Thermal Transient Flow Rate Sensor for High Temperature Liquid Metal Cooled Nuclear Reactor

In nuclear power plants and accelerator driven system (ADS) for nuclear waste treatment, it is important to monitor the coolant flow rate in the reactor core and pipe-line. In such a strong irradiation, high pressure and temperature environment, no accurate local flow measurement technique is readily available. Electromagnetic (EM) flow meter is popular in low temperature application as it is a non-intrusive technology. However, additional voltage will be produced due to temperature, flow, pressure, the chemical properties of the liquid metal and surface condition of the steel walls. In addition, the non-definite wetting behavior of liquid lead-bismuth to the electrically conducting structure material can lead to incorrect readings even during one measurement day. As the temperature measurement technique is well developed for high temperature applications, one alternative flow rate measurement technique is proposed here based on correlation velocity measurement using temperature sensors. The impulse response function (IRF) will be used instead of the cross-correlation function in the time delay estimation. The IRF method shows a more accurate estimation of the transit time, which allows extremely low velocities (down to 2 cm/sec) to be detected. In this research work, 2 the faster thermal diffusion effect in low Prandtl number liquid metal will be considered for the better delay time estimation. The proposed research will be completed in two years, and in specific, the PIs plan to fulfill the research missions by performing the following activities: 1. Review the related literature on correlation velocity measurement technique using temperature noise in the flow field; 2. Design and construct a correlation velocity measurement device with a possibility of changing the distances between the two temperature sensors; 3. Develop a signal processing and data reduction scheme and implement it to a LabVIEW data acquisition system; 4. Perform experiments with different sensor distances and various Reynolds numbers in several different water temperatures in single-phase water flows. Experimental results will be compared to a Pitot tube or hot-wire anemometry; 5. Evaluate the measurement device in the by-pass system of TC-1. 6. Design a circuit board for sensor integration