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, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. 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 leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.
About the RoleRadiant is seeking a Hardware-in-the-Loop (HIL) Engineer to support the development and maintenance of Radiant’s NI PXI-based HIL system for Kaleidos. You will work closely with senior engineers to assist in hardware integration, testing, and validation of critical systems. This role is ideal for someone with foundational experience in HIL systems and a desire to grow their skills in real-time testing, automated validation, and electrical integration within a collaborative team environment. You will have the opportunity to contribute to the development of electrical integration systems that support the first high-temperature gas-cooled portable microreactor ever commercialized.
Assist in designing, building, and maintaining HIL test bench systems.
Help configure test hardware, including power supplies, actuators, and sensor mapping.
Support communication and integration with Digital Twin systems.
Assist senior engineers with assembling and debugging HIL hardware and harnesses.
Execute test procedures, collect data, and support analysis.
Document test results, procedures, and lessons learned.
Troubleshoot electrical and hardware issues with guidance from senior team members.
Participate in design reviews and contribute ideas in a collaborative environment.
Required Skills and Qualifications:BS in Electrical Engineering, Computer Engineering, or a related field.
2+ years of experience with HIL systems such as dSpace, NI PXI, Speedgoat, or similar platforms.
Familiarity with NI HIL software (e.g., LabVIEW, TestStand) and programming/scripting in Python, C++, or C#.
Hands-on experience with data acquisition, test execution, or electrical integration.
Basic troubleshooting and debugging skills.
Ability to work effectively in a team and communicate across disciplines.
Desired Skills and Qualifications:Exposure to HW-SW integration and test procedures.
Understanding of fundamental controls, software testing, and test processes.
Interest in learning real-time simulation systems and FPGA-based systems.
Familiarity with trace capture tools or data acquisition/analysis tools.
Additional RequirementsMust be willing to work extended hours and weekends as necessary to accomplish our mission.
Must work 100% onsite at El Segundo HQ.
Benefits and PerksStock: Substantial incentive stock plan for all full-time employees.
Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
One Medical: Sponsored memberships for employees and their dependents.
Vision: 100% top tier plan coverage + 50% for dependents.
Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.
Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.
8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.
Daily catered lunch. Free snacks and drinks.
Flexible PTO policy. Remote workday allocation.
Company and team-bonding events, happy hours and in-person camaraderie.
Beautiful El Segundo headquarters close to the Pacific Ocean.
Total Compensation and Benefits
Radiant compensates people for impact and invests in those who continue to raise the bar. Radiant’s new hire compensation package includes base salary, substantial equity grants, and comprehensive health benefits. Total compensation and level are determined through a rigorous evaluation of interview performance, experience, education, and qualifications, and are designed to support continued growth as scope, responsibility, and impact expand at Radiant.
The best of today’s advanced reactor builders don’t wait for job postings. They join the winning team. If that’s you, contact us directly for immediate opportunities: recruiting@radiantnuclear.com.
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.
Compensation Range: $124,500 - $172,725
Read LessRadiant 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, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. 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 leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.
About the RoleRadiant is seeking a highly motivated Mechanical Engineer, Fluids Systems to help own critical Kaleidos fluid systems from preliminary design through build and production. These systems include the primary loop subsystems and power conversion loop, serving to convert heat from the reactor core into electrical power. You will be responsible for the following: trade studies, component selection, thermal hydraulic analysis, piping design, vendor selection, assembly, and testing. You will have an instrumental impact of fueling the first new commercial reactor design in over 50 years by 2026.
Responsibilities & Duties:
Help own end-to-end engineering of fluid systems and components, including compressors, valves, and heat exchangers.
Perform thermal and fluids analysis to drive design decisions, verify system performance, and ensure structural integrity using first-principle hand calculations and finite element tools.
Perform trade studies to optimize system and meet program requirements.
Develop and execute manufacturing/assembly instructions and test plans.
Create and manage a Bill-Of-Materials (BOM).
Find and develop suppliers for all components.
Own subassembly design, manufacturing, and test schedules.
Own risk analysis (FMEA) for subsystems.
Collect requirements, provide expertise and feedback to engineers in other functional areas via clear, constructive communication.
Required Qualifications & Skills:
Bachelor’s degree from an accredited institution in Mechanical, Materials, Aeronautical, Civil or Structural Engineering.
Experience with fluid system architecture design.
Experience in designing, building, and testing fluids systems.
Proficient knowledge in fluid dynamics and thermodynamics.
