CA2673710A1 - Apparatus for detecting leakage from channel closure plug for fuel channel in heavy water reactor - Google Patents
Apparatus for detecting leakage from channel closure plug for fuel channel in heavy water reactor Download PDFInfo
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- CA2673710A1 CA2673710A1 CA2673710A CA2673710A CA2673710A1 CA 2673710 A1 CA2673710 A1 CA 2673710A1 CA 2673710 A CA2673710 A CA 2673710A CA 2673710 A CA2673710 A CA 2673710A CA 2673710 A1 CA2673710 A1 CA 2673710A1
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- channel
- signal
- closure plug
- acoustic sensor
- heavy water
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- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C17/00—Monitoring; Testing ; Maintaining
- G21C17/017—Inspection or maintenance of pipe-lines or tubes in nuclear installations
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/26—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors
- G01M3/28—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors for pipes, cables or tubes; for pipe joints or seals; for valves ; for welds
- G01M3/2807—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors for pipes, cables or tubes; for pipe joints or seals; for valves ; for welds for pipes
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C17/00—Monitoring; Testing ; Maintaining
- G21C17/002—Detection of leaks
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
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- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- General Physics & Mathematics (AREA)
- Monitoring And Testing Of Nuclear Reactors (AREA)
- Examining Or Testing Airtightness (AREA)
Abstract
Disclosed herein is an apparatus for detecting leakage of heavy water from a fuel channel in a heavy water reactor. The apparatus includes a signal collector equipped with a piezoelectric acoustic sensor and a high-frequency microphone acoustic sensor contacting an end fitting of a channel closure plug, a driver moving and contacting the signal collector to the end fitting of the channel closure plug, a control and power supply unit controlling the driver and supplies power to the driver and a signal amplifier, a signal amplifier amplifying the measured signal, and a signal analyzer processing and displaying the measured signal. The apparatus is engaged with a head of a fuelling machine and approaches, along with the fuelling machine, each channel closure plug to perform leakage examination. Since the apparatus uses a fuelling machine which is in use in a power plant to examine the fuel channel, and simultaneously measures acoustic signals from the inside and outside of the fuel channel, it is possible to quickly perform the examination, prevent the inspector from being exposed to the radiation, and to prevent heavy water from leaking from the channel closure plug of the fuel channel.
Description
KRIO-2008-0091650(Sep. 18, 2008) APPARATUS FOR DETECTING LEAKAGE FROM CHANNEL CLOSURE PLUG
FOR FUEL CHANNEL IN HEAVY WATER REACTOR
BACKGROUND OF THE INVENTION
1. Field of the Invention The present invention relates to an apparatus for detecting leakage from a channel closure plug for a fuel channel in a heavy water reactor and, more particularly, to an apparatus for detecting leakage from a channel closure plug for a fuel channel in a heavy water reactor using a piezoelectric acoustic sensor and a microphone acoustic sensor each incorporated in a signal collector to simultaneously measure acoustic signals from the inside and outside of the channel closure plug.
FOR FUEL CHANNEL IN HEAVY WATER REACTOR
BACKGROUND OF THE INVENTION
1. Field of the Invention The present invention relates to an apparatus for detecting leakage from a channel closure plug for a fuel channel in a heavy water reactor and, more particularly, to an apparatus for detecting leakage from a channel closure plug for a fuel channel in a heavy water reactor using a piezoelectric acoustic sensor and a microphone acoustic sensor each incorporated in a signal collector to simultaneously measure acoustic signals from the inside and outside of the channel closure plug.
2. Description of the Related Art A heavy water reactor has a fuel channel closure plug which functions as a path for sealing of an end fitting of the channel closure plug, prevention of heavy water leakage, and fuel reloading. The sealing structure is formed with a metal seal insert ring and a channel closure. The sealing structures are provided at the respective end fittings of 380 fuel channels, and the channel closure plugs are periodically removed from and fitted into the fuel channel when fuel needs to be replaced.
Heavy water may leak from the fuel channel due to partial breakage of a sealing plate caused by inflow of a foreign body to the fuel channel when the fuel channel closure plug is removed and attached and pressure of a solid foreign body by high temperature and high pressure, or due to air-tightness failure caused by poor sealing and degraded parts.
The acoustic emission measuring technique has been applied to detect and monitor leakage of heavy water from the fuel channels during the operation of the reactor.
Fig. 1 is a perspective view of a heavy water reactor, where reference numeral denotes a heavy water reactor and reference numeral 101 denotes a set of fuel channels.
The set of fuel channels 101 is composed of, for example, 380 fuel channels which are arranged in parallel to one another so as to form a pressure boundary. The channel closure plugs are provided at end fittings of the 380 fuel channels to serve as paths for sealing, prevention of heavy water leakage, and fuel reloading.
