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Radiant is seeking a Principal Nuclear Engineer to lead interdisciplinary nuclear engineering efforts for Kaleidos, a 1-megawatt portable nuclear microreactor designed for rapid deployment to hospitals, data centers, remote sites, and military bases. The reactor can operate for up to 5 years without refueling and is positioned as a fail-safe alternative to diesel generators.
In this role, you will lead a multidisciplinary nuclear engineering team and serve as the technical authority across reactor physics, neutron and radiation transport, shielding, thermal-hydraulics, safety analysis, instrumentation and controls, and regulatory evaluations. You will own nuclear engineering projects from requirements and early design through analysis, verification, validation, testing, and regulatory documentation.
Key responsibilities include establishing technical priorities and resource allocation across the nuclear engineering organization; serving as an expert in neutron transport and Monte Carlo simulation methods; guiding analyses of criticality, reactivity control, power distribution, radiation transport, dose, and shielding; translating analytical results into actionable design decisions; establishing rigorous practices for model verification, peer review, and configuration control; collaborating across reactor systems, thermal, mechanical, electrical, test, operations, and regulatory teams; and mentoring junior engineers.
You will also support reactor testing and startup activities, identify technical risks, drive complex problems to closure, and communicate recommendations to engineering leadership. The ideal candidate brings 9+ years of nuclear engineering experience in design, analysis, testing, licensing, or operations, with demonstrated expertise in leading complex projects and managing technical teams. Deep knowledge of neutron transport theory, Monte Carlo methods, and practical experience with tools like MCNP or OpenMC is essential. Experience translating analysis into design decisions and familiarity with nuclear software quality practices are required. Preferred qualifications include advanced degrees, experience with advanced or microreactor systems, proficiency with simulation tools like SCALE or Serpent, Python programming skills, and exposure to NRC licensing or DOE authorization processes.
