Summer 2026 Internship - Nuclear Engineer

Nuclear Engineering Intern

Radiant is seeking a highly motivated Nuclear Engineering Intern to support the design and analysis of nuclear systems for a 1MW HTGR nuclear microreactor. As part of the engineering team, you will work alongside experienced nuclear engineers and gain hands-on experience in areas such as neutronics, thermal-hydraulics, shielding, and fuel analysis. This internship offers direct mentorship in a fast-paced startup environment, providing you with a unique opportunity to contribute to the development of the first new fueled reactor design in over 50 years.

Summer interns are eligible for a housing stipend in addition to their hourly rate.

Responsibilities & Duties

• Assist with nuclear design and analysis tasks, including shielding, neutronics, thermal, and fuel-related studies.
• Support coupled neutronics and thermal calculations to refine system performance models.
• Document methods, results, and findings in clear technical reports and presentations.
• Collaborate with cross-functional teams and provide technical input as projects evolve.
• Support the development of lower order shielding analysis models to develop rapid shielding design solutions.
• Support the development of uncertainty propagation methodology and its execution on the Kaleidos Demonstration Unit
• Perform criticality safety analysis for the Production Plant of Kaleidos reactors
• Present a final project review at the end of internship to engineers and leadership

Required Qualifications & Skills

• Currently pursuing a bachelor's or master's degree in nuclear engineering or a related discipline.
• Strong academic foundation in nuclear engineering principles (e.g., reactor physics, thermal-hydraulics, radiation shielding).
• Proficiency in at least one programming language (Python, C++, C#, or similar).

Desired Qualifications & Skills

• Hands-on experience through coursework, research, projects, or labs in nuclear system design or analysis.
• Familiarity with nuclear simulation codes (e.g., OpenMC, Serpent, MCNP, MOOSE, BISON, RELAP, CFD, Pronghorn, GRIFFIN).
• Prior software development experience or exposure to version control, testing, or documentation practices.
• Strong communication skills and ability to work in a collaborative team environment.
• Enthusiasm for Radiant's mission to rapidly deploy nuclear microreactors to provide clean energy in remote locations.

Additional Requirements

• This internship is based 100% onsite at Radiant's HQ in El Segundo, CA.
• Extended hours or occasional weekend work may be required to support project milestones.