About Radiant

Radiant is an El Segundo, CA-based company building the world's only mass-produced, transportable nuclear microreactors. The U.S. grid is under growing strain, with power demand accelerating, driving higher utility costs, rising carbon emissions, and interconnection backlogs. Radiant has a solution, transportable, on-site power. Our first reactor, Kaleidos, is 1 megawatt: small enough to be factory-built, transported by land, sea, or air, and deployed wherever power is needed. 1 MW can power 1000 homes for five years. Ship it back and we refuel for a 20 year operating life. We made energy a product that can be used for critical infrastructure like military bases, data centers, hospitals, and remote sites, as well as the commercial main street businesses that keep America running. Founded in 2020, Radiant is under contract to deliver power to the U.S. Army, Navy and Air Force and has signed pre-order agreements with Equinix, with deployments beginning in 2028.

We are seeking a Test Engineer to drive mission-critical test operations for the development, qualification, and acceptance our groundbreaking nuclear microreactor technology. This role offers a rare opportunity to bridge engineering, operations, and human factors in a highly technical and fast-paced environment. You will collaborate with a multidisciplinary team to translate complex hardware and software designs into clear, executable test operations, with encompassing test procedures that will efficiently and safely execute test, commissioning, and operational activities.

As part of a small, passionate, and accomplished team of test engineers, you will help drive test operations to meet Radiant’s requirements in a fast-paced production environment. You will directly contribute to test operations by assisting with test planning and execution, risk identification and mitigation, hardware integration for test campaigns, post-test inspections, data review, and hardware performance analysis.

This position goes beyond traditional systems engineering - you will also gain hands-on experience as a test conductor and test director, directly influencing the development of operational software, procedures, and test ground support equipment.

Responsibilities & Duties

Perform testing as a Test Conductor/Test Director to gain firsthand experience, ensuring procedures align with real-world execution.

Partner with design engineers to develop innovative test methods for complex mechanisms and structures.

Support testing and iterative improvements of fluid, electrical, and structural hardware of the Kaleidos reactor through development, qualification, and acceptance testing.

Identify and develop appropriate suppliers for component sourcing and fabrication.

Drive initiatives for continuous improvement in test processes and data delivery quality.

Support one-off test campaigns in a fast paced, minimum-requirements environment to drive hardware risk reduction.

Ensure compliance with DOE and NRC standards, maintaining strict formatting, clarity, and usability in procedural documentation.

Required Qualifications & Skills

2+ years of full-time professional experience in engineering problem-solving, including system design, analysis, or testing.

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

Ability to apply first principles thinking to solve problems and make decisions in uncertain or ambiguous situations.

Background in highly regulated industries (e.g., nuclear, aerospace, aviation, maritime).

Demonstrated ability to lead projects and work independently.

Strong technical fundamentals in fluids and thermodynamics.

Strong written and verbal communication skills.

Flexible and adaptable mindset - self-driven with the ability to seek out requirements with minimal direction.

Desired Qualifications & Skills

Prior experience working as an operator in fast-paced test environments (e.g., rocket engine testing, turbopump testing, component level testing), with familiarity in safety protocols, and high-reliability operations, high pressure gases, safety engineering (FMECAs, Keep-out Zone).