System Transients Analysis Engineer

Job Title: System Transients Analysis Engineer
Location: Bellevue, WA
Job Type: Contract
Work Model: Hybrid/Onsite Preferred

System One is seeking a highly capable and motivated System Transients Analysis Engineer to support an advanced sodium‑cooled reactor program. This role will focus on thermal hydraulic and transient analysis activities supporting advanced reactor system design, plant operations analysis, and control system integration.

The ideal candidate will have strong experience with system analysis codes such as RELAP5 or TRACE, along with a strong foundation in thermal hydraulics, heat transfer, fluid dynamics, and nuclear plant transient analysis.

• Develop RELAP5-3D models for steady‑state and transient one‑dimensional hydraulic network analyses
• Perform reactor and plant transient analyses for normal operations, upset conditions, emergency events, and faulted scenarios
• Develop plant‑level control strategies and component‑level controllers
• Perform calculations using first principles of heat transfer, thermodynamics, and fluid dynamics to validate analytical results
• Support evaluation of plant‑wide transients, operational narratives, and design solutions
• Perform multiscale and multidisciplinary thermal hydraulic analyses involving sodium, molten salt, and non‑condensable fluids
• Collaborate closely with safety, I&C, design engineering, and testing teams
• Support development of new analytical methods and advanced modeling techniques
• Prepare technical reports, calculations, and engineering documentation

• Bachelor’s degree or higher in Nuclear Engineering, Mechanical Engineering, Electrical Engineering, or related discipline
• Strong experience with thermal hydraulic system codes such as RELAP5 and/or TRACE
• Strong analytical background in:
  • Thermal hydraulics
  • Fluid dynamics
  • Heat transfer
  • Transient analysis
  • One‑dimensional hydraulic network modeling
• Strong technical writing and communication skills
• Ability to work effectively in a collaborative, fast‑paced engineering environment
• High level of professionalism, integrity, and teamwork

• Experience with ASME component design and analysis
• Experience modeling control systems and Instrumentation & Controls (I&C)
• Experience supporting nuclear power plant design or operations
• Experience developing new analytical methods
• Advanced reactor or sodium‑cooled reactor experience

• Ability to sit and/or stand for extended periods
• Minimal lifting requirements up to 25 pounds
• Prolonged computer and keyboard work
• Standard office or engineering work environment
• Occasional travel up to 5%

This position may require compliance with U.S. export control regulations. Applicants may be asked to provide information regarding citizenship or work authorization status as part of the hiring process.