Mechanical Engineer (Fluid Systems, Mechanisms, or Structures)

Job Description

Mechanical Engineer (Fluid Systems, Mechanisms, or Structures) – New Graduate

Radiant is seeking a highly motivated New Graduate Mechanical Engineer to join the KDU Engineering team. This role offers a unique opportunity to contribute directly to the design, assembly, and testing of the Kaleidos Development Unit (KDU), which is poised to be the United States’ first new fueled reactor design in over 50 years. Depending on your background and interests, you will take ownership of projects focusing on fluid systems, mechanisms, or structures, working within a dynamic, cross-disciplinary team to advance KDU’s readiness for fueled operations.

Responsibilities and Duties:

• Contribute to the design, analysis, and testing of KDU subsystems across fluid systems, mechanisms, or structural components.
• Manage deliverables from initial concept through build and validation phases, with guidance from senior engineers.
• Collaborate effectively across various engineering disciplines to integrate designs and resolve complex technical challenges.
• Provide support for system-level testing, troubleshooting, and design iteration to accelerate KDU development.
• Communicate project results through formal design reviews, technical reports, and presentations to peers and leadership.

Required Skills and Qualifications:

• Education: Bachelor’s (BS) degree in Mechanical Engineering, Aerospace Engineering, or a closely related discipline (completed or expected by Spring 2026).
• Technical Foundation: Strong understanding of engineering first principles, including thermodynamics, fluid mechanics, statics, dynamics, and strength of materials.
• Practical Experience: Hands-on experience in design and build through academic projects, research, lab work, or internships.
• Software Proficiency: Proficiency with essential engineering tools such as CAD, analysis software, and lab instrumentation.

Desired Skills and Qualifications:

• Advanced Education: Master’s (MS) degree in Mechanical Engineering, Aerospace Engineering, or a related discipline (completed or in progress).
• Relevant Experience: Prior internship, co-op, or project-based experience specifically related to fluid systems, mechanisms, or structures.
• Problem-Solving: Demonstrated ability to independently solve complex engineering tasks and proactively seek out necessary resources.
• Cultural Fit: Comfortable working in a fast-paced, startup environment with a collaborative, mission-driven mindset.
• Mission Alignment: Genuine excitement for Radiant’s mission to rapidly deploy nuclear microreactors to remote locations requiring abundant, clean energy.
• Domain Knowledge (Optional): Knowledge of reactor physics is helpful but not a requirement.

Additional Requirements:

• Location: This role is based onsite at Radiant’s Headquarters in El Segundo, CA.
• Work Schedule: Extended hours or occasional weekend work may be required to meet project milestones.
• Visa Sponsorship: Radiant is unable to provide visa sponsorship for this position.
• Export Controls: This position involves access to technology subject to U.S. export controls. Any job offer will be contingent upon the applicant’s capacity to serve in compliance with U.S. export controls.

Benefits and Perks:

• Equity: Substantial incentive stock plan for all full-time employees.
• Medical: 100% coverage up to a base silver level plan for employees + 50% for dependents, with options to upgrade 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, with orthodontia options and 50% for dependents.
• Voluntary Benefits: Employee-contributed benefits including life, accident, hospital, critical illness, commuter, and FSA/HSA.
• Parental Leave: 8 weeks of paid parental leave for all parents, plus additional paid pregnancy leave for CA employees.
• Food & Drink: Daily catered lunch, free snacks, and drinks.
• Time Off: Flexible PTO policy and remote workday allocation.
• Culture: Company and team-bonding events, happy hours, and in-person camaraderie.
• Location: Beautiful El Segundo headquarters situated close to the Pacific Ocean.

Total Compensation and Benefits:

Radiant rewards impact and invests in individuals who consistently raise the bar. The new hire compensation package comprises a base salary, substantial equity grants, and comprehensive health benefits. Total compensation and job 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.

Compensation Range: $74,000 – $130,000

Application Information:

Radiant is an equal opportunity employer. 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.

If you believe you are an advanced reactor builder and wish to join the winning team, please contact us directly for immediate opportunities at: recruiting@radiantnuclear.com.