Principal Nuclear Engineer - Monte Carlo & Reactor Physics

Radiant Industries; El Segundo (CA); On-site; USD 180,000 - 260,000; Full time

Benefits offered by this job

Stock incentives

Medical benefits

One Medical memberships

Vision coverage

Dental coverage

Voluntary benefits

Parental leave

Job summary

Radiant, an El Segundo, CA-based startup, seeks a Principal Nuclear Engineer to lead interdisciplinary work on Kaleidos, including core physics, shielding, and safety analyses. You will translate complex analyses into practical reactor design decisions and regulatory-ready documentation.

The role emphasizes leadership, advanced neutron transport methods, and collaboration with reactor systems, thermal, mechanical, electrical, and regulatory teams to advance next‑generation microreactor

Qualifications

• Bachelor’s degree in nuclear engineering or a related technical discipline from an accredited institution.
• 9+ years of relevant nuclear engineering experience across reactor design, analysis, testing, licensing, safety, or operations.
• Demonstrated experience leading complex nuclear engineering projects and multidisciplinary technical teams.
• Experience hiring, managing, mentoring, or technically leading nuclear engineers.
• Deep knowledge of neutron transport theory, Monte Carlo simulation methods, nuclear data, and statistical convergence.
• Professional experience developing and applying MCNP, OpenMC, or comparable neutron and radiation transport models.
• Strong understanding of criticality, reactivity coefficients, depletion, power distribution, shutdown margin, radiation transport, and uncertainty analysis.
• Experience translating analysis into reactor design decisions, technical requirements, safety conclusions, or regulatory documentation.
• Familiarity with model verification and validation, configuration control, peer review, and nuclear software quality practices.
• Strong written and verbal communication skills, including the ability to explain complex analyses, assumptions, uncertainties, and technical conclusions.

Responsibilities

• Lead an interdisciplinary team across reactor physics, core performance, shielding, dose and activation, thermal-hydraulics, safety analysis, I&C, and operations.
• Establish technical priorities, project plans, resource needs, and clear ownership across the nuclear engineering organization.
• Serve as a technical authority for neutron and radiation transport and Monte Carlo simulation methods.
• Own nuclear engineering projects from requirements capture and design iteration through model development, analysis, technical review, and final documentation.
• Guide analyses of criticality, reactivity control, shutdown margin, power distribution, depletion, temperature feedback, radiation transport, dose, activation, and shielding performance.
• Translate analytical results into actionable requirements and design decisions affecting the core, shielding, control systems, instrumentation, fluid systems, and structures.
• Establish technically rigorous practices for model verification and validation, peer review, configuration control, uncertainty evaluation, and documentation.
• Collaborate with reactor systems, thermal, mechanical, electrical, test, operations, safety, and regulatory teams to resolve multidisciplinary design challenges.
• Translate nuclear standards and regulatory requirements into analysis plans, design criteria, calculation packages, and verification activities.
• Support reactor testing and startup by defining analysis needs, instrumentation requirements, acceptance criteria, and methods for comparing predicted and measured performance.
• Identify technical risks, drive complex problems through closure, and communicate decisions and recommendations to engineering teams and company leadership.
• Mentor engineers through technical guidance, actionable feedback, and regular coaching.

Skills

Neutron transport

Monte Carlo methods

MCNP/OpenMC

Nuclear data

Criticality analysis

Leadership

Communication

Education

Bachelor’s degree in nuclear engineering

Tools

SCALE

Serpent

Shift

Griffin

MOOSE

Python

Job description

Radiant, an El Segundo, CA-based startup, seeks a Principal Nuclear Engineer to lead interdisciplinary work on Kaleidos, including core physics, shielding, and safety analyses. You will translate complex analyses into practical reactor design decisions and regulatory-ready documentation.

The role emphasizes leadership, advanced neutron transport methods, and collaboration with reactor systems, thermal, mechanical, electrical, and regulatory teams to advance next‑generation microreactor