Principal Nuclear Engineer (Nuclear Engineering)

Location: 100% onsite at hirify.global’s headquarters in El Segundo, California, United States

Salary: $195,713–$262,500 per year, plus equity

Company

hirify.global is a startup developing mass-produced, portable nuclear microreactors. Its first reactor, Kaleidos, is a 1-megawatt fail-safe microreactor designed for rapid deployment and operation for up to five years without refueling.

What you will do

• Lead interdisciplinary work across reactor physics, shielding, dose and activation, thermal-hydraulics, safety analysis, instrumentation and controls, and operations.
• Set technical priorities, project plans, resource requirements, and ownership across the nuclear engineering organization.
• Serve as the technical authority for neutron and radiation transport and Monte Carlo simulation methods.
• Own nuclear engineering projects from requirements and design iteration through analysis, technical review, verification, validation, and documentation.
• Translate analytical results into reactor design requirements and decisions, and support testing, startup, acceptance criteria, and regulatory documentation.
• Mentor engineers, resolve multidisciplinary technical risks, and communicate recommendations to engineering teams and company leadership.

Requirements

• Bachelor’s degree in nuclear engineering or a related technical discipline.
• 9+ years of relevant experience in reactor design, analysis, testing, licensing, safety, or operations.
• Experience leading complex nuclear engineering projects and multidisciplinary teams, including hiring, managing, mentoring, or technical leadership.
• Deep knowledge of neutron transport theory, Monte Carlo simulation, nuclear data, statistical convergence, criticality, reactivity, depletion, power distribution, shutdown margin, radiation transport, and uncertainty analysis.
• Professional experience developing and applying MCNP, OpenMC, or comparable neutron and radiation transport models.
• Ability to translate analysis into reactor design decisions, technical requirements, safety conclusions, and regulatory documentation.

Nice to have

• Master’s degree or Ph.D. in nuclear engineering or a related discipline.
• Experience with high-temperature gas-cooled reactors, microreactors, advanced reactors, or first-of-a-kind nuclear systems.
• Experience with SCALE, Serpent, Shift, Griffin, MOOSE-based applications, or similar tools.
• Proficiency with Python or another language for simulation automation and data post-processing.
• Experience with multiphysics analysis, nuclear licensing, reactor testing, commissioning, startup, or operational readiness.

Culture & Benefits

• Full-time employees receive a substantial incentive stock plan.
• Comprehensive medical, vision, dental, life, accident, hospital, critical illness, commuter, FSA, and HSA benefits are available.
• Eight weeks of paid parental leave for all parents, with additional paid pregnancy leave for California employees.
• Flexible PTO, a remote workday allocation, daily catered lunch, snacks, and drinks.
• Company and team events, happy hours, and an in-person collaborative environment at the El Segundo headquarters.