Proficient knowledge of heat exchanger design and analysis methods.
Desired Qualifications & Skills:
Knowledge of thermodynamic power cycles.
Prior experience with fluid system modeling via Matlab/Python.
Experienced in design for manufacturability and ramping up hardware build in a production environment.
Experienced in designing and operating test stands.
Takes extreme ownership of work and a high degree of responsibility.
Excellent communication across multidisciplinary teams.
Prior nuclear experience in not required for this role.
Benefits and PerksStock: Substantial incentive stock plan for all full-time employees.
Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
One Medical: Sponsored memberships for employees and their dependents.
Vision: 100% top tier plan coverage + 50% for dependents.
Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.
Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.
8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.
Daily catered lunch. Free snacks and drinks.
Flexible PTO policy. Remote workday allocation.
Company and team-bonding events, happy hours and in-person camaraderie.
Beautiful El Segundo headquarters close to the Pacific Ocean.
Total Compensation and Benefits
Radiant compensates people for impact and invests in those who continue to raise the bar. Radiant’s new hire compensation package includes base salary, substantial equity grants, and comprehensive health benefits. Total compensation and level are determined through a rigorous evaluation of interview performance, experience, education, and qualifications, and are designed to support continued growth as scope, responsibility, and impact expand at Radiant.
The best of today’s advanced reactor builders don’t wait for job postings. They join the winning team. If that’s you, contact us directly for immediate opportunities: recruiting@radiantnuclear.com.
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.
Compensation Range: $105K - $125K
Read LessRadiant 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, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. 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 leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.
About the RoleRadiant is seeking a highly motivated Mechanical Engineer, Fluids Systems to own critical Kaleidos fluid systems from preliminary design through build and production. These systems include the primary loop subsystems and power conversion loop, serving to convert heat from the reactor core into electrical power. You will be responsible for the following: trade studies, component selection, thermal hydraulic analysis, piping design, vendor selection, assembly, and testing. You will have an instrumental impact of fueling the first new commercial reactor design in over 50 years by 2026.
Responsibilities & Duties:
Own end-to-end engineering of fluid systems and components, including compressors, valves, and heat exchangers.
Perform complex thermal and fluids analysis to drive design decisions, verify system performance, and ensure structural integrity using first-principle hand calculations and finite element tools.
Perform trade studies to optimize system and meet program requirements.
Develop and execute manufacturing/assembly instructions and test plans.
Create and manage a Bill-Of-Materials (BOM).
Find and develop suppliers for all components.
Own subassembly design, manufacturing, and test schedules.
Own risk analysis (FMEA) for subsystems.
Collect requirements, provide expertise and feedback to engineers in other functional areas via clear, constructive communication.
Required Qualifications & Skills:
Bachelor’s degree from an accredited institution in Mechanical, Materials, Aeronautical, Civil or Structural Engineering.
Experience with fluid system architecture design.
2+ years of experience in designing, building, and testing fluids systems.
Proficient knowledge in fluid dynamics and thermodynamics.
Proficient knowledge of heat exchanger design and analysis methods.
Desired Qualifications & Skills:
Knowledge of thermodynamic power cycles.
Prior experience with designing piping system for thermal growth using hand calculations and FEA tools.
Experience with process piping design and testing codes, such as ASME B31.3 and ASME PCC-2.
Prior experience with fluid system modeling via Matlab/Python.
Experienced in design for manufacturability and ramping up hardware build in a production environment.
Experienced in designing and operating test stands.
Takes extreme ownership of work and a high degree of responsibility.
Excellent communication across multidisciplinary teams.
Prior nuclear experience in not required for this role.
Additional Requirements:
Must be willing to work extended hours and weekends as necessary to accomplish our mission.
Must work 100% onsite at El Segundo HQ.
Benefits and PerksStock: Substantial incentive stock plan for all full-time employees.
Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
One Medical: Sponsored memberships for employees and their dependents.
Vision: 100% top tier plan coverage + 50% for dependents.
Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.
Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.
8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.
Daily catered lunch. Free snacks and drinks.
Flexible PTO policy. Remote workday allocation.
Company and team-bonding events, happy hours and in-person camaraderie.
Beautiful El Segundo headquarters close to the Pacific Ocean.
Total Compensation and Benefits
Radiant compensates people for impact and invests in those who continue to raise the bar. Radiant’s new hire compensation package includes base salary, substantial equity grants, and comprehensive health benefits. Total compensation and level are determined through a rigorous evaluation of interview performance, experience, education, and qualifications, and are designed to support continued growth as scope, responsibility, and impact expand at Radiant.
