Senior Structural Engineer – Concrete & Precast Design

ABOUT RADIANT Radiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. The company’s first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. Portable nuclear power with rapid-deploy capability can replace similar-sized diesel generators and provide critical asset support for hospitals, data centers, remote sites, and military bases. Radiant’s unique, practical approach to nuclear development leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028. About the Role Radiant is seeking a highly motivated Senior Structures Engineer to design and develop critical concrete and precast structural systems supporting Radiant's manufacturing and deployment sites. You will solve unique challenges creating efficient, reliable concrete structures capable of surviving extreme thermal and seismic environments while meeting site and program constraints. You will be responsible for trade studies, material selection, detailed structural analysis, assembly, integration, and testing. You will play a critical role enabling the manufacturing, fueling, and safe storage infrastructure that supports Radiant's microreactors. Responsibilities & Duties: - Ownership of critical concrete structures such as spent fuel dry cask storage systems, factory and facility foundations, and precast concrete elements supporting manufacturing and site operations. - Conduct trade studies and develop designs to meet program requirements for static, thermal, and seismic loading conditions. - Perform detailed structural analysis (reinforced and precast concrete design, static strength, durability) and dynamic analysis (seismic qualification) to determine structural integrity (margins of safety) using both hand calculations and finite element tools. - Develop and execute construction, fabrication, and test plans for precast and cast-in-place concrete elements. - Create and manage a Bill-of-Materials (BOM). - Find and develop suppliers and fabricators for precast concrete components. - Own subassembly/structure design, fabrication, and test schedules. - Own risk analysis (FMEA) for concrete structural subsystems. - Collect requirements, provide expertise and feedback to engineers in other functional areas via clear, constructive communication. Required Qualifications & Skills: - Bachelor's degree from an accredited institution in Civil, Structural, or Mechanical Engineering. - 5+ years of experience designing concrete or reinforced concrete structures. - 4+ years of experience performing structural analysis using both hand calculations and finite element tools (Abaqus, Ansys, SAP2000, or similar). Desired Qualifications & Skills: - Active PE license (not required) - Experience with reinforced concrete design codes (ACI 318 or similar). - Experience designing precast concrete systems, including handling, transport, and erection considerations. - Experience with dry cask storage design or spent nuclear fuel storage systems. - Experience with seismic design/qualification of concrete structures. - Experience with nuclear or other critical-facility structural design. - Experience designing hardware/structures that were fabricated, deployed, and iteratively improved. - Experience resolving thermal expansion and thermal gradient issues in concrete designs. - Experience working with interdisciplinary teams (mechanical, civil, geotechnical). - Solid understanding and application of GD&T and construction tolerancing. - Proficiency with both "hand calc" analytical methods and higher-fidelity finite element-based analysis methods. - Ability to derive free-body diagrams for systems with which…