JPH0816610B2 - Round bar inspection device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a round bar inspection device for inspecting the shape of a round bar while rotating the round bar around its axis.
In particular, the present invention relates to an inspection device suitable for inspecting nuclear fuel rods and control rod guide tubes.

[Prior Art] As a round rod, for example, a nuclear fuel rod has a structure in which a large number of cylindrical uranium dioxide fuel pellets are filled and sealed inside a cylindrical fuel cladding tube. Strict quality control is required for the rod during its manufacturing process.

In particular, for surface defects that cannot be found by visual inspection, it is necessary to inspect their presence nondestructively. It is also necessary to check the straightness of the nuclear fuel rod, that is, the bending with respect to the axis.

[Problems to be Solved by the Invention] Conventionally, an automatic inspection such as a laser method has been attempted as an inspection method for such a defect on the surface of a nuclear fuel rod, but an S / N and an inspection speed sufficient for practical use are expected. could not.
Also, regarding the straightness of nuclear fuel rods, there was no device to automatically inspect it.

An object of the present invention is to provide an inspection device for a round rod body such as a nuclear fuel rod, which can automatically inspect the defect and straightness of the round rod body with high accuracy.

[Means for Solving the Problems] (1) The inspection device for a round rod according to the first aspect is a round rod for inspecting the shape of the round rod while rotating the round rod about its axis. An inspection device for a rod body, which comprises a laser light projector for irradiating a laser beam from the outside in the radial direction of the rod body to the peripheral surface of the rod body, and a reflected light from the peripheral surface of the rod body. , Based on the reflection position of the reflected light, the detection signal of the reflection position including the high frequency corresponding to the undulation of the surface of the round bar and the low frequency corresponding to the straightness of the round bar is output, and the light amount of the reflected light is output. A sensor that outputs a detection signal of the amount of reflected light based on the detection signal of the reflection position output by the sensor, a high-pass filter that extracts a high frequency corresponding to the undulations of the surface of the round bar as a defect signal of the round bar, and The detection signal of the amount of reflected light output from the sensor and the high-pass Based on the defect signal of the round bar material has been removed from filter, characterized by comprising; and a determining defect determining section defects round bar.

(2) In the round bar inspection device according to the second aspect, the low frequency corresponding to the straightness of the round bar is used as the straightness signal of the round bar from the detection signal of the reflection position output from the sensor. It is characterized by comprising a low-pass filter to be taken out, and a straightness judging section for judging the straightness of the round bar based on the straightness signal of the round bar taken out from the low-pass filter.

[Operation] The inspection device for a round rod body according to the present invention irradiates a laser beam on the peripheral surface of the round rod body while rotating the round rod body, and combines the reflection position and the reflected light amount of the reflected light into the round rod body. Inspect surface defects and straightness. As a result, the shape inspection over the entire length of the round bar is automatically and accurately performed only by rotating the round bar.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings of an inspection device for inspecting a nuclear fuel rod.

In the figure, reference numeral 1 denotes a nuclear fuel rod, which is placed on a plurality of rotary drive rollers 2 so that the axis line in the front and back direction (the left and right direction in FIG. 2) of the paper surface in FIG. The rotation of 2 in the direction of the arrow in FIG. 1 causes rotation about the horizontal axis. An axial feed roller 3 that feeds the nuclear fuel rods 1 in the axial direction is provided near the rotary drive roller 2.

A plurality of array type displacement / light quantity sensors 4 (four in the case of this example) are provided above the nuclear fuel rods 1 on the rotary drive roller 2. The displacement / light quantity sensor 4 includes a laser light projector 5 that irradiates the circumferential surface of the nuclear fuel rod 1 with laser light from a radial direction, and an imaging lens 6 that collects reflected light from the circumferential surface of the nuclear fuel rod 1. And a light spot position sensor 7 for injecting reflected light through the imaging lens 6.

 The sensor 7 has the following two detection functions.

A function of detecting the position of the surface of the nuclear fuel rod 1 immediately below the laser light projector 5 from the change in the light receiving position corresponding to the reflection position of the laser beam on the nuclear fuel rod 1 and outputting a position detection signal S1.

By detecting the amount of reflected laser light on the nuclear fuel rod 1,
A function to output the light intensity detection signal S2.

