The Senior Nuclear Systems Engineer supports the development of a next‑generation nuclear power plant as part of a multidisciplinary engineering team responsible for Nuclear Island (NI) systems‑level design. This role is intended for experienced engineers who can act as a technical authority for assigned NI systems, independently leading system‑level design, integration, and licensing activities while mentoring junior engineers in a highly regulated environment. Supporting the SMR‑300, this position works closely with engineering, manufacturing, and licensing teams as part of a U.S. Government cost‑shared development program, developing system requirements, specifications, analyses, and design documentation to support safe, compliant, and executable plant designs.
Location: Almondsburry, UK or Madrid, Spain
Primary Responsibilities
- Lead multi‑disciplinary system engineering and integration activities across major SMR‑300 plant systems, ensuring technical consistency and alignment across engineering disciplines
- Develop and manage system requirements, interface definitions,



and component specifications to support detailed design, analysis, and licensing activities
- Serve as a technical mentor to early‑career and mid‑level systems engineers, providing design guidance and reviewing calculations, specifications, and technical deliverables
- Perform and oversee engineering analyses and calculations, particularly in areas related to thermal‑fluids and overall plant system performance
- Conduct and support technical trade studies and design evaluations that inform high‑impact decisions affecting plant architecture, safety, and performance
- Coordinate closely with licensing, safety, and regulatory teams to ensure system designs support safety case development and meet applicable codes and regulatory expectations
- Collaborate with internal engineering teams, suppliers, and manufacturing partners to ensure system designs are technically sound, manufacturable, and execut

📌 Senior Nuclear Systems Engineer (Madrid)
🏢 Holtec
📍 Madrid