Fig. 2 illustrates a fuel channel of the set of fuel channels of Fig. 1, where reference numeral 200 denotes a channel closure plug and reference numeral 210 denotes an end fitting of a channel closure plug. Fig. 3 is a picture of the channel closure plug 200 of Fig. 2, where reference numeral 210 denotes an end fitting of a channel closure plug.
For each of the channel closure plugs 200, leakage examination is performed by acquiring an acoustic signal from each of 380 fuel channels using a high-temperature acoustic sensor, a sensor cable, a pre-amplifier, a signal cable, and a signal analyzer, while a piezoelectric acoustic sensor contacts the end fitting 210 of the channel closure plug 200.
For more information, for example, see O. A. Kupcis's article "Nondestructive Inspection of Pressure Tubes at the Pickering Nuclear Generating Station" 3rd Conference on Periodic Inspection of Pressurized Components, I. Mech. E., London, pp. 19-25, 1976.
Such a conventional inspection method has disadvantages in that it takes a long time, for example, in use of a couplant and movement of measurement equipment for inspection since signals are manually acquired. In addition, since inspectors attach an acoustic sensor to a channel closure plug in person to acquire signals, it is difficult to acquire uniform signals due to differences in coupling forces of coupling sensors according to the inspectors. Furthermore, although the inspection needs to be quickly performed in a high-temperature and radioactive environment, close inspection cannot be performed due to insufficient inspection time.
SUMMARY OF THE INVENTION
The present invention is conceived to solve the problems of the related art as described above, and an aspect of the present invention is to provide an apparatus for detecting leakage from a channel closure plug for a fuel channel in a heavy water reactor, which automatically inspects the channel closure plug by attaching the apparatus, attached to a head of a remote-controlled fuelling machine adapted to add and remove nuclear fuel, to an end fitting of the channel closure plug, instead of manually contacting an acoustic sensor to the end fitting of the channel closure plug.
According to an aspect of the present invention, an apparatus for detecting leakage from a channel closure plug having an end fitting at one side thereof for a fuel channel in a heavy water reactor is provided. The apparatus includes: a signal collector contacting the end fitting; a driver adapted to contact the signal collector to the end fitting;
a connector connecting the apparatus to a head bar of a fuelling machine of the fuel channel; and a signal processor processing signals collected by the signal collector, wherein the signal collector includes: a contactor contacting the end fitting;
a high-frequency acoustic sensor; a low-frequency acoustic collection horn; and a low-frequency acoustic sensor coupled to the low-frequency acoustic collection horn and providing a signal to the signal processor.
The high-frequency acoustic sensor may be a piezoelectric acoustic sensor, and the low-frequency acoustic sensor may be a microphone acoustic sensor.
The contactor may be made of a brass plate.
The connector may be coupled by a clamp to the head bar of the fuelling machine.
The low-frequency acoustic sensor may be provided in the driver.
The connector may be fixedly coupled to the driver.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other aspects, features and advantages of the present invention will become apparent from the following description given in conjunction with the accompanying drawings, in which:
Fig. 1 is a perspective view of an internal structure of a heavy water reactor;
Fig. 2 is a structural view of a fuel channel of a set of fuel channels;
Fig. 3 is a picture of an actual channel closure plug of Fig. 2;
Fig. 4 is a picture of an apparatus for detecting leakage from a channel closure plug for a fuel channel in a heavy water reactor according to one embodiment of the present invention, in which the apparatus is attached to a head of a fuelling machine and performing leakage detection;
Fig. 5 is a schematic diagram of an apparatus for detecting leakage from a channel closure plug for a fuel channel in a heavy water reactor according to the embodiment of the present invention;
Fig. 6 is a plan view of a driver according to one embodiment of the present invention;
Fig. 7 is a front view illustrating engagement between the apparatus for detecting leakage from a channel closure plug for a fuel channel in a heavy water reactor according to the embodiment of the present invention and a fuelling machine; and Fig. 8 is a block diagram of a signal analyzer.
DETAILED DESCRIPTION OF THE EMBODIMENT
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
Fig. 4 shows an apparatus for detecting leakage from a channel closure plug for a fuel channel in a heavy water reactor according to one embodiment of the present invention, in which the apparatus is attached to a head 607 of a remote-controlled fuelling machine adapted to add and remove nuclear fuel. It should be noted, however, that the present invention is not limited thereto and may readily be modified and changed by those skilled in the art without departing from the scope of the present invention.
As described in detail below, in order to check whether a channel closure plug for a fuel channel in a heavy water reactor leaks, the present invention provides an apparatus for simultaneously measuring acoustic signals from both the inside and outside of the fuel channel, i.e., a high-frequency elastic acoustic signal generated when heavy water leaks from the inside of the fuel channel and a low-frequency acoustic signal transmitted outside, using a piezoelectric acoustic sensor and a microphone acoustic sensor each built in a single signal collector at an end fitting of the fuel channel.
