Mechanical Engineer

Oxford Sigma

Our vision is to accelerate the deployment of energy and defence systems that strengthen energy security and national resilience. 

Our mission is to develop and deploy advanced materials technologies that meet the critical needs of fusion, nuclear, and security applications

About us: We are a small, organically grown, company owned and operated by scientists and engineers, with our roots and headquarters in Oxford. We have established ourselves as a highly respected technical service supplier for the fusion energy market, within both the private and public sectors, nationally and internationally. We are equally a research and technology development company developing novel disruptive materials and design technologies to help in the required fundamental shift for the world’s clean energy future.

We are expanding our wider team to support the business in bringing materials and process engineering solutions for fusion.

This role will include the following duties:

• Designing and developing comprehensive engineering systems for nuclear and non-nuclear projects.
• Complete, and justify structural integrity of, designs through finite element analysis (FEM) and thermomechanical assessments, including elevated temperature and pressure conditions.
• Developing specifications for prototypes and commercial products, ensuring alignment with performance and quality requirements.
• Produce detailed designs and engineering drawings in accordance with recognised codes, standards and specifications (such as ASTM, EN, BS, ASME BPC / B31).
• Collaborate with manufacturers to procure high-quality components and assemblies.
• Identify and implement environmental, health, and safety considerations for prototype and commercial products.
• Maintain clear documentation on development activities, engineering decisions using standard practices.
• Build and maintain relationships with subcontractors to support engineering progression.
• Supporting the upskilling of team members in structural analysis and FEM methodologies.

Ideally, you will have some of these:

• Bachelor’s (or higher) degree in Mechanical Engineering or a related discipline.
• 3 - 5 years industrial experience in structural mechanics design, ideally in nuclear.
• Proficiency in CAD software (SOLIDWORKS, AutoCAD, or similar).
• Proficiency in FEM software (COMSOL or similar).
• Strong understanding of materials, manufacturing, and mechanical systems.
• Demonstrated expertise in the design, manufacture, and operation of complex process engineering systems, consistently delivering high-quality outputs in accordance with recognised industrial standards (such as ASME BPV or B31).
• Strong motivation to solve engineering challenges using a blend of first-principles thinking, practical design experience, and advanced simulation techniques.
• Awareness of legal and contractual aspects of project activities, such as procurement, processes, negotiation strategies, and regulatory compliance.
• An ability to communicate technical concepts to technical non-specialists.
• Excellent verbal and written communication and presentation skills.
• Experience as a project team member in a multi-partner environment.

Additionally, it is desirable if you have:

• Experience in Model-Based Systems Engineering (MBSE).
• Experience in liquid metal systems.

Due to the nature of the work, candidates must be British citizens and have been continuously resident in the UK for the past five years.