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