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Assystem

CS&A Principal Engineer

Hybrid

Warrington, United kingdom

Senior

Freelance

04-03-2026

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Skills

Communication Leadership Project Management

Job Specifications

Assystem is an international company with one mission: accelerate the energy transition around the world.

Every day, our 8,000 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

Project Specific Requirements

Report to CSA RE on a daily basis

Provide leadership, guidance, and support to the JV CSA design and site engineering team

Attend the Warrington office a minimum of 3 days per week and visit the Sellafield site regularly (ideally fortnightly) to confidently engage with the multi-discipline JV construction team and subcontractors

Check and comment on CSA JV design submissions during development, including site modifications; complete NFR documents and submit to SL Doc Control

Review, check, accept or reject design submissions; sign and submit PMACD to SL Doc Control

Review, check, accept or reject TQ/PP submissions

Review the progress of all structural detail design drawings, calculations, and documents through to ‘As Built’ status by the JV CS&A designers

Demonstrate general understanding of service supports and blockwork wall substantiation

Possess a general understanding of fire strategy arrangements (preferred), including fire-rated service hanger supports; attend meetings with Fire Consultants to review conventional and nuclear fire issues

Interface with the multi-discipline design team on project issues; liaise with SL Capability as required to substantiate site issues encountered during construction

Provide support to Safety Case work, including DJRs

External Works

Demonstrate good design understanding of external works, including concrete slabs and surface water drainage standard details

Review and comment on all interfaces between the external works and the building external envelope as construction progresses

Engage regularly with the JV construction team and supply chain on site; attend weekly meetings as required

Attend weekly risk review meetings and support EWNs

Site Visits

Visit site weekly (minimum bi-weekly) for the day

Liaise with the site construction team and conduct or participate in site walkdowns to oversee, discuss, and resolve CS&A-related construction issues

Liaise and interface with SL Site Utilities and Infrastructure Capability to secure buy-in to contractor proposals prior to construction where applicable

Qualifications

Qualifications and Experience

Civil / Structural Engineering Degree, or equivalent

Chartered Engineer (CEng) – MICE or MIStructE

Demonstrable expertise in major project areas relevant to the engineering discipline, with a proven track record of successfully applying specialist knowledge and skills

Ability to provide strategic guidance based on experience across a portfolio of projects, helping to inform and direct programmes

Proven leadership capability within an engineering function

Experience working within the Nuclear Sector, including new build and decommissioning projects, in roles reliant upon professional engineering expertise and judgement

Strong understanding of design principles and the ability to apply them effectively

Working knowledge of British Standards

Excellent written and verbal communication skills

Full UK driving licence (or equivalent permitting driving in the UK)

Able to meet the requirements for UK security clearance

Additional Information

Security clearance**

This role requires the successful candidate to hold a minimum of a BPSS clearance without any caveats to that clearance.

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.

About the Company

Assystem, one of the world's leading independent nuclear engineering companies, is committed to accelerating the energy transition. We see ourselves as an activist in the development of nuclear energy, convinced that it is an essential part of the fight against climate change. 7,500 switchers, spread in 12 countries in Europe, Asia, Africa and the Middle East are working every day to make the energy switch by accelerating the development of nuclear and renewable energies, power grids, clean hydrogen projects and low-carbon ... Know more