Accelerated Life Testing and Performance Evaluation of Smart Pressure Transmitters for use in Nuclear Power Plants

Nuclear power plants (NPP) require continuous monitoring of various process parameters such as temperature, pressure and flow etc. for safe and reliable operation of the plant. Smart pressure transmitters (SPT) are increasingly being used in the nuclear industry over conventional pressure transmitters. Smart pressure transmitter offers the potential to improve safety and reliability for NPP by use of their advance featuressuch as self-diagnosis, remote configuration for field communication, etc. This has simultaneously increased the complexity of the smart transmitter and added additional challenges in reliability area. Therefore, it is important to assess the reliability of SPTs before their use in safety critical systems. This paper represents the findings from accelerated life testing and performance evaluation study carried out on smart pressure transmitters. An experimental investigation of 9 SPTs has been carried out by subjecting to accelerated thermal ageing under different temperature conditions [60°C, 70°C and 80°C] for approximately 4 months. Thestudy focused mainly on deriving the performance parameters from calibration, power supply and load variation effect, insulation resistance tests. The important parameters measured are the accuracy, repeatability, hysteresis etc. It was observed from the study that the performance of SPTs degrades due to ageing of its internal components such as sensors, electronic circuits, insulation degradation, etc. Based on the performance data obtained from the testing, the degradation models have also been developed for remaining useful life estimation of SPTs.