JPH0411838B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an ultrasonic fluoroscopy device for observing liquid sodium in a sodium-cooled fast breeder reactor to monitor equipment inside the reactor.

[Technical background of the invention]

In general, in sodium-cooled fast breeder reactors, when changing fuel, the core inside the reactor vessel and the upper core mechanism attached to the rotating plug are completely separated, and the rotating plug is rotated to perform fuel changes. It is configured as follows. By the way, when rotating the rotary plug, if there is an obstacle such as floating fuel in the gap between the upper surface of the core and the lower surface of the upper core mechanism (hereinafter referred to as core gear), this may interfere with the upper core mechanism and cause the upper core mechanism to or fuel may be damaged. On the other hand, since the coolant liquid sodium is optically opaque, it is not possible to monitor the existence of obstructions within the core gap by optical means. For this reason, such a nuclear reactor is equipped with an ultrasonic fluoroscopy device that uses ultrasonic waves to see through the liquid sodium to monitor whether there are any obstacles in the core gap.

The configuration of this ultrasonic fluoroscope will be explained below with reference to FIGS. 1 and 2. In the figure, 1 is a nuclear reactor vessel, and a reactor core 2 is accommodated within this reactor vessel 1. Further, the upper end of the reactor vessel 1 is closed by a shielding plug 3. and,
A rotating plug 4 is provided on this shielding plug 3, and a core upper mechanism 5 is attached to this rotating plug 4. An ultrasonic transducer 6 is provided within the reactor vessel 1. This ultrasonic transducer 6 is rotated in a horizontal plane by a scanning mechanism 7, and is rotated between the upper surface of the core 2 and the core upper mechanism 5.
It transmits ultrasonic waves in the horizontal direction into the core gap 8 between it and the lower surface, receives the reflected waves, and converts them into electrical reflected wave signals. It is configured to scan in a fan shape in the horizontal direction. Note that 9 is a control circuit for the scanning mechanism 7. Further, a reflector 10 is provided on the inner peripheral surface of the reactor vessel 1 on the opposite side of the ultrasonic transducer 6, and this reflector 1
A large number of reflecting surfaces directly facing the ultrasonic transducer 6 are formed on the ultrasonic transducer 0 . Therefore, the ultrasonic wave emitted from the ultrasonic transducer 6 passes through the core gap 8 and is reflected by the reflector 10, and this reflected wave passes through the core gap 8 again and is received by the ultrasonic transducer 6. It is composed of The reflected wave signal from this ultrasonic transducer 6 is configured to be sent to a signal processing circuit 11. The reflected wave signal sent to this signal processing circuit 11 is first transmitted to the wave height detection circuit 1.
2, is converted into a signal corresponding to the wave height, and is sent to the image composition circuit 13. Further, the image forming circuit 13 is configured so that a signal corresponding to the scanning angle of the ultrasonic transducer 6 is sent from the control circuit 9 of the scanning mechanism 7. The image signal configured by this image configuration circuit 13 is
It is sent to a display mechanism 14 such as a CRT and displayed.
The image configuration circuit 13 first displays a core image 2' simulating the reactor core 2 and a core upper mechanism image 5' simulating the core upper mechanism 5 on the display mechanism 14. Next, this image composition circuit 13 creates an obstacle display 15' between the core image 2' and the core upper mechanism image 5', the height of which is inversely proportional to the peak value of the reflected wave signal from the ultrasonic transducer 6. configured to display. Note that the obstacle display 15' is displayed at each scanning position of the ultrasonic transducer 6. Therefore, if there is an obstacle 15 such as floating fuel in the core gap 8, the ultrasonic waves passing through the core gap 8 will be reflected by the obstacle 15.
Scattered and weakened, the level of the reflected wave signal, i.e.
Obstacle display 15' at that position corresponding to the wave height value...
height increases. In addition, this obstacle display 15'
The height of ... increases as the peak value of the reflected wave signal decreases. Therefore, the heights of these obstacle displays 15' increase in accordance with the heights of the obstacles 15, and the display on the display mechanism 14 becomes equivalent to that seen through the core gap 8 from the horizontal direction.

[Problems with background technology]

In the conventional system, when an obstacle 15 is located in the core gap 8, it is possible to tell in which direction of the θ direction shown in FIG. The distance l from the transducer 6 to the obstacle 15 is not known. Therefore, it was not clear where the obstacle 15 was located in the reactor core 2, making it difficult to repair the obstacle 15.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an ultrasonic fluoroscopy device that can detect an obstacle in a core gap and its position, and can easily repair the obstacle.