The best of today’s advanced reactor builders don’t wait for job postings. They join the winning team. If that’s you, contact us directly for immediate opportunities: recruiting@radiantnuclear.com.
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.
Compensation Range: $107.5K - $150K
Read LessRadiant 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, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. 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 leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.
Thermal Modeling Engineer (CFD)
Radiant is seeking a driven Thermal Modeling Engineer with expertise in CFD and thermal FEA modeling. You will design, develop and implement simulations for the Kaleidos microreactor to ensure high fidelity, reliability, and safety of our systems. You’ll work on cutting edge technical problems for a high temperature gas reactor that inform decisions across reactor systems, cooling systems, shielding, and more. You will have an opportunity to work in an interdisciplinary environment and drive milestones forward to unlock commercialization of the first mass-produced nuclear reactor.
Responsibilities and Duties:
Develop and execute thermal analysis and CFD to evaluate design and performance of Kaleidos systems.
Document analysis results to communicate clear and actionable outputs.
Expand CFD capabilities, accuracy, and efficiencies via methods and workflow development projects.
Own pipeline for producing analysis geometry from mechanical design CAD
Develop methods and calculations to support and build confidence in lower-fidelity thermal analysis methods.
Required Qualifications and Skills:
Bachelor’s degree in engineering, physics, or similar field from an accredited institution.
3+ years experience with Star CCM+ or Ansys Fluent.
Proficiency with CAD software (Siemens NX).
Strong understanding of finite element and computational fluid dynamics modeling principles and methods.
Experience communicating and distilling information with cross-functional teams.
Desired Qualifications and Skills:
Experience with radiation heat transport modeling.
Knowledge of nuclear reactor design.
Driven, self-motivated, and takes ownership of work end to end.
Additional Requirements
Must be willing to work extended hours and weekends as necessary to accomplish our mission.
Must work 100% onsite at El Segundo HQ.
Benefits and PerksStock: Substantial incentive stock plan for all full-time employees.
Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
One Medical: Sponsored memberships for employees and their dependents.
Vision: 100% top tier plan coverage + 50% for dependents.
Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.
Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.
8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.
Daily catered lunch. Free snacks and drinks.
Flexible PTO policy. Remote workday allocation.
Company and team-bonding events, happy hours and in-person camaraderie.
Beautiful El Segundo headquarters close to the Pacific Ocean.
Total Compensation and Benefits
Radiant compensates people for impact and invests in those who continue to raise the bar. Radiant’s new hire compensation package includes base salary, substantial equity grants, and comprehensive health benefits. Total compensation and level are determined through a rigorous evaluation of interview performance, experience, education, and qualifications, and are designed to support continued growth as scope, responsibility, and impact expand at Radiant.
The best of today’s advanced reactor builders don’t wait for job postings. They join the winning team. If that’s you, contact us directly for immediate opportunities: recruiting@radiantnuclear.com.
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.
Compensation Range: $107.5K - $150K
Read LessRadiant 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, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. 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 leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.
About the RoleRadiant is seeking a highly motivated Senior Mechanical Engineer to own critical Kaleidos fluid systems from preliminary design through build and production. These systems include the primary loop subsystems and power conversion loop, serving to convert heat from the reactor core into electrical power. You will be responsible for the following: trade studies, component selection, thermal hydraulic analysis, piping design, vendor selection, assembly, and testing. You will have an instrumental impact of fueling the first new commercial reactor design in over 50 years by 2026.
Responsibilities & Duties:
Own end-to-end engineering of fluid systems and components, including compressors, valves, and heat exchangers.
Perform complex thermal and fluids analysis to drive design decisions, verify system performance, and ensure structural integrity using first-principle hand calculations and finite element tools.
Perform trade studies to optimize system and meet program requirements.
Develop and execute manufacturing/assembly instructions and test plans.
Create and manage a Bill-Of-Materials (BOM).
Find and develop suppliers for all components.
Own subassembly design, manufacturing, and test schedules.
Own risk analysis (FMEA) for subsystems.
Collect requirements, provide expertise and feedback to engineers in other functional areas via clear, constructive communication.
Required Qualifications & Skills :
Bachelor’s degree from an accredited institution in Mechanical, Materials, Aeronautical, Civil or Structural Engineering.
Experience with fluid system architecture design.
4+ years of experience in designing, building, and testing fluids systems.
Proficient knowledge in fluid dynamics and thermodynamics.
