Senior Nuclear Engineer - Microreactor Design Lead

Speedrun Talent Network; El Segundo, Northern (CA, KY); Hybrid; USD 190,000 - 260,000; Full time

Benefits offered by this job

Stock plan

Medical benefits

Lunch provided

Flexible PTO

Job summary

Radiant, an El Segundo, CA-based startup, seeks a Staff Nuclear Engineer to provide expert nuclear design and analysis for Kaleidos. You will own multidisciplinary workstreams from requirements through verification, validation, testing, and regulatory documentation.

The role requires deep reactor physics knowledge, Monte Carlo methods, and the ability to drive complex issues to closure with autonomy. Onsite collaboration with engineering teams is essential.

Qualifications

• Bachelor’s degree in nuclear engineering or related field.
• 8+ years of nuclear engineering experience across design, analysis, licensing, safety, or operations.
• Experience owning complex multi-disciplinary projects and delivering through closure.
• Deep knowledge of neutron transport, Monte Carlo methods, and uncertainty analysis.
• Experience with MCNP/OpenMC or comparable neutron/radiation transport tools.
• Ability to translate analyses into reactor design decisions and regulatory documentation.
• Strong written and verbal communication for multidisciplinary teams.

Responsibilities

• Provide technical leadership across reactor physics, shielding, dose, transport, safety analysis, I&C, and operations.
• Own complex projects from requirements to final documentation.
• Develop and validate high-fidelity neutron/ radiation transport models.
• Translate results into actionable design decisions and regulatory documents.
• Mentor engineers and establish analytical methods and standards.
• Collaborate with cross-disciplinary teams to resolve design challenges.
• Communicate status, risks, and recommendations to leadership.

Skills

Reactor physics

Monte Carlo methods

Uncertainty analysis

Technical leadership

Communication

Education

Bachelor’s in nuclear engineering

Master’s/PhD preferred

Tools

MCNP/OpenMC

Python

Job description

Radiant, an El Segundo, CA-based startup, seeks a Staff Nuclear Engineer to provide expert nuclear design and analysis for Kaleidos. You will own multidisciplinary workstreams from requirements through verification, validation, testing, and regulatory documentation.

The role requires deep reactor physics knowledge, Monte Carlo methods, and the ability to drive complex issues to closure with autonomy. Onsite collaboration with engineering teams is essential.