Materials Engineer - Core

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.

Position Description:  Radiant desires a motivated engineer who enjoys the fast-paced, creative environment of a startup coupled with a passion for developing advanced nuclear power systems.  The applicant would be the overall lead materials engineer for fuel, control materials, core graphite, and shielding materials, and would work closely with Radiant’s mechanical and nuclear engineering groups to evaluate long-term acceptability of these materials in a reactor environment. 

Key Duties and Responsibilities:

  • Core Graphite  Develop and implement a graphite qualification strategy for Radiant’s first reactor prototype. Specific details include:
    • Working with internal Radiant stakeholders to identify all graphite property design needs, as well as testing required per ASME Boiler and Pressure Vessel Code Section III Division V.
    • Reviewing literature on existing graphite grades to select a target graphite grade for qualification based on availability of design data, manufacturing constraints, and cost.
    • Planning and executing materials testing programs for a desired graphite grade.
    • Serving as a liaison between graphite vendors and internal Radiant stakeholders to develop a graphite procurement plan and requirements.
  • Reactor Control Materials
    • Lead materials assessments related to the use of boron carbide as a control material and burnable neutron absorber.
    • Lead design and materials assessments related to additional neutron poisons and reflectors.
  • Reactor Fuel Support - Team with internal nuclear engineering group to evaluate long-term performance of Tri-structural ISOtropic particle (TRISO) fuel for Radiant’s designs, and assist in specification development and procurement planning.
  • Shielding Materials – Perform life-performance assessments on high-Z and polymer-based shielding materials.

Required Qualifications & Skills:

  • Bachelor’s degree in materials engineering or mechanical engineering with materials focus.
  • Two or more years of job experience OR graduate/doctoral work in materials engineering, preferably related to at least one of the three areas discussed in “Key Duties and Responsibilities” section.
  • Familiarity with mechanical and thermal testing of metallic materials.
  • The ability to coordinate work and communicate in a dynamic, multi-disciplinary, multi-organization environment, which includes other engineers within Radiant as well as supporting engineers at universities and national laboratories.
  • Ability to work or gain permission to work on export controlled technologies based in the United States.

Desired Qualifications & Skills:

  • Five or more years of job experience OR graduate/doctoral work in materials engineering, preferably related to at least one of the three areas discussed in “Key Duties and Responsibilities” section.
  • Familiarity with ASME BPVC.
  • The ability to work with a high degree of autonomy to determine materials engineering initiatives that support the overall reactor design. This will involve navigating complex technical and regulatory requirements to establish materials analysis and testing needs, determining needed support from national labs/vendors/testing facilities, and leading large-scale work efforts.


  • 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