Proficient knowledge of heat exchanger design and analysis methods.
Desired Qualifications & Skills :
Professional Engineer (PE) Mechanical license.
Knowledge of thermodynamic power cycles.
Prior experience with designing piping system for thermal growth using hand calculations and FEA tools.
Experience with process piping design and testing codes, such as ASME B31.3 and ASME PCC-2.
Prior experience with fluid system modeling via Matlab/Python.
Experienced in design for manufacturability and ramping up hardware build in a production environment.
Experienced in designing and operating test stands.
Takes extreme ownership of work and a high degree of responsibility.
Excellent communication across multidisciplinary teams.
Prior nuclear experience in not required for this role.
Additional Requirements:
Must be willing to work extended hours and weekends as necessary to accomplish our mission.
Must work 100% onsite at El Segundo HQ.
Benefits and PerksStock: Substantial incentive stock plan for all full-time employees.
Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
One Medical: Sponsored memberships for employees and their dependents.
Vision: 100% top tier plan coverage + 50% for dependents.
Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.
Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.
8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.
Daily catered lunch. Free snacks and drinks.
Flexible PTO policy. Remote workday allocation.
Company and team-bonding events, happy hours and in-person camaraderie.
Beautiful El Segundo headquarters close to the Pacific Ocean.
Total Compensation and Benefits
Radiant compensates people for impact and invests in those who continue to raise the bar. Radiant’s new hire compensation package includes base salary, substantial equity grants, and comprehensive health benefits. Total compensation and level are determined through a rigorous evaluation of interview performance, experience, education, and qualifications, and are designed to support continued growth as scope, responsibility, and impact expand at Radiant.
The best of today’s advanced reactor builders don’t wait for job postings. They join the winning team. If that’s you, contact us directly for immediate opportunities: recruiting@radiantnuclear.com.
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.
Compensation Range: $158,000 - $219,450
Read LessRadiant 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, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. 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 leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.
About the RoleRadiant is seeking a highly motivated Staff Mechanical Engineer to own critical Kaleidos fluid systems from preliminary design through build and production. These systems include the primary loop subsystems and power conversion loop, serving to convert heat from the reactor core into electrical power. You will be responsible for the following: trade studies, component selection, thermal hydraulic analysis, piping design, vendor selection, assembly, and testing. You will have an instrumental impact of fueling the first new commercial reactor design in over 50 years by 2026.
Responsibilities & Duties:
Own end-to-end engineering of fluid systems and components, including compressors, valves, and heat exchangers.
Perform complex thermal and fluids analysis to drive design decisions, verify system performance, and ensure structural integrity using first-principle hand calculations and finite element tools.
Perform trade studies to optimize system and meet program requirements.
Develop and execute manufacturing/assembly instructions and test plans.
Create and manage a Bill-Of-Materials (BOM).
Find and develop suppliers for all components.
Own subassembly design, manufacturing, and test schedules.
Own risk analysis (FMEA) for subsystems.
Collect requirements, provide expertise and feedback to engineers in other functional areas via clear, constructive communication.
Required Qualifications & Skills :
Bachelor’s degree from an accredited institution in Mechanical, Materials, Aeronautical, Civil or Structural Engineering.
Experience with fluid system architecture design.
7+ years of experience in designing, building, and testing fluids systems.
Proficient knowledge in fluid dynamics and thermodynamics.
Proficient knowledge of heat exchanger design and analysis methods.
Desired Qualifications & Skills :
Professional Engineer (PE) Mechanical license.
Knowledge of thermodynamic power cycles.
Prior experience with designing piping system for thermal growth using hand calculations and FEA tools.
Experience with process piping design and testing codes, such as ASME B31.3 and ASME PCC-2.
Prior experience with fluid system modeling via Matlab/Python.
Experienced in design for manufacturability and ramping up hardware build in a production environment.
Experienced in designing and operating test stands.
Takes extreme ownership of work and a high degree of responsibility.
Excellent communication across multidisciplinary teams.
Prior nuclear experience in not required for this role.
Additional Requirements:
Must be willing to work extended hours and weekends as necessary to accomplish our mission.
Must work 100% onsite at El Segundo HQ.
Benefits and PerksStock: Substantial incentive stock plan for all full-time employees.
Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
One Medical: Sponsored memberships for employees and their dependents.
Vision: 100% top tier plan coverage + 50% for dependents.
Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.
Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.
8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.
Daily catered lunch. Free snacks and drinks.
Flexible PTO policy. Remote workday allocation.
