Nuclear Engineer

El Segundo, CA

Radiant is a nuclear technology company developing Kaleidos, a 1.2 MWe portable nuclear microreactor. Based in El Segundo, CA and made up of engineers from the Naval Reactors Program, national labs, and SpaceX, Radiant’s product is meant to offer a viable zero-emissions option for power in remote locations and as a backup for critical resources. Our reactors are designed to be factory produced and operated as a fleet, enabling the lowest operating costs and deployment timelines. The safety and reliability of Kaleidos will be demonstrated through a full-scale prototype on a 5-year development timeline – faster than any modern competing design. Radiant partners with many national laboratories and universities to advise on computational modeling, hardware development, and regulatory interaction that supports the fast-paced in-house design. Radiant is funded by awards from the Department of Energy and the Department of Defense as well as venture capital investment.

Key Duties & Responsibilities:

  • Nuclear engineer to aid design efforts for the Kaleidos Fission Battery (KFB), a 1 MWe high-temperature gas microreactor utilizing Tri-Structural Isotropic (TRISO) particle fuel in a prismatic block design.
  • Develop analysis cases to automate reactor design calculations within our simulation pipeline.
  • Participate in development of multiphysics models.
  • Investigate various methods of reactivity control for regulating power, preventing accident scenarios, and extending core lifetime.
  • Provide expertise on nuclear engineering to engineers in other functional areas.
  • Must be willing to relocate to Radiant office in Los Angeles, CA.

Required Qualifications & Skills:

  • Hold at least Bachelor’s degree in nuclear engineering, physics, engineering physics or equivalent degree from accredited institution
  • Understand reactor physics fundamentals: neutron transport, heat transfer, fluid dynamics
  • Familiarity with analysis code: reading syntax, developing analysis cases, object-oriented programming principles
  • Communicate effectively within a collaborative and interdisciplinary group
  • Have an attitude of ownership and mentorship over core design aspects
  • Hands-on experience owning or building projects

Desired Qualifications & Skills:

  • Analysis experience in Monte Carlo neutron transport codes: Serpent, MCNP, OpenMC
  • MOOSE framework and applications: MOOSE, BISON, RELAP-7
  • Specific programming language experience: Python, C#
  • Reactor design optimization experience
  • Automation experience
  • Test design experience 


  • Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
  • Vision: 100% coverage
  • Dental: 100% coverage, orthodontia extra
  • Voluntary Life, Accident, Hospital, Critical Illness, Commuter Benefits, and FSA are offered as employee contributed benefits.
  • Vacation/Sick time