Conventionally, an inspector only attaches a piezoelectric acoustic sensor on a channel closure plug for a fuel channel in person to check whether heavy water leaks from the inside of the fuel channel. According to the present invention, however, since all of the fuel channels can be checked with a fuelling machine and acoustic signals can be simultaneously measured from the inside and outside of the channel closure plug of the fuel channel, the apparatus according to the present invention can provide fast and close examination.
Furthermore, since an inspector is not exposed to a high-temperature and radioactive environment, the inspector is safe and can perform the examination during the operation. In addition, it is possible to perform more precise and reliable measurement of signals by contacting the channel closure plug without using a couplant that can increase acoustic signal reception efficiency.
The apparatus for detecting leakage from a channel closure plug for a fuel channel in a heavy water reactor according to the embodiment of the present invention will be described in detail.
In Fig. 5, the apparatus according to the embodiment of the present invention includes a signal collector, a driver 600, a control and power supply unit 800, signal amplification and analyzing units 700, 900, and a connector for connecting to a head bar of a fuelling machine. It should be noted that Fig. 5 is a block diagram of the apparatus corresponding to the picture of Fig. 4 and shows a schematic side view of some essential components of the apparatus, for explanation convenience.
The signal collector is an acoustic signal collector which contacts a channel closure plug for a fuel channel to be examined, and includes both a piezoelectric acoustic sensor and a microphone acoustic sensor to simultaneously measure acoustic signals from the inside and outside of the channel closure plug for the fuel channel.
The signal collector simultaneously collects elastic waves (i.e., acoustic signals) from the inside and outside of the channel closure plug 200 for the fuel channel regardless of the examination environment, where the elastic waves are generated when heavy water leaks from the inside and outside of the channel closure plug 200 for the fuel channel, thereby obtaining quick and reliable examination results.
The apparatus for detecting leakage from a channel closure plug for a fuel channel in a heavy water reactor will be described in detail.
Heavy water may leak from the fuel channel due to partial breakage of a sealing plate caused by inflow of a foreign body to the fuel channel when the fuel channel closure plug is removed and attached and pressure of a solid foreign body by high temperature and high pressure, or due to air-tightness failure caused by poor sealing and degraded parts.
The acoustic emission measuring technique has been applied to detect and monitor leakage of heavy water from the fuel channels during the operation of the reactor.
Fig. 1 is a perspective view of a heavy water reactor, where reference numeral denotes a heavy water reactor and reference numeral 101 denotes a set of fuel channels.
The set of fuel channels 101 is composed of, for example, 380 fuel channels which are arranged in parallel to one another so as to form a pressure boundary. The channel closure plugs are provided at end fittings of the 380 fuel channels to serve as paths for sealing, prevention of heavy water leakage, and fuel reloading.
Fig. 2 illustrates a fuel channel of the set of fuel channels of Fig. 1, where reference numeral 200 denotes a channel closure plug and reference numeral 210 denotes an end fitting of a channel closure plug. Fig. 3 is a picture of the channel closure plug 200 of Fig. 2, where reference numeral 210 denotes an end fitting of a channel closure plug.
For each of the channel closure plugs 200, leakage examination is performed by acquiring an acoustic signal from each of 380 fuel channels using a high-temperature acoustic sensor, a sensor cable, a pre-amplifier, a signal cable, and a signal analyzer, while a piezoelectric acoustic sensor contacts the end fitting 210 of the channel closure plug 200.
For more information, for example, see O. A. Kupcis's article "Nondestructive Inspection of Pressure Tubes at the Pickering Nuclear Generating Station" 3rd Conference on Periodic Inspection of Pressurized Components, I. Mech. E., London, pp. 19-25, 1976.
Such a conventional inspection method has disadvantages in that it takes a long time, for example, in use of a couplant and movement of measurement equipment for inspection since signals are manually acquired. In addition, since inspectors attach an acoustic sensor to a channel closure plug in person to acquire signals, it is difficult to acquire uniform signals due to differences in coupling forces of coupling sensors according to the inspectors. Furthermore, although the inspection needs to be quickly performed in a high-temperature and radioactive environment, close inspection cannot be performed due to insufficient inspection time.
SUMMARY OF THE INVENTION
The present invention is conceived to solve the problems of the related art as described above, and an aspect of the present invention is to provide an apparatus for detecting leakage from a channel closure plug for a fuel channel in a heavy water reactor, which automatically inspects the channel closure plug by attaching the apparatus, attached to a head of a remote-controlled fuelling machine adapted to add and remove nuclear fuel, to an end fitting of the channel closure plug, instead of manually contacting an acoustic sensor to the end fitting of the channel closure plug.
