Staff Nuclear Engineer — Microreactor Design Lead

Speedrun Talent Network; El Segundo (CA); On-site; USD 180,000 - 280,000; Full time

Benefits offered by this job

Stock plan

Medical coverage

One Medical

Vision plan

Dental plan

Parental leave

Education program

Lunch provided

Flexible PTO

Onsite HQ

Job summary

Radiant in El Segundo, CA seeks a Staff Nuclear Engineer to oversee nuclear design and analysis for Kaleidos, spanning core physics, shielding, and regulatory work. You’ll lead major workstreams, mentor engineers, and own analytical methods while collaborating across reactor systems, safety, and regulatory teams.

The role requires deep technical judgment, the ability to work autonomously, and strong communication to translate complex analyses into practical design decisions.

Qualifications

• Bachelor’s degree in nuclear engineering or related technical discipline required.
• 8+ years of nuclear engineering experience across reactor design, analysis, testing, licensing, safety, or operations.
• Experience owning complex projects with multiple disciplines and stakeholders.
• Strong knowledge of reactor physics, criticality, depletion, and uncertainty analysis.
• Experience applying nuclear analysis tools and regulatory documentation.

Responsibilities

• Provide technical leadership across reactor physics, core performance, shielding, dose and activation, and safety analysis.
• Own complex projects from requirements capture through model development, analysis, and final documentation.
• Develop and guide analyses of criticality, power distribution, depletion, and dose.
• Create and review high-fidelity neutron and radiation transport models.
• Translate results into actionable design decisions for core and systems.
• Lead multidisciplinary trades and ensure technical closure.
• Establish model verification, validation, and documentation practices.
• Document assumptions, uncertainties, and conclusions clearly.
• Develop methods and tools to improve analytical capability.
• Collaborate with systems, safety, and regulatory teams to resolve challenges.
• Support testing, startup, acceptance criteria, and comparison of predictions with measurements.
• Mentor engineers and provide technical reviews across programs.

Skills

Reactor physics

Monte Carlo methods

Neutron transport

Dose and activation

Uncertainty analysis

Technical leadership

Independent work

Technical communication

Education

Bachelor’s degree in nuclear engineering

Tools

MCNP/OpenMC

Job description

Radiant in El Segundo, CA seeks a Staff Nuclear Engineer to oversee nuclear design and analysis for Kaleidos, spanning core physics, shielding, and regulatory work. You’ll lead major workstreams, mentor engineers, and own analytical methods while collaborating across reactor systems, safety, and regulatory teams.

The role requires deep technical judgment, the ability to work autonomously, and strong communication to translate complex analyses into practical design decisions.