Commisioning Engineer - Mechanical & Fuel Route

⚡️💡 About Assystem

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.

🤝 Why Join the Community of Switchers?

As a member of Assystem, you'll be part of a team driving the low-carbon energy future. We’re ranked second globally in nuclear engineering, offering you the chance to work on world-class projects like Hinkley Point C. Together, we’ll innovate and shape tomorrow’s energy solutions.

Role Overview

Working on a major nuclear power plant project, the Commissioning Engineer within the Mechanical & Fuel Route Team is responsible for the planning, execution, and delivery of commissioning activities associated with mechanical systems supporting the fuel route and reactor operations of the plant. The role ensures that systems are commissioned safely, compliantly, and in accordance with project schedules, regulatory requirements, and operational readiness objectives.

Working as part of a multidisciplinary commissioning team, the Commissioning Engineer will support the transition of systems from construction through testing, commissioning, and handover to operations, ensuring that all activities are conducted to the highest standards of nuclear safety and quality.

Framework & Boundaries
Throughout the project's lifecycle, the role of the Senior Commissioning Engineer will evolve, combining
technical expertise with project management skills. At the early stages you will contribute to detailed
planning and preparation for the start of the Commissioning phase. Following this, you will oversee the
execution of factory tests and commissioning tests as part of a team and analyse of the results to justify the
readiness of the HPC units to safely enter commercial operation.

As part of the role, you will collaborate closely with Responsible Designers and project contract partners.
Together, you will ensure compliance with a comprehensive set of commissioning documents that
incorporate technical test programs and safety justifications, which will form an integral part of the
Commissioning Arrangements. Building strong collaborative relationships with designers, contractors, the
project delivery team, site engineering, and the plant operational organization will be crucial in
ensuring well-defined and controlled interfaces with the commissioning process.

Key Responsibilities

• Develop, review, and implement commissioning documentation, including:
  • Commissioning Test Documents (CTDs)
  • Commissioning Work Instructions (CWIs)
  • Test Procedures
  • Method Statements
  • Risk Assessments
• Execute commissioning activities for mechanical systems associated with the fuel route, including:
  • Fuel handling equipment
  • Mechanical handling systems
  • Cooling and auxiliary systems
  • Ventilation and process systems
  • Mechanical plant and equipment
• Coordinate and supervise commissioning technicians, contractors, and specialist vendors during testing and commissioning activities.
• Ensure all commissioning activities are conducted in compliance with:
  • Nuclear site licence conditions
  • Regulatory requirements
  • Commissioning processes
  • Safety, environmental, and quality standards
• Review construction completion records and verify system readiness for commissioning.
• Identify and manage commissioning defects, non-conformances, and punch list items through to closure.
• Support system walkdowns, inspections, and turnover activities between construction, commissioning, and operations teams.
• Participate in commissioning risk assessments and hazard identification workshops.
• Record, analyse, and report test results, ensuring accurate documentation and configuration control.
• Interface with engineering, construction, operations, quality, and project management teams to resolve technical issues and maintain programme milestones.
• Support integrated system testing and operational readiness activities.
• Contribute to lessons learned, continuous improvement initiatives, and commissioning best practices.

Key Accountabilities

• Delivery of commissioning activities in accordance with the project schedule.
• Compliance with nuclear safety culture and regulatory expectations.
• Production of high-quality commissioning records and documentation.
• Safe execution of testing activities without incident.
• Effective management of commissioning issues and technical risks.
• Successful handover of systems to Operations.

Essential Qualifications & Experience

• Degree or HNC/HND in Mechanical Engineering or a related engineering discipline.
• Strong experience in commissioning, testing, operation, or maintenance of complex mechanical systems in highly regulated sectors preferably nuclear or O&G.
• Familiarity with UK nuclear regulatory requirements and ONR expectations.
• Experience in FAT oversight, supplier engagement, and specialist testing.
• Knowledge of mechanical plant, rotating equipment, piping systems, valves, and process equipment.
• Experience producing and reviewing technical procedures and engineering documentation.
• Strong understanding of safe systems of work and risk management processes.
• Excellent communication and stakeholder management skills.
• Ability to interpret engineering drawings, specifications, and technical standards.

Desirable Experience

• Experience within the nuclear industry, preferably on new build or major infrastructure projects.
• Knowledge of EPR reactor systems and fuel route equipment.
• Experience with nuclear plant systems commissioning, operations, or maintenance.
• Experience with EPR (NNB) electrical system architecture.
• Chartered Engineer or working toward professional accreditation.
• Experience of commissioning within highly regulated environments such as nuclear, power generation, oil & gas, or defence.
• Previous experience of system handover and operational readiness programmes.

Key Competencies

• Strong commitment to nuclear safety and human performance principles.
• Analytical and problem-solving skills.
• Attention to detail and quality focus.
• Ability to work effectively within multidisciplinary teams.
• Planning and organisational capability.
• Leadership and supervision of field activities.
• Proactive approach to identifying and resolving technical issues.

🌟 What we offer
🏠 Hybrid Working – Flexibility to work from home and the office
🏖️ 25 Days Annual Leave + Bank Holidays
🔄 Buy & Sell Holiday – Make your time off work for you
💰 8% Company Pension Contributions
🛡️ Income Protection & 3x Salary Death-in-Service Cover
🤒 Competitive Sick Pay – Support when you need it
🏥 Healthcare Cash Plan – Claim back on dental, optical & more
💪 Free Digital Gym Access – Expert-led fitness classes
🎁 Exclusive Discounts – Restaurants, days out & top brands
📞 24/7 Employee Support Line – Mental health, financial & legal help
🚴 Cycle to Work Scheme – Save money & go green
💉 Free Flu Jabs & Eye Test Vouchers
🧾 Paid Professional Membership Fees
❤️ Volunteer Days – Make a difference on company time

Join Assystem and contribute to delivering sustainable and innovative engineering solutions for the Hinkley Point C project.

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