According to an aspect of the present invention, an apparatus for detecting leakage from a channel closure plug having an end fitting at one side thereof for a fuel channel in a heavy water reactor is provided. The apparatus includes: a signal collector contacting the end fitting; a driver adapted to contact the signal collector to the end fitting;
a connector connecting the apparatus to a head bar of a fuelling machine of the fuel channel; and a signal processor processing signals collected by the signal collector, wherein the signal collector includes: a contactor contacting the end fitting;
a high-frequency acoustic sensor; a low-frequency acoustic collection horn; and a low-frequency acoustic sensor coupled to the low-frequency acoustic collection horn and providing a signal to the signal processor.
The high-frequency acoustic sensor may be a piezoelectric acoustic sensor, and the low-frequency acoustic sensor may be a microphone acoustic sensor.
The contactor may be made of a brass plate.
The connector may be coupled by a clamp to the head bar of the fuelling machine.
The low-frequency acoustic sensor may be provided in the driver.
The connector may be fixedly coupled to the driver.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other aspects, features and advantages of the present invention will become apparent from the following description given in conjunction with the accompanying drawings, in which:
Fig. 1 is a perspective view of an internal structure of a heavy water reactor;
Fig. 2 is a structural view of a fuel channel of a set of fuel channels;
Fig. 3 is a picture of an actual channel closure plug of Fig. 2;
Fig. 4 is a picture of an apparatus for detecting leakage from a channel closure plug for a fuel channel in a heavy water reactor according to one embodiment of the present invention, in which the apparatus is attached to a head of a fuelling machine and performing leakage detection;
Fig. 5 is a schematic diagram of an apparatus for detecting leakage from a channel closure plug for a fuel channel in a heavy water reactor according to the embodiment of the present invention;
Fig. 6 is a plan view of a driver according to one embodiment of the present invention;
Fig. 7 is a front view illustrating engagement between the apparatus for detecting leakage from a channel closure plug for a fuel channel in a heavy water reactor according to the embodiment of the present invention and a fuelling machine; and Fig. 8 is a block diagram of a signal analyzer.
DETAILED DESCRIPTION OF THE EMBODIMENT
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
Fig. 4 shows an apparatus for detecting leakage from a channel closure plug for a fuel channel in a heavy water reactor according to one embodiment of the present invention, in which the apparatus is attached to a head 607 of a remote-controlled fuelling machine adapted to add and remove nuclear fuel. It should be noted, however, that the present invention is not limited thereto and may readily be modified and changed by those skilled in the art without departing from the scope of the present invention.
As described in detail below, in order to check whether a channel closure plug for a fuel channel in a heavy water reactor leaks, the present invention provides an apparatus for simultaneously measuring acoustic signals from both the inside and outside of the fuel channel, i.e., a high-frequency elastic acoustic signal generated when heavy water leaks from the inside of the fuel channel and a low-frequency acoustic signal transmitted outside, using a piezoelectric acoustic sensor and a microphone acoustic sensor each built in a single signal collector at an end fitting of the fuel channel.
Conventionally, an inspector only attaches a piezoelectric acoustic sensor on a channel closure plug for a fuel channel in person to check whether heavy water leaks from the inside of the fuel channel. According to the present invention, however, since all of the fuel channels can be checked with a fuelling machine and acoustic signals can be simultaneously measured from the inside and outside of the channel closure plug of the fuel channel, the apparatus according to the present invention can provide fast and close examination.
Furthermore, since an inspector is not exposed to a high-temperature and radioactive environment, the inspector is safe and can perform the examination during the operation. In addition, it is possible to perform more precise and reliable measurement of signals by contacting the channel closure plug without using a couplant that can increase acoustic signal reception efficiency.
The apparatus for detecting leakage from a channel closure plug for a fuel channel in a heavy water reactor according to the embodiment of the present invention will be described in detail.
In Fig. 5, the apparatus according to the embodiment of the present invention includes a signal collector, a driver 600, a control and power supply unit 800, signal amplification and analyzing units 700, 900, and a connector for connecting to a head bar of a fuelling machine. It should be noted that Fig. 5 is a block diagram of the apparatus corresponding to the picture of Fig. 4 and shows a schematic side view of some essential components of the apparatus, for explanation convenience.
The signal collector is an acoustic signal collector which contacts a channel closure plug for a fuel channel to be examined, and includes both a piezoelectric acoustic sensor and a microphone acoustic sensor to simultaneously measure acoustic signals from the inside and outside of the channel closure plug for the fuel channel.
