Director, Nuclear Engineering

FELICIS; El Segundo (CA); On-site; USD 200,000 - 260,000; Full time

Benefits offered by this job

Stock plan

Medical coverage (base Silver + depend

One Medical membership

Vision coverage

Dental coverage

FSA/HSA options

Paid parental leave

Daily catered lunch

Flexible PTO

In-person events

El Segundo HQ by the ocean

Job summary

Radiant in El Segundo, CA seeks a Director of Nuclear Engineering to organize design and analysis strategy for its microreactor fleet. Lead core physics, shielding, dose and instrumentation, guiding a team through design margins, peer reviews, and regulatory engagements.

The role requires a strong physics/engineering foundation, 10+ years of leadership in reactor design, and ability to communicate across disciplines. Onsite work only with relocation supported.

Qualifications

• Degree in nuclear engineering, physics, or engineering physics.
• Demonstrated leadership of a reactor design/analysis team (≥10 years).
• Strong grounding in nuclear, thermal, electrical, and mechanical principles.
• Excellent ability to communicate complex concepts to diverse audiences.
• Familiarity with DOE/NRC safety bases and regulatory processes.
• Willingness to relocate to El Segundo, CA.
• Experience with Monte Carlo neutron transport codes.

Responsibilities

• Lead and grow a team of nuclear engineers across multiple domains.
• Drive strategy execution, remove blockers, adapt to priorities.
• Identify and communicate technical, schedule, and regulatory risks.
• Develop analysis roadmaps for fast iteration across reactor programs.
• Collaborate with universities and national labs to achieve objectives.

Skills

Team leadership

Engineering first principles

Technical communication

Nuclear regulatory familiarity

Monte Carlo methods (OpenMC/Serpent/MC

Education

Nuclear engineering / physics / engineering physics degree

Tools

OpenMC

Serpent

MCNP

Job description

Radiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. The company’s first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. Portable nuclear power with rapid-deploy capability can replace similar-sized diesel generators and provide critical asset support for hospitals, data centers, remote sites, and military bases. Radiant’s unique, practical approach to nuclear development leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.

Radiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. The company’s first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. Portable nuclear power with rapid-deploy capability can replace similar-sized diesel generators and provide critical asset support for hospitals, data centers, remote sites, and military bases. Radiant’s unique, practical approach to nuclear development leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.

Radiant is seeking a highly motivated Director, Nuclear Engineering to organize nuclear design and analysis strategy spanning the design, operation, and iteration of our microreactor fleet.

Responsibilities & Duties

• Lead and grow a team of nuclear engineers spanning core physics, shielding performance, dose and consequence analysis, and nuclear instrumentation domains
• Manage team execution to efficiently deliver against the strategy, remove roadblocks, and adapt to shifting priorities
• Identify, manage, and effectively communicate technical, schedule, and regulatory risks
• Develop and standardize analysis roadmaps to enable fast iteration across multiple reactor programs
• Foster an attitude of ownership and mentorship within the team
• Define the approach to nuclear engineering design margins and methodical peer reviews
• Interact with universities, national labs, and other outside entities as necessary to accomplish key objectives

Required Qualifications & Skills

• Hold a degree in nuclear engineering, physics, or engineering physics from an accredited institution
• Minimum 10 years of experience managing a team in reactor design and analysis
• Fluency in engineering first principles across nuclear, thermal, electrical, and mechanical domains
• Excellence in communicating nuclear engineering concepts to a multidisciplinary audience
• Familiarity with DOE authorization and/or NRC requirements and processes, and demonstrated experience with the development of nuclear facility safety bases
• Must be willing to relocate to Radiant’s El Segundo office
• Experience with Monte Carlo neutron transport codes, including OpenMC, Serpent, or MCNP

Desired Qualifications & Skills

• Hands‑on experience designing products, hardware, or tests

Additional Requirements

• Must be willing to work extended hours and weekends as necessary to accomplish our mission
• Must work 100% onsite at El Segundo HQ

Benefits And Perks

• Stock: Substantial incentive stock plan for all full‑time employees.
• Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
• One Medical: Sponsored memberships for employees and their dependents.
• Vision: 100% top tier plan coverage + 50% for dependents.
• Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.
• Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.
• 8‑weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.
• Daily catered lunch. Free snacks and drinks.
• Flexible PTO policy. Remote workday allocation.
• Company and team‑bonding events, happy hours and in‑person camaraderie.
• Beautiful El Segundo headquarters close to the Pacific Ocean.

Total Compensation And Benefits

Radiant compensates people for impact and invests in those who continue to raise the bar. Radiant’s new hire compensation package includes base salary, substantial equity grants, and comprehensive health benefits. Total compensation and level are determined through a rigorous evaluation of interview performance, experience, education, and qualifications, and are designed to support continued growth as scope, responsibility, and impact expand at Radiant.

We are an equal opportunity employer and all qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity or expression, pregnancy, age, national origin, disability status, genetic information, protected veteran status, or any other characteristic protected by law.

This position involves access to technology that is subject to U.S. export controls. Any job offer made will be contingent upon the applicant’s capacity to serve in compliance with U.S. export controls.