A

ASSYSTEM

Engineering services for design, construction, commissioning

Principal Stress Engineer

Full-Time
No salary listed
Expert
Bachelor's
London, UK+6 moreMore locations: Derby, UK | Bristol, UK | Newcastle, UK | Warrington, UK | Glasgow, UK | Bolton, UK
HybridOne to two days of remote work per week.
Mechanical EngineeringDesign Engineering

About the job

Requirements
  • Must have experience in the nuclear sector or a comparable highly regulated sector.
  • Must have experience in stress assessments in the nuclear sector.
  • Must hold a degree in engineering and Chartered Engineer (CEng) status.
  • Must have expert finite element analysis capability covering strength, fatigue, defects, and lifetime assessments.
  • Must be able to apply ASME III, ASME VIII, and R6 codes.
  • Must be expert in ABAQUS or comparable tools such as ANSYS or LS-DYNA.
  • Must have experience with Altair HyperWorks or similar tools.
  • Must have coding and scripting skills using languages such as Python.
  • Must have knowledge of manufacturing methods, materials, and inspection techniques.
  • Must be able to lead teams supporting a range of customers and industry sectors, lead stress and structural integrity assessment projects, deliver and review technical assessments to recognised standards, mentor and guide junior engineers, work directly with clients, and demonstrate commercial awareness.
Responsibilities
  • Lead the scoping, bidding, and delivery of stress engineering work packages, and build and lead a team to deliver this work.
  • Lead bids and projects, develop future technical leaders, and plan capability, resourcing, and business-winning activities with the leadership team.
  • Lead project teams and technical work in client-facing roles, delivering stress analysis and structural integrity assessments.
  • Act as a technical lead for stress and structural integrity, providing expert advice, troubleshooting, and technical oversight.
  • Represent Assystem in client meetings.
  • Serve as an Independent Technical Approver to ensure engineering standards are met.
  • Use finite element analysis and traditional hand calculations to justify strength, fatigue, defect tolerance, and structural performance against international codes and standards, including pressure-vessel and defect-tolerance codes.
  • Collaborate with safety case authors, design engineers, and multidisciplinary delivery teams.
  • Mentor junior engineers, provide technical guidance, and help develop stress specialists.
  • Support the strategic development roadmap for the UK stress engineering capability.
  • Maintain and improve technical processes, methods, best-practice guides, and quality frameworks.
  • Monitor workload, skill gaps, and training needs across the stress discipline.
  • Lead technical upskilling initiatives, including internal training pathways.
  • Work with Engineering Directors and Business Management teams to forecast demand, plan workforce requirements, and shape the long-term capability pipeline.
  • Support recruitment campaigns, interviewing, and candidate selection.
  • Support retention by fostering a supportive culture, mentoring talent, and providing growth opportunities.
  • Collaborate with Sales and Business Development teams to identify opportunities where stress capability adds value.
  • Lead bids, proposals, client presentations, and technical sales materials.
  • Represent stress capability in major pursuits and innovation initiatives.
  • Act as a visible leader and ambassador for stress engineering across Assystem and with clients.
  • Build and maintain relationships with key technical stakeholders, partners, and industry bodies.
  • Hold or be able to obtain Security Check (SC) clearance without caveats.
Desired Qualifications
  • Experience in computational fluid dynamics, dynamics, fatigue, and degradation mechanisms.

About the company

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

Get referred to ASSYSTEM

See people who can refer or advise you

Simplify Jobs

Simplify's Take

What believers are saying

  • H1 2026 revenue grew 2.5% organically; nuclear grew 8.0%.
  • France delivered 4.2% organic growth on new-builds, fuel cycle, and digitalisation.
  • UK momentum accelerated after April 2026 SMR, CPS2, and MoD framework wins.

What critics are saying

  • Nuclear concentration leaves Assystem exposed if French EPR2 schedules slip beyond 2027.
  • H1 2026 international revenue fell from currency hits and project endings in India.
  • Rolls-Royce SMR still needs FID, regulatory clearance, and site decisions before revenue scales.

What makes ASSYSTEM unique

  • Assystem derived 81% of H1 2026 revenue from nuclear engineering.
  • April 2026 UK wins placed Assystem on CPS2 and MoD delivery frameworks.
  • January 2025 Mactech Energy Group deepened Assystem's UK nuclear construction capabilities.

Help us improve and share your feedback! Did you find this helpful?

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

Company News

Yahoo Finance
Jul 23rd, 2026
Assystem's H1 revenue rises 2.5% organically to $371.2M on nuclear growth

Assystem reported consolidated revenue of €328.5 million for the first half of 2026, representing organic growth of 2.5% despite a 1.9% negative currency effect. The French engineering group's nuclear activities drove performance with 8.0% organic growth, accounting for 81% of total revenue. Revenue in France rose 4.2% organically to €201.1 million, led by strong momentum in nuclear new-builds and fuel cycle activities. International operations generated €127.4 million, remaining stable organically despite currency headwinds from the pound sterling, Indian rupee, and Saudi riyal. The UK showed robust growth in civil nuclear engineering and defence. However, business volumes declined in the Middle East, Central Asia region and India due to project endings and slower contract phasing. Assystem confirmed its full-year 2026 targets.

Yahoo Finance
Apr 23rd, 2026
Assystem posts $187.4M Q1 revenue with 2.2% organic growth driven by nuclear sector

Assystem, an international engineering group, reported first-quarter 2026 consolidated revenue of €165.8 million, representing 2.2% organic growth driven by strong nuclear sector performance of 8.0%. Nuclear activities accounted for 81% of total revenue, up from 76% in the prior year. French operations grew 4.4% to €102.6 million, driven by momentum in fuel cycle activities, new-builds and digitalisation. International revenue declined 7.1% to €63.2 million, primarily due to a 6.0% negative currency effect from the pound sterling, Indian rupee and Saudi riyal. The UK showed robust growth in civil nuclear engineering and defence. Assystem secured key positions on government frameworks and its client Rolls-Royce SMR signed a contract with Great British Energy for three small modular reactors.

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 has… | 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
France’s Assystem acquires India’s L&T Infrastructure Engineering - Global Construction Review

France-headquartered engineer and project manager Assystem has acquired India’s L&T Infrastructure Engineering, a subsidiary of the Larsen & Toubro group.