JPH0660893B2 - Ultrasonic inspection device - Google Patents

Description

The present invention relates to an ultrasonic inspection apparatus for an object to be inspected such as a round tube or a round bar.

(Prior Art) Generally, in flaw detection of an end plug welding portion of a nuclear fuel rod, flaw detection is performed in a state of being filled with water so that ultrasonic waves can pass between an ultrasonic probe and an object to be inspected. An ultrasonic inspection apparatus by the immersion method is used.

That is, FIG. 4 is a view showing a schematic configuration of the ultrasonic inspection apparatus, in which the probe 2 is arranged on the upper part of the water tank 1 so as to be directed downward, and the side wall of the water tank 1 is arranged. A hole 4 into which a nuclear fuel rod 3 which is an object to be inspected is inserted is provided in a protruding manner, and a receiving tray 5 for receiving water discharged from the hole 4 is provided on one side of the water tank 1. Then, water is supplied to the water tank 1 through the water supply pipe 6, and the water discharged from the hole 4 is once received by the tray 5 and then drained from the drain pipe 7.

Therefore, in the ultrasonic inspection, the nuclear fuel rods 3 to be inspected
Is inserted into the water tank 1 through the hole 4 so that the portion to be inspected, that is, the end plug welding portion 3a is located directly below the probe 2, and the nuclear combustion rod 3 is gripped by the rotary chuck 8. By rotating the nuclear fuel rod 3 around the axis by the rotation of the rotary chuck 8, the probe 11 is scanned over the entire circumference of the end plug welding portion 3a, and the portion concerned is inspected.

(Problems to be Solved by the Invention) However, in the above-described device, since rotational vibration occurs when inspecting a long object such as a nuclear fuel rod, it is necessary to hold the nuclear fuel rod over the entire length during rotation. .

That is, as shown in FIG. 5, a nuclear fuel rod 3 is placed on an axial feed roller 10 arranged vertically movable on a base 9 disposed on one side of the inspection device, and the nuclear fuel Stick 3
Is moved in the axial direction and its tip is inserted into the water tank 1, where the nuclear fuel rod 3 is held rotatably around the axis by the roller 11 and the pinch roller 12 provided on the base 9. After being gripped by the chuck 8, the axial feed roller 10 is moved downward, and the nuclear fuel rod 3 is rotated while being held by the pinch roller 12 or the like.

Therefore, a complicated supporting device including a roller for axial feed of the nuclear fuel rod 3 and a pinch roller for rotatably holding the nuclear fuel rod 3 is required, and the nuclear fuel rod is fixed to the rotary chuck 8 to some extent as described above. Since it requires a firm grip, the chuck portion may slightly scratch the fuel rod surface.

Further, rotating the nuclear fuel rod in a state where ceramic pellets are loaded in the nuclear fuel rod poses a problem that pellets may be chipped.

Further, in the above-mentioned inspection apparatus, since the nuclear fuel rods are successively taken in and out of the water tank through the holes 4, bubbles easily enter the water tank, and also bubbles are attached to the probe 2 and the welded portion 3a of the nuclear fuel rod. This is easy, and in this case, it is necessary to manually remove the air bubbles each time in order to perform flaw detection reliably, which poses a problem of obstacles to automation.

In view of such a point, the present invention has an object to obtain an ultrasonic inspection apparatus which does not have the above-mentioned inconvenience.

[Structure of Invention]

(Means for Solving the Problem) The present invention relates to an ultrasonic inspection apparatus for inspecting a welded portion of an object to be inspected such as an elongated round tube or a round bar by using ultrasonic waves, and rotating it around a longitudinal axis on a pedestal. A hollow rotating body that is freely supported and has an opening at one end through which the object to be inspected can be inserted and removed, and a probe that is attached to the hollow rotating body and that transmits and receives ultrasonic waves in the axial direction of the hollow rotating body, An ultrasonic flaw detector connected to the probe via a rotatable signal coupling and an ultrasonic flaw detector connected to the hollow rotating body via a rotatable water supply coupling to supply and fill the hollow rotating body with ultrasonic transmission liquid. It has a liquid supply device and an inspection object holding device for inserting and supporting the inspection object in the hollow rotating body through the opening concentrically with the hollow rotating body.

