CS&A Principal Engineer

ASSYSTEM; Whitehaven; On-site; GBP 85,000 - 120,000; Full time

Job summary

ASSYSTEM is leading a major Box Encapsulation Plant project at Sellafield, Cumbria, seeking a CS&A Engineering professional with 10+ years in nuclear. You will drive engineering design, governance, and site collaboration, reporting to the Sellafield CS&A Responsible Engineer.

The role requires Chartered status, extensive nuclear project experience, and the ability to lead multidisciplinary teams in a regulated environment. Occasional site visits and UK driving licence are essential.

Qualifications

• Degree in Civil or Structural Engineering or equivalent.
• CEng accreditation with ICE (MICE) or IStructE (MIStructE).
• Proven major project experience in the nuclear sector.
• Strong design knowledge and standards.
• Ability to lead and mentor engineering teams.
• UK driving licence and BPSS clearance eligibility.

Responsibilities

• Lead and inspire CS&A design and site engineering teams.
• Collaborate daily with Sellafield CS&A Responsible Engineer.
• Review CS&A design submissions and technical documentation.
• Approve or reject design submissions and TQ/PP records.
• Track structural detail drawings, calculations and As-Built status.
• Support fire strategy reviews and related issues.
• Contribute to safety case activities and DJRs.
• Resolve engineering challenges with design team and stakeholders.
• Support design reviews and risk assessments.
• Review external works design including concrete slabs and drainage.
• Assess interfaces between external works and building envelope.
• Work with construction teams to resolve technical issues.
• Attend weekly risk review meetings and EWNs.

Skills

Leadership

Communication

UK Driving Licence

Security clearance eligible

Nuclear experience

Education

Civil/Structural Engineering degree

Chartered Engineer (CEng/MICE or MIStructE)

Job 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

The Box Encapsulation Plant (BEP) is a major nuclear construction project at Sellafield, Cumbria, forming a critical part of the Magnox Swarf Storage Silo (MSSS) Programme.

The Mission: Tackle one of Sellafield’s most hazardous legacy facilities by retrieving, treating and immobilising nuclear waste for safe, long-term storage.

The Bigger Picture: The BEP may also support waste processing from other major decommissioning projects, including the First Generation Magnox Storage Pond and Pile Fuel Storage Pond.

We’re looking for an experienced Civil, Structural & Architectural (CS&A) Engineering professional with a minimum of 10 years’ nuclear experience, a strong technical background and the confidence to lead engineering activities within a regulated, quality-assured environment.

• Lead & Inspire – Provide leadership, technical guidance and support to the JV CS&A design and site engineering teams.
• Work with Sellafield – Report daily to the Sellafield CS&A Responsible Engineer (RE), maintaining strong communication and collaboration.
• Design Assurance – Review, check and comment on CS&A design submissions, site modifications and technical documentation.
• Engineering Approvals – Review, accept or reject design submissions and TQ/PP documentation, completing and submitting the required records through Sellafield Document Control.
• Structural Design Oversight – Track structural detail design drawings, calculations and documents through to As-Built status.
• Fire Strategy & Compliance – Support fire strategy reviews, including fire-rated service hanger supports, and engage with fire consultants on conventional and nuclear fire issues.
• Safety Case Support – Contribute to safety case activities, including Design Justification Reports (DJRs).
• Multidisciplinary Collaboration – Resolve engineering challenges with the wider design team, Sellafield Capability and construction stakeholders.
• Technical Governance – Support design reviews, engineering substantiation, risk reviews and Early Warning Notices (EWNs).
• Design Review – Review external works design, including concrete slabs, surface water drainage and standard details.
• Interface Management – Assess interfaces between external works and the building envelope as construction progresses.
• Construction Engagement – Work closely with the JV construction team and supply chain to resolve technical issues.
• Risk Management – Attend weekly risk review meetings and support the management of emerging project risks and EWNs.
• Utilities & Infrastructure – Engage with Sellafield Site Utilities and Infrastructure Capability to secure alignment on contractor proposals before construction, where required.
• Warrington Office – Minimum of 3 days per week.
• Sellafield Site – Regular visits, ideally fortnightly, with site attendance generally weekly or at least once every two weeks.
• Site Walkdowns – Work alongside construction teams to identify, discuss and resolve CS&A engineering issues directly on site.
• Stakeholder Engagement – Build strong working relationships with Sellafield, JV construction teams, subcontractors and multidisciplinary engineering specialists.

Qualifications

Qualifications and experience

What You’ll Bring to the Role

• Qualified Engineer – Degree in Civil or Structural Engineering, or equivalent.
• Chartered Status – CEng accreditation with ICE (MICE) or IStructE (MIStructE).
• Technical Excellence – Proven expertise across major projects, applying specialist engineering knowledge to deliver results.
• Strategic Vision – Experience shaping project and programme direction across a portfolio, providing expert guidance and insight.
• Engineering Leadership – Ability to lead, inspire and drive excellence within an engineering function.
• Nuclear Experience – Proven experience in the nuclear sector, including new-build and decommissioning projects, applying professional engineering judgement.
• Design Expertise – Strong understanding of engineering design principles and their practical application.
• Standards Knowledge – Working knowledge of relevant British Standards.
• Communication Skills – Excellent written and verbal communication, with the ability to influence and engage stakeholders.
• UK Driving Licence – Full UK driving licence, or equivalent licence permitting you to drive in the UK.
• Security Clearance – Eligible to meet UK security clearance requirements.

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 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.