JPS6140321B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sodium fluoroscopy system, and in particular, uses a rotating plug and a retractable pantograph arm to inspect a wide range of the inner wall surface of a reactor vessel in a short period of time. By making it possible to freely differentiate between observation in a narrow area and intensive observation in a narrow area, and then using a simple mechanism, the failure rate can be reduced, and overall, it is possible to This invention relates to a sodium fluoroscopy device that can improve the safety and operation rate of a furnace.

It is an essential condition for the safety of a nuclear reactor plant that the reactor vessel remains sound even after long-term operation, and for this purpose, the reactor vessel, especially the weld lines, must be regularly inspected. It is necessary to confirm that it is healthy. There is a method of inspecting from the outside of the reactor vessel, but in actual reactor vessels, cracks may enter from the inner wall surface due to poor environmental conditions, so it is recommended to inspect the inner wall surface from the inside of the reactor vessel. desired. In the case of fast reactors, the inside of the reactor vessel is filled with opaque sodium, so direct visual inspection is not possible. Even if the sodium inside is drained to another system, sufficient visual inspection is difficult due to residual sodium adhering to the inner wall of the reactor vessel. Therefore, a device is needed to see through the sodium and inspect the wall surface of the reactor vessel.

Incidentally, sodium fluoroscopy equipment for observing the upper surface of the reactor core and the gap between the upper core mechanism and the upper core has been devised in the past, but a sodium fluoroscopy equipment for observing and inspecting the inner wall surface of the reactor vessel has not yet been devised. It was also desired that this sodium fluoroscopy system would be able to shorten the reactor shutdown time for inspection as much as possible and improve reactor operating efficiency.

Therefore, an object of the present invention has been made in view of the above-mentioned circumstances, and is to provide a sodium fluoroscopy device that can inspect the inner wall surface of a reactor vessel by looking through sodium, and which can reduce the time required for inspection. be.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

Figure 1 is a diagram showing the present sodium fluoroscope installed in a nuclear reactor, Figure 2 is a detailed side view of the internal transducer section and pantograph arm of the sodium fluoroscope, and Figure 3 is a diagram showing the state in which the sodium fluoroscope is installed in a nuclear reactor. Fig. 4 is a plan view showing a state in which the pantograph mechanism is operated in Fig. 3 and the direction of the transducer has been changed, and Fig. 5 is a plan view showing the sodium fluoroscopy device installed in the reactor vessel. FIG. As shown in FIG. 1, a rotating housing 8 having a drive unit 5 at the top and a pantograph mechanism 6 and a transducer holding link 7 at the bottom passes through the rotating plug 1 and is inserted into the reactor vessel 2 filled with sodium 4. It has been inserted. Further, a rotation device 9 is installed on the through hole of the rotation plug 1 to rotate the rotation housing 8, the drive unit 5, the pantograph mechanism 6, and the transducer holding link 7 together via the floor door valve 3. There is. The rotating housing 8 passes through the swivel device 9 . Furthermore,
Above the swivel device 9, via a door valve 10,
A lifting device 11 is provided for raising and lowering the rotating housing 8, the drive unit 5, the pantograph mechanism 6, and the transducer holder 7 together. The lifting device 11 is connected to the drive section 5 via a drive shaft 12.

FIG. 2 shows details of the mechanism section below the liquid surface of the sodium fluoroscope shown in FIG. 1. The pantograph mechanism 6 is rotatably pin-connected at one end to the rotating housing 8 and at the other end to the transducer retaining link 7. Of these, the upper pins 21 and 22 are fitted into grooves so that they can move up and down when the pantograph mechanism 6 is opened and closed. Further, the pins 21 and 27 on the side of the transducer holding link 7 are ball joints so that they can be tilted laterally as shown in FIG. Furthermore, the rotating housing 8
The upper pin 22 is rotatably connected to a pantograph mechanism opening/closing operation shaft 24 installed in the rotating housing 8. The pantograph mechanism opening/closing operation shaft 24 is connected to a drive section 5 installed above. In addition, as shown in FIG. 3, the pantograph mechanism 6 and the pantograph opening/closing operation link 2
4 is separated so that the left and right sides can be moved separately.
A large number of transducers 25 are attached to the outer end surface of the transducer retainer link 7 in a row, and the signal cable 26 is wound into a coil so that it can be expanded and contracted in the opening and closing directions of the pantograph mechanism 6 and rotates. The wires are wired inside the housing 8, and further passed through the rotary housing 8 and drawn out into the furnace vessel.

