Senior Stress Engineer

Radiant; El Segundo (CA); On-site; USD 120,000 - 170,000; Full time

Benefits offered by this job

Equity grants

Health benefits

Onsite lunch & snacks

Flexible PTO

Nuclear cert program

Job summary

Radiant in El Segundo, CA seeks a Stress Engineer to own structural loads, vibration, and dynamic analyses for Kaleidos, a portable nuclear microreactor platform. You will ensure structural integrity across manufacturing, transport, and operation, collaborating with structures, mechanical, thermal, nuclear, and test teams.

The role requires hands-on engineering in ambiguous, fast-paced environments with extensive on-site work at our El Segundo HQ, plus interactions with design teams for hardware

Qualifications

• BS in Mechanical/Aerospace/Structural Engineering or related field.
• 4+ years in stress, loads, dynamics, or structural analysis for complex mechanical systems.
• Strong fundamentals in structural mechanics, dynamics, and vibration.
• Experience with FEA tools (ANSYS/Abaqus/Nastran).
• Familiarity with design allowables, safety factors, and margin-of-safety methodologies.
• Ability to communicate analysis results to technical and non-technical stakeholders.

Responsibilities

• Develop static, dynamic, and transient loads for reactor systems and support structures.
• Perform structural dynamics analyses (modal, random vibration, shock, fatigue).
• Model nonlinear reactor response with explicit dynamics for transient events.
• Define transport environments and load cases for verification plans.
• Conduct FEAs using ANSYS/Abaqus/Nastran; collaborate on hardware design.
• Support test planning and data correlation; maintain analysis docs.
• Contribute to failure investigations and design improvements.

Skills

Structural mechanics

Dynamics & vibration

Communication

Cross-functional collaboration

FEA interpretation

Education

Bachelor’s degree in Mechanical/Aerospace/Structural Engineering

Tools

ANSYS

Abaqus

Nastran

LD-Dyna

Job description

About Radiant

Radiant is an El Segundo, CA-based company building the world's only mass-produced, transportable nuclear microreactors. The U.S. grid is under growing strain, with power demand accelerating, driving higher utility costs, rising carbon emissions, and interconnection backlogs. Radiant has a solution, transportable, on-site power. Our first reactor, Kaleidos, is 1 megawatt: small enough to be factory-built, transported by land, sea, or air, and deployed wherever power is needed. 1 MW can power 1000 homes for five years. Ship it back and we refuel for a 20 year operating life. We made energy a product that can be used for critical infrastructure like military bases, data centers, hospitals, and remote sites, as well as the commercial main street businesses that keep America running. Founded in 2020, Radiant is under contract to deliver power to the U.S. Army, Navy and Air Force and has signed pre-order agreements with Equinix, with deployments beginning in 2028.

About the Role

Radiant is seeking a Stress Engineer to own and execute structural loads, vibration, and dynamic analyses for complex mechanical systems associated for Kaleidos, the world's first portable microreactor and supporting hardware. You will play a critical role in ensuring structural integrity and survivability across all phases of the product lifecycle, including manufacturing, transportation, handling, deployment, and operational environments.

This role requires a hands‑on engineer who is comfortable working in ambiguous, fast‑paced environments and collaborating closely with structures, mechanical design, thermal, nuclear, and test teams.

Responsibilities & Duties:

• Develop and own static, dynamic, and transient loads for reactor systems, support structures, and transport configurations.

• Perform structural dynamics analyses, including modal, random vibration, shock, sine vibration, and fatigue assessments.

• Implement explicit dynamics simulations to model nonlinear reactor response under transient seismic and transportation event cases.

• Define and analyze transportation and handling environments, including shock and vibration from road, rail, air, or sea transport.

• Generate load cases and environments to support structural sizing, design margins, and verification plans.

• Conduct finite element analyses (FEA) using tools such as ANSYS, Abaqus, or similar tools.

• Collaborate with design engineers to influence hardware architecture, material selection, and joint design.

• Support test planning and correlation, including shaker tests, modal surveys, and structural verification testing.

• Develop and maintain analysis documentation, reports, and requirements for internal reviews and regulatory interfaces.

• Contribute to failure investigations, root cause analyses, and design improvements

• Help establish best practices for loads, dynamics, and structural verification within a growing engineering organization.

Required Qualifications & Skills:

• Bachelor’s degree in Mechanical Engineering, Aerospace Engineering, Structural Engineering, or a related field.

• 4+ years of professional experience in stress, loads, dynamics, or structural analysis for complex mechanical systems.

• Strong fundamentals in structural mechanics, dynamics, and vibration.

• Experience with finite element modeling and analysis of metallic and composite structures.

• Proficiency with industry-standard FEA tools (e.g., ANSYS, Abaqus, Nastran).

• Familiarity withdesign allowables, safety factors, and margin-of-safety methodologies.

• Ability to work cross-functionally and communicate analysis results clearly to both technical and non-technical stakeholders.

Desired Qualifications & Skills:

• Experience inaerospace, launch, defense, nuclear, or heavy industrial hardware environments.

• Dynamics modeling software experience (LD-Dyna, Abaqus explicit, or other).

• Background in shock and vibration testing and test-article correlation.

• Knowledge offatigue, fracture mechanics, and bolted joint analysis.

• Experience defining or interpreting environmental specifications and requirements.

• Master’s degree or PhD in a relevant engineering discipline.

• Familiarity with nuclear, spaceflight, or safety-critical system requirements.

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.

• Nuclear Engineering Certificate Program: 100% covered educational program with Penn State University, for eligible employees, to rapidly upscale into nuclear.

• 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 full-time 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.

The best of today’s advanced reactor builders don’t wait for job postings. They join the winning team.

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.