The development of a BWR main steam safety/relief valve monitoring system

Abstract

As a means for monitoring key nuclear power plant valves to improve the availability and productivity of nuclear power plant, a BWR main steam safety relief valve leak monitoring system has been developed. Acoustic sensors, such as accelerometers and acoustic emission (AE) sensors were, used for detecting of a small steam leakage from the valve, so as to allow corrective maintenance to be scheduled. After the fundamental test, the leakage test, utilizing an actual BWR safty relief valve, was performed at the test facility (10 – 70 kg/cm 2 pressure and 280°c temperature). The linear relation between the leakage flow rate and the accoustic sensor output signal value was obtained in a range of 0.065 to 3.04 1/min and also in a range of 5 × 10 2 to 2.6 × 10 3 l/min. Based on these results, the leakage monitoring system, composed of acoustic sensors, amplifiers and a data processing system, was developed.