[Summary of the invention]

The present invention relates to an ultrasonic transducer that transmits ultrasonic waves toward a core gap formed between a reactor core and an upper core mechanism and receives ultrasonic echoes, and the ultrasonic transducer. a scanning mechanism that rotates in a horizontal plane to horizontally scan the ultrasonic waves; a position detector that detects the scanning position of the ultrasonic transducer; and a peak of the ultrasonic echo received by the ultrasonic transducer. a peak value detection circuit that detects a value; and a distance detection circuit that detects a distance from an obstacle present in the core gap to the ultrasonic transducer based on an output signal from the peak value detection circuit.
a wave height detector that detects the signal level of the ultrasonic echo received by the ultrasonic transducer; and a height detector that detects the height of an obstacle present in the core gap based on the output signal from the wave height detector. and a display mechanism that displays the position and height of the obstacle on the reactor core based on signals from the position detector, distance detection circuit, and height detector. Therefore, if there is an obstacle in the core gap, the direction of the obstacle relative to the ultrasonic transducer and the distance from the ultrasonic transducer to the obstacle can be determined. The location of this obstacle in the reactor core can be determined, making it easy to repair this obstacle.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 3 to 5. In the figure, 101 is a reactor vessel, and this reactor vessel 101 houses a reactor core 102 and liquid sodium 103, which is a coolant. Further, the upper end of this reactor vessel 101 is closed by a shielding plug 104. A rotary plug 1 is placed on this shielding plug 104.
05, and a core upper mechanism 106 is attached to this rotary plug 105. An ultrasonic transducer 107 is provided within the reactor vessel 101. This ultrasonic transducer 107 is rotated in a horizontal plane by a scanning mechanism 108, and is rotated between the upper surface of the core 102 and the core upper mechanism 1.
The ultrasonic wave is transmitted horizontally into the core gap 109 between the lower surface of the 06 and the reflected wave is received and converted into an electrical reflected wave signal, and the inside of the core gap 109 is scanned horizontally in a fan shape. is configured to do so. Note that 110 is a control circuit for the scanning mechanism 108 and is configured to control scanning of the ultrasonic transducer 107. Further, 111 is a position detection circuit configured to detect the scanning position of the ultrasonic transducer 107, that is, the direction in which the ultrasonic transducer 107 is pointing.
Further, a reflector 112 is provided on the inner peripheral surface of the reactor vessel 101 on the opposite side of the ultrasonic transducer 107.
The reflector 112 is provided with a large number of reverse slopes facing the ultrasonic transducer 107. Therefore, the ultrasonic wave emitted from the ultrasonic transducer 107 passes through the core gap 109 and is reflected by the reflector 112, and this reflected wave passes through the core gap 109 again and is received by the ultrasonic transducer 107. It is configured. In addition, when there is an obstacle 113 such as floating fuel in the core gap 109, this ultrasonic transducer 107
It is configured to also receive reflected waves from 13. And this ultrasonic transducer 107
The reflected wave signal is sent to a signal processing circuit 114, and is configured to be processed and then displayed on a display mechanism 115 such as a CRT.

This signal processing circuit 114 is configured as follows. 116 is a drive circuit which sends a drive current to the ultrasonic transducer 107;
The ultrasonic transducer 107 is configured to oscillate ultrasonic waves. Also, 117
is a receiver, and an ultrasonic transducer 10
The reflected wave signal from 7 is first sent to this receiver 117. The signal output from this receiver 17 is then sent to a first gate circuit 118 and a second gate circuit 119. Then, the first gate circuit 118 extracts only the component reflected by the reflector 112 from the reflected wave signal from the input time of the reflected wave signal, and sends it to the wave height detector 120.
It is configured to send to. The signal from this wave height detector 120 is transmitted to a gap detector 121.
The signal is sent to the core gap 109 and converted into a signal corresponding to the gap of the core gap 109. That is,
When there is an obstacle 113 such as floating fuel in the core gap 109, the ultrasonic waves passing through the core gap 109 are reflected and scattered by the obstacle 113, so the level of the reflected wave received by the ultrasonic transducer 107 is becomes lower. The higher the height of the obstacle 113, that is, the smaller the gap between the core gap 109, the lower the level of the reflected wave. Then, the gap detector 121 calculates the gap of the core gap 109 from the wave height, that is, the signal level, of the reflected wave signal from the ultrasonic transducer 107, and sends a signal corresponding to the gap to the height signal conversion circuit 122. This height signal conversion circuit 122 converts the signal from the gap detector 121 into the display mechanism 1.
It is configured to convert the signal into a signal corresponding to the height of the obstacle display displayed on the screen 15 and send it to the image composition circuit 123.

