Senior Scientific Software Engineer (Fed Gov)

Accountabilities:: Sustain, analyze, maintain, and modernize scientific software applications, including complex legacy systems. Refactor existing codebases to improve portability, performance, efficiency, maintainability, and overall software stability. Support computational modeling activities involving conceptual, process-based, and numerical models. Debug, profile, benchmark, and evaluate scientific software to identify performance bottlenecks and scalability limitations. Support Linux-based development environments, high-performance computing workflows, and job-scheduler operations. Develop and maintain scientific software using Fortran, Python, C, and C++. Apply software engineering best practices, including testing, verification, validation, and quality assurance procedures. Document source code, technical debt, software risks, system dependencies, and development workflows. Support reproducible builds, scientific data processing workflows, and software migration readiness. Work with parallel computing environments and scientific applications using MPI technologies such as OpenMPI, MPICH, or Intel MPI. Maintain and improve serial and parallel scientific code execution and reliability. Support software compilation, debugging, and build processes using GNU/Linux development toolchains. Perform software development and documentation activities in accordance with applicable Nuclear Quality Assurance (NQA-1) requirements. Collaborate with scientific, engineering, and software development teams to ensure technical accuracy, software integrity, and mission readiness. Requirements: A Master's degree in Computer Science, Engineering, or a related discipline such as Environmental Science, Mathematics, or Physics, with at least 5 years of relevant experience in computational modeling, software development, and technical documentation; alternatively, a Bachelor's degree in a related discipline with at least 10 years of relevant experience. Demonstrated experience on at least one project completed within the 5 years preceding the response deadline that involved both computational modeling and software development in a regulated, safety-critical, high-consequence, or comparable mission-critical environment. Ability to clearly describe the project environment, responsibilities, technical activities, deliverables, and the reasons the work was considered high-consequence or mission-critical. Strong scientific programming experience with Fortran, Python, and C and/or C++. Proficiency in Python 2 and Python 3, including maintaining and modernizing legacy Python applications. Experience developing and debugging software in GNU/Linux or equivalent Unix-based environments. Strong understanding of Linux build systems, compilation processes, debugging toolchains, and development workflows. Hands-on experience with high-performance computing systems and job schedulers such as Slurm or equivalent platforms. Proficiency in Bash or comparable Unix/Linux shell scripting languages. Experience with software quality practices, testing methodologies, scientific data formats, and scientific computing workflows. Strong debugging, profiling, benchmarking, and performance analysis capabilities. Demonstrated ability to modernize legacy scientific software while maintaining correctness and reliability. Experience with Git or equivalent version control systems and reproducible software builds. Familiarity with source-code documentation tools such as Doxygen or equivalent. Experience with OpenMPI, MPICH, Intel MPI, or comparable parallel computing frameworks. Knowledge of serial and parallel scientific computing applications and computational modeling techniques. Strong analytical and problem-solving skills, with a high degree of attention to detail. Ability to work effectively in highly regulated and technically demanding environments. Excellent written and verbal communication skills, particularly in technical documentation and collaborative engineering work. Benefits: Flexible work schedules to support work-life balance. Paid parental leave. 401(k) retirement plan with employer matching contributions of up to 4%. Employee Stock Ownership Plan (ESOP), offering opportunities to participate in company ownership. Professional development and technical training opportunities. Tuition reimbursement to support continued education and career growth. Employee Assistance Program (EAP). Comprehensive medical, dental, and vision insurance plans. Opportunity to contribute to impactful scientific computing and mission-critical engineering projects. Collaborative environment focused on technical excellence, professional growth, and meaningful work.