Senior Mechanical Engineer, Mechanisms Hardware

Front Door Defense; El Segundo (CA); On-site; USD 133,500 - 184,800; Full time

Job summary

Radiant in El Segundo, CA, seeks a Senior Mechanical Engineer for their innovative portable nuclear microreactor project. This role involves designing critical mechanical systems and ensuring their reliability and safety. Candidates should have a Bachelor's degree in Mechanical or Aeronautical Engineering, alongside substantial experience in mechanism design and stress analysis.

Successful applicants will be responsible for the development of manufacturing instructions, managing Bill-Of-Materials, and leading cross-functional discussions to ensure project success. The position requires strong analytical, organizational, and communication skills, as well as a willingness to work onsite and potentially extended hours.

Qualifications

• 4+ years of experience designing mechanisms.
• 4+ years of experience performing stress analysis using hand calculations and finite element tools.

Responsibilities

• Ownership of critical mechanisms such as the control blade actuator or air jacket valves.
• Conduct trade studies and develop designs to meet program requirements.
• Perform detailed thermomechanical and kinematic analysis.
• Develop and execute manufacturing instructions and test plans.
• Create and manage a Bill-Of-Materials (BOM).
• Find and develop suppliers for components.

Skills

Designing mechanisms

Stress analysis

Finite element tools (Abaqus, Ansys)

Interdisciplinary teamwork

Organizational skills

Communication skills

Education

Bachelor's degree in Mechanical or Aeronautical Engineering

Tools

CAD software (NX or similar)

Job description

Senior Mechanical Engineer, Mechanisms

Lead the mechanical mechanisms design for Kaleidos, delivering reliable actuation and safety features.

Location: El Segundo, California, United States

Compensation: $133,500 - 184,800 USD / year

Job Tags: Hardware

About The Role

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.

Responsibilities & Duties

• Ownership of critical mechanisms such as the control blade actuator or air jacket valves.
• Conduct trade studies and develop designs to meet program requirements.
• Perform detailed thermomechanical analysis (static strength, durability/fatigue) and kinematic analysis to determine structural integrity and performance margins using both hand calculations and finite element tools.
• Develop and execute manufacturing/assembly instructions and test plans.
• Create and manage a Bill-Of-Materials (BOM).
• Find and develop suppliers for components.
• Own subassembly design, manufacturing, and test schedules.
• Own risk analysis (FMEA) for subsystems.
• Collect requirements, provide expertise and feedback to engineers in other functional areas via clear, constructive communication.

Required Qualifications & Skills

• Bachelor's degree from an accredited institution in Mechanical or Aeronautical Engineering.
• 4+ years of experience designing mechanisms.
• 4+ years of experience performing stress analysis using both hand calculations and finite element tools (Abaqus, Ansys, FEMAP, or similar).

Desired Qualifications & Skills

• Experience with design of multi-component assemblies in CAD (NX or similar).
• Experience designing hardware that was manufactured, deployed, and iteratively improved.
• Experience designing pneumatic systems.
• Experience integrating electromechanical components such as motors or encoders.
• Experience working with interdisciplinary teams.
• Solid understanding and application of GD&T.
• Proficiency with both 'hand calc' analytical methods and higher fidelity finite element-based analysis methods.
• Ability to derive free-body diagrams for systems with which one was not previously familiar.
• Self-motivated with strong organizational, written, and oral communication skills.
• Experience with using text-based software development tools.

Additional Requirements:

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