the IMA does not have the power to mandate a set of standard procedures to prevent damaging interactions between civilian vessels and nuclear submarines.

A detailed review of the behaviour and fate of radioactivity discharged from UK nuclear submarine bases during repair, maintenance and refit operations on SSNs and ballistic missile submarines has been undertaken.

It reveals discrepancies between the traditional official monitoring, analytical and dosimetry programmes deployed by UK nuclear regulatory agencies and the conclusions of recent scientific reviews and studies.

Those studies identify flaws in the official programmes leading to inadequate understanding of the dose pathways by which coastal populations may be exposed to doses of radioactivity from nuclear submarine bases.

Reactors

A number of case studies are reviewed, including a study which demonstrated that a coastal population living about 20 miles downstream of a UK nuclear submarine base received a higher dietary dose of man-made radioactivity from locally grown terrestrial food stuffs than a population living next to a four-reactor civilian nuclear power station.

An unchallenged independent interpretation of this study showed that the radionuclide implicated in the higher dose was Cobalt-60, a radionuclide characteristic of naval PWR discharges and indicated the likelihood that the Cobalt-60 and other nuclear submarine derived radioactivity had transferred from the sea to the land.

Information from a number of countries indicates that Belgium, Canada, the Czech Republic, Finland, France, Germany, Luxembourg, Sweden and Switzerland have pre-distributed iodine in the vicinity of nuclear reactors – the area covered has ranged from 4 km to 20 km radius of the nuclear reactors. 

In the UK, the decision to pre-distribute rests with the local authority and it has only occurred in a limited number of cases and a three kilometre radius has tended to be used. As of yet, no decisions on these issues have been made within Australia.

This Author

Tim Deere-Jones has a BSc in Maritime Studies and has since the 1980s operated a Marine Pollution Research Consultancy focusing on the behaviour and fate of marine anthropogenic radioactivity, causes/outcomes of hazardous cargos and shipping accidents, marine hydrocarbon, radioactivity and chemical spills. His report, ‘The British experience with nuclear-powered submarines: lessons for Australia’, is now online.