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Radiant is building the world's first mass-produced, portable nuclear microreactors. The company's flagship product, Kaleidos, is a 1-megawatt, fail-safe microreactor designed for rapid deployment to hospitals, data centers, remote sites, and military bases. Founded in 2020, Radiant is preparing for testing at Idaho National Laboratory with initial customer deliveries planned for 2028.
You will lead an interdisciplinary nuclear engineering team responsible for the design, analysis, and licensing of Kaleidos. This role combines hands-on technical leadership with team management and project ownership. You will guide nuclear engineering work across all phases: requirements definition, design trades, analysis, verification and validation, testing, and regulatory documentation.
Key responsibilities include:
- Leading a team across reactor physics, core performance, shielding, thermal-hydraulics, safety analysis, instrumentation and controls, and reactor operations
- Hiring, managing, and developing high-performing nuclear engineers with clear expectations, technical guidance, and coaching
- Establishing team priorities, project plans, schedules, resource allocation, and budgets
- Owning nuclear engineering projects from requirements through final documentation
- Guiding analyses of criticality, reactivity control, power distribution, radiation transport, dose, activation, and shielding
- Translating analytical results into actionable design requirements affecting core, shielding, control systems, and hardware
- Establishing rigorous practices for model verification, validation, peer review, configuration control, and technical documentation
- Ensuring analytical assumptions, uncertainties, margins, and conclusions are clearly documented and defensible
- Collaborating across reactor systems, thermal, mechanical, electrical, test, operations, safety, and regulatory teams
- Working with regulatory teams to translate nuclear standards into analysis plans, design criteria, and verification activities
- Supporting reactor testing and startup by defining analysis needs, instrumentation requirements, and acceptance criteria
- Identifying and mitigating technical and programmatic risks
- Communicating technical status, risks, and recommendations to engineering teams and leadership
The ideal candidate brings deep technical judgment, strong engineering fundamentals, and the ability to translate complex nuclear analysis into practical design decisions. You should be comfortable in a fast-moving, interdisciplinary environment while developing engineers and driving difficult technical problems to closure. The role requires 100% onsite presence at Radiant's El Segundo headquarters and willingness to support extended hours for critical program milestones.
REQUIREMENTS:
- Bachelor's degree in nuclear engineering or related technical discipline from an accredited institution
- 5+ years of relevant nuclear engineering experience across reactor design, analysis, testing, licensing, safety, or operations
- 1+ year of experience managing direct reports
- Demonstrated experience leading complex nuclear engineering projects involving multiple technical disciplines and stakeholders
- Deep knowledge of neutron transport theory, Monte Carlo simulation methods, nuclear data, and statistical convergence
- Professional experience developing and applying MCNP, OpenMC, or comparable neutron and radiation transport models
- Strong understanding of reactor physics concepts including criticality, reactivity coefficients, depletion, power distribution, shutdown margin, neutron and gamma transport, and uncertainty analysis
- Experience translating analytical results into reactor design decisions, technical requirements, safety conclusions, or regulatory documentation
- Familiarity with model verification and validation, configuration control, peer review, and nuclear software quality practices
- Strong written and verbal communication skills for explaining complex analyses, assumptions, uncertainties, and technical conclusions to multidisciplinary teams
PREFERRED QUALIFICATIONS:
- Master's degree or Ph.D. in nuclear engineering or related technical discipline
- Subject-matter expertise in safety analysis, shielding, radiation dose and activation, instrumentation and controls, reactor operations, thermal-hydraulics, or radioactive-material transportation
- Experience with high-temperature gas-cooled reactors, microreactors, advanced reactors, or first-of-a-kind nuclear systems
- Experience with SCALE, Serpent, Shift, Griffin, MOOSE-based applications, or similar nuclear analysis tools
- Proficiency with Python or another language for simulation automation, model generation, and analysis post-processing
- Experience with coupled neutronics and thermal-hydraulics or other multiphysics analyses
- Familiarity with DOE authorization processes, NRC licensing, nuclear industry codes and standards, or regulatory safety analysis
- Experience supporting reactor testing, commissioning, startup, or operational readiness
- Experience building or expanding a nuclear engineering team or analytical capability