The signal collector simultaneously collects elastic waves (i.e., acoustic signals) from the inside and outside of the channel closure plug 200 for the fuel channel regardless of the examination environment, where the elastic waves are generated when heavy water leaks from the inside and outside of the channel closure plug 200 for the fuel channel, thereby obtaining quick and reliable examination results.
The apparatus for detecting leakage from a channel closure plug for a fuel channel in a heavy water reactor will be described in detail.
Referring again to Fig. 5, the signal collector includes a sensor housing 400 which is provided with a contactor to contact an end fitting of the fuel channel.
The contactor may be made of a brass plate 401 to reduce acoustic impedance upon signal acquisition without a couplant, thereby increasing acoustic signal reception efficiency.
The signal collector includes a high-frequency acoustic sensor 500 for high-temperature and radioactive applications; a sensor cable 501 connected to the high-frequency acoustic sensor 500, a low-frequency acoustic horn 502, a guide pipe 503, and a low-frequency acoustic sensor (i.e., microphone acoustic sensor) 504.
The low-frequency acoustic sensor 504 coupled to the low-frequency acoustic collection horn to provide signals to a signal processor may be incorporated either in the signal collector or in the signal amplifier 700 which receives sensing signals through the sensor cable 501 of the high-frequency acoustic sensor 500 and the guide pipe 503 of the low-frequency acoustic sensor 504, as shown in Fig. 5. However, it should be noted that the arrangement of these components can be changed according to design.
Reference numera1402 of the drawing denotes a spring.
The driver 600 employs a driving force from a motor to allow the signal collector, i.e., the brass plate 401, to approach and come into slight surface contact with the end fitting of the channel closure plug (e.g., reference numeral 210 in Fig. 3), as shown in Fig.
4. Reference numeral 403 in Fig. 5 denotes a hinge by which the sensor housing 400 is hinged to the driver 600.
The driver 600 is designed to be coupled to the signal collector and a signal acquisition and amplification housing 710 according to an exemplary embodiment of the present invention, which are shown in plan view in Fig. 6.
Referring to Fig. 6, the driver 600 includes an upper drive arm 601, a lower drive arm 602, an arm drive roller 603, three guide rollers 604, and an arm support bolt 605 to allow the signal collector to approach and come into contact with the end fitting of the channel closure plug. The sensor cable 501 and the acoustic guide pipe 503 are in the lower drive arm 602.
The signal acquisition and amplification housing 710 is engaged with the head bar 607 of the fuelling machine using a clamp 606 (see Fig. 4), which are shown in front view in Fig. 7.
The signal amplification unit 700 incorporated in the signal acquisition and amplification housing 710 amplifies weak acoustic signals acquired by the high-frequency acoustic sensor 500 and the low-frequency acoustic sensor (microphone acoustic sensor) 504 from several microvolts to several millivolts. The amplified high-frequency acoustic signal and low-frequency acoustic signal are input to the signal analyzer 900 through a high-frequency acoustic signal cable 801 and a low-frequency acoustic signal cable 802, respectively.
The control and power supply unit 800 supplies power to the driver 600 and the signal amplifier 700. The control and power supply unit 800 applies 12V DC to the signal amplifier 700 to amplify an acoustic signal, drives a motor with 220V AC to move the driver 600 back and forth, and applies 12V DC to a limit switch 404 engaged to the sensor housing 400. The limit switch 404 is used to prevent the brass plate 401 engaged with the spring 402 from further moving forward after the brass plate 401 approaches and contacts the end fitting of the channel closure plug.
The signal analyzer 900 will be described with reference to Fig. 8.
The signal analyzer 900 is provided to receive an acoustic signal from the signal amplifier 700 and analyze the amplitude, voltage and frequency of the acoustic signal. For this purpose, the signal analyzer 900 processes and displays the acoustic signal on a display.
Fig. 8 is a block diagram of the signal analyzer 900.
Weak acoustic signals acquired by the high-frequency acoustic sensor 500 and the low-frequency acoustic sensor 504 are amplified by the amplifier (AMP). The amplified high-frequency acoustic sensor signal is input to and averaged by an RMS
circuit 901, and the amplified low-frequency acoustic sensor signal is input to and averaged by another RMS circuit 902.
The averaged high-frequency acoustic signal is applied to an analog-to-digital converter (ADC) 903, and the averaged low-frequency acoustic signal is applied to an analog-to-digital converter (ADC) 904. The digitized low-frequency and high-frequency acoustic signals are stored, for example, in a memory (RAM) 905 in a computing device 909.
The contactor may be made of a brass plate 401 to reduce acoustic impedance upon signal acquisition without a couplant, thereby increasing acoustic signal reception efficiency.
