Principal Stress Engineer

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.

Job Description

Principal Stress Engineer / Technical Lead

Join the Fusion and Modular Nuclear Business Unit! Assystem's Fusion and Modular Nuclear team are working on some of the most projects in the UK. Our Simulation and Assessment team of stress engineers support these projects by producing design and regulatory justification assessments of high-integrity and safety critical components to international codes and standard such as RCC-M or ASME III.

We are seeking a Principal Stress Engineer role who will lead the scoping, bidding and delivery of stress engineering work packages, and building and leading a team to deliver this work.

• Lead bids and projects
• Develop future technical leaders
• Plan capability, resourcing and business wining alongside our leadership team

Your Mission: 1. Technical Delivery

You will lead project teams and technical work in client facing roles, delivering high-quality stress analysis and structural integrity assessments:

• Act as a technical lead for stress and structural integrity, providing expert advice, troubleshooting, and technical oversight.
• Serve as an Independent Technical Approver to ensure the highest engineering standards.
• Use Finite Element Analysis and traditional hand calculations to justify strength, fatigue, defect tolerance, and structural performance to international codes and standards (including pressure vessel and defect-tolerance codes).
• Collaborate closely with safety case authors, design engineers, and multidisciplinary delivery teams.
• Mentor junior engineers, offering technical guidance and helping shape our next generation of stress specialists.

2. Capability Development

Your role will play an important part in developing and growing Assystem's internal stress capability:

Capability Development

• Support the strategic development roadmap for the UK stress engineering capability.
• Maintain and improve technical processes, methods, best-practice guides and quality frameworks.
• Monitor workload, skill gaps and training needs across the stress discipline.
• Lead technical upskilling initiatives such as internal training pathways.

Team Growth, Recruitment & Retention

• Work with the Engineering Directors and Business Management teams to forecast demand, plan workforce requirements, and shape the long-term capability pipeline.
• Support recruitment campaigns, interviewing and selecting high-quality candidates.
• Ensure strong retention by fostering a supportive culture, mentoring talent, and providing growth opportunities.

Bidding & Business Development

• Collaborate with Sales and Business Development teams to identify opportunities where stress capability adds value.
• Lead bids, proposals, client presentations and technical sales materials.
• Represent stress capability in major pursuits and innovation initiatives.

Internal & External Leadership

• Act as a visible leader and ambassador for stress engineering across Assystem and with clients.
• Build and maintain relationships with key technical stakeholders, partners and industry bodies.

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.

Qualifications We Want Someone Who Can

• Lead high-performing teams supporting a range of customers and industry sectors.
• Lead stress and structural integrity assessment projects using modern techniques.
• Deliver and review high-quality technical assessments to recognised standards.
• Mentor and guide junior engineers while acting as a senior technical reference point.
• Work directly with clients to tackle complex stress and integrity challenges.
• Demonstrate expert FE analysis capability (strength, fatigue, defects, lifetime assessments).
• Apply ASME III / ASME VIII, RCC-M, R6 codes.
• Desirable: experience in CFD, dynamics, fatigue, and degradation mechanisms.
• Must have experience in the nuclear sector or a comparable highly regulated sector.

Your Toolbox Should Include

• Experience in stress assessments in the nuclear sector.
• Strong communicator with excellent commercial awareness.
• Expert in ABAQUS (or ANSYS, LS-Dyna, etc.).
• Experience with Altair Hyperworks or similar tools.
• Familiarity with code assessments (e.g. ASME III, ASME VIII, RCC-M, PD5500, R6).
• Coding and scripting using languages such as Python.
• Knowledge of manufacturing methods, materials, and inspection techniques.

Additional Information Security Clearance

This role requires the successful candidate to hold (or be able to obtain) Security Check (SC) clearance without any caveats.

We are committed to equal treatment and fostering diversity. Skills, talent, and the courage to innovate are what matter most.

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.

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