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The Thermal Hydraulics Group specialises in applied research in reactor cooling and heat transfer for fusion and related areas.

This includes modelling complex fluid and heat transfer processes as well as performing experimental validation of these phenomena.

Thermal Hydraulics and Fusion

In order to deliver sustainable fusion energy, the challenge for future power plants is a balance between effectively cooling components such that they remain below temperatures where material damage occurs and extracting the heat at a high enough temperature to generate electricity efficiently.

In meeting this challenge, Thermal Hydraulics is the study of how fluids flow, behave, and interact with different structures to transfer heat between the structure and the fluid.

While UKAEA has a predominant focus on fusion technology, the same issues can be found in a large number of sectors including fission, oil and gas, and aerodynamics, leading to significant potential for knowledge transfer.

Thermal hydraulics at UKAEA

The Thermal Hydraulics Group has several key areas of focus:

  • Applying state-of-the-art techniques for simulation of complex thermal hydraulic problems to solve specific fusion challenges
  • Developing high-resolution diagnostic experiments to improve understanding of thermal hydraulic phenomena and validate the performance of simulations
  • Maximising the exploitation of UKAEA’s combined load experiments, such as CHIMERA, through thermal hydraulic aspects of experiment design

The ANNA Thermal Hydraulics Test Facility

UKAEA is working with the University of Manchester to deliver a state-of-the-art thermal hydraulic experimental facility that will provide open access to a wide range of researchers through EPSRC’s National Nuclear User Facility (NNUF) project.

The ANNA Thermal Hydraulics Test Facility will be able to generate unique, high-resolution experimental data on steady-state and transient thermal hydraulic phenomena at both component and system level, of relevance to water-cooled fission and fusion powerplant technology.  When ANNA is operational, users will be able to investigate a range of multi-physics problems, including conjugate heat transfer, two-phase flow, flow-induced vibration, and natural convection flows.

ANNA will be located at UKAEA’s Fusion Technology Facilities (FTF) in South Yorkshire and will be open for use in early 2024.


The Thermal Hydraulics Group is keen to collaborate on research projects that relate to any of the above areas. If you would like to know more, please contact

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