CNC Machinist

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.

CNC Machinist

Radiant is seeking an CNC Programmer and Machinist who will contribute to the development of our microreactor unit. You’ll be a key contributor to Radiant, programming, setting up, and operating CNC machines to produce precision components that power our most critical systems. You’ll translate engineering designs into high-quality, manufacturable parts ensuring accuracy, efficiency, and innovation at every step.

This role requires hands-on experience with CNC machining, a deep understanding of G-code and CAM software, and a passion for solving complex manufacturing challenges. You’ll work closely with engineers, machinists, and quality teams to push the limits of what’s possible in precision manufacturing.

Responsibilities and Duties:

• Develop and optimize CNC programs for 3-axis, 4-axis, and 5-axis mills, lathes, and multi-axis machining centers.

• Set up and operate CNC equipment to validate new programs and processes.

• Read and interpret complex engineering drawings, 3D models, and GD&T specifications.

• Collaborate with design and manufacturing engineers to improve part manufacturability and reduce cycle times.

• Select proper tooling, workholding, and cutting parameters for a variety of materials (aluminum, titanium, stainless steel, Inconel, etc.).

• Troubleshoot machining and programming issues on the floor to maintain high-quality output and machine uptime.

• Continuously improve machining processes through data-driven feedback and experimentation.

• Maintain adherence to safety and quality standards across all machining operations.

• Support additional technician duties or cross-functional shop activities as needed based to achieve company priorities.

Required Skills and Qualifications:

• 5+ years of experience in CNC machining and programming in a precision manufacturing or aerospace environment.

• Proficiency in CAM software (e.g., Mastercam, Siemens NX, Fusion 360, or CATIA).

• Strong understanding of G-code, M-code, feeds, speeds, and toolpath strategies.

• Hands-on experience setting up and operating mills, lathes, and multi-axis machining centers.

• Ability to interpret complex technical drawings, GD&T, and 3D CAD models.

• Proven ability to take a part from print to finished component.

• Strong problem-solving skills and attention to detail.

Desired Skills and Qualifications:

• Experience with 5-axis machining and post-processor development.

• Familiarity with aerospace or high-performance hardware manufacturing.

• Experience with exotic materials (e.g., titanium, Inconel, carbon composites).

• Working knowledge of ERP/MES systems and digital manufacturing workflows.

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.

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.