<div>Radiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. The company’s first reactor, Kaleidos, is a 1-megawatt failsafe microreactor that can be transported anywhere power is needed and run for up to five years without the need to refuel. Portable nuclear power with rapid deploy capability can replace similar-sized diesel generators, and provide critical asset support for hospitals, data centers, remote sites, and military bases. Radiant’s unique, practical approach to nuclear development utilizes modern software engineering to rapidly achieve safe, factory-built microreactors that leverage existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor next year at the Idaho National Laboratory, with initial customer deliveries beginning in 2028.</div>Senior Materials EngineerRadiant is seeking a highly motivated Sr. Materials Engineer to own development, testing, and qualification of in-core materials and related manufacturing processes used in the Kaleidos 1MW nuclear microreactor. The ideal candidate takes great ownership of their work end-to-end, is proficient in materials selection, testing, and analysis, and is excited to work in a highly cross-functional, fast-paced environment. You will be a key contributor to building the world's first mass-produced, rapidly-deployable nuclear reactor. Responsibilities &amp; Duties  <ul><li>Develop radiation resistant structural composite materials for Kaleidos and additional nuclear applications.</li><li>Plan and execute materials testing of ceramic composite materials to obtain material properties and inform design decisions.</li><li>Identify, procure, and operate equipment for composite development and production, materials characterization, and materials testing.</li><li>Evaluate data quality and accuracy of material property data for use in company materials database.</li><li>Define or improve manufacturing processes of components to achieve desired material properties.</li></ul>Required Qualifications &amp; Skills  <ul><li>Bachelor’s degree from an accredited institution in Materials Science and Engineering, or in Mechanical, Aeronautical, Nuclear, or Chemical Engineering with a materials science and engineering focus.  </li><li>Hands-on experimental or testing experience in laboratory or production environments.</li><li>5+ years of experience working in the development, testing, and/or analysis of materials for demanding load cases and environments.</li></ul>Desired Qualifications &amp; Skills  <ul><li>Master’s or PhD degree from an accredited institution in Materials Science and Engineering, or in Mechanical, Aeronautical, Nuclear, or Chemical Engineering with a materials science and engineering focus.  </li><li>Experience with structural ceramics design, characterization, and/or manufacturing.</li><li>Experience with Carbon-Carbon (C/C) Composites or Ceramic Matrix Composites (CMCs), such as C/SiC or SiC/SiC.</li><li>Experience with NDT (non-destructive testing) and inspection of composite materials.</li><li>Knowledge of standard test methods for materials and experience with development of design allowables.</li><li>Self-motivated with strong organizational, written, and oral communication skills. </li><li>Demonstrated ability to work collaboratively with design and operations teams to deliver high-value results.</li><li>Experience with using text-based software development tools (Python or similar).</li></ul>Additional Requirements<ul><li>Must be willing to work extended hours and weekends as necessary to accomplish our mission.</li><li>Must work 100% onsite at El Segundo HQ.</li></ul><div>Total Compensation and BenefitsRadiant's new hire compensation package includes base salary, substantial equity grants, and comprehensive benefits. Total compensation and level are determined through a holistic evaluation of your interview performance, experience, education, and qualifications. Benefits and Perks for Eligible Employees:<ul><li>Stock: Substantial incentive stock plan for all full-time employees.</li><li>Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.</li><li>One Medical: Sponsored memberships for employees and their dependents.</li><li>Vision: 100% top tier plan coverage + 50% for dependents.</li><li>Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.</li><li>Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.</li><li>8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.</li><li>Daily catered lunch. Free snacks and drinks.</li><li>Flexible PTO policy. Remote workday allocation.</li><li>Company and team-bonding events, happy hours and in-person camaraderie.</li><li>Beautiful El Segundo headquarters close to the Pacific Ocean.</li></ul>We are an equal opportunity employer and all qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity or expression, pregnancy, age, national origin, disability status, genetic information, protected veteran status, or any other characteristic protected by law.Unfortunately, we are unable to provide visa sponsorship at this time. This position involves access to technology that is subject to U.S. export controls. Any job offer made will be contingent upon the applicant’s capacity to serve in compliance with U.S. export controls. </div>

Radiant is a clean energy startup building a nuclear microreactor. A climate-friendly alternative to diesel generators, Radiant's Kaleidos 1MW microreactor will be the world's first portable, zero-emissions power source that works anywhere. We plan to test our development reactor by 2026 and if successful, it will be the first new commercial reactor design to achieve a fueled test in over 50 years. Our microreactor can bring power to remote parts of the world and provide backup power for life-saving applications in hospitals or disaster-relief scenarios.&nbsp;

