Principal Software Engineer, Compute

About the Company

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 designed to provide critical power to hospitals, data centers, and remote sites.

Responsibilities

• Lead HPC initiatives, establishing project scope and providing technical mentorship
• Own workflows and performance for scientific computing tools including Ansys, STAR-CCM+, and Abaqus
• Build and maintain robust, high-throughput Linux systems for workload scheduling and data movement
• Serve as the primary liaison between engineering teams and software teams regarding HPC and simulation needs
• Modernize legacy scientific computing systems and migrate to current stacks
• Design and maintain networking infrastructure for distributed simulation systems
• Partner with DevOps to architect systems across AWS and on-premises Linux environments
• Architect tools for build systems, testing frameworks, and deployment automation

Requirements

• Bachelor's degree in Computer Science, Engineering, Physics, or a related technical field
• 8+ years of professional experience in HPC, scientific computing, infrastructure, or platform engineering
• Deep Linux and sysadmin fluency, including file systems and networking
• Hands-on experience with HPC environments (SLURM, PBS, MPI, Lustre, EFS, or AWS ParallelCluster)
• Proficiency in Python, Golang, Rust, C#, or C/C++
• Strong code review and debugging skills in high-compliance environments
• Ability to work 100% onsite in El Segundo, CA

Preferred Qualifications

• Master's degree or higher in a related technical field
• Experience with physical infrastructure, server hardware, and data center operations
• Experience with Kubernetes and Docker
• Cloud infrastructure experience with Ansible, Terraform, or AWS
• Experience with AI/ML training infrastructure or GPU acceleration
• Familiarity with React or JavaScript