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Radiant is building the world's first mass-produced, portable nuclear microreactors. The Kaleidos microreactor is a 1-megawatt, fail-safe system designed for rapid deployment to hospitals, data centers, remote sites, and military bases, capable of running up to 5 years without refueling. The company is on track to test its first reactor at Idaho National Laboratory in summer 2026, with customer deliveries beginning in 2028.
As Nuclear Engineer for Sensors & Instrumentation, you will own the design, specification, and qualification of sensor and instrumentation solutions for the Kaleidos microreactor. This role encompasses radiation detection systems (fission chambers, ion chambers), neutron flux monitoring, and instrumentation design for reactor physics, shielding, and safety analysis.
Key responsibilities include: designing and specifying in-core and ex-core detector systems; supporting detector response modeling using radiation transport codes (MCNP, OpenMC, Serpent); evaluating sensor survivability under high-temperature, high-radiation, and accident conditions; integrating sensor outputs with reactor control and data acquisition systems; and supporting verification and validation against customer and regulatory requirements. You will work closely with reactor control engineers, DAQ specialists, and a collaborative nuclear engineering team in a fast-paced startup environment.
Required qualifications: Bachelor's degree in nuclear engineering; 1–2+ years of nuclear engineering industry experience with exposure to radiation detection or instrumentation; experience with radiation transport methods; proficiency in Python, C++, C#, FORTRAN, or similar scientific computing languages; basic knowledge of thermal hydraulic principles; and strong communication and organizational skills.
Desired qualifications include hands-on sensor/instrumentation design and testing in harsh environments, data acquisition systems experience, familiarity with variance reduction techniques (Attila4MC, ADVANTG), CAD software (NX, SolidWorks, SpaceClaim), dose consequence methods, and hardware design/testing experience.
The role requires 100% onsite work at El Segundo headquarters and willingness to work extended hours as needed. Radiant offers substantial equity grants, comprehensive health benefits (medical, dental, vision), 8 weeks paid parental leave, daily catered lunch, flexible PTO, and a collaborative team environment near the Pacific Ocean.
