Radiant · 7 hours ago
Mechanical Engineer - 2026 New Grad (Fluid Systems, Mechanisms, or Structures)
El Segundo, CA
Internship
Onsite
Intern, Entry LevelRadiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. They are seeking a highly motivated New Graduate Mechanical Engineer to contribute to the design, assembly, and testing of the Kaleidos Development Unit (KDU), working alongside a cross-disciplinary team of engineers.
Clean EnergyEnergyEnergy EfficiencyRenewable Energy
No H1B
Responsibilities
Contribute to the design, analysis, and testing of KDU subsystems (fluid systems, mechanisms, or structural components)
Take ownership of deliverables from concept through build and validation, with guidance from senior engineers
Collaborate across disciplines to integrate designs and resolve technical challenges
Support system-level testing, troubleshooting, and design iteration to accelerate KDU development
Communicate results through design reviews, technical reports, and presentations to peers and leadership
Qualification
Required
BS in Mechanical Engineering, Aerospace Engineering, or a related discipline (completed or expected Spring 2026)
Strong foundation in engineering first principles, including thermodynamics, fluid mechanics, statics, dynamics, and strength of materials
Hands-on experience in design and build through projects, research, labs, or internships
Proficiency with engineering tools (e.g., CAD, analysis software, lab instrumentation)
Preferred
MS in Mechanical Engineering, Aerospace Engineering, or related discipline (completed or in progress)
Prior internship, co-op, or project-based experience related to fluid systems, mechanisms, or structures
Ability to independently solve complex engineering tasks and seek out resources proactively
Comfortable working in a fast-paced, startup environment with a collaborative, mission-driven mindset
Excitement for Radiant's mission to rapidly deploy nuclear microreactors to remote locations requiring abundant, clean energy
Knowledge of reactor physics is helpful but not required
Benefits
Substantial incentive stock plan for all full-time employees.
100% premium coverage for base Silver level plan for employee + 50% premium coverage for dependents. Platinum plans available.
Sponsored memberships for eligible employees and their dependents.
100% premium coverage for top tier plan + 50% for dependents.
100% premium coverage for top tier plan (including orthodontia) + 50% for dependents.
Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.
8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.
Daily catered lunch. Free snacks and drinks.
Flexible PTO policy. Remote workday allocation.
Company and team-bonding events, happy hours and in-person camaraderie.
Beautiful El Segundo headquarters close to the Pacific Ocean.
Company
Radiant
Radiant develops portable nuclear microreactors designed to generate electricity and heat in a compact, factory-built form.
Founded in 2019
51-200 employees
Funding
Current Stage
Late StageTotal Funding
$518.82MKey Investors
Andreessen HorowitzUnion Square Ventures
2025-12-17Series D· $300M
2024-11-14Series C· $165M
2023-04-18Series B· $40M
Leadership Team
Doug Bernauer
Chief Executive Officer
Recent News
2026-01-07
The Motley Fool
2026-01-04
Globe and Mail
2026-01-03
Company data provided by crunchbase