The signal collector includes a high-frequency acoustic sensor 500 for high-temperature and radioactive applications; a sensor cable 501 connected to the high-frequency acoustic sensor 500, a low-frequency acoustic horn 502, a guide pipe 503, and a low-frequency acoustic sensor (i.e., microphone acoustic sensor) 504.
The low-frequency acoustic sensor 504 coupled to the low-frequency acoustic collection horn to provide signals to a signal processor may be incorporated either in the signal collector or in the signal amplifier 700 which receives sensing signals through the sensor cable 501 of the high-frequency acoustic sensor 500 and the guide pipe 503 of the low-frequency acoustic sensor 504, as shown in Fig. 5. However, it should be noted that the arrangement of these components can be changed according to design.
Reference numera1402 of the drawing denotes a spring.
The driver 600 employs a driving force from a motor to allow the signal collector, i.e., the brass plate 401, to approach and come into slight surface contact with the end fitting of the channel closure plug (e.g., reference numeral 210 in Fig. 3), as shown in Fig.
4. Reference numeral 403 in Fig. 5 denotes a hinge by which the sensor housing 400 is hinged to the driver 600.
The driver 600 is designed to be coupled to the signal collector and a signal acquisition and amplification housing 710 according to an exemplary embodiment of the present invention, which are shown in plan view in Fig. 6.
Referring to Fig. 6, the driver 600 includes an upper drive arm 601, a lower drive arm 602, an arm drive roller 603, three guide rollers 604, and an arm support bolt 605 to allow the signal collector to approach and come into contact with the end fitting of the channel closure plug. The sensor cable 501 and the acoustic guide pipe 503 are in the lower drive arm 602.
The signal acquisition and amplification housing 710 is engaged with the head bar 607 of the fuelling machine using a clamp 606 (see Fig. 4), which are shown in front view in Fig. 7.
The signal amplification unit 700 incorporated in the signal acquisition and amplification housing 710 amplifies weak acoustic signals acquired by the high-frequency acoustic sensor 500 and the low-frequency acoustic sensor (microphone acoustic sensor) 504 from several microvolts to several millivolts. The amplified high-frequency acoustic signal and low-frequency acoustic signal are input to the signal analyzer 900 through a high-frequency acoustic signal cable 801 and a low-frequency acoustic signal cable 802, respectively.
The control and power supply unit 800 supplies power to the driver 600 and the signal amplifier 700. The control and power supply unit 800 applies 12V DC to the signal amplifier 700 to amplify an acoustic signal, drives a motor with 220V AC to move the driver 600 back and forth, and applies 12V DC to a limit switch 404 engaged to the sensor housing 400. The limit switch 404 is used to prevent the brass plate 401 engaged with the spring 402 from further moving forward after the brass plate 401 approaches and contacts the end fitting of the channel closure plug.
The signal analyzer 900 will be described with reference to Fig. 8.
The signal analyzer 900 is provided to receive an acoustic signal from the signal amplifier 700 and analyze the amplitude, voltage and frequency of the acoustic signal. For this purpose, the signal analyzer 900 processes and displays the acoustic signal on a display.
Fig. 8 is a block diagram of the signal analyzer 900.
Weak acoustic signals acquired by the high-frequency acoustic sensor 500 and the low-frequency acoustic sensor 504 are amplified by the amplifier (AMP). The amplified high-frequency acoustic sensor signal is input to and averaged by an RMS
circuit 901, and the amplified low-frequency acoustic sensor signal is input to and averaged by another RMS circuit 902.
The averaged high-frequency acoustic signal is applied to an analog-to-digital converter (ADC) 903, and the averaged low-frequency acoustic signal is applied to an analog-to-digital converter (ADC) 904. The digitized low-frequency and high-frequency acoustic signals are stored, for example, in a memory (RAM) 905 in a computing device 909.
The computing device 909 includes a microprocessor 906, a RAM 905, a display 910, a USB interface 907, and an RS-232 interface 908 to analyze the input amplitude, voltage and frequency of the acoustic signal. The computing device 909 may further include a terminal block 920 and a data acquisition board (DAQ) to input and display external voltage signals.
The computing device, for example, may determine acoustic signal levels, perform voltage analysis and Fast Fourier Transform (FFT) operations on acquired sensing signals, and display the results on the display 910.
The present invention provides a method and apparatus for improving a conventional technology for examining leakage from a channel closure plug for a fuel channel. Accordingly, the present invention provides a quick and reliable examination technology since it is possible to conveniently examine all of the fuel channels using a single apparatus coupled to a fuelling machine to simultaneously measure acoustic signals from the inside and outside of the channel closure plug for the fuel channel.
Furthermore, since an inspector is not exposed to a high-temperature and radioactive environment, the inspector is safe and can perform the examination during the operation. In addition, it is possible to perform more precise and reliable measurement of signals by contacting the channel closure plug without using a couplant to increase acoustic signal reception efficiency. Accordingly, the present invention provides a useful technology for the leakage examination of a channel closure plug.
