Reliability modeling of field calibration data for pressure transmitters in nuclear power plants

To ensure the safe and reliable operation of nuclear power plants, continuous monitoring of key process parameters using transmitters is essential. Accordingly, evaluating the reliability of these instruments is critical for maintaining long-term performance and safety. This study presents a nonlinear Wiener process-based method for reliability analysis and prediction of pressure transmitters in nuclear environments. The approach begins by extracting the maximum absolute error from field calibration data as a degradation indicator. A Wiener process model is then developed to capture the inverse S-shaped degradation trend observed under nuclear conditions. Subsequently, the reliability prediction is achieved based on the first passage time (FPT) theory. A case study based on actual plant data shows that the reliability remains above 99.9943 % even when the calibration interval is extended to 24 months, thereby providing quantitative support for interval extension.