Principal Software Engineer, HPC DevOps

Front Door Defense; El Segundo (CA); On-site; USD 200,500 - 314,475; Full time

Job summary

Radiant seeks a Principal Software Engineer to own and optimize the on-site HPC infrastructure enabling nuclear engineering simulations. Location is El Segundo, CA, with compensation $200,500-$314,475 USD per year.

You will lead workflows, tooling, and compute environments for scientific computing, collaborating across engineering and software teams to deliver scalable, resilient systems and high-availability workloads.

Qualifications

• Bachelor's degree in Computer Science, Engineering, Physics or related technical field.
• 8+ years in developer productivity, site reliability, DevOps, infrastructure, or platform engineering.
• Deep Linux and sysadmin fluency, with a problem-solving mindset.
• Proficiency in Python, Golang, Rust, C#, or C/C++.
• Strong code-review skills and ability to read complex stack traces.
• Excellent communication, organizing, and stakeholder collaboration skills.
• Ability to dive deep into complex legacy stacks and synthesize findings.

Responsibilities

• Own workflows, tooling, and performance for scientific computing, including Ansys, STAR-CCM+, and Abaqus.
• Serve as liaison for engineering and software teams, translating HPC needs into actionable work.
• Triage inbound infrastructure requests, HPC/MPI/Linux debugging, and mentorship; prioritize and communicate clearly.
• Modernize legacy scientific computing systems and tooling; migrate to current stacks.
• Partner with DevOps to architect and maintain AWS and on-prem Linux environments; ensure availability, security, and performance.
• Architect tools for build systems, testing frameworks, deployment automation, and developer environments.

Skills

Python

Golang

C/C++

Linux

DevOps

CI/CD

Education

Bachelor's degree in CS/Engineering/Physics

Master's degree (desired)

Tools

Kubernetes

Docker

AWS

Ansible

Terraform

Job description

Principal Software Engineer, HPC DevOps

Own and optimize the on-site HPC infrastructure to accelerate nuclear engineering simulations

Location: El Segundo, California

Compensation: $200,500 - 314,475 USD / year

About The Role

Principal Software Engineer

Radiant is seeking a driven Principal Software Engineer to own developer productivity, compute infrastructure, and scientific computing workflows. You'll build and maintain the on-site HPC infrastructure and scientific computing environments that hard-science users depend on daily, working closely with the software team to design scalable, resilient tooling that lets engineers focus on their science, not their infrastructure.

As a technical lead, you'll define team scope, shape individual responsibilities, and serve as the primary liaison between engineering and software teams, the subject-matter expert on workflows, tooling, and compute optimization. The ideal candidate is patient and organized, comfortable managing high volumes of cross-disciplinary requests, and capable of diving deep into complex legacy stacks to synthesize findings. The infrastructure and culture you build will help design, run, and mass-produce the first high-temperature gas-cooled portable microreactor ever to be commercialized.

Responsibilities & Duties

• Own workflows, tooling, and performance for scientific computing, including Ansys, STAR-CCM+, and Abaqus, covering licensing, environment setup, job orchestration, and results infrastructure.
• Serve as the go-between for engineering teams and software, fielding HPC questions, simulation software issues, and infrastructure needs from nuclear, thermal, materials, mechanical, and electrical engineers, translating them into actionable work.
• Triage inbound infrastructure requests, HPC/MPI/Linux debugging, job failure analysis, and shell and systems mentorship, while prioritizing effectively and communicating clearly across stakeholders.
• Modernize legacy scientific computing systems and tooling, migrating to current stacks to improve maintainability, performance, and developer experience.
• Partner with DevOps engineers to architect and maintain systems across AWS and on-premises Linux environments, ensuring high availability, security, and performance for mission-critical workloads.
• Architect tools supporting build systems, testing frameworks, deployment automation, and developer environments.

Required Qualifications & Skills

• Bachelor's degree in Computer Science, Engineering, Physics or a related technical field.
• 8+ years of professional experience in developer productivity, site reliability, DevOps, infrastructure, or platform engineering.
• Deep Linux and sysadmin fluency, file systems, process management, and networking, with a hard-science approach to problem-solving.
• Strong proficiency in one or more languages: Python, Golang, Rust, C#, or C/C++.
• Strong code review skills, including the ability to read stack traces and chase down dense rabbit holes in high-compliance, legacy scientific software environments.
• Exceptional communication skills; organized and effective when fielding a high volume of questions and requests from engineering stakeholders.
• Ability to dive deep into complex, nested legacy stacks and then zoom out to synthesize findings clearly for a broader technical audience.

Desired Qualifications & Skills

• Master's degree or higher in Computer Science, Engineering, Physics, or a related technical field.
• Hands-on physical infrastructure experience: server hardware, rack configuration, data center ops, or high-throughput networking (InfiniBand, Slingshot, AWS EFA).
• Experience working cross-functionally with engineering teams across mechanical, electrical, materials, and nuclear disciplines.
• Working experience with Kubernetes and Docker for orchestration and deployment.
• Cloud infrastructure experience with Ansible, Terraform, or AWS in a cloud-native or hybrid environment.
• Hands-on experience with HPC environments, simulation workloads, or academic/research computing (SLURM, PBS, MPI, Lustre, EFS, AWS ParallelCluster, or similar).
• Comfortable picking up frontend work when needed, React or general JavaScript experience is a plus; an open mind toward full-stack contributions is more important than depth here.

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.

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. 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.