Mechanical Engineer

Assystem is a global leader committed to accelerating the energy transition. With 7,500 employees across 12 countries, we tackle the monumental task of switching to low‑carbon energy. Our 55+ years of experience in highly regulated sectors enable us to deliver top‑notch engineering, project management, and digital solutions.

The Mechanical Engineer will support the design of advanced thermal and fluid systems for the Fusion and Modular Nuclear Business Unit. The role provides analysis and calculation support across all Cooling Water Island Systems and contributes to an internal centre of excellence for methodology. This innovative project aims to deliver commercially viable solutions.

• Analyze and calculate support for Cooling Water Island Systems
• Contribute to the centre of excellence for analysis methodologies
• Generate static and transient flow and thermal analyses using various software tools

• System design and integration
• Producing, reviewing, and updating system documentation
• Performing analysis to define system control philosophy
• Sizing of components
• Conducting thermal‑hydraulic calculations and modelling
• Formulating equipment specifications

• 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 managers are promoted internally
• Hybrid work: 1–2 days remote per week

• Minimum 2:1 BEng in Mechanical Engineering or equivalent
• Relevant senior engineering experience in offshore, renewables, nuclear, or other highly regulated industries
• Solid background in mechanical and structural engineering
• Proficient with CAD software (Autodesk Inventor, AutoCAD, Catia)
• Strong mathematical skills; experience with MathCAD
• Skilled in producing technical reports (design, substantiation, assembly procedures)
• Knowledge of manufacturing processes (welding, machining)
• Experienced with the engineering design cycle from concept to manufacture

• Familiar with European and offshore standards (Eurocode 3, DNV)
• Master’s degree is a plus
• Skilled in checking and approving engineering CAD assemblies and drawings
• Proficient in verifying engineering documentation (manual calculations, reports)
• Excellent Finite Element Analysis skills (ANSYS Workbench); experience in non‑linear and fatigue FEA, familiar with DNV and Eurocodes

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. Values, talent and the ability to dare are what matter. Bring your unique contributions and help us shape the future.