Next, a method of visually inspecting the inner wall surface of a furnace vessel filled with sodium using the apparatus described above will be described. First, pantograph mechanism 6
With the transducer holding link 7 closed and the transducer holding link 7 housed in the rotating housing 8, the sodium fluoroscope is inserted into the reactor vessel 2 filled with sodium 4. The drive unit 5 is operated and the pantograph mechanism operating shaft 24 is pushed in to open the pantograph mechanism 6 to the state shown in FIG. The signal cable is formed into a coil and is stretchable, so no excessive force is applied to the mechanism. By operating the rotating device 9, the rotary housing 8 is rotated, and the transducer 25 is opposed to the inner surface of the furnace vessel in parallel, as shown in FIG. If the transmitting and receiving surfaces of the transducer 25 are tilted with respect to the inner wall of the reactor vessel, push or pull one side of the two pantograph mechanism opening/closing operation shafts 24 to adjust the opening/closing degree of the left and right pantograph mechanisms 6. By changing the angle, the inclination of the transducer 25 is adjusted as shown in FIG. Further, the distance between the transducer 25 and the observation wall surface can be adjusted by adjusting the degree of opening and closing of the pantograph mechanism 6. In this state, the rotary plug 1 is rotated while transmitting and receiving ultrasonic waves from the transducer 25. After scanning the entire circumference of the reactor vessel, the lifting device 9 is activated to raise the whole by several mm, and the rotary plug 1 is rotated again. and scan the entire circumference of the furnace vessel. By repeating this, the entire inner wall surface of the reactor vessel is scanned by ultrasonic waves to inspect the presence or absence of defects such as flaws and cracks.
If you wish to inspect a localized area, rotate the rotary plug 1 to release the transducer retaining link 7.
the transducer 25 near the area to be inspected.
While transmitting and receiving ultrasonic waves from the transducer holder, the transducer holder is rotated and scanned by the rotating device 9, and the necessary locations are scanned and inspected by raising or lowering the transducer holder in steps of several mm using the lifting device.

As explained above, by using the sodium fluoroscopy apparatus of the present invention, it is possible to visually inspect the inner wall surface of the reactor vessel while it is filled with sodium, and to check for the presence of flaws, cracks, etc. When confirming the health of a reactor vessel, visual inspection of the inner wall surface of the reactor vessel, particularly the welded portion, is an essential condition, and the sodium fluoroscopy apparatus according to the present invention makes this possible. Therefore, according to the present invention, the safety of the reactor vessel can be confirmed, and the reliability of the nuclear reactor plant can be improved. In addition, this sodium fluoroscopy system is equipped with a large number of transducers, so it can inspect the inner wall of the reactor vessel in a short period of time, reducing the amount of time the reactor is shut down for inspection, which helps improve reactor operating efficiency. It is very effective. Furthermore, in addition to the method of uniformly scanning the inner surface of the reactor vessel using the rotation of a rotating plug, this sodium fluoroscope can also use a method of intensively scanning a localized area using the rotation of a rotating device. can.

When scanning with a rotating device, the center of the reactor vessel and the center of rotation of the sodium fluoroscopy device are different.
As the transducer rotates, there is a deviation in the facing angle between the transducer transmitting and receiving surface and the observation wall surface, so it is only possible to observe a narrow range where this deviation is within the allowable value, but it is easier to operate than operating a rotating plug. It has the advantage of being able to carry out predetermined inspections in a short period of time.

Therefore, it is very effective for intensive inspection of local areas. Furthermore, this sodium fluoroscopy device uses a pantograph mechanism, a simple link mechanism that has been used in sodium, so the device itself is highly reliable.

[Brief explanation of the drawing]

FIG. 1 is a side view showing the sodium fluoroscopy device of the present invention installed in a nuclear reactor, FIG. 2 is a detailed side view of the transducer section and pantograph mechanism of the sodium fluoroscopy device of the present invention, and FIG.
The figure is a plan view of Fig. 2, Fig. 4 is a plan view showing the state in which the direction of the transducer is changed by operating the pantograph mechanism in Fig. 3, and Fig. 5 is a plan view of the sodium fluoroscopy device of the present invention inside the reactor. FIG. DESCRIPTION OF SYMBOLS 1... Rotating plug, 5... Drive unit, 6... Pantograph mechanism, 7... Transducer holding link, 8... Rotating housing, 9... Swivel device, 1
1... Lifting device, 12... Drive shaft, 21... Ball joint (pin), 22... Pin, 24...
Pantograph mechanism opening/closing operation axis, 25...Transducer, 26...Signal cable, 27...Ball joint (pin).

Claims (1)

[Claims] 1. A rotating plug, a rotating device installed on the rotating plug, a rotating housing inserted into the rotating device, a pair of pantograph mechanisms installed in parallel below the rotating housing, and a tip of the pantograph mechanism. a transducer retaining link provided in the section; a plurality of transducers incorporated in the transducer retaining link;
A drive shaft installed in the rotary housing for opening and closing the pantograph, a drive section for operating the drive shaft, and a lifting device for vertically moving the rotary housing together with the transistor user holding link and the pantograph mechanism. 1. A sodium fluoroscopy apparatus, wherein one of the attachment parts of the transducer holding link to the pantograph mechanism is fixed, and the other is fixed so as to be slidable in the vertical direction.