Principal Mechanical Engineer
| Posting date: | 23 February 2026 |
|---|---|
| Salary: | £65,000.0 to £80,000.0 per year |
| Additional salary information: | £65,000 - £80,000 |
| Hours: | Full time |
| Closing date: | 02 March 2026 |
| Location: | Warrington, Cheshire, WA3 6AE |
| Company: | Hays Specialist Recruitment |
| Job type: | Permanent |
| Job reference: | 4773259_1771844831 |
Summary
Role Overview
An exceptional opportunity has arisen for a Principal Mechanical Engineer to join a major programme developing next‑generation Small Modular Reactor technology. This role offers the chance to work at the forefront of advanced nuclear engineering, contributing to one of the most innovative and high‑profile clean‑energy initiatives in the world. Engineers who are currently operating at Senior level and are ready to step up into a principal role will also be considered.
Key Responsibilities
- Lead the design and analysis of mechanical systems central to SMR performance, including pressure systems, thermal‑mechanical components, and plant‑wide mechanical assemblies.
- Act as Technical Authority for mechanical engineering, providing oversight, verification, and approval of design outputs.
- Ensure all work aligns with nuclear safety principles, regulatory expectations, and SMR‑specific design requirements.
- Lead the development and substantiation of safety‑classified mechanical systems, producing evidence to support safety case submissions.
- Conduct and review HAZOP, FMEA, reliability assessments, and stress/thermal analyses.
- Manage project delivery across multidisciplinary teams, ensuring outputs meet quality, cost, and schedule expectations.
- Engage with clients, regulators, and stakeholders, representing mechanical engineering interests in design reviews and technical discussions.
- Drive innovation in advanced nuclear mechanical systems, contributing to the evolution of SMR technology and engineering best practice.
Required Experience
- Extensive experience in nuclear mechanical engineering or other highly regulated, safety‑critical industries.
- Strong understanding of safety‑classified equipment, substantiation, and safety case requirements.
- Proven ability to lead engineering teams delivering complex mechanical design packages.
- Experience with pressure systems, thermal‑mechanical design, and plant mechanical infrastructure.
- Familiarity with UK nuclear regulatory bodies, standards, and relevant BS/EN/ASME codes.
Desirable ExpertiseExperience in one or more of the following areas would be highly advantageous:
- Water systems - cooling circuits, heat exchangers, reactor support systems.
- Material handling - lifting, transport, and remote handling systems used in nuclear environments.
- Rotating machinery - pumps, turbines, compressors, or other high‑integrity rotating equipment.
Preferred Qualifications
- Chartered Engineer (CEng) or working toward chartership.
- Degree in Mechanical Engineering or a related discipline.
- Experience with digital engineering tools, modelling platforms, or nuclear‑specific analysis software.
SummaryThis is a rare opportunity to contribute to a landmark SMR programme, working on advanced technologies that will define the next generation of clean, secure, and scalable nuclear power. Senior engineers with the ambition to step into a principal‑level role are strongly encouraged to apply.
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