Thermal-Hydraulics Engineer / Thermal-Hydraulics Engineeress

Transmutex SA - July 9, 2025

Summary

Transmutex is seeking a skilled and highly motivated Thermal-Hydraulics Engineer to drive the design development of our transmutation reactor. Join us if you have a passion for systems behavior and a drive to advance cutting-edge nuclear designs.

About Us

We are a Geneva-based start-up founded in 2019. Our mission is to reinvent nuclear energy by utilizing an accelerator-driven system (ADS) to optimize the transmutation of long-lived nuclear waste. By innovatively combining particle accelerators and fuel based on existing long-lived radioactive waste, we aim to develop energy processes that are intrinsically safe, minimize the stockpile of long-lived waste, resist proliferation, and remain cost-competitive.

Job Description

We are seeking an adaptable and skilled Thermal-Hydraulics Engineer, preferably with a background in nuclear engineering, to contribute to the design and development of the lead-cooled fast reactor. This role will involve performing system thermal-hydraulics analysis, supporting design optimization and safety analysis of the subcritical reactor's lead cooling system.

Key Responsibilities

  • Perform system thermal-hydraulic analyses for normal operations and accidental conditions within the framework of reactor safety analysis.
  • Conduct core sub-channel analyses.
  • Execute detailed computational fluid dynamics (CFD) analysis for key reactor components.
  • Contribute to and perform multi-physics calculations that couple neutronics, thermal-hydraulics, and thermo-mechanical simulations.
  • Develop, maintain, and validate thermal-hydraulic methodologies and modeling codes.
  • Collaborate with cross-functional teams for integrated reactor performance evaluations.
  • Contribute to internal reports and documentation for licensing efforts.

Ideal Candidate Profile

  • Secondary university degree in Thermal Hydraulics Engineering or a related field (Master’s or Ph.D. preferred).
  • 3-5 years of experience in core and plant thermal-hydraulic analysis.
  • A solid foundation in benchmarked system codes such as RELAP5 and TRACE.
  • The ability to work collaboratively in multicultural and multidisciplinary teams.
  • A willingness to continuously learn and adapt to project needs.
  • Proficiency in English.

Additional Advantages

  • Knowledge and understanding of the RELAP5-based thermal-hydraulic code structure, numerical methods, and correlations, particularly their applicability in lead-based reactors.
  • Prior experience with CFD using ANSYS-Fluent.
  • Proficiency in Fortran and Python programming languages.
  • A clear understanding of reactor systems and their technical specifications.
  • Experience in coupled multi-physics calculations.
  • Proficiency in French, German, or Italian.

Apply online using the form below. Please note that only applications matching the job profile will be considered.

Location : Vernier
Country : Switzerland

Application Form

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