Principal Mechanical Engineer

Assystem Warrington, England, United Kingdom

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

🚀 Join the Fusion and Modular Nuclear Business Unit! 🚀 Reporting to the FEED Engineering Manager, you will be responsible for delivering Front Engineering activities for Small Modular Reactors, Advanced Modular Reactors, and Fusion projects. The Principal Engineer will work closely with multidisciplinary teams and lead an engineering design team.

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• Spearhead delivery of cutting‑edge power station systems.
  
• Lead optioneering studies to pinpoint the ultimate solution that aligns with client objectives.
  
• Lead a dynamic team in crafting and refining essential design documents, from Process Flow Diagrams to Equipment Datasheets.
  
• Direct the development of Design Description Documents and Requirement Specifications to drive innovation and efficiency.
  
• Integrate developed systems into the broader plant infrastructure for optimal performance and functionality.
  
• Serve as the technical guru for designated scopes, guaranteeing top‑notch expertise and oversight.
  
• Chair design reviews and lead HAZID/HAZOP studies with multidisciplinary teams to ensure safety and excellence.
  
• Enforce strict adherence to company statutory H&S policies and regulations, ensuring compliance with project and Quality Management System standards.
  

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• 🌟 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.
  

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• Strong previous experience in highly regulated industries such as nuclear, thermal power generation, or oil and gas.
  
• Expertise in thermal power systems and equipment, from steam turbines to pumps, and a keen understanding of nuclear power plant operations.
  
• Proficiency in optioneering and conducting studies, with a track record of crafting compelling ALARP and BAT arguments.
  
• Experience mentoring and developing junior staff and proven leadership in managing small teams.
  
• Exceptional communication skills for seamless interaction with internal and external stakeholders.
  
• Familiarity with ASME, European, and UK codes and standards, and understanding of Product Safety Legislation.
  
• Appreciation for requirements management and systems engineering principles.
  
• Results‑oriented, capable of working independently and collaboratively, with strong organizational skills.
  
• British National with eligibility for obtaining and maintaining full UK security clearance.
  

Due to the nature of the work, applicants must meet UK security clearance criteria.

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.

Seniority Level: Mid‑Senior level

Employment Type: Full‑time

Industry: Business Consulting and Services