Full-Time

CS&A Principal Engineer

ASSYSTEM

ASSYSTEM

5,001-10,000 employees

Engineering services for design, construction, commissioning

No salary listed

Warrington, UK

Hybrid

Office presence in Warrington required; minimum 3 days/week; regular site visits to Sellafield (fortnightly).

Category
Software Engineering (1)

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Requirements
  • Civil / Structural Engineering Degree, or equivalent
  • Chartered Engineer (CEng) โ€“ 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
  • Must hold a BPSS clearance without caveats
Responsibilities
  • 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 โ€˜As Builtโ€™ 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
  • 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
  • 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
Desired Qualifications
  • 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

Assystem provides engineering services for complex projects, covering design, construction, supervision, commissioning, and operation, with a strong focus on the nuclear and energy sectors. Its approach combines multidisciplinary engineering teams and project-management capabilities to move projects from initial concept through to operation. The company differentiates itself through a long track record, strategic acquisitions (including Alphatem in 1995 and Mactech Energy Group in 2025) and an early public offering in 2013, which have expanded its capabilities and market reach in the energy and nuclear fields. Its goal is to be a leading, reliable partner for clients by delivering end-to-end engineering services and helping them meet safety, performance, and regulatory requirements across the project lifecycle.

Company Size

5,001-10,000

Company Stage

IPO

Headquarters

Paris, France

Founded

1966

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Simplify Jobs

Simplify's Take

What believers are saying

  • H1 2026 nuclear revenue grew 8.0% organically, reaching 81% of sales.
  • France grew 4.2% organically on nuclear new-builds and fuel-cycle work.
  • UK civil nuclear engineering, defence, and SMR frameworks create repeatable project pipelines.

What critics are saying

  • Revenue is heavily concentrated in nuclear, increasing exposure to schedule delays.
  • Project endings and slower phasing already hurt India and Middle East volumes.
  • Currency weakness in sterling, rupee, and riyal reduces reported growth.

What makes ASSYSTEM unique

  • Founded in 1966, Assystem specializes in nuclear engineering lifecycle services.
  • Its French nuclear roots support commissioning, design, construction, and supervision.
  • Mactech Energy Group expanded its 2025 nuclear-industry footprint.

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Benefits

Health Insurance

Dental Insurance

Vision Insurance

Unlimited Paid Time Off

Flexible Work Hours

Remote Work Options

Paid Vacation

Paid Holidays

Hybrid Work Options

401(k) Retirement Plan

Wellness Program

Mental Health Support

Gym Membership

Professional Development Budget

Conference Attendance Budget

Stock Options

Company Equity

Phone/Internet Stipend

Home Office Stipend

Relocation Assistance

Childcare Support

Meal Benefits

Parental Leave

Family Planning Benefits

Fertility Treatment Support

Company News

Bdaily
Jan 30th, 2025
Assystem expands UK footprint with takeover

A global nuclear engineering firm has strengthened its UK presence with the acquisition of a specialist construction company. Paris-headquartered Assystem hasโ€ฆ | North East | Construction | Engineering | International | Energy | Mergers & Acquisitions | Commercial Partnerships | Manufacturing & Construction |

Assystem
Jan 17th, 2024
Assystem acquires KEOPS Automation, engineering specialist in automated systems and data enhancement

Assystem, an international engineering, digital services and project management company, has acquired 100% of the shares of KEOPS Automation, a French company specializing in the integration of industrial operating platforms and the enhancement of their data (industrial OT and IT, automated systems, supervision systems, BI applied to manufacturing).

Global Construction Review
Jan 5th, 2024
Franceโ€™s Assystem acquires Indiaโ€™s L&T Infrastructure Engineering - Global Construction Review

France-headquartered engineer and project manager Assystem has acquired Indiaโ€™s L&T Infrastructure Engineering, a subsidiary of the Larsen & Toubro group.

Tech.eu
Feb 11th, 2022
Germanyโ€™s SQS acquired by Assystem Technologies for over ยฃ280 million

German company Software Quality Systems (SQS), a provider digital quality assurance services,โ€ฆ