CNC Machinist El Segundo, California,

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.

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.

• 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, work holding, 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.

• 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.

• 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.

• Must be willing to work extended hours and weekends as necessary to achieve company goals.
• Must work 100% onsite at El Segundo HQ.

Radiant'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.

• Stock:
  Substantial incentive stock plan for all full‑time employees.
• Medical: 100% premium coverage for base Silver level plan for employee + 50% premium coverage for dependents. Platinum plans available.
• One Medical:
  Sponsored memberships for eligible…