Principal Mechanical Engineer; Building Services

Position: Principal Mechanical Engineer (Building Services)
Our Vacancy# Principal Mechanical Engineer (Building Services)
* Defence* Contracting /
* Helensburgh* United Kingdom
* 23/02/26
* Hybrid work
* Share The UK’s nuclear sector has entered a renaissance, with Nuclear Energy now a vital component as the country moves towards a target of Net Zero.  Assystem provides critical support to this mission, accelerating the decommissioning and remediation of our legacy assets with a view to enabling a swifter energy transition, in parallel overcoming some of the largest engineering and environmental challenges of our generation.  

As a Global top 3 independent nuclear engineering organisation, Assystem is active across the full decommissioning lifecycle. In the UK, we work across the Civil and Defence nuclear estates, pioneering agile and fit-for purpose, customer-focused solutions, drawing on our established pedigree for delivery engineering excellence. Assystem have a proud heritage gained over decades both in the UK and overseas, (delivering, supporting, managing) some of the most complex engineering projects in decommissioning, repurposing legacy assets and key new build projects such as Hinkley Point

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Job Description
** Summary of the Role
** The role involves working as part of a multi-disciplinary engineering team within the Approving Authority. The primary purpose of the role is to directly support current operations and future programmes.

The team consists of Mechanical, Civil, Building Services and Electrical Engineers and are responsible for the authorship, development, assessment, and maintenance of engineering design substantiation for Clyde Nuclear Facilities.
** TASKS
* ** Authoring, development, assessment, maintenance and management of the suite of Clyde Nuclear Infrastructure Design Substantiation documents.
* Authoring, development, assessment, maintenance and management of design changes/concessions
* Presentation of Clyde Design substantiations, to Clyde ‘Due Process’ nuclear safety committees
* Production and development of Examination, Inspection, Maintenance & Testing (EIMT) Schedule, operating procedures and results to satisfy design requirements and safety case through life
* Producing Periodic Review of Safety reports
* Providing advice and direction to internal and external stakeholders
* Production of Independent Technical Review (ITA)/Independent Peer Review (IPR)
* Use a combination of general and specialist engineering knowledge and understanding to apply existing and emerging technology
* Apply appropriate theoretical and practical methods to design, develop, manufacture, construct, commission, operate, maintain, decommission and re-cycle engineering processes, systems, services and products in a nuclear/high risk environment
* Producing robust technical justification to allow for relevant mechanical/structural design modifications to be authorised within a high hazard industry
** EXPERIENCE
* *** Essential:
*** 5 Years
*** Mechanical/Building Services design experience
**** Experience of producing robust technical justification to allow for relevant design modifications to be authorised
* Knowledge of key legislation and Standards applicable to the built environment and building services design.
* Familiarity with recognised industry technical guidance such as CIBSE guides and ASHRAE standards.
* Experience working on multi-discipline projects providing mechanical/BS engineering input
** Desirable:
*** Experience in a commissioning management role with familiarity of CIBSE commissioning codes and BSRIA commissioning guides.
* Experience applying appropriate theoretical and practical methods to design, develop, manufacture, construct, commission, operate, maintain, decommission and re-cycle engineering processes, systems, services and products in a nuclear or similar high hazard industry
* Ideal candidates would already have experience within Clyde or a similar high-risk environment
* Familiarity with safety case development techniques e.g. HAZID/HAZOP studies.
** QUALIFICATIONS & TRAINING
**** Essential:
*** HNC/HND or equivalent in Mechanical Engineering or Building Services or similar plus demonstrable experience in the discipline.
** Desirable:
*…