Further, the second gate circuit 119 described above is configured to extract only the component corresponding to the reflected wave reflected by the obstacle 113 from the reflected wave signal.
The signal extracted by the second gate circuit 119 is sent to the peak value detection circuit 124, where the peak value is detected. The signal from this peak value detection circuit 124 is sent to a reflection time detection circuit 125, and the reflection time from the transmission of the ultrasonic wave to the peak value of this reflected wave is detected. The signal from this reflection time detection circuit 125 is sent to a distance detection circuit 126, which calculates the distance from the ultrasonic transducer 107 to the obstacle 113 based on this reflection time, and calculates the distance from the ultrasonic transducer 107 to the obstacle 113. 1
23. Further, the position detection circuit 111 is configured to send a signal corresponding to the scanning position of the ultrasonic transducer 107 to the display mechanism 115.

This image composition circuit 123 is connected to the display mechanism 1.
As shown in FIG. 4, a core image 102' simulating the reactor core 102 and a core upper mechanism image 106' simulating the core upper mechanism 106 are displayed on the 15, as shown in FIG. Display.
Since the heights of these obstacle displays 113' correspond to the heights of the obstacles 113 in the core gap 109, the display on this display mechanism 115 is equivalent to an image seen through the core gap 109 from the horizontal direction. Become. Further, this image composition circuit 123 has a fifth
As shown in the figure, the position of the obstacle 113 is determined from the angle _θ As shown in FIG. 5, it is configured to be displayed together with a planar image 102'' of the reactor core.

Therefore, according to such an ultrasonic fluoroscope, it is possible to detect the presence, height, and position of the obstacle 113 in the core gap 109.
3 can be repaired easily and quickly.

〔Effect of the invention〕

As described above, the present invention includes an ultrasonic transducer that transmits ultrasonic waves toward a core gap formed between the core of a nuclear reactor and an upper core mechanism, and receives ultrasonic echoes, and this ultrasonic transducer. a scanning mechanism that rotates a transducer in a horizontal plane to scan the ultrasonic waves in the horizontal direction; a position detector that detects the scanning position of the ultrasonic transducer; and an ultrasonic wave received by the ultrasonic transducer. a peak value detection circuit that detects a peak value of an echo; a distance detection circuit that detects a distance from an obstacle present in the core gap to the ultrasonic transducer based on an output signal from the peak value detection circuit; a wave height detector that detects the signal level of the ultrasonic echo received by the ultrasonic transducer; and a height detector that detects the height of an obstacle present in the core gap based on the output signal from the wave height detector. and a display mechanism that displays the position and height of the obstacle on the reactor core based on signals from the position detector, distance detection circuit, and height detector. Therefore, according to the present invention, the distance from the ultrasonic transducer to the obstacle can be detected, and the position of fuel, etc. floating up from the core can be accurately detected. In addition, in the present invention, the height of an obstacle can be detected by detecting the signal level of the ultrasonic echo received by the ultrasonic transducer with a wave height detector, and the height of the obstacle can be detected by detecting the height of the obstacle. can be easily understood.

[Brief explanation of drawings]

1 and 2 show a conventional example, with FIG. 1 being a schematic configuration diagram and FIG. 2 being a view taken along the - arrow in FIG. FIGS. 3 to 5 show an embodiment of the present invention, with FIG. 3 being a schematic diagram, and FIGS. 4 and 5 being schematic diagrams showing examples of display on the display mechanism. 101...Reactor vessel, 102...Reactor core, 10
6... Core upper mechanism, 107... Ultrasonic transducer, 108... Scanning mechanism, 114... Signal processing circuit, 115... Display mechanism, 118... First
Gate circuit, 119...Second gate circuit, 126
...Distance detection circuit.

Claims (1)

[Claims] 1 An ultrasonic transducer that transmits ultrasonic waves toward the core gap formed between the reactor core and the upper core mechanism and receives the ultrasonic echoes; a scanning mechanism that rotates to scan the ultrasonic waves in a horizontal direction; a position detector that detects the scanning position of the ultrasonic transducer; and a peak value of the ultrasonic echoes received by the ultrasonic transducer. a distance detection circuit that detects a distance from an obstacle present in the core gap to the ultrasonic transducer based on an output signal from the peak value detection circuit; a wave height detector for detecting the signal level of the ultrasonic echo received by the core gap; a height detector for detecting the height of an obstacle present in the core gap based on the output signal from the wave height detector; and a position detector for detecting the position of the obstacle. 1. An ultrasonic fluoroscopy apparatus comprising: a display mechanism that displays the position and height of an obstacle on the reactor core based on signals from a sensor, a distance detection circuit, and a height detector.