Conventionally, since an inspector uses a fuelling machine or an acoustic examination device to individually examine 380 fuel channels and it takes about 10 minutes to examine a single fuel channel, the inspector may suffer from radiation problems and it may take up to 3,800 minutes for full examination. The apparatus according to the present invention, however, is attached to a fuelling machine in use in an existing power plant, and is remotely controlled to quickly scan the 380 fuel channels.
In addition, the inspector conventionally attaches only a piezoelectric acoustic sensor on a channel closure plug of a fuel channel in person to examine leakage from the fuel channel. However, since the apparatus according to the present invention uses a fuelling machine which is currently used in a power plant to examine the fuel channel, and simultaneously measures acoustic signals from the inside and outside of the fuel channel, it is possible to quickly perform the examination, prevent the inspector from being exposed to radiation, and to prevent heavy water from leaking from the channel closure plug of the fuel channel.
Although some embodiments have been provided to illustrate the- present invention, the embodiments are given by way of illustration, and that various modifications, changes, and substitutions can be made by a person having ordinary knowledge in the art without departing from the spirit and scope of the present invention.
Accordingly, the scope of the present invention should be limited only by the accompanying claims and equivalents thereof.
The computing device, for example, may determine acoustic signal levels, perform voltage analysis and Fast Fourier Transform (FFT) operations on acquired sensing signals, and display the results on the display 910.
The present invention provides a method and apparatus for improving a conventional technology for examining leakage from a channel closure plug for a fuel channel. Accordingly, the present invention provides a quick and reliable examination technology since it is possible to conveniently examine all of the fuel channels using a single apparatus coupled to a fuelling machine to simultaneously measure acoustic signals from the inside and outside of the channel closure plug for the fuel channel.
Furthermore, since an inspector is not exposed to a high-temperature and radioactive environment, the inspector is safe and can perform the examination during the operation. In addition, it is possible to perform more precise and reliable measurement of signals by contacting the channel closure plug without using a couplant to increase acoustic signal reception efficiency. Accordingly, the present invention provides a useful technology for the leakage examination of a channel closure plug.
Conventionally, since an inspector uses a fuelling machine or an acoustic examination device to individually examine 380 fuel channels and it takes about 10 minutes to examine a single fuel channel, the inspector may suffer from radiation problems and it may take up to 3,800 minutes for full examination. The apparatus according to the present invention, however, is attached to a fuelling machine in use in an existing power plant, and is remotely controlled to quickly scan the 380 fuel channels.
In addition, the inspector conventionally attaches only a piezoelectric acoustic sensor on a channel closure plug of a fuel channel in person to examine leakage from the fuel channel. However, since the apparatus according to the present invention uses a fuelling machine which is currently used in a power plant to examine the fuel channel, and simultaneously measures acoustic signals from the inside and outside of the fuel channel, it is possible to quickly perform the examination, prevent the inspector from being exposed to radiation, and to prevent heavy water from leaking from the channel closure plug of the fuel channel.
Although some embodiments have been provided to illustrate the- present invention, the embodiments are given by way of illustration, and that various modifications, changes, and substitutions can be made by a person having ordinary knowledge in the art without departing from the spirit and scope of the present invention.
Accordingly, the scope of the present invention should be limited only by the accompanying claims and equivalents thereof.
Claims (6)
1. An apparatus for detecting leakage from a channel closure plug having an end fitting at one end for a fuel channel in a heavy water reactor, comprising:
a signal collector contacting the end fitting;
a driver adapted to contact the signal collector to the end fitting;
a connector connecting the apparatus to a head bar of a fuelling machine of the fuel channel; and a signal processor processing signals collected by the signal collector, the signal collector comprising:
a contactor contacting the end fitting;
a high-frequency acoustic sensor;
a low-frequency acoustic collection horn; and a low-frequency acoustic sensor coupled to the low-frequency acoustic collection horn to provide a signal to the signal processor.
a signal collector contacting the end fitting;
a driver adapted to contact the signal collector to the end fitting;
a connector connecting the apparatus to a head bar of a fuelling machine of the fuel channel; and a signal processor processing signals collected by the signal collector, the signal collector comprising:
a contactor contacting the end fitting;
a high-frequency acoustic sensor;
a low-frequency acoustic collection horn; and a low-frequency acoustic sensor coupled to the low-frequency acoustic collection horn to provide a signal to the signal processor.
2. The apparatus according to claim 1, wherein the high-frequency acoustic sensor is a piezoelectric acoustic sensor, and the low-frequency acoustic sensor is a microphone acoustic sensor.
