Control Systems Test Engineer

About Radiant

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 next year, with initial customer deliveries beginning in 2028.

Radiant is seeking a highly motivated and detail‑oriented Control Systems Test Engineer to join our team. In this role, you will be responsible for developing, maintaining, executing, and automating test cases across the full testing lifecycle for our reactor control systems. You will collaborate closely with systems engineers, controls developers, and software teams to ensure the highest quality and reliability in safety‑critical control software.

• Analyze and review control system Simulink models and associated design artifacts to understand system behavior and expected performance.
• Study and interpret system requirements for the reactor control system to develop comprehensive test coverage.
• Develop and maintain detailed test artifacts, including:
  • Unit test cases
  • Software‑in‑the‑Loop (SiL) test cases
  • Hardware‑in‑the‑Loop (HiL) test cases
  • Hardware test cases
• Execute all test cases across the testing spectrum:
  • Unit testing
  • SiL testing
  • HiL testing
  • Full hardware testing
• Automate testing workflows for SiL, HiL, and HW test cases using scripting languages such as Python or Go (Golang).
• Run and manage structured test campaigns, including regression suites.
• Execute and manage unit tests within the Simulink Test environment.
• Document all testing results clearly and concisely in test reports, including metrics, pass/fail criteria, and issues.
• Work collaboratively with developers and system engineers to identify root causes and support the resolution of defects.
• Contribute to continuous improvement of test processes, frameworks, and tools.

• Bachelor’s degree in Electrical Engineering, Computer Engineering, Mechanical Engineering, Controls Engineering, Computer Science, or related discipline.
• 2+ years of experience with Simulink/Matlab and working with dynamic system models.
• Strong understanding of software testing principles, including 2+ years of experience in unit, integration, SiL, HiL, and system testing.
• Proficiency in coding/scripting for test automation (e.g., Python, Golang, or similar).
• Hands‑on experience with Simulink Test or equivalent test execution frameworks.
• Excellent analytical skills and attention to detail.
• Strong written and verbal communication skills.

• Experience with safety‑critical or regulated systems (e.g., aerospace, automotive, energy).
• Familiarity with version control systems (e.g., Git) and CI/CD pipelines.
• Prior exposure to automated test frameworks, hardware interfaces, and real‑time data capture.

• Must be willing to work extended hours and weekends as necessary to accomplish our mission.
• Must work 100% onsite at El Segundo HQ.

Compensation Range: $74,000 - $172,725