Senior / Principal CE&I Design Engineer - Silos MSSS SEP1&2 Sellafield Site (3 days/week on plant) | West Cumbria Design Office | Monthly Warrington visit Up to £80/hour (Inside IR35) | SC Clearance required | An opportunity has arisen for a Senior or Principal CE&I Design Engineer to join the Silos MSSS SEP1&2 CE&I design team, supporting one of the UK's most complex and safety-critical nuclear environments at Sellafield. This role is central to providing front-line, site-based design support to Commissioning teams, ensuring that detailed CE&I designs and changes are delivered, reviewed, and verified to meet stringent functional and business requirements. You will play a key role in shaping safe, compliant, and buildable engineering solutions-while delivery and commissioning execution is handled by dedicated site teams. Key Responsibilities Provide site-based CE&I design support to commissioning activities on MSSS plant (SEP1 & SEP2) Deliver and/or check detailed CE&I designs and modifications Support and guide delivery of engineering outputs across multidisciplinary teams Ensure compliance with relevant external standards, including: PES-based control systems Process instrumentation standards Work closely with commissioning and site delivery teams to resolve technical issues in real time Contribute to design assurance and technical governance Mentor and support early career engineers where appropriate Essentia...