Senior thermal-hydraulics engineer

THORIZON; Lyon; Hybrid; EUR 90,000 - 120,000; Full time

Job summary

Thorizon, a pioneering nuclear-tech company with teams in Amsterdam and Lyon, seeks a senior thermal-hydraulics expert to support design studies for MSR projects. You will apply CFD tools and system codes to analyse safety and performance, collaborate with design, safety, and neutronics teams, and lead validation efforts.

The role demands a master’s degree with 8 years’ experience, knowledge of MSR, and strong communication in English (French or Dutch preferred).

Qualifications

• Master's degree in engineering with 8 years in thermal-hydraulics.
• PhD in nuclear engineering, fluid mechanics, heat transfer or numerical methods is a plus.
• Experience with system engineering approaches is a plus.
• CFD: RANS/LES/DES with OpenFOAM, STAR-CCM+/Fluent.
• Knowledge of system codes: SPECTRA, CATHARE, TRACE, ATHLET.
• Ability to build multiscale/multiphysics computational schemes.
• Programming knowledge for data pre/post processing and tool integration.
• Knowledge of MSR specifics and nuclear coupling with neutronics.
• Excellent written and spoken English; French or Dutch preferred.

Responsibilities

• Perform high-quality thermal-hydraulics studies using appropriate computational tools.
• Provide expertise to system design teams for FOAK/NOAK and non-nuclear pilots.
• Define and execute validation programs with experiments, tests and prototyping.
• Guide junior colleagues and share best practices within the team.
• Engage regulators and maintain dialogue on design assumptions and analyses.
• Specify, select, and manage external contractors and suppliers.
• Participate in international initiatives (IAEA, Euratom) for TH.
• Stay updated on industry trends and tooling in thermal-hydraulics.
• Report to the TH lead and collaborate across project teams.

Skills

CFD proficiency (RANS, LES, DES)

OpenFOAM

STAR-CCM+/Fluent

multiphysics coupling

Python/ data processing

effective communication

team collaboration

Education

Master's degree in engineering

PhD in related field (plus)

Tools

SPECTRA

CATHARE

TRACE

ATHLET

Job description

Your mission
Are you motivated to apply your expertise and know-how to the ongoing design studies for the Thorizon One reactor? Are you passionate about designing cutting-edge thermal-hydraulics systems and solving complex engineering challenges? Do you get energized by innovation, and transforming ideas into tangible solutions?
You will be a major contributor of the thermal-hydraulics expertise center, whose primary missions are, on the one hand, to provide comprehensive support and expertise in this area to the system design teams in charge of the reactor design and safety studies and, on the other hand, to define, execute, and adapt where needed the validation program combining experiments, tests, prototyping, either carried out on our own or through shared initiatives, designed to ultimately prove that the innovations in our solution are feasible within the performance, cost, and time constraints of our project.
Within this general framework, you will develop thermal-hydraulics methods and tools, possibly in collaboration with external thermal-hydraulics specialists, perform high quality studies with the appropriate computational tools, and validate the computational tools.
In your role, you can carry out an analysis to meet any thermal-hydraulics needs for Thorizon projects (non-nuclear Pilot design, Pioneer nuclear demonstrator design, FOAK/NOAK design), including budget, planning, tools selection, calculations, report issuance. You interact easily with other areas of expertise (such as nuclear safety, neutronics, chemistry and mechanics).
Your level of expertise allows you to prioritize based on the importance of the needs, and as an expert, you have the power to recommend any necessary actions for the project related to your area of expertise.
Furthermore, you participate in external networks, including international initiatives, to stay at the forefront of industry developments.
In this environment, you get the unique opportunity to put your knowledge to the best use, develop your ideas, and explore various aspects of thermal-hydraulics engineering.
This role is based in Amsterdam, Netherlands or in Lyon, France.

In This Role You Will

• Perform high quality thermal-hydraulics studies applying appropriate Computational Tools.
• Provide comprehensive support and expertise in thermal-hydraulics to the system design teams, including FOAK/NOAK, Pioneer nuclear demonstrator, as well as non-nuclear Pilot.
• Contribute to the definition, execution, and adaptation where needed of the validation program combining experiments, tests, prototyping, designed to ultimately prove that the innovations in our solution are feasible within the performance, cost, and time constraints of our project. This program includes the validation of the thermal-hydraulics Computational Tools to be used for design and safety, applying national (e.g., ASNR guide 28) or international (IAEA in particular) approaches.
• Guide junior colleagues in the same discipline and share your knowledge and good practices with your teammates.
• Participate in meetings with regulators with the aim of defending in-house positions and contribute to maintaining an active dialogue with regulators (in particular ANVS, ASNR and FANC).
• Participate in specifying, selecting, and managing external contractors and suppliers that support the project.
• Be involved in various international initiatives (IAEA, Euratom…) dedicated to thermal-hydraulics discipline applied to nuclear projects.
• Stay updated on industry trends and advancements in approaches, methodologies, Computational Tools in thermal-hydraulics.
• Report to the Thermal-Hydraulics lead and work in different project teams.
  

About You

• You have a master's degree and proven experience in thermal-hydraulics engineering (8 years).
• PhD in nuclear engineering, fluid mechanics, heat transfer or numerical method development is a plus.
• Experience with system engineering approaches is a plus.
• You master CFD techniques (RANS, LES, DES…) and CFD tools like OpenFOAM, STAR-CCM+, or Fluent.
• You master thermal-hydraulics system codes like SPECTRA, CATHARE, TRACE, or ATHLET.
• You have a firm understanding of numerical methods and modelling approaches, and you use your expert judgement to select the most suitable tool for a given application.
• You can create complex computational schemes involving multiscale and/or multiphysics coupling.
• You have knowledge in programming to pre-process data, post-process results, and transfer data from one computational tool to another.
• You know the MSR specificities related to thermal-hydraulics.
• You have a nuclear background, you know the main thermal-hydraulics transients of a nuclear reactor, and the coupling between thermal-hydraulics and neutronics.
• You have a good knowledge of national or international (IAEA, NRC, ASNR or other) standards on scientific computing tool qualification.
• You have experience in projects including thermal-hydraulics systems and components (heat exchanger, pump…) design.
• You have strong organizational and multitasking abilities, with drive for quality and accuracy.
• You get inspired by an organisation with a large variety of people, with different experiences and background.
• You are eager to learn and like challenges.
• You are creative and innovative: You rethink issues to find practical solutions to difficult problems, and you demonstrate agility by minimizing complexity. You have a pragmatic and constructive mindset.
• You have a good sense of judgement: you think strategically (in your field and taking into account all the dimensions of the project), and you know how to prioritise your actions according to the key issues at stake.
• You have excellent communication skills: you listen before you react, you are concise, you treat people with respect, you keep calm in stressful situations, you have excellent writing skills.
• You are an excellent communicator in English, and preferably also French or Dutch, both spoken and written.
• You create impact: your productions are models for your colleagues.
  

About Us

At Thorizon, we’re a passionate team spread across Amsterdam and Lyon, all working together to develop new nuclear power solutions. We design and create frontier technology for Molten Salt Reactors (MSRs).
Our purpose is to accelerate the availability of clean energy and help solve the climate crisis.
We are in the development phase and aim to solidify our design through analyses, simulations, experiments, prototyping, and partnerships. At Thorizon, we believe a strongly coupled multidisciplinary technology development requires a culture of full openness and transparency. That’s why we foster values like unity, communication, and support to ensure we grow together as a team while achieving our purpose.