Company and team-bonding events, happy hours and in-person camaraderie.
Beautiful El Segundo headquarters close to the Pacific Ocean.
Total Compensation and Benefits
Radiant compensates people for impact and invests in those who continue to raise the bar. Radiant’s new hire compensation package includes base salary, substantial equity grants, and comprehensive health benefits. Total compensation and level are determined through a rigorous evaluation of interview performance, experience, education, and qualifications, and are designed to support continued growth as scope, responsibility, and impact expand at Radiant.
The best of today’s advanced reactor builders don’t wait for job postings. They join the winning team. If that’s you, contact us directly for immediate opportunities: recruiting@radiantnuclear.com.
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.
Compensation Range: $200,500 - $314,475
Read LessRadiant 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, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. 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 leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.
About the RoleRadiant is seeking a Reactor Operations Training Specialist to play a critical role in enabling safe, scalable operations for the line of Kaleidos reactors. In this role, you will be responsible for building Reactor Operator training resources to enable timely and effective training and certification of operators. This role goes beyond traditional documentation, requiring close, daily collaboration with operators, engineers, and test teams to rapidly translate emerging system knowledge into clear, actionable content. This role may also support engineering operations through the development of test plans, data reviews, and other key technical documentation needed to move from prototype to commercial deployment.
Responsibilities & Duties:
Develop and continuously refine Reactor Operator training materials, including operator manuals, learning objectives, lesson plans, operating procedures, and evaluation tools.
Maintain records of operator qualification to DOE/NRC standards. Translate evolving reactor designs and operational concepts into clear, concise, and easily understood training content.
Embed with engineering, test, and operations teams to capture real-time technical insights and lessons learned and reflect them in documentation.
Establish and maintain documentation standards, templates, and style guides suited for a fast-paced startup environment.
Manage document lifecycles within configuration-controlled systems, including version control, change tracking, and rapid updates.
Balance speed and rigor to ensure documentation supports both rapid development and regulatory expectations.
Capture operational lessons learned and support development of regulatory documents, to include white papers and topical reports.
Required Qualifications & Skills:
Bachelor’s degree in Engineering, Physics, Technical Communication, or a related technical discipline.
2+ years of technical writing experience in a complex, engineering-driven environment (e.g., nuclear, aerospace, energy, or advanced hardware).
Familiarity with complex systems and the ability to distill them into operator-focused training content through both written and verbal mediums.
Ability to deliver instructional material in both group and one-on-one classroom environments.
Ability to read and interpret engineering drawings, specifications and procedures.
Ability to work with incomplete or evolving technical information and produce clear, accurate documentation.
Experience developing training materials, technical references, or test documentation.
Strong collaboration skills and comfort working directly with engineers and operators in a dynamic setting.
Familiarity with document control and configuration management principles.
Desired Qualifications & Skills:
Direct experience with nuclear systems, reactor operations, or operator training programs.
Background in instructional design or building technical training programs
Familiarity with NRC or DOE regulatory instructions and licensing considerations for commercial reactors.
Ability to operate with a high degree of ownership and autonomy in an evolving organizational structure.
Additional Requirements:
Must be willing to work extended hours and weekends as necessary to accomplish our mission.
Must work 100% onsite at El Segundo HQ.
Benefits and PerksStock: Substantial incentive stock plan for all full-time employees.
Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
One Medical: Sponsored memberships for employees and their dependents.
Vision: 100% top tier plan coverage + 50% for dependents.
Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.
Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.
8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.
Daily catered lunch. Free snacks and drinks.
Flexible PTO policy. Remote workday allocation.
Company and team-bonding events, happy hours and in-person camaraderie.
Beautiful El Segundo headquarters close to the Pacific Ocean.
Total Compensation and Benefits
Radiant compensates people for impact and invests in those who continue to raise the bar. Radiant’s new hire compensation package includes base salary, substantial equity grants, and comprehensive health benefits. Total compensation and level are determined through a rigorous evaluation of interview performance, experience, education, and qualifications, and are designed to support continued growth as scope, responsibility, and impact expand at Radiant.
The best of today’s advanced reactor builders don’t wait for job postings. They join the winning team. If that’s you, contact us directly for immediate opportunities: recruiting@radiantnuclear.com.
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.
Compensation Range: $139.5K - $172.2K
Read LessRadiant 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, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. 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 leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.