In addition, a large diameter portion is formed in the void of the hollow rotating body, and a small hole for passing bubbles is provided in the vicinity of the large diameter portion in the circumferential direction. One of the object holding devices is movable in the axial direction of the hollow rotating body with respect to the other.

(Operation) Insert the tip of the object to be inspected held by the object to be inspected into the hollow rotating body through the opening, and set the inspected part to the position facing the probe. The hollow rotating body is rotated around the axis line in a state where the ultrasonic transmission liquid is filled and filled in the void of the rotating body. Therefore, the probe rotates around the object to be inspected and scans the entire circumference,
It is possible to perform flaw detection over the entire circumference.

Further, in the hollow rotating body having a large diameter portion formed in the void, bubbles are naturally collected in the large diameter portion and discharged through the small holes, and it is possible that the inspection is hindered by the generation of bubbles. Absent. Further, by moving either one of the hollow rotating body and the object holding device to be inspected with respect to the other, the inspection target portion can be scanned in a plane.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

In FIG. 1, reference numeral 20 denotes a pedestal fixedly mounted on a base 21, on which a substantially cylindrical hollow rotor 22 is rotatably rotatable about a horizontal axis through bearings 23, 23. It is pivotally supported.

The hollow 22a of the hollow rotating body 22 is formed such that the inner diameter thereof gradually increases from one end side toward the other end side, and a plurality of small holes are circumferentially formed in the peripheral wall near the large diameter portion. 24 is provided, and an opening 25 through which the nuclear fuel rod 3, which is the inspection object, can be inserted is provided in the center of the other end side end wall. An ultrasonic probe 26 is fixed to the hollow rotating body 22 so as to face the central axis of the hollow rotating body 22, while a pulley 27 is fixed to the one end of the hollow rotating body 22. A belt 30 is wound between the pulley 27 and a pulley 29 fixed to the motor 28.

Furthermore, one end of the hollow rotating body 22 is rotatably connected to a water supply coupling 32 via an O-ring 31,
The water supply coupling 32 is connected to a water supply pump (not shown) via a water supply pipe 33, and the water supplied by the water supply pump is supplied to the inside of the hollow rotary body 22 via the water supply pipe 33 and the water supply coupling 32. To be supplied to.

Further, a rotary disc-shaped rotor 34 is mounted on the hollow rotary body 22, and the rotor 34 is connected to the probe 26 via a coaxial cable 35. On the other hand, a slider 36 is in sliding contact with the rotor 34, and the slider 3
6 is connected via a coaxial cable 37 to an ultrasonic flaw detector (not shown) (FIG. 2).

By the way, a portion of the hollow rotating body 22 in which the opening 25 and the like are bored projects into the water receiving tank 38, and a drain pipe 39 is connected to the water receiving tank 38.

Further, with the water receiving tank 38 as the center, the hollow rotating body 2
A nuclear fuel rod holding device 40 is arranged on the side opposite to the position 2.

That is, the base 41 is provided on the base 21,
The gantry 41 is equipped with an axial X table 42 that supports the nuclear fuel rods 3 on the same axis as the hollow rotator 22 and is movable in the axial direction. A support roller 43 for supporting the fuel rod 3 and a fuel rod coarse movement mechanism 44 are provided.

In the figure, reference numeral 45 is a clamp 46 provided on the axial X table 42 and a balance weight.

Therefore, when inspecting the nuclear fuel rods 3, the water as the ultrasonic transmission liquid is supplied from the water supply pump through the water supply coupling 32 and the like into the space 22a of the hollow rotary body 22 to be filled.
The water is collected by the water receiving tank 38 discharged from the opening 25, returned to a tank (not shown) by the drain pipe 39, and returned to the hollow rotor by the water supply pump.

Therefore, after the fuel rod 3 is fed to a predetermined position by the coarse movement mechanism 44, the fuel rod is clamped by the clamp 45 of the axial X table 42, and the axial X table 42 is driven to bring the inspected portion to the flaw detection position. send. When the hollow rotary body 22 is subsequently rotated through the motor 28, the belt 30 and the like, the probe 26 also rotates around the fuel rod 3, and the portion to be inspected is circumferentially scanned for flaw detection. You can After the flaw detection is completed, the axial X table 42 is driven back to the original position, and the fuel rod is pulled out by the coarse movement mechanism 44 to complete the inspection of the inspected portion of the fuel rod.