A large number of sensors 7 having such two detection functions are provided near each of the displacement / light quantity sensors 4 along the axial direction of the nuclear fuel rod 1, and a large number of points on the surface of the nuclear fuel rod 1 are provided. Is to be detected. For example, total length 25
In the displacement / light quantity sensor 4 of about cm, 4000 sensors 7 are arranged at intervals of about 0.15 to 0.2 mm. Therefore, in this case, the number of measurement points per displacement / light quantity sensor 4 is 4000 points. In addition, in the case of this embodiment, a large number of sensors 7 in the four displacement / light quantity sensors 4 rotate once at the position where the nuclear fuel rod 1 is shown by the solid line in FIG. 2, and are further shown by the chain double-dashed line in FIG. By rotating once at the position, the reflected light from the peripheral surface of the nuclear fuel rod 1 over the entire length can be received.

The high-frequency component of the position detection signal S1 output from the sensor 7 is passed through the high-pass filter 8, converted into a digital signal, and then captured in the first frame memory 9. At the same time, the low-frequency component of the position detection signal S1 is passed through the low-pass filter 10, converted into a digital signal, and then taken into the second frame memory 11. On the other hand, the light amount detection signal S2 is converted into a digital signal and then taken into the third frame memory 12. Data for one rotation of the nuclear fuel rod 1 is stored in each of the frame memories 9, 11 and 12.

The data of the high frequency components fetched in the first and third frame memories 9 and 12 are input from the defect extraction unit 13 to the defect determination unit 14. The functions of the defect extracting unit 13 and the defect determining unit 14 will be described later together with the operation. On the other hand, the second frame memory
The low frequency component data captured in 11 is used by the straightness calculation section.
Input from 15 to the straightness determination unit 16. The functions of the straightness degree calculation unit 15 and the straightness degree determination unit 16 will also be described later.

In FIG. 1, reference numeral 17 denotes a controller. The controller 17 controls the timing of fetching data in the frame memories 9, 11, 12 and also supplies the correction data obtained in advance to the defect extraction unit 13 and straightness calculation unit 15. It is designed to output to. The function of the controller 17 will also be described later.

 Next, the operation will be described.

First, prior to the inspection of the nuclear fuel rod 1, correction data is obtained using a dummy nuclear fuel rod. Then, the nuclear fuel rod 1 is automatically set and inspected. In the following, the former operation will be described separately as the preparatory operation A and the latter operation will be described as the automatic inspection operation B.

A: Preparation Operation First, an ideal shape of the nuclear fuel rod 1, that is, a dummy nuclear fuel rod (hereinafter referred to as “dummy rod”) having no surface defects and no bending with respect to the axis is set on the rotary drive roller 2. Then, while rotating the dummy rod by the rotation driving roller 2 at the position shown by the solid line in FIG. 2, the laser beam is emitted from the laser beam projector 5, and the position detection signal S1 per rotation of the dummy rod is obtained. The light amount detection signal S2 is taken out.

Originally, these signals S1 and S2 are data for measuring the defect and straightness of the nuclear fuel rod 1, and here, the correction data due to the characteristics of the device are targeted for the dummy rod having no defect or bending. Taken out to ask.

Therefore, the original position detection signal S1 and the light amount detection signal S2 in the case of targeting the nuclear fuel rod 1 will be described.

[Regarding Position Detection Signal S1] The position detection signal S1 includes a high frequency component and a low frequency component as shown in FIG.

(I) High-frequency component This high-frequency component is caused by fine undulations on the peripheral surface of the nuclear fuel rod 1, and has a size corresponding to the size of the defect on the peripheral surface, particularly the depth of the defect. It is effective as measurement data.

(Ii) Low frequency component This low frequency component is caused by the bending of the nuclear fuel rod 1 with respect to the axis, and has a magnitude depending on the straightness.

[Regarding Light Quantity Detection Signal S2] This light quantity detection signal S2 is caused by the degree of diffused reflection on the peripheral surface of the nuclear fuel rod 1, and is particularly effective as measurement data of the size of a defect.

Here, such detection signals S1 and S2 are taken out for the dummy rod. The former high-frequency component (i) of the position detection signal S1 is filtered by a high-pass filter similar to the reference numeral 8 in FIG. 1 and then digitally converted, and the low-frequency component (ii) is shown in FIG. It is digitally converted after being filtered by a low-pass filter similar to the code 10 of. Further, the light amount detection signal S2 is also digitally converted. Then, based on the digitally converted high-frequency component (i) and the light amount detection signal S2, a defect signal corresponding to the size and depth of the defect on the peripheral surface of the dummy rod (the device originally has no defect, so Data resulting from the characteristics of (1) is stored as correction data for defect determination. On the other hand, the straightness of the dummy rod (which originally is data due to the characteristics of the device because the dummy rod does not have a bend) is calculated based on the digitally converted low-frequency component (ii) and used for straightness determination. Stored as the correction data of.

