Senior Nuclear Thermal-Hydraulics Engineer

TL;DR

Senior Nuclear Thermal-Hydraulics Engineer (Nuclear Microreactors): Leading thermal-hydraulics and coupled-physics analysis for the Kaleidos portable microreactor with an accent on heat transfer, reactor systems modeling, and safety performance. Focus on developing multiphysics models, automating simulation workflows, and supporting complex design, licensing, and accident-analysis challenges.

Location: 100% onsite at hirify.global’s headquarters in El Segundo, California, United States. Extended hours and weekends may be required as necessary.

Salary: $139,500–$196,875 per year, plus equity.

Company

hirify.global is a startup developing portable, factory-built nuclear microreactors for hospitals, data centers, remote sites, and military bases.

What you will do

• Own thermal-hydraulics analysis for the Kaleidos reactor under normal and accident conditions.
• Develop coupled physics models integrating thermal-hydraulics with neutronics and structural response.
• Establish best practices for reactor thermal-hydraulics and systems-code analysis.
• Build automated workflows that improve simulation capability, accuracy, and efficiency.
• Collaborate with reactor physics, mechanical engineering, and safety teams on licensing and design trade studies.

Requirements

• Bachelor’s degree in nuclear engineering, mechanical engineering, physics, or a related field.
• 5+ years of relevant industry or national laboratory experience.
• Experience with thermal-hydraulics analysis and reactor systems codes such as RELAP5, TRACE, CTF/COBRA-TF, SAM, or TRANSFORM.
• Experience analyzing high-temperature heat transfer above 500°F, including conduction, convection, and radiation.
• Ability to communicate and distill technical information for cross-functional teams.
• Must work 100% onsite in El Segundo and be willing to work extended hours and weekends when necessary.

Nice to have

• Experience with coupled multiphysics modeling using tools such as MOOSE, BISON, or MARMOT, or with neutronics coupling.
• Experience with STAR-CCM+, Ansys Fluent, or Siemens NX.
• Experience at a national laboratory, reactor vendor, or advanced reactor developer.
• Demonstrated ownership and ability to drive work end to end.

Culture & Benefits

• Substantial incentive stock plan for full-time employees.
• Comprehensive medical, vision, dental, life, accident, hospital, critical illness, commuter, FSA, and HSA benefit options.
• Eight weeks of paid parental leave for all parents, with additional paid pregnancy leave for California employees.
• Flexible PTO, catered daily lunch, snacks, drinks, and sponsored One Medical memberships.
• Company events, team-bonding activities, and in-person collaboration at the El Segundo headquarters.