Bristol, UK · Hybrid
Astral Systems is an innovative startup at the forefront of Nuclear Fusion and Neutron Source technology. Our mission is to create groundbreaking solutions that revolutionise industries and improve everyday life, particularly in medical, space, and nuclear fusion applications. We are dedicated to addressing global health and energy challenges by providing cutting-edge systems that enhance access to medical isotopes and accelerate fusion research.
Astral Systems is hiring a Thermal Hydraulics Engineer to deliver thermal, heat transfer, and CFD models for IEC neutron source hardware, including cathode and target assemblies, support structures, and heat removal systems. The role focuses on turning uncertain and coupled heat sources into validated engineering models that inform design, reliability, and operating envelopes.
This position is open at team member and senior level. All levels include code development and workflow automation, with an emphasis on open-source toolchains where practical. MHD and plasma-adjacent flow modelling may be relevant to specific concepts but is optional and not expected as a baseline requirement.
Develop and maintain thermal and CFD models for cathode, target, and associated assemblies, including steady-state and transient operating regimes.
Translate particle and radiation heating outputs into thermal boundary conditions and volumetric source terms, in coordination with plasma and neutronics teams.
Design and evaluate cooling concepts, including heat removal constraints, manufacturability, and integration with the wider system.
Support thermo-mechanical assessments by providing validated thermal fields and modelled operational cycles.
Develop and extend simulation tooling, including automation, parameter sweeps, uncertainty studies, and reproducible reporting pipelines.
Optional: contribute to modelling of electrostatic/ magnetically influenced flow, MHD, or plasma-adjacent transport for specialised designs.
Support verification and validation activities, including correlation against test data and instrumentation, and maintain model assurance documentation.
Liaise with internal and external stakeholders, including suppliers and project partners, to translate modelling outputs into design requirements.
Support the preparation of technical reports, design documentation, and compliance-relevant evidence.
Stay updated on industry best practices in thermal modelling, CFD assurance, and safety relevant to high voltage and test facilities.
MSc or PhD in Mechanical Engineering, Nuclear Engineering, Aerospace Engineering, Chemical Engineering, Physics, or a related field.
Demonstrated experience in heat transfer modelling and CFD, including model setup, verification, and interpretation.
Proficiency in one or more of: Python, Julia, C++, Fortran.
Experience with CFD and multiphysics solvers, for example OpenFOAM, Fluent-class, Comsol-class or ANSYS-class toolchains.
Ability to integrate external heat maps or deposition fields into thermal models and build automated analysis pipelines.
Experience with Linux-based workflows, version control, and reproducible analysis practices.
Clear written and verbal communication, including decision-oriented reporting.
Willingness to undergo employment screening and security checks where required for facility access.
Competitive salary and benefits package
Opportunities for professional development and career progression
Flexible working arrangements and a supportive team culture
The chance to contribute to pioneering advancements in fusion and medical technology
Pension Matching
Private Health Insurance
This is a hybrid role, with onsite as required by test and facility work in Bristol and partner facilities. Travel may be required to support hardware testing and integration activities. Successful candidates would be reporting to the Director of Research/Chief Technical Officer.
To apply, please submit a CV/resume detailing your qualifications and experiences.
Thank you for considering a career at Astral Systems. We look forward to receiving your application!
Astral Systems Ltd
Thermal Hydraulics Modelling Engineer
Full-time
Bristol, UK · Hybrid
Negotiable
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