Senior Mechanical Engineer

At Amentum, we're not just solving problems; we're engineering the future. Our team is driven by an unyielding commitment to innovation, integrity, and collaboration, tackling some of the most significant challenges in science, security, and sustainability. If you're passionate about making a real impact and want to be part of a community that values ethical excellence, this is the place where your ambition can thrive.
Here, we believe that success comes from continuously pushing boundaries and working together to deliver on our promises. We embrace challenges with confidence and are dedicated to creating a secure and vibrant future for all.

We'll inspire and empower you to deliver your best work so you can evolve, grow and succeed - today and into tomorrow. We offer an exciting range of opportunities to develop your career within a supportive team who always strive to do the right thing for our people, clients and communities.

People are our greatest asset, and we offer a competitive package to retain and attract the best talent.

In addition to the benefits you'd expect, UK employees also receive free single medical cover and digital GP service, family-friendly benefits such as enhanced parental leave pay and free membership of employee assistance and parental programmes, plus reimbursement towards relevant professional development and memberships.

Work-life balance and flexibility is a key focus area for us. We're happy to discuss hybrid, part-time and flexible working hours, patterns and locations to suit you and our business.

The Opportunity
Amentum is the Design and Engineering partner for Sellafield under the PPP (Programme and Project Partners). This is a 20-year arrangement to deliver ~£7bn of major projects. We are looking to recruit high value expertise from across regulated and comparable sectors to work in a collaborative environment. PPP is delivering major projects, site wide improvements and provision of supporting services.

PPP is an exciting model to work in with Four world class organisations who have come together as one team, to create a clean and safe environment for future generations. The programme arrangement is set to deliver ~£7bn worth of major projects creating a lasting legacy through the long-term partnerships.

We are continually recruiting high value expertise from across regulated and comparable sectors to work in a collaborative environment. PPP is continually delivering major projects over the next couple of decades, so there are lots of opportunities to develop your careers with a leading multinational company that put people first.

Being part of the PPP Team offers a unique opportunity to cultivate change and creativity in engineering, safety, and delivery solutions in one of the most complex industrial sites in the UK, if not the world.

The Role

We are currently looking for Senior Mechanical Engineer to join the Lightly Shielded Store Project (LSS1) to be based out of Birchwood.LSS1 is a 7200m2 footprint major project new build on the Sellafield site. It will be a new class of Intermediate Level Waste store for Sellafield with a design life of 100 years.

As a Senior Mechanical Engineer, with a proven track record in Mechanical Engineering, your responsibilities could include:

• Planning and co-ordinating engineering and design activities for yourself and others.
• Developing and implementing engineering solutions for complex engineering projects, from concept design proposals through to design for manufacture, the full project life cycle
• Identifying design, statutory and regulatory requirements, and contributing to risk assessments
• Producing technical reports, technical specifications and scoping calculations
• Reviewing technical deliverables, including reports and drawings
• Presenting engineering solutions to stakeholders and as part of design reviews

As a Senior Mechanical Engineer you will already have:

• Degree qualified in Mechanical Engineering or equivalent (e.g. HNC/HND with significant experience)
• Attained/ or working towards chartered or incorporated status with a recognised professional body (e.g. IMechE)
• Experience of highly regulated environments would be advantageous
• Familiarity with UKCA/CE Marking, CDM, PUWER, LOLER, PED, Machinery's Directive

Our Culture
Our values are built on a strong foundation of safety, integrity, and respect for every individual. People are at the heart of our mission, and we believe in supporting one another through a culture of care and collaboration.

We strive to create a workplace where everyone feels they belong and can thrive. Supporting mental wellbeing and fostering a sense of connection are essential to how we work.

When we embrace different perspectives and work together, we become more innovative, more agile, and more successful.

We partner with VERCIDA, for greater online accessibility please visit to view and access our roles. As a Disability Confident employer, we will interview all disabled applicants who meet the minimum criteria for a vacancy. We welcome applications from candidates who are seeking flexible working and from those who may not meet all the listed requirements for a role.

If you require further support or reasonable adjustments with regards to the recruitment process (for example, you require the application form in a different format), please contact the team.