Senior Tooling Engineer

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.

Radiant is seeking a highly motivated Senior Tooling Engineer who will be working closely with design engineers and the manufacturing team to develop and innovate custom tooling to build and assemble our microreactor system. You will be part of the early team that develops production tooling for the factory that will mass produce, fuel, and refuel Kaleidos.

Responsibilities & Duties:

• Partner with design and manufacturing engineers to develop innovative production tooling for fabricating and assembling complex mechanisms and structures. 

• Design, analyze, and fabricate tooling that enables semi-remote operations for fueling/defueling of the reactor. 

• Identify and develop appropriate suppliers for tooling components, fabrication. 

Required Qualifications & Skills:

• Bachelor’s degree from an accredited institution in mechanical, manufacturing, or other related engineering discipline. 

• 4+ years of experience in mechanical tooling design and fabrication of multi-component assemblies in CAD (NX or similar). 

• Solid understanding of Geometric Dimensioning & Tolerancing (GD&T) with experience applying it to fabrication drawings.

Desired Qualifications & Skills:

• Master’s degree from an accredited institution in mechanical, manufacturing, or other related engineering discipline. 

• Proficiency with both “hand calc” analytical methods and higher fidelity finite element-based analysis methods. 

• Self-motivated with strong organizational, written, and oral communication skills. 

• Experience with custom machine design; electromechanical systems, motors, actuators, linear rails, bearings, lifting/rigging, etc. 

• Strong problem-solving skills and attention to detail. 

• Demonstrated ability to work collaboratively with design and operations teams. 

Additional Requirements:

• Must be willing to work extended hours and weekends as necessary to achieve company goals. 

• Must work 100% onsite at El Segundo HQ. 

• Stock: 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: [email protected].
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.