United Kingdom

Amentum combines programme, project and engineering experience with deep technical capabilities to solve complex challenges for major UK organisations in the energy and defence sectors.

Amentum is at the heart of the UK’s nuclear industry. We deliver complex major programmes including construction of new power stations, operational support and life extension for the existing fleet, and clean-up of the nuclear legacy.

We are leaders in reactor technology, conceptual design and engineering for new nuclear technologies including Generation IV advanced reactors, small modular reactors and fusion power.

In our work on decommissioning and remediation, we are a major supplier of engineering design, safety case and project management services at Sellafield and other major UK sites; and we operate the country’s largest private sector complex of nuclear laboratories and engineering test facilities.

In the defence sector, Amentum has an essential role in the UK’s continuous at-sea deterrent. We’re also active in naval infrastructure and shipbuilding, at the Atomic Weapons Establishment, and in procurement and operational delivery across the whole of the UK Ministry of Defence.

Military-Friendly Employer

Employees Based in the UK

Employees Globally

Markets

Defence

Energy

Environment

Our Capabilities

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Advanced Energy Solutions

We deliver safe, innovative solutions for high-risk, technically complex nuclear projects worldwide.

Nuclear offers emission-free, reliable energy to accelerate the shift away from fossil fuels and power a range of other uses including space exploration, desalination plants and data centers.

Amentum is at the forefront of conceptual design and optimization of new nuclear technologies like Generation IV, small modular and advanced reactors and fusion power.
Amentum is sharing its multi-technology expertise, deep nuclear knowledge, skills in advanced engineering and licensing, and special technical capabilities with small modular and advanced reactor developers from the UK, USA and continental Europe.

We have a decades-long involvement in fusion power research with the UK Atomic Energy Authority and with ITER, the world’s largest nuclear fusion project, where our work ranges from designing prototypes for key components to complex remote handling systems essential for reactor operations.
And we are creating the infrastructure for the hydrogen economy of the future, from feedstock processing facilities to converting the pipeline network.

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Nuclear Decommissioning and Remediation

Amentum brings decades of experience to decommissioning and cleanup, drawn from our work at the world’s most challenging nuclear sites including Sellafield, Fukushima and Chornobyl.

We tackle our client’s biggest challenges and help transform contaminated sites into safe environments for future generations.

We help asset owners manage the cultural and mindset shifts required to move from operations to decommissioning. We bring practical, technically and commercially innovative strategies to address the decontamination, dismantling, deactivation and demolition of high-hazard plants and sites.

By adopting a waste-informed approach, underpinned by unrivalled expertise in radioactive material characterisation, shielding and containment we minimize handling and storage costs.

In continental Europe, we manage key hazard reduction projects at Chornobyl, Ukraine and Ignalina, Lithuania, and in Slovakia we played a major role in the first ever dismantling of a Soviet-designed VVER-440 reactor.

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Nuclear New Build

Amentum is working with clients around the world on their nuclear new build programs – helping them provide a secure, low-carbon, large-scale energy supply for the future.

In the U.K., we’re supporting a range of SMR vendors, helping to develop a new type of smart, compact, modular nuclear power plant; we’re a major contributor to ITER, the world’s largest fusion power project based in Provence, France; and we’re delivering key facilities for the United Kingdom Atomic Energy Authority’s fusion research program.

We helped design the first and second generation of the U.K.’s nuclear power plants and now we’re providing diverse capability for current new build programs including EDF’s Hinkley Point C and Sizewell C.

As owner’s engineer and technical adviser, we have been closely involved with Poland’s new nuclear program since its inception; and we have provided the Emirates Nuclear Energy Corporation with program management support since the start of the Barakah program in Abu Dhabi.

Drawing on our extensive engineering design and construction management capabilities, and our global licensing, environmental and site hazard evaluation knowledge, our work with commercial and governmental clients has helped advance their civil nuclear new build programs.

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Reactor Operational Support

We use our comprehensive knowledge of reactor technology, regulatory requirements and the management of aging plants to optimize plant performance.

Nuclear power is one of the most regulated industries, demanding the highest standards in safety, security and environmental management.

We help our clients interpret regulations, investigate practical environmental options and implement benchmarking. Our bold thinkers challenge and innovate across diverse projects to improve operational performance and extend power plant life.

With our comprehensive knowledge of reactor technology, regulatory requirements and the management of aging plants, we bring a thoughtful and collaborative approach to support programs – finding new ways to deliver plant life extension and tackle emerging challenges.

When fleet critical issues arise for reactor operators, we have the capability to diagnose the problem accurately, conceptualize the solution, design and manufacture the necessary equipment, and then deploy a team to plan and implement major engineering change.

