Lead Nuclear Engineer — Onsite Microreactor Design Leader

Radiant; El Segundo (CA); On-site; USD 180,000 - 240,000; Full time

Benefits offered by this job

Stock options

Medical benefits

Parental leave

Education program

Daily catered lunch

Flexible PTO

Onsite headquarters

Job summary

Radiant in El Segundo, CA is seeking a Lead Nuclear Engineer to provide technical and people leadership within the nuclear design and analysis organization supporting Kaleidos.

You will lead an interdisciplinary team working across core physics, neutron and radiation transport, shielding, activation and dose, thermal-hydraulics, safety analysis, instrumentation and controls, reactor operations, and regulatory evaluations.

Qualifications

• Requires a Bachelor’s degree in nuclear engineering or related field.
• 5+ years of nuclear engineering experience across reactor design, analysis, testing, licensing, safety, or operations.
• 1+ year managing direct reports.
• Experience leading complex projects with multiple disciplines and stakeholders.
• Deep knowledge of neutron transport theory, Monte Carlo methods, nuclear data, and statistical convergence.
• Professional experience with MCNP/OpenMC/Serpent or comparable neutron transport models.
• Strong reactor physics understanding including criticality, depletion, and uncertainty analysis.
• Ability to translate analyses into reactor design decisions and regulatory documentation.
• Familiarity with model verification, configuration control, and technical documentation.
• Strong written and verbal communication to multidisciplinary teams.

Responsibilities

• Lead an interdisciplinary team across reactor physics, shielding, dose, thermal-hydraulics, and I&C.
• Hire, manage, and develop nuclear engineers with clear expectations and feedback.
• Define team priorities, plans, schedules, budgets, and ownership for deliverables.
• Own projects from requirements through design iteration, modeling, and documentation.
• Guide analyses of criticality, reactivity, power distribution, and shielding performance.
• Translate analytical results into actionable design decisions and constraints.
• Ensure rigorous verification, validation, and technical documentation practices.
• Collaborate with reactor systems, thermal, mechanical, electrical, and safety teams.
• Interface with regulatory teams to align standards with analysis plans and criteria.
• Support reactor testing and startup by defining analysis needs and acceptance criteria.
• Identify risks and drive complex problems to closure.
• Communicate status, risks, and recommendations to leadership.

Skills

Leadership & people management

Team collaboration

Technical communication

Analytical mindset

Education

Bachelor’s in nuclear engineering

Master’s or PhD in nuclear engineering

Tools

MCNP

OpenMC

Serpent

Griffin

MOOSE-based tools

Python

Job description

Radiant in El Segundo, CA is seeking a Lead Nuclear Engineer to provide technical and people leadership within the nuclear design and analysis organization supporting Kaleidos.

You will lead an interdisciplinary team working across core physics, neutron and radiation transport, shielding, activation and dose, thermal-hydraulics, safety analysis, instrumentation and controls, reactor operations, and regulatory evaluations.