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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.
As Senior Safety Analysis Engineer, you will lead comprehensive reactor safety analyses supporting the design, testing, and deployment of Kaleidos. You will evaluate reactor behavior across normal operations, transient events, and postulated accident scenarios, assess safety margins, and develop technically defensible analyses that inform both design decisions and regulatory evaluations.
Key responsibilities include:
- Leading deterministic reactor safety analyses covering anticipated operational occurrences, transients, and accident scenarios
- Developing and applying system-level thermal-hydraulic and transient models to evaluate reactor response, operating limits, and safety margins
- Performing source term and radiological consequence analyses, including fuel performance, fission product release and transport, and dose evaluations
- Evaluating uncertainties in reactor physics, power distributions, fuel behavior, and thermal-hydraulic models and their impact on safety conclusions
- Applying sensitivity studies, bounding assumptions, and phenomena-ranking methods to develop technically defensible analysis approaches
- Collaborating with nuclear, mechanical, thermal, materials, and controls teams to establish analysis inputs, evaluate design alternatives, and resolve safety-related technical challenges
- Partnering with testing and materials teams to identify data gaps, establish validation requirements, and correlate analytical predictions with experimental results
- Developing and improving safety analysis methods, models, and tools, including verification and validation, configuration control, and uncertainty quantification
- Preparing and technically reviewing calculation packages, safety analysis reports, and regulatory documentation supporting reactor design and licensing activities
- Working with regulatory and safety teams to establish safety requirements, support technical submissions, and resolve technical issues through closure
This role combines reactor systems and thermal-hydraulic analysis with fuel performance, source term development, and radiological consequence assessments. You will own complex analytical work from methodology development and model execution through uncertainty evaluation, technical review, and documentation, working closely with cross-functional teams.
REQUIREMENTS:
- Bachelor's degree in nuclear engineering, mechanical engineering, or related technical discipline from an accredited institution
- 5+ years of relevant experience in reactor safety analysis, thermal-hydraulics, nuclear systems modeling, or related engineering disciplines
- Experience developing and applying reactor systems or safety analysis codes such as RELAP5-3D, TRACE, SAM, MELCOR, or equivalent tools
- Strong understanding of reactor thermal-hydraulics, transient behavior, heat transfer, and deterministic safety analysis
- Knowledge of reactor physics, fuel performance, fission product behavior, and radiological safety principles
- Experience developing or evaluating source terms, radiological consequences, or other safety-related performance calculations
- Experience evaluating modeling assumptions, uncertainty, sensitivity, and conservatism in engineering analyses
- Demonstrated ability to independently own complex analytical projects and translate results into design requirements, safety conclusions, and technical documentation
- Strong written and verbal communication skills, including experience preparing rigorous calculation packages, technical reports, or safety-related engineering documentation
PREFERRED QUALIFICATIONS:
- Master's degree or Ph.D. in nuclear engineering, mechanical engineering, or related technical discipline
- Experience with high-temperature gas-cooled reactors, microreactors, advanced reactors, or first-of-a-kind nuclear systems
- Experience with TRISO fuel performance, irradiation behavior, fuel failure mechanisms, and fission product release and transport
- Familiarity with source term, dose consequence, or fuel performance tools such as ORIGEN, MACCS, PARFUME, or BISON
- Experience with reactor physics and neutronics tools such as MCNP, OpenMC, Serpent, or SCALE
- Familiarity with probabilistic risk assessment (PRA), licensing basis event selection, and risk-informed safety methodologies
- Experience with safety analysis code verification and validation, uncertainty quantification, and nuclear quality assurance practices
- Familiarity with DOE authorization processes, NRC licensing frameworks, nuclear industry codes and standards, or regulatory safety analysis
- Experience supporting reactor testing, safety basis development, regulatory submissions, or technical engagement with regulators
Must be mission-driven and willing to support extended hours when needed. Must work 100% onsite at Radiant's El Segundo headquarters.
