How UVP-DUO Helps to Investigate Thermal Striping in Lead-Bismuth Eutectic (LBE) Loops

24 June 2024 by
How UVP-DUO Helps to Investigate Thermal Striping in Lead-Bismuth Eutectic (LBE) Loops
Met-Flow SA

Summary of the Experiment: 

The Japan Atomic Energy Agency (JAEA) conducted a study to investigate the flow conditions and thermal striping phenomena in Lead-Bismuth Eutectic (LBE) loops, which are crucial for accelerator-driven systems (ADS) used for the transmutation of long-lived radioactive nuclides. The study focused on measuring the velocity profiles and erosion-corrosion effects of LBE flow on various materials under high-temperature conditions. The experimental setup involved a test pipe within an LBE loop, maintained at 350°C, with an operational duration of 3000-3600 hours. The primary objective was to develop high-temperature transducers suitable for precise velocity measurements in LBE flows.

UVP-DUO Usage: 

The Ultrasonic Velocity Profiler (UVP-DUO) was utilized to measure the velocity profiles of LBE flow at high temperatures. The UVP-DUO setup included a high-temperature ultrasonic transducer capable of operating at 150°C. The experimental parameters for the UVP-DUO included:

  • Ultrasonic Frequency: 4 MHz
  • Transducer Material: SUS304 stainless steel
  • Measurement Position: Along the flow passage of the LBE loop
  • Data Acquisition: Averaged velocity profiles under various flow conditions (U1, U2, U3, U4 = 0.25, 0.50, 0.75, 1.00 m/sec)

Result of the Experiment and How UVP-DUO Contributed: 

The experiment demonstrated that LBE flow causes significant erosion-corrosion on materials, with SUS304 stainless steel showing a material loss of 100 μm in the straight tube section and 500 μm in the diffuser section. F82H Ferritic steel exhibited lower erosion, with a maximum material loss of 50-100 μm. Additionally, thermal striping was observed, characterized by temperature fluctuations of about 15°C at the tip of the beam window model, leading to substantial thermal stress (approximately 50 GPa).

The UVP-DUO's high-precision measurements were critical in understanding the flow dynamics and erosion patterns within the LBE loop. The data collected enabled accurate profiling of velocity distributions and identification of areas prone to erosion-corrosion. Furthermore, the development of the high-temperature transducer, guided by the UVP-DUO measurements, proved effective in capturing detailed flow characteristics under extreme conditions.

Overall, the UVP-DUO significantly contributed to the experimental study by providing precise and reliable velocity profiles of LBE flow, which are essential for optimizing the design and safety of ADS components. The findings from this research underscore the importance of advanced ultrasonic measurement techniques in addressing the challenges associated with high-temperature liquid metal flows in nuclear applications.

Read the full paper on the Digital Library here.

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