JPH04235390A - Abnormality diagonostic device for nuclear plant piping systems - Google Patents

Abstract

PURPOSE:To detect abnormal symptoms of apparatuses such as valves and pipings hear the apparatuses, which are attached to piping systems of a nuclear power plant. CONSTITUTION:Apparatuses 19 such as valves, having driving mechanism 24 thereof, are attached to pipings 20 of a nuclear power plant. Also, sensors 25 such as acceleration sensors or sonic sensors are attached to the apparatuses 19 or pipings 20 near the equipments 19. A signal judgment device 36 is provided for processing signal of the sensors 25. The signal judgment device 36 is so designed as to select electrical signal representing acceleration or sound with a specific frequency range by a filter 33, to counts the number of the signals exceeding a limiting valve per unit time using a counter 35 through a comparator 34, and to generate an alarm when the preset number is exceeded. In this way, operating conditions of the apparatuses such as valves under normal operation of the nuclear power plant can be accurately monitored.

Description

[Detailed description of the invention]

[Object of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abnormality diagnosis apparatus for a piping system of a nuclear power plant for detecting signs of abnormality in equipment such as valves attached to the piping system of a nuclear power plant or piping in the vicinity of the equipment.

0003

2. Description of the Related Art FIG. 6 schematically shows the main piping systems that are constantly in operation during steady operation of a nuclear reactor in a boiling water nuclear power plant. Note that these piping systems are stored within the reactor containment vessel 5.

[0004] The output of a nuclear reactor is mainly controlled by the flow rate of reactor water flowing through a reactor core 2 within a reactor pressure vessel 1 . The recirculation loop system includes a recirculation loop 3 attached to the reactor pressure vessel 1 and a recirculation pump 4, and generates a flow within the reactor pressure vessel 1. In addition, the steam generated in the reactor pressure vessel 1 flows through the main steam pipe 6 to the turbine 7, from the turbine 7 to the condenser 8, and then returns from steam to water in the condenser 8, passing through the water supply pump 9 and the water supply pipe. 10 to return to the reactor pressure vessel 1. A purification system for water flowing inside the reactor pressure vessel 1 branches off from the recirculation loop 3, passes through a desalination pump 12, a filtration desalination device 11, and joins a water supply pipe 10.

[0005] These piping systems include many devices such as pumps to drive the flow in the piping, flow control valves to control the flow rate, and isolation valves to prevent reactor water from flowing out in the event of an accident. . In conventional nuclear reactors, the recirculation pump 4 is used as a constant abnormality monitoring mechanism for devices with drive parts in these pipings.
An accelerometer is attached to the top of the motor, and the vibration amplitude of the motor is determined from the signal, and the system is set to issue a warning if the vibration amplitude exceeds a limit value. In addition, normal valve operation is not monitored for abnormalities, and some valves are overhauled and checked for operation during annual inspections.

[0006]

[Problem to be Solved by the Invention] However, when any driving part is exposed to the flow in the piping, pressure pulsations caused by the pump that drives the flow in the piping and due to the flow path structure of the piping system occur. Vibration occurs due to the influence of force due to flow turbulence, Karman vortices generated in the wake of the drive unit, and flow separation. When this vibration becomes large, it damages the joint between the valve body and the valve body, making it difficult to drive the valve body. In the worst case, the valve body may stop working and the valve stem may be damaged.

The present invention has been made to solve the above-mentioned problems, and by attaching a sensor to equipment such as a valve having a driving part in the piping system of a nuclear power plant, and processing the signal of the sensor, It can monitor the status of valves, etc., and issue a warning if the limit value is exceeded.
Abnormalities in the piping system of nuclear power plants that can improve safety during normal operation of the nuclear reactor, prevent unnecessary overhaul during periodic inspections, and improve work efficiency and economic efficiency. The objective is to provide diagnostic equipment. [Structure of the invention]

[0008]

[Means for Solving the Problems] The present invention attaches an acceleration sensor or an acoustic sensor to equipment such as a valve having a driving part attached to the piping system of a nuclear power plant or to piping in the vicinity of the equipment. The signal determining device selects a specific frequency range by filtering the electric signal of acceleration or sound, counts the number of times the limit value is exceeded per unit time with a counter, and calculates the set number of times. It is characterized in that it is configured to issue a warning when the limit is exceeded.

[0009]

[Operation] The status of valves, etc. during normal operation is monitored by constantly operating sensors, signal processing, and judgment mechanisms on devices that have driving parts such as valves in the piping system of nuclear power plants. Also,
The signal processing system is equipped with a signal judgment function to issue a warning if the limit value is exceeded. In addition to improving safety during normal operation of a nuclear reactor, it is possible to prevent unnecessary disassembly and inspection during periodic inspections, thereby improving work efficiency and economic efficiency.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS First to third embodiments of the apparatus for diagnosing abnormalities in piping systems of nuclear power plants according to the present invention will be described with reference to the drawings.

