Mechanical Commissioning Engineer

Assystem UK Ltd; Brandon; On-site; GBP 45,000 - 65,000; Full time

Job summary

Assystem UK Ltd in Derby on-site is seeking a Mechanical Commissioning Engineer to join a nuclear licensed site project. The role starts with a 2-shift pattern Monday to Friday, with a high likelihood of moving to a 3-shift pattern from February 2026.

You will author and execute commissioning tests, maintain records, and ensure safety and compliance across nuclear, conventional, and environmental safety systems, including wastewater tanks and cranes.

Qualifications

• Experience with commissioning gas, fluid and vacuum systems.
• Familiarity with Licence Condition 21 site arrangements, health and safety standards, permits, and safety case adherence.
• Ability to perform initial operator duties during commissioning testing phases (non-active commissioning).
• Experience witnessing, supervising and accepting vendor/supplier testing on-site.
• Skilled in authoring test procedures and reports.
• Understanding of design, construction, and handover processes.

Responsibilities

• Author and manage commissioning test procedures and prepare safe systems of work
• Maintain accurate records of test results
• Conduct commissioning tests and analyse results
• Communicate effectively and manage processes
• Carry out commissioning duties on systems such as nuclear, conventional, and environmental safety systems, wastewater tanks, nuclear-qualified cranes

Skills

Gas systems

Fluid systems

Vacuum systems

Licence Condition 21

Test procedures

Vendor testing on-site

Job description

Mechanical Commissioning Engineer

2026-09-29T00:00:00

Location: East Midlands, GB, NG32 3JE

Any

Application Deadline: 2026-12-28T19:00:31.953

ASYS 46,55 EURMechanical Commissioning EngineerOur Vacancy# Mechanical Commissioning Engineer

• Defence Contracting / Derby United Kingdom 04/02/26 On site Share

About Us

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 future team

You will be joining a dynamic and collaborative commissioning team on-site at our Client in Derby, which is a Nuclear Licensed Site. This is an exciting opportunity for a contractor looking to contribute to a critical project and work within an embedded team. This role will be based in Derby and will initially be working a 2-shift pattern Monday to Friday. There is a high possibility that it will increase to a 3-shift pattern from February 2026.

Your Missions

• Author and manage commissioning test procedures and prepare safe systems of work
• Maintain accurate records of test results
• Conduct commissioning tests and analyse results
• Communicate effectively and manage processes
• Carry out commissioning duties on systems such as nuclear, conventional, and environmental safety systems, wastewater tanks, nuclear-qualified cranes

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

Collaborative Environment

Join a dynamic team of experts who are passionate about driving progress and supporting each other's growth.

My Profile

PROFILE

Your strengths and prerequisites for success:

• Experienced with commissioning gas, fluid, and vacuum systems and mechanical handling equipment
• Familiar with Licence Condition 21 site arrangements, health and safety standards, permits, and safety case adherence
• Able to perform initial operator duties during commissioning testing phases (i.e., non-active commissioning)
• Previous experience of witnessing, supervision, and acceptance of vendor and supplier testing on-site
• Skilled in authoring test procedures and reports
• Understanding of design, construction, and handover processes

Please be aware that many roles at Assystem are subject to security and export control restrictions. These restrictions mean that factors such as your nationality, any nationalities you may have previously held, and your place of birth can restrict the roles you are eligible to perform within the organisation.

All applicants must at minimum achieve the Baseline Personnel Security Standard. Many roles also require higher levels of National Security Vetting, where applicants typically must have 5 to 10 years of continuous residency in the UK depending on the vetting level required for the role, to allow for meaningful security vetting checks.

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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