Senior Mechanical Design Engineer (Fluid Systems)
Confirmed on the employer's own hiring board on Oct 19, 2026. First seen by Alion on Oct 6, 2026. Assystem scores B on the Alion truth index.
Today, Assystem is among the top three independent nuclear engineering firms worldwide. With over 60 years of experience in highly regulated sectors, the group supports public and industrial stakeholders in the execution of complex and strategic infrastructure projects, subject to high safety and security requirements.
Assystem mobilizes 8,000 experts in 13 countries and intervenes across the entire project lifecycle, in engineering, project management and digital solutions.
The Role:
Reporting to the Turbine Island Lead, the Senior Mechanical Design Engineer will be responsible for developing fluid systems. The Senior Mechanical Design Engineer shall work closely with multi-disciplined teams and the supply chain to help deliver the system design.
Key Responsibilities:
- Develop 2D CAD drawings, including process flow diagrams (PFD) and process and instrumentation diagrams (P&ID).
- Prepare 3D CAD/BIM models, plant layouts, piping design, isometrics, MTO, general arrangement drawings, detail drawings and sketches.
- Perform layout optimisation engineering across design phases.
- Participate to 3D model reviews, layout reviews, design reviews and technical meetings.
- Ensure compliance with required design safety factors, tolerances, specifications, standards, codes, legislation and requirements.
- Collaborate with multi-disciplinary engineering teams to ensure a coordinated design.
- Maintain records of design process in accordance with sound design practices
- Maintain and update databases for CAD/BIM design documentation.
- Report status and updates to management line
- Support team and maintain required standards and expectations. Meet targets, quality, time and budget constraints.
- Support and mediate solutions and issues with resolution with all stakeholders being aligned.
- Ensure adherence to the company statutory H&S Policies and rules and compliance with the project and Quality
Why Join the Community of Switchers?
- Over 55 years in nuclear engineering.
- Ranked among the top 3 largest nuclear engineering companies.
- Attractive social benefits, including an engaging Employee Committee and holiday bonuses.
- Ongoing training with numerous career opportunities.
- 70% of our managers are promoted internally!
- Hybrid work: 1-2 days remote per week.
Essential Skills, Qualifications and Experience:
- Previous experience as a Mechanical Design Engineer or a similar role
- Ability to work within the engineering team to realise designs
- Familiarity with 2D CAD systems (AutoCAD) for drawing creation
- Familiarity with 3D CAD/BIM systems (Revit, Inventor, Solidworks, Solid Edge, Siemens NX, PDMS, AutoCAD Plant 3D or similar) for model and drawing creation
- Professional qualification in an engineering related field
- SC Clearance or capable of achieving it
Personal Specification/Attributes:
- Good communication skills, written and oral
- Focus on delivering quality output to time and budget
- Act with integrity and instils this in others
- Ability to work with a good degree of independence, using their own initiative and self-motivation
- Flexible, agile to the role needs, to maintain delivery targets
- Confident in being suggestive to alternative solutions that provide safety, time, cost and quality solutions
- Team player
- Ability to manage own time and to deliver within agreed timescales
Security clearance:
Due to the nature of work to be undertaken applicants will be required to meet certain residency criteria in order to attain a minimum level of UK security clearance if not already security cleared to a minimum SC level.
We are committed to equal treatment of candidates and promote, as well as foster all forms of diversity within our company. We believe that bringing together people with different backgrounds and perspectives is essential for creating innovative and impactful solutions. Skills, talent, and our people’s ability to dare are the only things that matter !. Bring your unique contributions and help us shape the future.
NOTICE TO CANDIDATES ON RECRUITMENT FRAUD - We are committed to safeguarding candidates from fraudulent activity associated with our recruitment process. Please note that we will never offer specialist CV writing services, request payment or ask for sensitive personal information during the recruitment process.
We are committed to equal treatment of candidates and promote, as well as foster all forms of diversity within our company. We believe that bringing together people with different backgrounds and perspectives is essential for creating innovative and impactful solutions. Skills, talent, and our people’s ability to dare are the only things that matter !. Bring your unique contributions and help us shape the future.