New infrastructures – upgrade of the THESYS facility for the interwrapper flow experiment

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SESAME Newsletter #2 (February 2017) 

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New infrastructures – upgrade of the THESYS facility for the interwrapper flow experiment

The THESYS facility (Technology for Heavy Liquid Metals Systems) uses lead-bismuth eutectic (LBE) as working fluid for loop thermal-hydraulic studies. It is designed to operate between 190°C and 450°C, and controls the oxygen content with a main piping inner diameter of 60.1 mm and a total inventory of ca. 300 liters. A shell-and-tube air cooler is installed, with a maximum capacity of 200 kW.

Pacio-KIT-SESAME-Newsletter-FigureAlthough it is not strictly a new infrastructure, it is currently being upgraded for new advanced studies within the SESAME project. It was first built in 2001 in a horizontal arrangement in order to develop and test technologies adapted to an LBE environment, such as:

  • An electromagnetic annular linear induction pump (ALIP) provides a maximum flow rate of 16 m3/h (46.5 kg/s at 200°C) and pressure head of 3.0 bar
  • Several flow meters based on different principles are connected in series, allowing a direct comparison. Both AC and DC electromagnetic flow meters are calibrated against momentum-based techniques, such as Vortex and Annubar flow meters. Moreover, local flow velocity can be measured with miniature Pitot and Prandtl probes. Ultrasonic methods and permanent magnets were also tested.

In 2005, the THESYS loop was updated to a vertical configuration to install test sections representative of reactor core geometries. In particular, a heated rod in an annular channel was tested. The rod could be moved axially and the instrumentation radially. Thus, detailed velocity and temperature profiles could be obtained, including the flow developing region, and used for validation the applicability of turbulence models to LBE conditions.

This facility is currently being upgraded, and will include the following main new features:

  • Separation of the main upward flow in four channels: three with 27.3mm inner diameter and one smaller of 16mm, with individual valves and flow meters for each channel. Venturi flow meters were fabricated in-house and calibrated using water as a model fluid.
  • Three DC electrical power supply units, up to 50 kVA each, for heating test section elements independently.
  • The monitoring and control system is updated with Siemens SPS-S7 components.

Within the SESAME project, a test section including three heated fuel assembly mockups of 7 rods each and the gap channel between them is installed in the THESYS facility. This study intends to provide empirical information on the heat transfer processes in a scenario of inter-wrapper flow, relevant for passive decay heat removal conditions.

In this new, upgraded configuration, the THESYS loop facility can be used for experiments in liquid metals involving multiple parallel (heated) flow channels. These investigations include fundamental studies for benchmarking exercises, such as mixing jets, as well as tests on prototypical mockups of reactor components, e.g. above-core structures, at representative operating conditions.