Principal Mechanical Engineer

The Opportunity

Are you ready to play a leading role in shaping the future of clean energy? This is a unique opportunity to join a growing engineering team supporting the development of Small Modular Reactor (SMR) technology, alongside transformation work across the UK nuclear fleet. With increasing demand from SMR developers and major infrastructure programmes, this role has arisen as part of a significant expansion phase.

You’ll take a senior technical leadership role, delivering complex mechanical design solutions across high-profile nuclear projects. In return, you’ll benefit from flexible working, strong career development support, professional membership funding, private medical cover, and a culture that genuinely prioritises wellbeing and progression.

• Lead and deliver mechanical design solutions to time, cost and quality requirements
• Take ownership of technical challenges, developing strategies and implementing solutions
• Produce and review key design documentation (e.g. specifications, calculations, methodology plans)
• Collaborate with multidisciplinary and international teams, including SMR technology developers
• Support regulatory processes, including contributing to the Generic Design Assessment (GDA)
• Present and justify engineering decisions to regulatory bodies
• Fulfil and manage CDM responsibilities where applicable
• Work closely with Engineering and Operations Managers to maximise project delivery value

• Degree qualified in Mechanical Engineering (BEng, MEng, MSc or equivalent)
• Experience delivering design solutions within nuclear or other highly regulated industries
• Chartered Engineer status (or working towards) with a relevant institution
• Strong background in mechanical equipment design (e.g. pumps, valves, heat exchangers, HVAC systems)
• Experience producing technical documentation and engineering drawings (BS EN standards, P&IDs)
• Knowledge of CAD tools such as AutoCAD, Inventor, Creo or Solid Works
• Familiarity with safety cases and engineering design in regulated environments
• Experience working within multidisciplinary engineering teams

• Experience working with or applying American design codes
• Understanding of UK nuclear regulatory processes and requirements
• Experience with tools such as MATLAB or MathCAD
• Background in writing test plans for equipment qualification
• Exposure to the Generic Design Assessment (GDA) process

This role is based within a collaborative and supportive engineering environment working across multiple UK locations, with flexible and hybrid working options available. You’ll be part of a team delivering critical infrastructure projects that support the transition to low‑carbon energy, with strong emphasis on safety, inclusion, and professional growth.

Millbank Holdings Ltd is an equal opportunities employer committed to creating an inclusive and diverse workforce. We welcome applications from all suitably qualified individuals, regardless of background, and encourage candidates from underrepresented groups to apply.

We are proud to be a member of the Disability Confident Scheme, and we are committed to ensuring an accessible and supportive recruitment process for everyone. If you require any adjustments at any stage, please let us know and we’ll do our best to accommodate.

Millbank operates as both an Employment Agency and an Employment Business.