Nuclear Methods Software Engineer (Year-Long Contract) Location: On-site, Bellevue, WA System One is seeking a highly motivated Nuclear Methods Software Engineer for a year-long contract position based in Bellevue, WA. In this role, you will support the nuclear methods team by creating and documenting software requirements, designs, implementation, and testing for reactor licensing. You will play a critical role in enhancing and validating nuclear simulation models, and work to ensure compliance with licensing requirements for our client's reactors. Responsibilities: Create formal documentation of nuclear methods software requirements, design, implementation, and testing in support of reactor licensing. Update, improve, and create software to meet licensing requirements during the Validation and Verification (V&V) process. Incorporate third-party programs into the simulation ecosystem as necessary to support licensing. Design and execute sensitivity studies to assess the impact and validity of various modeling assumptions (e.g., meshing, physics coupling, transport options, cross-section preparation, fission product models, spatial kinetics), adjusting methods as required. Train and support reactor designers and developers in the use of design software tools. Build and apply methods to assess the propagation of uncertainty and its effect on safety margins. Enhance the engineering team’s ability to build models and draw meaningful conclusions from simulation outputs through input tools, visualization, reports, etc. Key Qualifications and Skills: PhD and 3+ years of relevant experience or equivalent work experience in nuclear engineering or related field. Intuition and expertise in fast reactor physics and design. Experience with nuclear design/analysis methodologies, including criticality, flux/power distributions, fuel management optimization, reactivity coefficients, shielding, activation, control rod worth, detector response, and uncertainty analysis—ideally with a focus on fast-neutron reactors. Deep knowledge of reactor physics analysis methods (e.g., deterministic and stochastic particle transport, isotopic depletion, perturbation theory, nuclear data, kinetics). Experience with nuclear engineering software tools such as DIF3D, MC2, PARTISN, MCNP, Serpent, SCALE, PARCS, APA, CASMO, DRAGON, ARMI, or similar (preferred). Strong computational expertise; comfortable using computers as powerful tools for simulation rather than just necessities. Strong programming skills in any language required (Python, C++, Fortran are preferred). Proven ability to integrate and automate simulation tools to improve efficiency. Familiarity with software development tools (e.g., IDEs, version control systems, profilers, debuggers, documentation builders, packaging tools). Experience interacting with the NRC on nuclear methodology in an ASME NQA-1 compliant QA environment (preferred). Good working knowledge of numerical methods and applied mathematics (e.g., PDEs, numerical stability, statistics, numerical analysis, dynamics). Strong formal technical documentation skills. Ability to consistently meet aggressive project deadlines. Self-motivated and proactive in seeking out tasks aligned with team goals. Passion for software best practices and an eagerness to improve development processes. Open to giving and receiving professional feedback through code reviews and other professional channels. Strong verbal communication skills, with an ability to articulate complex technical information effectively. A high degree of trust, integrity, and professionalism, with the ability to foster teamwork and communicate openly. Additional Information: The position is a year-long contract based on-site in Bellevue, WA. The starting level and title will be determined based on the assessment of qualifications. Ref: #161-Managed Staffing Charlotte System One, and its subsidiaries including Joulé, ALTA IT Services, CM Access, TPGS, and MOUNTAIN, LTD., are leaders in delivering workforce solutions and integrated services across North America. We help clients get work done more efficiently and economically, without compromising quality. System One not only serves as a valued partner for our clients, but we offer eligible full-time employees health and welfare benefits coverage options including medical, dental, vision, spending accounts, life insurance, voluntary plans, as well as participation in a 401(k) plan. System One is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, age, national origin, disability, family care or medical leave status, genetic information, veteran status, marital status, or any other characteristic protected by applicable federal, state, or local law.