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Research, Analytics and Technology

Amentum’s technical capabilities are underpinned by extensive laboratory and research and development facilities in the UK and Europe. We provide a range of research, analysis, testing and bespoke engineering solutions for sectors including nuclear, aerospace, clean energy, and infrastructure.

Complex analytical challenges demand extensive capacity, capability and often a different way of tackling the issue. We operate a 12,000m² complex of more than 20 separate laboratories, with a multi-skilled team of 800 technicians, graduate scientists and PhD-level specialists. Our teams provide extensive fingerprinting to enable customers to understand the radiological profile of waste streams and determine appropriate waste disposal routes.

We typically analyze more than10,000 samples every year for clients such as CERN, EDF Energy, Magnox Ltd, Dounreay Site Restoration Ltd, URENCO and Sellafield Ltd. Our work enables customers to ensure safety, meet regulatory requirements and reduce the cost of treating and disposing of waste.

We are the largest supplier of professional services to Nuclear Waste Services, which is responsible for the U.K.’s radioactive waste. We compile the U.K.’s radioactive waste inventory and carry out consultancy and testing work associated with the planned geological disposal facility.

Amentum’s ANSWERS® radiation transport software is used worldwide to solve problems in nuclear safety, plant performance and operational efficiency.

Our SIAL® geopolymer encapsulation product has been used to immobilize more than 3,000 tons of radioactive waste from nuclear power plants in central Europe.

We design robots and autonomous systems to gather data and implement engineering change in situations where humans would find it impossible or hazardous to enter. Going beyond the nuclear industry, we are developing systems to inspect sewers, pipelines, storage tanks, riverbeds and transportation networks.

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Defence – Sustaining the UK’s Nuclear Deterrent

Amentum focuses on providing advanced engineering, design, project management and mission support to enhance our military readiness and national security.

We are working across all the key sites that enable the UK’s continuous-at-sea deterrent (CASD) program, including HMNB Clyde, home base for the Royal Navy’s operational submarines; HMNB Devonport, the largest naval base in Western Europe, BAE Systems Maritime in Barrow-in-Furness, where the Royal Navy’s submarines are built, at Rolls-Royce Nuclear in Derby, where submarine reactors are manufactured, and the Atomic Weapons Establishment in Berkshire, which is responsible for nuclear warhead design and manufacturing.

Amentum employs more than 350 multi-disciplinary engineers and project delivery professionals supporting the submarines which deliver Operation Relentless, the longest-running military operation in the history of the Ministry of Defence.

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Defence – Procurement and Logistics Support

Amentum provides deep technical delivery capabilities, strategic insight and thought leadership to help the MOD find cutting-edge cyber security solutions across various domains.

As joint project delivery partner under the Project Delivery Partner-Successor (PDP-S) framework, we assist the MOD’s Defence Equipment and Support (DE&S) with the procurement of world-class equipment and support across the whole UK defense enterprise, working jointly with Turner & Townsend as the lead parties for the Equinox joint venture. Our role with D&ES covers project and operational delivery across all MOD departments, spanning the UK’s global defense operations, as well as advisory services.

For the MOD’s Defence Infrastructure Organisation, we’re responsible for strategic disposal of sites, allocation of assets, and construction and maintenance of facilities worldwide, including military bases that accommodate service personnel and their families.

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The Forum

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  • Lab pic
    Press release

    Amentum to create 3,000 jobs as U.K. nuclear renaissance and defence spending boost growth
  • Drum 960x640
    Press release

    Amentum to Provide Specialist Services for UK’s Nuclear Waste Management Organization
  • Press release

    Norway Selects Amentum to Study Nuclear Power Options  
  • Two people walk on a paved path near modern, cylindrical and rectangular buildings surrounded by grass and trees under a clear blue sky.
    Press release

    Amentum Selected for Next Phase of Norway’s Nuclear Clean-up

Key Projects

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  • Sizewell C

    Amentum is sole program and project management delivery partner for Sizewell C, a new nuclear power station that will strengthen the United Kingdom’s energy security. The UK government gave the go ahead for the project in June 2025, saying that new nuclear was needed to deliver “a golden age of clean energy abundance”. As well…

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  • Robotics Design and Development for Harsh Environments 

    Amentum’s expertise in robotics was born in the harshest environment possible – the interior of nuclear reactors. The skills we have developed are now being used to gather data to inform how we can extend the life of infrastructure from roads to waterways and energy networks.  When a rise in temperature was detected inside reactors…

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We specialize in the design, construction, commissioning, and operations of innovative solutions for the world’s most complex challenges. We’re positioned to deliver hydrogen technology through a series of demonstration projects to achieve a secure, resilient, and clean energy source by 2030. We’re eager to partner with you to build a clean, resilient, secure energy future.

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