By the way, at the start of water supply to the hollow space 22a of the hollow rotating body 22, the air in the hollow space 22a is discharged with the inflow of water. Large bubbles gather in the vicinity of a portion of the place 22a having the maximum diameter. Therefore, the bubbles are discharged from the inside of the hollow rotating body 22 through the small holes 24, and the space 22a is filled with water. Further, even if air bubbles enter during the inspection, the air bubbles are discharged from the small holes 24 regardless of the rotational positional relationship of the hollow rotator 22, so that the air bubbles do not remain in the void 22a and the flaw detection is hindered. There is no such thing.

Further, since the fuel rods need only be fixed in place and no rotating chuck or many rotating rollers are required, there is no scratch on the surface of the fuel rods and there is no influence on the pellets due to rotation. .

Further, in the above-described embodiment, the water is supplied from the side opposite to the fuel rod insertion side, but a water supply coupling may be provided on the fuel rod insertion side as shown in FIG.

Further, as the rotatable signal coupling, an electrostatic coupling, a coupling using mercury for the sliding contact portion, or a coupling using electromagnetic induction may be used. Further, in the above embodiment, the inspection of the fuel rod has been described, but it is needless to say that the present invention can be applied to other types of rods or round tubes.

〔The invention's effect〕

Since the present invention is configured as described above, it is possible to perform flaw detection scanning in the circumferential direction without rotating the inspection object, simplification of the device, it is possible to prevent the occurrence of scratches due to the rotation of the inspection object, In particular, even when the object to be inspected is a nuclear fuel rod, there is no possibility of damaging the contents such as fuel pellets.

In addition, since a large diameter portion is formed in the cavity of the hollow rotating body and a plurality of small holes for passing bubbles are formed in the vicinity of the large diameter portion, the bubbles generated in the cavity gather in the large diameter portion. Since it is automatically discharged into the atmosphere through the small holes, it is possible to minimize interference with the flaw inspection by bubbles. Further, in the case where one of the hollow rotating body and the inspection object holding device is movable with respect to the other, it is possible to perform flaw detection over a certain surface of the inspection object.

[Brief description of drawings]

FIG. 1 is a front view of an ultrasonic inspection apparatus of the present invention, FIG. 2 is a partially enlarged explanatory view of FIG. 1, FIG. 3 is a view showing another embodiment of the present invention, and FIG. FIG. 5 is an explanatory view of the ultrasonic inspection apparatus, and FIG. 5 is a front view of the conventional ultrasonic inspection apparatus. 20 ... Stand, 22 ... Hollow rotating body, 24 ... Small hole, 2
5 ... Aperture, 26 ... Ultrasonic probe, 32 ... Water supply coupling, 34 ... Rotor, 36 ... Slider, 38 ...
Water receiving tank, 40 ... Nuclear fuel rod holding device, 42 ... Axial X table, 44 ... Coarse movement mechanism.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 62-91855 (JP, A) JP 58-168959 (JP, A) JP 54-82691 (JP, U)

Claims (2)

[Claims] 1. An ultrasonic inspection apparatus for inspecting a welded portion of an object to be inspected, such as an elongated round tube or a round rod, using ultrasonic waves, which is rotatably supported on a pedestal about a longitudinal axis.
A hollow rotating body having an opening for inserting and removing the object to be inspected at one end, a probe mounted on the hollow rotating body for transmitting and receiving ultrasonic waves in the axial direction of the hollow rotating body, and a rotatable signal coupling. An ultrasonic flaw detector connected to the probe via a liquid supply device, which is connected to the hollow rotating body via a rotatable water supply coupling and supplies and fills the hollow rotating body with an ultrasonic transmission liquid, The object to be inspected for inserting and supporting the object to be inspected concentrically with the hollow rotating body from the opening is provided, and a large diameter portion is formed in the void of the hollow rotating body, and the large diameter thereof is formed. An ultrasonic inspection apparatus, characterized in that a small hole for passing bubbles is provided at a position near the portion in the circumferential direction. 2. The ultrasonic inspection apparatus according to claim 1, wherein one of the hollow rotating body and the inspection object holding device is movable in the axial direction of the hollow rotating body with respect to the other.