Mechanical Engineer Internship, Radiant Nuclear
Summer 2026, Fluid Systems, Mechanisms, or Structures
Offers equity
More information about location
Office located in El Segundo, CA
Making nuclear power portable
Job no longer available
Making nuclear power portable
201-500 employees
Job no longer available
Offers equity
More information about location
Office located in El Segundo, CA
201-500 employees
Company mission
To bring one of the world's first factory-constructed microreactors to market.
Role
Who you are
- Strong connection to engineering first principles expected from a third-year engineering student (thermodynamics, fluid mechanics, statics, dynamics, strength of materials)
- Currently pursuing BS in mechanical engineering, aerospace engineering, or related discipline
- Hands on project examples outside of the classroom such as extracurricular projects, clubs, research, lab work or personal projects
Desirable
- Currently pursuing MS in mechanical engineering, aerospace engineering, or related discipline
- A high level of independence in solving challenging engineering tasks is preferred
- Ability to seek out resources and proactively ask questions to finish projects through completion effectively, accurately, and timely
- Ability to work in a fast-paced startup environment with a proactive and collaborative attitude
- Genuinely excited for our mission to rapidly deploy nuclear microreactors to remote locations requiring abundant, clean energy
- Knowledge of reactor physics will provide useful context but is not necessary
- Prior internship experience helpful but not required
What the job involves
- Radiant is seeking a highly motivated Mechanical Engineering Intern for SUMMER 2026
- Under the KDU Engineering team, you will be responsible for a project tailored towards the finalization of the design, assembly and testing of the Kaleidos Development Unit – the United States’ first new fueled reactor design in over 50 years
- You will be tasked with this project based on your skillset (fluid systems, mechanisms, or structures) and our organization’s priority
- You’ll learn from a direct mentor, cross-functional teammates, and have a tangible impact on the readiness of KDU for fueled operations next year
- Own all aspects of a project within given discipline
- Deliver project on time and with minimal supervision to accelerate KDU development
- Present a final project review at the end of internship to engineers and leadership
- You may be asked to work extended hours or weekends occasionally to support project goals
Application process
- We plan to begin interviewing for Summer 2026 internships in November/December
Our take
To support the clean energy revolution, Radiant Nuclear is developing a portable, containerised nuclear microreactor. Once launched, it will have the potential to provide power to remote parts of the world or act as a backup supply to vital infrastructure such as hospitals and data centres.
Typically, these backup systems are powered by diesel generators - making them extremely bad for the environment. Radiant's microreactors could allow the replacement of these generators whilst supplying the same critical asset support, enabling a substantial reduction in carbon footprint.
Having completed the design phase of the project, Radiant has taken a step closer towards realising its portable microreactor (known as Kaleidos). On the back of impressive Series D funding, the company intends to test a prototype as early as mid-2026 and has secured considerable funding to support its work towards that goal.
Kirsty
Company Specialist at Welcome to the Jungle
Company
Funding (last 2 of 7 rounds)
Dec 2025
$300m
SERIES D
May 2025
$165m
SERIES C
Total funding: $620.7m
Company benefits
- Equity: Substantial incentive stock plan for all salaried employees
- Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans
- Vision: 100% coverage + 50% for dependents
- Dental: 100% coverage, orthodontia extra, 50% for dependent
- Flexible PTO policy
- Voluntary Life, Accident, Hospital, Critical Illness, Commuter and FSA are offered as employee contributed benefits
- Team-bonding company outings, happy hours and in-person camaraderie
- Beautiful El Segundo headquarters close to the Pacific Ocean
Company HQ
El Segundo, CA
Leadership
Doug Bernauer
(CEO)Previously Senior Avionics Systems Engineer at Space Exploration Technologies and Applications Engineer at Rockwell Automation.
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