IN-SITU MEASUREMENT OF TEMPERATURE INSTRUMENTS IN NPPS

抄録

The fast and accurate response of the temperature sensors important to nuclear power plant (NPP) safety can ensure that the control room make timely response in case of large process temperature transients. At present, the response time of temperature sensors in most nuclear power plants is measured during plant maintenance with plunge method under laboratory conditions, although it does not reflect the sensors’ real performance under operating conditions.

This paper studies the in situ measurement of response time of resistance temperature detectors (RTDs) based on noise analysis technology, which measures the response time with no interference to in-service RTDs. It can be used to identify degradation or fault of RTD response time without affecting the operation of the plant and to remind maintenance personnel to fix or replace the sensors in time, so as to ensure the safe and stable operation of NPPs. In this paper, the intensity and frequency distribution of RTD noise signal under different installation modes are analyzed, and the influence of acquisition frequency on power spectral density is studied. In this paper, the noise analysis method is used to analyze the output data of temperature sensor collected by nuclear power plant, and calculate and generate PSD curve, which provides convenience for obtaining response time. This method relies on measured data and processing algorithms, and is in line with the intelligence needs of future generation NPPs. It has potential benefits for the operation and maintenance of NPPs.