Institut für Neutronenphysik und Reaktortechnik (INR)




The KASOLA (KArlsruhe SOdium LAboratory) at INR is a versatile experimental facility to investigate flow phenomena in liquid sodium for nuclear and non-nuclear applications. The facility fills a cylindrical steel building with an inner diameter of 7.7 m and a usable height of 12.5 m. It hosts a sodium inventory of 7 m³, and it can operate in the range of about 150–550 °C. A magneto-hydrodynamic (MHD) pump can deliver a flow rate up to 150 m³/h at a pressure head of 0.4 MPa. Due to the specific features of this type of pump, such as flow direction reversal, the investigation of numerous potentially occurring technical scenarios can be performed.

Three experimental ports are foreseen to serve all needs of liquid metal experimental investigations.

The versatile test section has a height of nearly 6 m. It is situated above the MHD pump and can be used for development and investigation of targets, component tests, and/or experiments, which require high mass flow rates.

The second test port, the versatile port, will house a direct thermal storage device, which is foreseen to test the dynamic capabilities of a frozen thermocline single tank (FlexStor). Alternatively, a slab pool can be installed to be used for tests of components at a scale of about 1:5. A third port, namely a low temperature port, is foreseen as an auxiliary port to connect separate experimental loops or devices, which can use the calibration and cleaning units of KASOLA.

A key feature of the facility is its flexibility with respect to a wide spectrum of thermal-hydraulic experiments. Capabilities include non-nuclear and nuclear applications for prototypical configurations. As examples, the following list is given:


  • Validation and improvement of turbulent liquid metal heat transfer models in CFD tools on limited geometric scale
  • Development of free surface liquid metal targets for accelerator applications
  • Development of models to describe free surface liquid metal flow
  • Investigation of transition in convective flow patterns between forced, mixed and free convection modes.
  • Qualification of CFD and system codes to simulate adequately the transition from the channel flow to large plenum (collector tank)
  • Thermal-hydraulic investigations of flow patterns in fuel bundles or pool configurations at prototypical or scaled heights
  • In-Service Inspection & Repair (ISIR) monitors for liquid metal systems
  • Provide backbone for sodium based CSP systems


The KASOLA facility contributes to the Helmholtz alliance on liquid metal technology (LIMTECH) and the Helmholtz Energy Materials Characterization Platform (HEMCP). LIMTECH has been created to help German Helmholtz centers and universities to bundle their R&D activities on liquid metals for the various research fields and applications. HEMCP was founded to respond to the needs of innovative energy systems, which will face much higher temperatures to enhance their efficiency. It will also boost the developments and qualification of instrumentation and materials used for liquid metal technology.



[1]  W. Hering et al.:Scientific program of the Karlsruhe Sodium Laboratory (KASOLA), IAEA-CN-199/257, Int. Conf. on Fast Reactors and Related Fuel Cycles, Paris, France, March 4.–7, 2013.
[2]  W Hering, A. Möslang, A. Onea, J. Reiser, R. Stieglitz, A. Weisenburger, A high temperature technology: AMTEC (Alkali Thermo Electric Conversion) – Challenges and Perspectives within the HGF-energy research, Kolloquium zur offiziellen Eröffnung der Helmholtz Energy Materials Characterization Platform (HEMCP). 20.11.2015, Jülich.

W. Jaeger, F. Trimborn, W. Hering, B. Pritz, M. Gabi, Thermo-Hydraulic Investigations of a vertical Rectangular Duct with Liquid Metal Flow by Means of System Code and CFD Code Prediction, ICAPP 2016, International Congress on Advances in Nuclear Power Plants, 17 - 20 April 2016 / USA, San Francisco, CA.

 [4] W. Hering, N. Diez de los Rios Ramos, A. Onea, R. Stieglitz, Liquid metal as heat transfer fluid – requirements to avoid risks, SOLAR PACES 2017 (Solar Power and Chemical Energy Systems) September 26-29, 2017, Santiago, Chile.