Senior Materials Engineer, Composites

<div>Radiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. The company’s first reactor, Kaleidos, is a 1-megawatt failsafe microreactor that can be transported anywhere power is needed and run for up to five years without the need to refuel. Portable nuclear power with rapid deploy capability can replace similar-sized diesel generators, and provide critical asset support for hospitals, data centers, remote sites, and military bases. Radiant’s unique, practical approach to nuclear development utilizes modern software engineering to rapidly achieve safe, factory-built microreactors that leverage existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor next year at the Idaho National Laboratory, with initial customer deliveries beginning in 2028.</div>Senior Materials EngineerRadiant is seeking a highly motivated Sr. Materials Engineer to own development, testing, and qualification of in-core materials and related manufacturing processes used in the Kaleidos 1MW nuclear microreactor. The ideal candidate takes great ownership of their work end-to-end, is proficient in materials selection, testing, and analysis, and is excited to work in a highly cross-functional, fast-paced environment. You will be a key contributor to building the world's first mass-produced, rapidly-deployable nuclear reactor.&nbsp;Responsibilities &amp; Duties&nbsp;&nbsp;<ul><li>Develop radiation resistant structural composite materials for Kaleidos and additional nuclear applications.</li><li>Plan and execute materials testing of ceramic composite materials to obtain material properties and inform design decisions.</li><li>Identify, procure, and operate equipment for composite development and production, materials characterization, and materials testing.</li><li>Evaluate data quality and accuracy of material property data for use in company materials database.</li><li>Define or improve manufacturing processes of components to achieve desired material properties.</li></ul>Required Qualifications &amp; Skills&nbsp;&nbsp;<ul><li>Bachelor’s degree from an accredited institution in Materials Science and Engineering, or in Mechanical, Aeronautical, Nuclear, or Chemical Engineering with a materials science and engineering focus.&nbsp;&nbsp;</li><li>Hands-on experimental or testing experience in laboratory or production environments.</li><li>5+ years of experience working in the development, testing, and/or analysis of materials for demanding load cases and environments.</li></ul>Desired Qualifications &amp; Skills&nbsp;&nbsp;<ul><li>Master’s or PhD degree from an accredited institution in Materials Science and Engineering, or in Mechanical, Aeronautical, Nuclear, or Chemical Engineering with a materials science and engineering focus.&nbsp;&nbsp;</li><li>Experience with structural ceramics design, characterization, and/or manufacturing.</li><li>Experience with Carbon-Carbon (C/C) Composites or Ceramic Matrix Composites (CMCs), such as C/SiC or SiC/SiC.</li><li>Experience with NDT (non-destructive testing) and inspection of composite materials.</li><li>Knowledge of standard test methods for materials and experience with development of design allowables.</li><li>Self-motivated with strong organizational, written, and oral communication skills.&nbsp;</li><li>Demonstrated ability to work collaboratively with design and operations teams to deliver high-value results.</li><li>Experience with using text-based software development tools (Python or similar).</li></ul>Additional Requirements<ul><li>Must be willing to work extended hours and weekends as necessary to accomplish our mission.</li><li>Must work 100% onsite at El Segundo HQ.</li></ul><div>Total Compensation and BenefitsRadiant's new hire compensation package includes base salary, substantial equity grants, and comprehensive benefits. Total compensation and level are determined through a holistic evaluation of your interview performance, experience, education, and qualifications.&nbsp;Benefits and Perks for Eligible Employees:<ul><li>Stock: Substantial incentive stock plan for all full-time employees.</li><li>Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.</li><li>One Medical: Sponsored memberships for employees and their dependents.</li><li>Vision: 100% top tier plan coverage + 50% for dependents.</li><li>Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.</li><li>Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.</li><li>8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.</li><li>Daily catered lunch. Free snacks and drinks.</li><li>Flexible PTO policy. Remote workday allocation.</li><li>Company and team-bonding events, happy hours and in-person camaraderie.</li><li>Beautiful El Segundo headquarters close to the Pacific Ocean.</li></ul>We are an equal opportunity employer and all qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity or expression, pregnancy, age, national origin, disability status, genetic information, protected veteran status, or any other characteristic protected by law.Unfortunately, we are unable to provide visa sponsorship at this time. This position involves access to technology that is subject to U.S. export controls. Any job offer made will be contingent upon the applicant’s capacity to serve in compliance with U.S. export controls. </div>

Senior Materials Engineer, Composites

About the Job

About the Company

Radiant

Similar Jobs

Senior Materials Process Engineer

Senior Materials Process Engineer

Materials Engineer, Hydrides

Materials Engineer, Hydrides

Materials Engineer, Shielding Materials

Materials Engineer, Shielding Materials

Senior Structures Engineer

Senior Structures Engineer

Materials and Processes Engineer, Airframe

Materials and Processes Engineer, Airframe

Materials and Processes Engineer, Metallics

Materials and Processes Engineer, Metallics

Fall 2025 Internship - Materials Engineer

Fall 2025 Internship - Materials Engineer

Materials Engineer - 2026 New Graduate

Materials Engineer - 2026 New Graduate

Summer 2026 Internship - Materials Engineer

Summer 2026 Internship - Materials Engineer

Sr. Material and Process Engineer

Sr. Material and Process Engineer