This website emits an average of 1.6 g of CO₂ per page, find out more

Our Vacancy

Principal/Senior Mechanical Engineer

  • Defence
  • Contracting /
  • Helensburgh
  • 10/06/24
  • On site

Assystem is an international company with one mission: accelerate the energy transition around the world.

Every day, our 6,500 switchers located in 12 countries (Europe, Middle East, Pacific Asia & Africa) connect their six thousand billion neurons to tackle the task of the century: switching to low-carbon energy.

We are a collective committed to the actors who are making the energy switch. Sharing our knowledge, expertise and values allows us to innovate and think differently about the energy transition.

Drawing on more than 55 years’ experience in highly regulated sectors subject to strict security and safety requirements, we provide our customers with engineering and project management services, as well as digital services and solutions to optimize the performance of complex infrastructure projects throughout their life cycle. The Group is currently ranked second in the world for nuclear engineering.

To ensure a viable, efficient, and reliable energy future for all.

Job Description

Your Mission:

Join our team as a Mechanical Engineer within our Client organization, supporting nuclear facilities and future programs. Work alongside a multi-disciplinary team to author, develop, assess, and maintain Engineering Design Substantiation documents for Client Facilities, ensuring compliance with safety and operational requirements.


  1. 📝 Author, develop, assess, and manage Nuclear Infrastructure Design Substantiation documents.
  2. 🔄 Manage design changes/concessions.
  3. 📊 Present Design Substantiations to nuclear safety committees.
  4. 📅 Develop Examination, Inspection, Maintenance & Testing (EIMT) schedules and safety reports.
  5. 📈 Produce Periodic Review of Safety reports.
  6. 🤝 Provide advice and direction to internal and external stakeholders.
  7. 🛠 Conduct Independent Technical Reviews.
  8. 🧠 Apply engineering knowledge to apply existing and emerging technology.
  9. 🏗 Utilize theoretical and practical methods in a high-risk environment.


My profile




  • 🎖️ Incorporated Engineer status or equivalent experience.
  • 🛠️ Experienced Mechanical Engineer with knowledge of Marine Diesel Engines or Mechanical Handling Systems.
  • 📊 Proven experience in producing technical justifications for mechanical design modifications in high hazard industries.
  • 🧠 Ability to apply engineering knowledge to existing and emerging technology.
  • 🏗️ Experience in designing, developing, and operating engineering processes in a high-risk environment, particularly on brownfield modifications projects.


  • ☢️ Experience in a nuclear environment.

🎓 Qualifications & Training:


  • 🚀 For non-nuclear background candidates, completion of a Nuclear introductory course within 6 months of joining.
  • 📚 Minimum HNC or equivalent qualification in a relevant discipline.


  • 🎓 Engineering degree.
  • 🎖️ Chartered Engineer status.

Why join the Switchers community?

💥 Assystem has over 55 years of experience in nuclear engineering. We are among the top 3 largest nuclear engineering companies.

💥 Attractive social benefits: an engaging and dynamic Employee Committee (CE), holiday bonuses…

💥 Ongoing training throughout your career. Numerous career opportunities: 70% of our managers come from internal promotions!

💥 1 to 2 days of remote work per week.


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.

Other vacancies might interest you