Lead Nuclear Engineer — Onsite, Equity-Backed Growth

Radiant; El Segundo, Northern (CA, KY); Hybrid; USD 180,000 - 250,000; Full time

Benefits offered by this job

Stock: incentive equity

Comprehensive health benefits

Daily catered lunch

Flexible PTO

Onsite gym/amenities

Job summary

Radiant, an El Segundo, CA-based startup, seeks a Lead Nuclear Engineer to lead an interdisciplinary design and analysis team for Kaleidos. You will guide reactor physics, shielding, activation, and regulatory work, managing priorities, resources, and schedules while mentoring engineers.

The role requires strong MCNP/OpenMC expertise, reactor physics mastery, and proven leadership in complex projects. Onsite work at Radiant’s El Segundo headquarters is essential, with comprehensive benefits and

Qualifications

• Bachelor’s degree in nuclear engineering or a related technical discipline.
• 5+ years of nuclear engineering experience across reactor design, analysis, testing, licensing, safety, or operations.
• 1+ year of experience managing direct reports.
• Experience leading complex nuclear engineering projects with multiple disciplines.
• Deep knowledge of neutron transport theory and Monte Carlo methods.
• Professional experience with neutron and radiation transport models (MCNP/OpenMC).
• Strong reactor physics knowledge including criticality and depletion.
• Experience translating analyses into design decisions and regulatory documentation.
• Familiarity with model verification, validation, and nuclear software quality.

Responsibilities

• Lead an interdisciplinary team across reactor physics, shielding, dosimetry, and reactor operations.
• Hire and develop a high-performing team of nuclear engineers.
• Set priorities, plans, budgets, and ownership for deliverables.
• Own projects from requirements to design and verification.
• Translate analyses into actionable design decisions and regulatory outputs.
• Collaborate with cross-functional teams to resolve design challenges.
• Ensure documentation, validation, and regulatory readiness for analyses.

Skills

Neutron transport theory

Monte Carlo methods

Nuclear data analysis

MCNP/OpenMC

Reactor physics

Leadership

Python

Education

Bachelor’s degree in nuclear engineering

Master’s degree or PhD (preferred)

Tools

MCNP

OpenMC

SCALE

Griffin

Python

Job description

Radiant, an El Segundo, CA-based startup, seeks a Lead Nuclear Engineer to lead an interdisciplinary design and analysis team for Kaleidos. You will guide reactor physics, shielding, activation, and regulatory work, managing priorities, resources, and schedules while mentoring engineers.

The role requires strong MCNP/OpenMC expertise, reactor physics mastery, and proven leadership in complex projects. Onsite work at Radiant’s El Segundo headquarters is essential, with comprehensive benefits and