The on-line detection of entrapped air voids in liquidfilled sensing lines will be investigated. In nuclear plants the sensing lines used for measurement of feedwater flowrate and reactor coolant level are often several hundred feet in length. The problem associated with the presence of entrapped air can manifest itself as either a static or dynamic offset error in the process parameter measurement. In certain applications in nuclear power plants, this can pose a safety concern. In the on-line, active acoustic detection technique to be studied, an input signal is supplied directly to the liquid at the process end of the sensing line. This input signal will have a known spectral content. A transducer also will be placed at the opposite end of the sensing line to monitor the signal. The relationship between the spectrum of the input signal and the monitored signal is a function of the quantity and location of air voids in the line.Anticipated Results/Potential Commercial Applications as described by the awardee:The anticipated result of the project is the development of an on-line technique for detection of air voids entrained in liquid-filled sensing lines. During the Phase III work, the technique would be developed into a commercial system for approval by the Nuclear Regulatory Commission (NRC) for installation in nuclear power plants. The commercial system would allow the plant operator to determine whether the lines had air voids entrained in them.
