Leakage Monitoring System Research Articles

Experimental and theoretical investigations of KWU on leak-before-break behaviour and its application on excluding of breaks in nuclear piping of KWU-plants

The fracture of pipes with longitudinal and circumferential cracks was investigated by experiments and theoretical approaches (flow stress criteria and limit load analyses). The experiments show that the critical crack dimensions can conservatively be determined by fracture mechanics. The tests and calculations are applied to the primary coolant piping with hypothetical longitudinal and circumferential defects. Reactor systems, design, fabrication, stress analysis, material, non-destructive testing, quality control and inservice inspection are considered referring to the leak-before-break behaviour. On the basis of the extreme toughness of the materials, the known loads, the high level of non-destructive examinations, the leakage monitoring system and the high quality of manufacture and processing it is shown that a spontaneous failure need not to be postulated.

Development of leak monitoring system for pressurizer valves

Acoustic monitoring by acoustic emission sensor is effective for detecting small leak at sheet of pressurizer (PRZR) valves. Background noise in actual power station was measured and it was very small, also the acoustic signal generated by valve leak was enough high, so acoustic valve leak monitoring system has been developed.

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

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.

Advances in Acoustic Leak Monitoring Instrumentation

A microprocessor-based acoustic leak monitoring system is described. The system provides a nuclear reactor operator with continuous data regarding the presence of leaks in plant fluid systems. The features of the system are briefly discussed with emphasis on the specially developed acoustic transducer and data processing. Data gathered at several power plants covering various leak types are presented.

On-line leak detection method for OWL-1 loop by ARX modeling using dewpoint signals.

Model identification technique based on ARX (autoregressive model with exogenous variable) process was applied to dewpoint data recorded at OWL-1 (Oarai Water Loop No. 1) loop cubicle in JMTR (Japan Materials Testing Reactor) and the dynamical interrelationship between the supply and exhaust dewpoints in the ventilation system of the cubicle was empirically determined. It was shown that the information so derived on the dewpoint dynamics can assist to enhance the sensitivity of leak detection, if it was incorporated into a leak monitoring system for the OWL-1 loop. A simple digital filter incorporating the dewpoint dynamics was designed in an attempt to develop an efficient leak monitor for the OWL-1 loop. This filter was applied to the dewpoint data recordings during an abnormal leak that had occurred at the OWL-1 loop in the 43 rd cycle of JMTR operation, which demonstrated the effectiveness of the present method for leak detection at its early stage.

On-line surveillance of LWR primary systems state of the art and development trends of vibration-, loose parts — and leakage monitoring systems in the Federal Republic of Germany

On-line surveillance of LWR primary systems state of the art and development trends of vibration-, loose parts — and leakage monitoring systems in the Federal Republic of Germany