Aging of Nuclear Plant Resistance Temperature Detectors

This report provides key results of a 30-month experimental research and development project to identify and quantify the effects of normal aging on the performance of nuclear safety-related resistance temperature detectors (RTDs). The limit for initial accuracy of RTD elements was established and the range of their response time was determined. Seventy-two representative nuclear-grade RTDs were tested for calibration drift at simulated reactor conditions and for shelf-life drift. This included a number of naturally aged RTDs received from nuclear power plants. The authors demonstrate that periodic calibration and response time testing performed once every fuel cycle is a reasonable approach for managing the aging of nuclear grade RTDs.