Effect of Aging on Response Time of Nuclear Plant Pressure Sensors

This report provides key results of a six-month feasibility study on the effects of normal aging on the performance of pressure transmitters in nuclear power plants. Using experimental methods for response time testing of transmitters and aging tests on representative transmitters, the authors found that five reasonably effective methods are available for response time testing of pressure transmitters, two of which provide on-line measurement capability. The authors show that 38 percent of the problems reported in the 1,325 cases of the U.S. NRC's Licensee Event Report database over a nine-year period involved potential age-related cases such as calibration shifts and response time degradation.