Senior Principal Mechanical Engineer – Nuclear Fusion, Hybrid

Assystem UK Ltd; Olney; Hybrid; GBP 110,000 - 140,000; Full time

Benefits offered by this job

Holiday bonuses

Employee Committee

Training opportunities

Hybrid work: 1–2 days remote per week

Job summary

Assystem UK Ltd, a leading nuclear engineering firm, invites applications for a Senior Principal Mechanical Engineer joining the Fusion and Modular Nuclear (FMN) unit. You will lead design development across cutting-edge projects enabling net-zero power generation, with emphasis on safety, reliability, and regulatory compliance.

Based in the UK with potential for international collaboration, you will oversee multi-disciplinary teams, manage risk, and deliver high-quality design packages and

Qualifications

• Experience leading engineering teams across multiple disciplines.
• Budgeting and lifecycle planning experience.
• Knowledge of ONR, Environment Agency, and HSE.
• Security clearance eligibility (SC).
• Strong systems engineering mindset.

Responsibilities

• Lead and oversee design package production aligned with specifications and standards.
• Coordinate interfaces between engineering teams, suppliers, and stakeholders.
• Develop technical specifications for procurement, fabrication, and installation of cooling water components.
• Maintain Risk Register and support HAZID/DFMEA activities.
• Collaborate with cross-functional teams across engineering and project functions.

Skills

Multi-Disciplinary Team Leadership

Systems Engineering Awareness

Regulatory & Compliance Knowledge

Security Clearance Eligibility

Chartered Engineer (CEng)

Education

CEng (Chartered Engineer)

Job description

Assystem UK Ltd, a leading nuclear engineering firm, invites applications for a Senior Principal Mechanical Engineer joining the Fusion and Modular Nuclear (FMN) unit. You will lead design development across cutting-edge projects enabling net-zero power generation, with emphasis on safety, reliability, and regulatory compliance.

Based in the UK with potential for international collaboration, you will oversee multi-disciplinary teams, manage risk, and deliver high-quality design packages and