Senior Nuclear Thermal-Hydraulics Engineer

Radiant Industries•El Segundo, CA

9h•$139,500 - $224,700•Onsite

About The Position

Radiant is seeking a Senior Nuclear Thermal-Hydraulics Engineer to lead thermal-hydraulics and coupled physics analysis for the Kaleidos microreactor. You will own the modeling that determines how heat, coolant, and reactor core behavior interact under normal and accident conditions — work that directly informs core design, cooling systems, and safety case development for the first mass-produced nuclear reactor. This role is suited to engineers with reactor-specific thermal-hydraulics or coupled multiphysics experience who want to apply that depth to a fast-moving, factory-built reactor program.

Requirements

Bachelor's degree in nuclear engineering, mechanical engineering, physics, or similar field from an accredited institution.
5+ years of relevant industry or national laboratory experience.
Experience with thermal-hydraulics analysis and/or reactor systems codes (e.g., RELAP5, TRACE, CTF/COBRA-TF, SAM, TRANSFORM).
Experience with high-temperature (500°F+) heat transfer analysis involving conduction, convection, and radiation.
Experience communicating and distilling technical information with cross-functional teams.

Nice To Haves

Experience with coupled multiphysics modeling (e.g., MOOSE, BISON, MARMOT) or neutronics coupling.
Experience with commercial CFD/FEA tools (STAR-CCM+, Ansys Fluent) and CAD (Siemens NX).
Prior experience at a national laboratory, reactor vendor, or advanced reactor developer.
Driven, self-motivated, and takes ownership of work end to end.

Responsibilities

Own and execute thermal-hydraulics analysis to evaluate design and safety performance of Kaleidos reactor systems under normal and accident conditions.
Develop and apply coupled physics models integrating thermal-hydraulics with neutronics and/or structural response.
Identify and implement best practices for reactor thermal-hydraulics and systems-code analysis.
Build automated workflows to expand simulation capabilities, accuracy, and efficiency.
Collaborate across reactor physics, mechanical, and safety teams to support licensing and design trade studies.

Benefits

Substantial incentive stock plan for all full-time employees.
100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
Sponsored memberships for employees and their dependents.
100% top tier plan coverage + 50% for dependents.
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.