Senior Nuclear Engineer - Multiphysics Reactor Design (Onsite)

Cantos Ventures; El Segundo (CA); On-site; USD 180,000 - 280,000; Full time

Benefits offered by this job

Stock plan

Medical benefits

Parental leave

Daily catered lunch

Job summary

Radiant, an El Segundo, CA-based startup, seeks a Staff Nuclear Engineer to lead nuclear design and analysis of Kaleidos. You will own complex reactor physics workstreams, develop high-fidelity transport models, and drive regulatory documentation.

This role requires deep technical judgment, autonomy, and collaboration across disciplines to translate analyses into practical reactor design decisions. You will mentor engineers, establish standards, and contribute to testing, startup, and regulatory

Qualifications

• Bachelor’s degree in nuclear engineering or related technical field.
• 8+ years of nuclear engineering experience across design, analysis, testing, licensing, safety, or operations.
• Experience owning complex multidisciplinary nuclear projects.
• Deep knowledge of neutron transport, Monte Carlo methods, nuclear data, and convergence.
• Experience with MCNP/OpenMC or similar transport models.
• Strong reactor physics understanding: criticality, depletion, shutdown margin, etc.
• Ability to translate analyses into design decisions, safety conclusions, regulatory docs.

Responsibilities

• Provide technical leadership across reactor physics, shielding, dose, activation, and I&C.
• Own complex projects from requirements through model development and documentation.
• Develop high-fidelity neutron transport models for design, safety, testing, and regulatory work.
• Translate results into actionable design decisions affecting core, shielding, controls, and systems.
• Mentor engineers and establish analytical methods and technical standards.
• Collaborate with cross-disciplinary teams to resolve design challenges.
• Document uncertainties, margins, assumptions, and conclusions clearly.

Skills

Nuclear theory

Monte Carlo

Dose analysis

Neutron transport

Engineering leadership

Analytical thinking

Python scripting

Regulatory awareness

Education

Bachelor’s in Nuclear Engineering

Accredited program

Tools

MCNP

OpenMC

Python

Nuclear analysis tools

Job description

Radiant, an El Segundo, CA-based startup, seeks a Staff Nuclear Engineer to lead nuclear design and analysis of Kaleidos. You will own complex reactor physics workstreams, develop high-fidelity transport models, and drive regulatory documentation.

This role requires deep technical judgment, autonomy, and collaboration across disciplines to translate analyses into practical reactor design decisions. You will mentor engineers, establish standards, and contribute to testing, startup, and regulatory