3. The apparatus according to claim 1, wherein the contactor is made of a brass plate.
4. The apparatus according to claim 1, wherein the connector is coupled by a clamp to the head bar of the fuelling machine.
5. The apparatus according to claim 1, wherein the low-frequency acoustic sensor is provided in the driver.
6. The apparatus according to claim 1, wherein the connector is fixedly coupled to the driver.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR10-2008-0091650 | 2008-09-18 | ||
| KR1020080091650A KR100987166B1 (en) | 2008-09-18 | 2008-09-18 | Acoustic Leak Detector for Fuel Channels in Heavy Water Reactor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2673710A1 true CA2673710A1 (en) | 2010-03-18 |
| CA2673710C CA2673710C (en) | 2014-01-21 |
Family
ID=42029343
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2673710A Expired - Fee Related CA2673710C (en) | 2008-09-18 | 2009-07-23 | Apparatus for detecting leakage from channel closure plug for fuel channel in heavy water reactor |
Country Status (5)
| Country | Link |
|---|---|
| KR (1) | KR100987166B1 (en) |
| CN (1) | CN101676703B (en) |
| AR (1) | AR073383A1 (en) |
| CA (1) | CA2673710C (en) |
| RO (1) | RO126250B1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2756850C1 (en) * | 2021-04-05 | 2021-10-06 | Акционерное общество «Научно-технический центр «Диапром» | Moisture measuring channel |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101070322B1 (en) | 2011-05-11 | 2011-10-06 | 진흥산업 주식회사 | Testing device for static seal of candu fueling machine |
| CN103247358B (en) * | 2013-04-16 | 2015-11-25 | 中国核电工程有限公司 | Nuclear power station high energy pipeline local leakage monitoring test stand |
| KR101926956B1 (en) * | 2017-01-02 | 2018-12-07 | 한국수력원자력 주식회사 | method of Failed Feul Location Monitoring |
| CN109973826B (en) * | 2019-04-26 | 2020-05-15 | 西安交通大学 | Experimental device and method for measuring leakage rate of nuclear reactor pipeline |
| RU2709474C1 (en) * | 2019-09-04 | 2019-12-18 | Акционерное общество "Научно-технический центр "Диапром" | System of acoustic leak monitoring of npp pipeline |
| RU2722684C1 (en) * | 2019-11-15 | 2020-06-03 | Акционерное общество "Научно-технический центр "Диапром" | Monitoring system for leakage of heat exchanger of passive heat removal system by acoustic method |
| RU2760604C1 (en) * | 2021-04-05 | 2021-11-29 | Акционерное общество «Научно-технический центр «Диапром» | Acoustic measuring channel |
| KR20220151509A (en) | 2021-05-06 | 2022-11-15 | 한국수력원자력 주식회사 | Fuel handling system modeling method, evaluation method, and evaluation system for safety analysis of candu plant |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA933646A (en) * | 1970-06-16 | 1973-09-11 | Canadian General Electric Company Limited | Ultrasonic leak detection |
| CN2166436Y (en) * | 1993-09-01 | 1994-05-25 | 东南大学 | Anti-strong noise ultrasonic leakage testing instrument |
| KR20040046596A (en) * | 2002-11-28 | 2004-06-05 | 황후 | Mobile Phone Having a Mirror |
| JP4157466B2 (en) * | 2003-10-28 | 2008-10-01 | 株式会社東芝 | Valve leak detection system |
| KR200446596Y1 (en) * | 2007-09-27 | 2009-11-11 | 한국전력공사 | The Acoustic Emission Signal Acquisition Assembly for Leak Detection of Closure Plug in Heavy Water Reactor |
-
2008
- 2008-09-18 KR KR1020080091650A patent/KR100987166B1/en active IP Right Grant
-
2009
- 2009-07-23 CA CA2673710A patent/CA2673710C/en not_active Expired - Fee Related
- 2009-07-28 RO ROA200900591A patent/RO126250B1/en unknown
- 2009-09-16 CN CN200910171889.9A patent/CN101676703B/en not_active Expired - Fee Related
- 2009-09-18 AR ARP090103583A patent/AR073383A1/en not_active Application Discontinuation
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2756850C1 (en) * | 2021-04-05 | 2021-10-06 | Акционерное общество «Научно-технический центр «Диапром» | Moisture measuring channel |
Also Published As
| Publication number | Publication date |
|---|---|
| RO126250A2 (en) | 2011-04-29 |
| RO126250B1 (en) | 2015-10-30 |
| CN101676703B (en) | 2014-05-07 |
| KR100987166B1 (en) | 2010-10-11 |
| CA2673710C (en) | 2014-01-21 |
| CN101676703A (en) | 2010-03-24 |
| AR073383A1 (en) | 2010-11-03 |
| KR20100032669A (en) | 2010-03-26 |
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