About the RoleRadiant is seeking a Principal Turbomachinery Engineer to serve as the Responsible Engineer for the turbomachinery within our nuclear-driven power generation system. This role owns the mechanical design, integrity, and performance of the core rotating assembly at the heart of our 1MW closed-loop Brayton cycle.
You will define and drive the mechanical architecture of high-speed rotating hardware operating at extreme temperatures, pressures, and rotational speeds. As a deeply technical individual contributor, you will set direction for rotor dynamics, structures, bearings, seals, and system integration while working closely with electrical, thermal, and manufacturing teams.
This is a hands-on, high-ownership role focused on technical excellence, sound engineering judgment, and delivering reliable, production-ready turbomachinery.
Responsibilities & Duties:
Technical Ownership & System Architecture
Serve as Responsible Engineer for the turbomachinery mechanical system.
Own the mechanical architecture and design strategy for high-speed rotating assemblies (up to ~30 krpm).
Lead rotor dynamics, structural integrity, and life analysis for rotating components and assemblies.
Define and flow down requirements from system-level constraints including thermal, structural, and operational environments.
Make key technical decisions on rotor layout, shafting, bearings, seals, materials, and clearances.
Ensure designs meet performance, reliability, safety, and regulatory requirements.
Establish and uphold standards for mechanical design rigor, analysis quality, and documentation.
Mechanical Design & Analysis
Lead detailed design of turbomachinery components including rotors, shafts, housings, and support structures.
Test and validate rotordynamic systems, driving model correlation, risk reduction, and performance verification.
Perform and review structural and thermal analysis to ensure integrity under high-speed and high-temperature operation.
Define tolerances, fits, stack-ups, and alignment strategies for precision rotating assemblies.
Partner with electrical engineering on alternator rotor integration, including electromagnetic and structural coupling.
Cross-Functional Integration
Partner closely with turbomachinery aero, motor design, thermal, manufacturing, and test teams.
Ensure seamless integration between turbine, compressor, and alternator subsystems.
Drive clear interface definitions across mechanical, electrical, and thermal boundaries.
Collaborate with manufacturing to ensure designs are producible, inspectable, and scalable.
Engage with suppliers on technically critical components and design decisions.
Prototyping, Testing & Validation
Support assembly, integration, and test of turbomachinery hardware.
Define validation strategies including spin testing, thermal testing, and system-level operation.
Lead root cause analysis and drive design iteration for test failures or performance gaps.
Remain hands-on in hardware bring-up, troubleshooting, and refinement.
Technical Influence
Act as a subject matter expert in turbomachinery mechanical design and rotating systems.
Provide technical guidance and design reviews across the team without direct people management responsibility.
Influence engineering direction through deep expertise, data-driven decisions, and strong judgment.
Contribute to technical roadmap, risk identification, and mitigation strategies.
Required Qualifications & Skills:
B.S. in Mechanical Engineering or related field.
8+ years of experience designing high-speed rotating machinery (turbines, compressors, or similar systems).
Deep expertise in structural analysis and mechanical design of turbomachinery.
Experience with bearings, seals, and high-speed shafting design.
Expert-level proficiency with analysis tools (e.g., ANSYS) and advanced use of NX and Teamcenter for complex design, simulation, and product lifecycle management.
Strong understanding of tolerancing, GD&T, and precision mechanical assembly.
Experience owning hardware through design, build, and test cycles.
Hands-on experience with assembly, integration, and troubleshooting of turbomachinery.
Strong system-level thinking and mechanical intuition.
Excellent engineering judgment and decision-making capability.
Ability to influence without authority across cross-functional teams.
Clear communicator capable of articulating complex technical concepts.
High ownership mindset and accountability for hardware outcomes.
Ability to operate effectively in a fast-paced, first-of-a-kind development environment.
Desired Qualifications & Skills:
10+ years of turbomachinery or rotating equipment experience.
M.S. or Ph.D. in Mechanical Engineering.
Experience with closed-loop Brayton cycle systems or similar energy systems.
Familiarity with high-temperature materials and extreme environment design.
Experience integrating mechanical systems with high-speed electric machines.
Prior experience as a Responsible Engineer for complex hardware.
Experience scaling hardware from prototype to production.
Additional Requirements:
Must be willing to work extended hours and weekends as necessary to accomplish our mission.
Must work 100% onsite at El Segundo HQ.
Benefits and PerksStock: Substantial incentive stock plan for all full-time employees.
Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
One Medical: Sponsored memberships for employees and their dependents.
Vision: 100% top tier plan coverage + 50% for dependents.
Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.
Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.
8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.
