ASSYSTEM
Principal Mechanical Engineer
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Principal Mechanical Engineer
Job Title: Senior Mechanical Engineer
Company Description
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 executing complex infrastructure projects, subject to high safety and security requirements.
Assystem mobilises 8,000+ experts across 13 countries and intervenes across the entire project lifecycle, including engineering, project management, and digital solutions.
About the Role
Are you an experienced Mechanical Engineer looking to lead exciting, technically challenging projects within a highly regulated industry? We are seeking a motivated and collaborative professional who thrives on solving complex engineering challenges, leading teams, and delivering innovative solutions for clients.
If you are passionate about engineering excellence and enjoy working in a dynamic, multidisciplinary environment, we’d love to hear from you!
Key Responsibilities
The Senior Mechanical Engineer will provide technical leadership and ensure the successful delivery of engineering solutions that meet customer requirements. Key duties include:
- Lead and inspire engineering teams to develop innovative technical solutions
- Work closely with Lead Engineers and Project Managers, providing regular updates on technical progress and project delivery
- Mentor and supervise engineers, supporting the development of junior team members
- Delegate work effectively while promoting teamwork and collaboration
- Proactively identify, review, and manage technical risks and opportunities
- Oversee the delivery of engineering work packages, ensuring technical quality
- Produce and review technical design reports, calculations, and engineering documentation to support technical files
- Manage workloads and support team delivery within time, budget, and quality standards
- Continuously develop expertise with an emphasis on knowledge transfer for project objectives
- Liaise with clients and subject matter experts in engineering, nuclear safety, operations, and safety disciplines
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Requirements
Qualifications & Experience
Minimum Requirements:
- 2:1 BEng in Mechanical Engineering (or equivalent)
- Demonstrable experience working in a highly regulated industry
- Working knowledge of relevant engineering legislation, including PED, PUWER, and LOLER
- Experience using 3D CAD software (e.g., Autodesk Revit, Inventor, AutoCAD, CATIA) (training provided if needed)
- Basic mathematical ability
Desirable Attributes:
- Master’s degree in Mechanical Engineering
- Chartered Engineer status (CIMP, IMechE, ICE, or equivalent) – desirably on track
- Comprehensive experience with FEA tools such as ANSYS, CAESAR II, or FlowMaster
- Strong understanding of mechanical and structural engineering principles, including pipework and vessel design
- Expertise with design lifecycle phases (concept to manufacture)
- Experience in Requirements-Led Design and/or Model-Based Systems Engineering (MBSE)
- Knowledge of producing technical files and LTQR packs
- Nuclear safety engineering experience
- Certification in Functional Safety (BS EN 61508/61511)
- Strong working knowledge of NEC3/NEC4 contracts
- Proven experience in engaging with supply chain partners to specify and develop equipment
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Desirable Skills
- Understanding of Functional Safety standards
- Experience with pipeline and mechanical systems (valves, pumps, supports, and ancillary components)
- Flexibility to manage multiple concurrent projects in a fast-paced environment
Additional Information
Security Restrictions
This role is subject to security and export control restrictions, meaning that nationality, past nationalities, and birthplace may affect eligibility. All applicants must meet Baseline Personnel Security Standards, with some roles requiring National Security Vetting (typically requiring 5–10 years of UK residency).
Fraud Awareness
We are committed to safeguarding candidates from recruitment fraud. We will never request payment or sensitive personal data at any stage of the process.
Diversity & Inclusion
Assystem is committed to diversity and equal opportunity. We believe diverse perspectives drive innovation and impact. Skills, talent, and vision are what matter—apply with confidence!
Job Details
Type: Permanent Sector: Defence & Nuclear Engineering Location: Global (Assystem presence in 13 countries)
📌 Join Assystem and shape the future of engineering excellence.
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