Mechanical Commissioning Engineer

Assystem UK Ltd; East Midlands; On-site; GBP 60,000 - 85,000; Full time

Job summary

Assystem is seeking a Mechanical Commissioning Engineer to join the on-site commissioning team at a Nuclear Licensed Site in Derby. The role starts with a 2-shift pattern (Mon–Fri) and may move to 3 shifts from February 2026, supporting commissioning of gas, fluid and vacuum systems and safety-related equipment.

Key tasks include authoring test procedures, recording results, conducting tests, and coordinating with vendors and internal teams to ensure safe, compliant commissioning across nuclear

Qualifications

• Experience 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.

Responsibilities

• Author and manage commissioning test procedures and prepare safe systems of work.
• Maintain accurate records of test results.
• Conduct commissioning tests and analyze 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 commissioning

Licence Condition 21 familiarity

Operator duties during commissioning

Vendor/supplier testing on-site

Test procedures & reports authoring

Design/construction handover knowledge

Job description

Mechanical Commissioning Engineer

Date: 2026-10-09T00:00:00

Location: Derby, Derbyshire, GB, DE1 3

Applicant Type: Any

Company: Assystem

Last Updated: 2027-01-08T11:02:24.613

Company Description

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

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 analyze 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

Why join the community of Switchers?

• 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.

Qualifications

Profile

• 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

Additional Information

Please be aware that many roles at Assystem are subject to both 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 a minimum achieve the Baseline Personnel Security Standard. Many roles also require higher levels of National Security Vetting, where applicants must typically 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!

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.

Summary

• Type: Full-time


• Function: Engineering


• Experience level: Executive


• Industry: Management Consulting