Daily catered lunch. Free snacks and drinks.
Flexible PTO policy. Remote workday allocation.
Company and team-bonding events, happy hours and in-person camaraderie.
Beautiful El Segundo headquarters close to the Pacific Ocean.
Total Compensation and Benefits
Radiant compensates people for impact and invests in those who continue to raise the bar. Radiant’s new hire compensation package includes base salary, substantial equity grants, and comprehensive health benefits. Total compensation and level are determined through a rigorous evaluation of interview performance, experience, education, and qualifications, and are designed to support continued growth as scope, responsibility, and impact expand at Radiant.
The best of today’s advanced reactor builders don’t wait for job postings. They join the winning team. If that’s you, contact us directly for immediate opportunities: recruiting@radiantnuclear.com.
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.
Compensation Range: $200,500 - $314,475
Read LessRadiant 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, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. 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 leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.
About the RoleRadiant is seeking a Principal Electrical Engineer with deep expertise in PCB design to define and lead the electrical architecture for terrestrial reactor control systems, with a long-term path toward space reactor applications. You will serve as the foremost technical authority for custom hardware across the organization — setting design standards, driving architecture decisions, and owning the end-to-end development of high-reliability, low-noise printed circuit boards from requirements definition and schematic capture through layout, bring-up, validation, and field deployment.
This role emphasizes full-stack PCB development, including mixed-signal design, high-speed interfaces, power distribution, and signal integrity, while supporting data acquisition, signal conditioning, estimation, and real-time processing functions critical to reactor control. As a principal-level contributor, you will shape the technical roadmap for Radiant's hardware platform and mentor engineers across the electrical team.
Responsibilities & Duties:
Own the design and development of multilayer PCBs for reactor control and instrumentation systems (terrestrial, with future space applications).
Define and own the electrical architecture strategy for mixed-signal systems, including power distribution, analog front ends, and digital control interfaces.
Design low-noise analog front-end circuits and ensure robust integration with ADC/DAC and digital subsystems.
Perform schematic capture, component selection, and PCB layout with focus on signal integrity, power integrity, grounding, and EMI/EMC mitigation.
Develop and review high-speed, high-precision layouts (e.g., sensor interfaces, data-acquisition paths, communication buses).
Bring up, debug, and validate hardware, including board-level testing, instrumentation, and root-cause analysis.
Create and execute hardware validation and qualification test plans for performance, reliability, and environmental conditions.
Collaborate cross-functionally with firmware, FPGA, DSP, and responsible engineers to ensure seamless hardware/software integration.
Provide technical leadership and mentorship to junior and senior electrical engineers; lead design reviews and own hardware risk identification and mitigation.
Required Qualifications & Skills:
Bachelor's degree in Electrical Engineering or a related field.
8+ years of experience designing custom PCBs, including multilayer and mixed-signal boards.
Demonstrated experience setting electrical architecture direction and driving decisions across complex, multi-disciplinary programs.
Strong experience with schematic capture and PCB layout tools (e.g., Altium, Cadence, or similar).
Solid understanding of signal integrity, power integrity, grounding strategies, and EMI/EMC mitigation techniques.
Experience with analog and mixed-signal design, including sensor interfaces, ADC/DAC integration, and low-noise design practices.
Familiarity with high-speed interfaces (e.g., SPI, I2C, UART, Ethernet) and layout constraints.
Hands-on experience with board bring-up, debugging, and lab instrumentation (oscilloscopes, spectrum analyzers, VNAs, etc.).
Ability to work across disciplines and support system integration in a complex engineering environment.
Desired Qualifications & Skills:
Master's degree in Electrical Engineering or a related field.
Experience designing for high-reliability or harsh environments (nuclear, aerospace, defense, or industrial).
Familiarity with radiation effects and radiation-tolerant electronics design.
Experience with power electronics or power distribution design.
Exposure to FPGA or embedded systems to support hardware/software co-design.
Familiarity with nuclear instrumentation or detector interface electronics.
Experience with design for manufacturability (DFM), design for test (DFT), and production bring-up.
Additional Requirements:
Must be willing to work extended hours and weekends as necessary to accomplish our mission.
Must work 100% onsite at El Segundo HQ.
Benefits and PerksStock: Substantial incentive stock plan for all full-time employees.
Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
One Medical: Sponsored memberships for employees and their dependents.
Vision: 100% top tier plan coverage + 50% for dependents.
Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.
Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.
8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.
Daily catered lunch. Free snacks and drinks.
