Senior or Principal Mechanical Engineer

Contract Opportunity: Senior / Principal Mechanical Engineer

Sellafield MSSS-OBLM Projects

51-61 per hour (Inside IR35)
Hybrid - 3 days per week in Warrington
Sector: Nuclear | MSSS-OBLM Programme

Are you an experienced Senior or Principal Mechanical Engineer looking to play a key role on one of Sellafield's most critical programmes? This opportunity sits within the MSSS-OBLM (Multi-Storey Seismic Stores - On-Balance Legacy Materials) projects, delivering essential mechanical engineering support to safety-critical, legacy nuclear infrastructure.

You'll provide technical leadership and delivery assurance across task-based mechanical work packages, supporting the safe progression of complex designs within a highly regulated environment. The role offers a hybrid working model, balancing collaboration in Warrington with remote working flexibility.

Key Responsibilities

• Deliver and manage mechanical engineering tasks across MSSS-OBLM project scopes
• Develop, review and approve designs, calculations, specifications, and technical documentation
• Ensure compliance with Sellafield engineering standards, nuclear safety requirements, and site licence conditions
• Support design reviews, optioneering studies, risk assessments, and HAZOPs
• Provide technical leadership, mentoring and assurance to junior engineers
• Collaborate closely with multi-disciplinary teams to achieve safe, efficient project delivery

What We're Looking For

• Proven experience operating at Senior or Principal Mechanical Engineer level
• Background in nuclear or similarly highly regulated industries
• Strong technical capability across mechanical systems, structures, and process equipment
• Experience delivering task-based engineering packages to programme, cost and quality requirements
• Familiarity with Sellafield MSSS / OBLM design processes and standards (highly advantageous)
• SC clearance preferred or the ability to obtain

Why This Role?

• Competitive 51-61/hour (Inside IR35)
• Long-term opportunity on a high-profile Sellafield MSSS-OBLM programme
• Hybrid working with 3 days per week in Warrington
• Technically complex, safety-critical work with real national importance
• Opportunity to influence design decisions and support the next generation of engineers

Apply now to bring your mechanical engineering expertise to one of Sellafield's most significant legacy infrastructure programmes.