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Senior Mechanical Designer

Amentum

Hybrid
Warrington, UK
Full-time
Senior
Salary not listedPosted 55m ago

Real job — pulled straight from Amentum’s careers page · Verified September 5, 2026 · No reposts.

Job description

Amentum is hiring a Senior Mechanical Designer — a full-time, based in Warrington, UK role. Apply directly on Amentum's careers page below.

Senior Mechanical Designer

Location: OCONUS-UK-Warrington

Remote Type: Hybrid

Time Type: Full time

Job Description

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. 

The Project
The Sellafield Product & Residue Store (SPRS) Retreatment Plant (SRP) Project will provide a facility that receives Special Nuclear Material (SNM) from existing stores across the Sellafield site and processes it into a form suitable for safe and secure storage until 2120.

The Role
We are currently recruiting a Senior Mechanical Designer to produce and update 3D models and mechanical design drawings including but not limited to GA’s, sub assemblies detail design drawings, layouts, MFDs etc.

As A Senior Mechanical Designer, other responsibilities could include:

  • Providing support to resolution of testing Queries

  • Providing support to resolution of manufacturing Technical Queries/production permits/concessions

  • Provide design/detail design of machines, plant & equipment

  • Involvement in the production of O&M manuals

  • Involvement in the production of Design Risk assessment in accordance with BS EN 12100

As a Senior Mechanical Designer, you will already be:

  • Qualified to HNC Standard as a minimum in a relevant discipline, or equivalent experience and knowledge

  • Experienced in the use of Auto desk inventor

  • Experienced in the use of Auto desk vault Basis or Vault Pro (file management).

  • Have working knowledge of the BS 8888, BS EN ISO 8015, BS EN ISO 1101 & BS EN ISO 5459

  • Have knowledge of key legislation CDM, SoMSR, PUWER & LOLER

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 www.vercida.com 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 

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Frequently asked questions

What is the seniority level for Senior Mechanical Designer at Amentum?

Senior Mechanical Designer at Amentum is a Senior level position.

How do I apply for Senior Mechanical Designer at Amentum?

You can view the full description and apply for Senior Mechanical Designer at Amentum on EchoJobs: https://echojobs.io/job/amentum-senior-mechanical-designer-i6jdd.