Summer 2026 Internship - Nuclear Engineer

Summary: 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. Responsibilities: - 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: - 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) Preferred Qualifications: - 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 Required Skills: Nuclear engineering principles, Neutronics, Thermal-hydraulics Important Skills: Programming Python, Programming C++, Programming C#, Nuclear simulation codes Nice-to-Have Skills: Collaborative team environment Internship Start Date: Start in 2026 Summer Benefits: Stock: Substantial incentive stock plan for all full-time employees., Medical: 100% up to base silver level plan for employee + 50% dependents, offers up 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, orthodontia extra, 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.