FIG. 1 is a schematic flow diagram showing a first embodiment of an abnormality diagnosis apparatus for equipment such as valves attached to a piping system of a nuclear power plant according to the present invention. This flow diagram describes the case of a valve as an example of a device.

In FIG. 1, reference numeral 20 indicates a piping system of a nuclear power plant, and the piping 20 has a valve body 21, a valve rod 22,
The device 1 is a valve consisting of a valve box 23 and a mechanism 24 that drives the valve body.
It is set as 9. A plurality of sensors 25 that capture acceleration or sound are fixed on the surface of the pipe 20 and the surface of the valve box 23 near the valve, and signals from the sensors 25 are connected to an amplifier 26. The output of the amplifier 26 is sent to a recorder 2 such as a data recorder in parallel.
7, connected to a signal judgment device 36 consisting of a time history waveform display 28, an acoustic amplifier 29 and a speaker 30, a frequency analyzer 31 and its output display 32, a filter 33, a comparator 34 and a counter 35. The time history waveform display generally displays an acceleration signal and monitors the behavior of the valve body during operation. Generally, the time history waveform during normal operation has a shape as shown in FIG. 2, and when an abnormality occurs, since impact acceleration is also captured, the time history waveform has a shape as shown in FIG. 3. Similarly, when the signal is processed through the acoustic amplifier 29 and outputted from the speaker 30, impact sounds and sliding sounds can be heard in the event of an abnormality, and the behavior of the valve body can be monitored. The frequency analyzer 31 and its output display are used to check the frequency characteristics of acceleration and sound during normal and abnormal conditions, and to examine the frequency band of the filter 33 of the signal judgment device 36. In the signal judgment device 36,
The filter 33 discriminates only signals in a frequency band that can accurately capture abnormal signs, and the comparator 34 is provided with a set value, and when a signal exceeding the set value is input, it is output to the counter 35 at the subsequent stage. A signal is sent. The counter 35 counts and displays the number of signals per unit time, and if the number of times exceeds a set value, a warning is issued.

Next, a second embodiment will be explained with reference to FIG. Note that the same parts in the figure as in FIG. 1 are denoted by the same reference numerals, and the explanation of the overlapping parts will be omitted.

As shown in the flowchart of FIG. 4, instead of inputting the first stage amplified signal of the sensor to the signal determining device, the signal amplified by the acoustic amplifier again is input to the signal determining device. The basic operation of the device is the same as in the previous embodiment.

Next, a third embodiment of the present invention will be explained with reference to FIG.

FIG. 5 shows that after passing through a specific filter 33,
An example is shown in which a signal is input to the signal determining device 36a. At this time, only the impact and sliding phenomena are input to the speaker 30 through the acoustic amplifier 29 and directly to the comparator 34, and are counted by the counter 35. This embodiment has the effect that the phenomenon can be easily determined.

[0017]

[Effects of the Invention] According to the present invention, the status of equipment such as valves during normal operation can be monitored by constantly operating sensors, signal processing, and judgment mechanisms in a mechanism that has a driving part in a piping system such as valves in a nuclear reactor. Can be monitored. In addition, the signal processing system is equipped with a signal judgment function to issue a warning when the limit value is exceeded, improving safety during normal operation of the reactor.
It is possible to prevent unnecessary disassembly and inspection during periodic inspections, improving work efficiency and economic efficiency.

[Brief explanation of the drawing]

FIG. 1 is a flow diagram showing a first embodiment of an abnormality diagnosis device for a piping system of a nuclear power plant according to the present invention.

FIG. 2 is a time history waveform diagram showing normal signals in FIG. 1;

FIG. 3 is a time history waveform diagram showing signals at abnormal times in FIG. 2;

FIG. 4 is a flow diagram showing a second embodiment of the present invention.

FIG. 5 is a flow diagram showing a third embodiment of the present invention.

FIG. 6 is a system diagram showing a main piping system of a nuclear power plant to explain a conventional example.

[Explanation of symbols]

19...Equipment, 20...Piping, 21...Valve body, 22...Valve stem, 2
3...Valve box, 24...Drive mechanism, 25...Sensor, 26...Amplifier, 27...Recorder, 28...Waveform display, 29...Acoustic amplifier, 30...Speaker, 31...Frequency analyzer, 32...Frequency distribution display , 33... Filter, 34... Comparator, 35...
Counter, 36...Signal judgment device.

Claims (1)

[Claims] Claim 1: An acceleration sensor or an acoustic sensor is attached to a device such as a valve having a drive unit attached to a piping system of a nuclear power plant, or to piping near the device, and a signal judgment device that processes the sensor signal is provided. The signal determining device selects a specific frequency range by filtering the electric signal of acceleration or sound, counts the number of times the limit value is exceeded per unit time with a counter, and issues a warning when the set number of times is exceeded. An abnormality diagnosis device for a piping system of a nuclear power plant, characterized in that it is configured as follows.