Flexible PTO policy. Remote workday allocation.
Company and team-bonding events, happy hours and in-person camaraderie.
Beautiful El Segundo headquarters close to the Pacific Ocean.
Total Compensation and Benefits
Radiant compensates people for impact and invests in those who continue to raise the bar. Radiant’s new hire compensation package includes base salary, substantial equity grants, and comprehensive health benefits. Total compensation and level are determined through a rigorous evaluation of interview performance, experience, education, and qualifications, and are designed to support continued growth as scope, responsibility, and impact expand at Radiant.
The best of today’s advanced reactor builders don’t wait for job postings. They join the winning team. If that’s you, contact us directly for immediate opportunities: recruiting@radiantnuclear.com.
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.
Compensation Range: $200,500 - $314,475
Read LessRadiant 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, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. 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 leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.
About the RoleWe're building a new team to own Radiant's internal data infrastructure, executive analytics, and AI capabilities. As a Senior Data Platform Engineer, you'll be hands-on building the integrations and pipelines that connect Radiant's operational systems, Finance, HR, Supply Chain, Manufacturing, and Recruiting, into a unified data platform.
Your first priority will be the ION-Ramp integration: building the pipeline that enables three-way matching (PO + Receipt + Invoice) between our manufacturing execution system and payments platform. This directly reduces manual work for the Finance team. From there, you'll expand to connect 9 enterprise systems, build dbt transformation models, and ensure data quality across the platform.
Responsibilities & Duties:
Build integrations: Configure Fivetran connectors, build custom pipelines, and connect 9 enterprise systems (ION, Ramp, QuickBooks, Rippling, Ashby, Salesforce, SharePoint, Smartsheet, DocuSign)
Develop the ION-Ramp pipeline: Build the Snowflake → Databricks → Ramp pipeline that enables three-way matching for Finance
Write dbt models: Transform raw data into clean, documented, tested models for dashboards and analytics
Ensure data quality: Implement testing, monitoring, and alerting for data pipelines; catch issues before they reach dashboards
Support dashboards: Work with stakeholders to ensure the data models support Finance, Operations, and HR/Recruiting dashboards.
Document everything: Maintain clear documentation for pipelines, models, and data definitions
Required Qualifications & Skills:
Bachelor's degree in computer science, physics, or a similar field.
4+ years of data engineering or software engineering experience.
Strong experience in Python, C++/C, Java or a similar language.
Experience with data warehouses, Databricks, Snowflake, BigQuery, or Redshift
ETL/ELT pipeline development, Fivetran, Airbyte, Stitch, or custom pipeline experience
API integration experience, REST, GraphQL; you're comfortable reading API docs and building integrations with enterprise SaaS tools
Data modeling skills, dimensional modeling, schema design, understanding of how data will be used downstream
Desired Qualifications & Skills:
6+ years of data engineering or software engineering experience
Background in hardware or hardtech companies—you understand manufacturing, supply chain, and physical product development
Experience with dbt (data build tool)
Experience with data quality frameworks and testing (Great Expectations, dbt tests, etc.)
Comfortable building lightweight internal tools—Python/Flask, basic frontend—or using AI coding assistants (Cursor, Copilot) to extend your capabilities
Familiarity with MES, ERP, or supply chain systems (ION, SAP, NetSuite, etc.)
Additional Requirements:
Must be willing to work extended hours and weekends as necessary to accomplish our mission
Must work 100% onsite at El Segundo HQ.
Benefits and PerksStock: Substantial incentive stock plan for all full-time employees.
Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
One Medical: Sponsored memberships for employees and their dependents.
Vision: 100% top tier plan coverage + 50% for dependents.
Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.
Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.
8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.
Daily catered lunch. Free snacks and drinks.
Flexible PTO policy. Remote workday allocation.
Company and team-bonding events, happy hours and in-person camaraderie.
Beautiful El Segundo headquarters close to the Pacific Ocean.
Total Compensation and Benefits
Radiant compensates people for impact and invests in those who continue to raise the bar. Radiant’s new hire compensation package includes base salary, substantial equity grants, and comprehensive health benefits. Total compensation and level are determined through a rigorous evaluation of interview performance, experience, education, and qualifications, and are designed to support continued growth as scope, responsibility, and impact expand at Radiant.
The best of today’s advanced reactor builders don’t wait for job postings. They join the winning team. If that’s you, contact us directly for immediate opportunities: recruiting@radiantnuclear.com.
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.
Compensation Range: $158,000 - $219,450
Read Less