In this way, after the dummy rod is rotated once at the position shown by the solid line in FIG. 2, the dummy rod is sent to the position shown by the chain double-dashed line in FIG. repeat. Thereby, the correction data for the entire length of the dummy rod is obtained and stored.

In addition, the sensor 7 is associated with the operation of rotating the dummy rod about its axis and the operation of sending it in the axial direction.
The controller 17 stores the acquisition timing of the detection data in. Hereinafter, the data will be referred to as timing data.

B: Automatic inspection operation The nuclear fuel rod 1 is set on the rotary drive roller 2 and is rotated once at the position indicated by the axis in FIG. By irradiating light, the position detection signal S1 and the light amount detection signal S2 per one rotation of the nuclear fuel rod 1 are extracted.

The high frequency component (i) contained in the position detection signal S1 is filtered by the high pass filter 8 and then digitally converted, and the low frequency component (ii) is filtered by the low pass filter 10 and then digitally converted. Then, these data per one rotation of the nuclear fuel rod 1 are loaded into the frame memories 9 and 11. Further, the light amount detection signal S2 per one rotation of the nuclear fuel rod 1 is digitally converted and then taken into the frame memory 12. At the time of fetching these data, the timing data stored in the controller 17 is used to start fetching the data in association with the operation of rotating the nuclear fuel rod 1 once.

Then, the defect extraction unit 13 detects the high frequency component (i) taken into the first frame memory 9 and the third frame memory.
The light amount detection signal S2 captured in 12 is integrated to output a defect signal corresponding to the size and depth of the defect in the nuclear fuel rod 1. The defect signal is corrected by the correction data stored in the controller 17 and then input to the defect determination unit 14. The defect determination unit 14 is based on the input data,
The size and depth of the defect on the peripheral surface of the nuclear fuel rod 1 are determined. Further, the straightness calculation unit 15 obtains the maximum displacement amount per revolution of the nuclear fuel rod 1 from the low frequency component (ii) taken into the second frame memory 11. The calculated value is corrected by the correction data stored in the controller 17 and then input to the straightness determination unit 16. The straightness determination unit 16
The straightness of the nuclear fuel rod 1 is determined based on the input data.

Next, the nuclear fuel rod 1 is sent to the position shown by the chain double-dashed line in FIG. 2 and further rotated once, and the above-mentioned operation is repeated. In this way, the defect and straightness of the entire length of the nuclear fuel rod 1 are inspected.

After sending out the nuclear fuel rods 1 that have been inspected, the next nuclear fuel rods 1 are automatically set, and the nuclear fuel rods 1 are inspected one after another in the same manner.

In addition, in the case of the present embodiment, the shape is inspected over the entire length of the nuclear fuel rod 1 by rotating the nuclear fuel rod 1 a total of two times. However, the displacement / light quantity sensor 4 is arranged so as to face the entire length of the nuclear fuel rod 1. When deploying, one rotation is enough. Also,
One rotation is required by sending the nuclear fuel rod 1 in the axial direction while rotating it.

[Effects of the Invention] As described above, the inspection device for a round rod according to the present invention irradiates a laser beam on the peripheral surface of the round rod while rotating the round rod, and the reflection position and the amount of the reflected light. Since it is a structure for inspecting the surface defects and straightness of the round rod body in a comprehensive manner, the shape over the entire length can be automatically and accurately inspected simply by rotating the round rod body.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an embodiment of the present invention, FIG. 1 is a block configuration diagram of a main part, and FIG. 2 is a side view of a nuclear fuel rod during an inspection. 1 ... Nuclear fuel rod (round bar), 2 ... Rotation drive roller, 3 ... Axial feed roller, 4 ... Displacement / light quantity sensor, 5 ... Laser light projector, 6 ... Imaging lens, 7 ... … Light point position sensor, 8 …… High pass filter, 9,11,12 …… Frame memory, 10 …… Low pass filter, 15 …… Defect determination unit, 16 …… Squareness determination unit.

Claims (2)

[Claims] 1. An inspection device for a round bar body, which inspects the shape of the round bar body while rotating the round bar body around its axis, comprising: A laser light projector that irradiates a laser beam toward the peripheral surface, and a high frequency wave that corresponds to the undulations on the surface of the round bar based on the reflection position of the reflected light from the peripheral surface of the round bar. A sensor that outputs a detection signal of a reflection position including a low frequency corresponding to the straightness of the round bar, and a sensor that outputs a detection signal of the reflection light amount based on the light amount of the reflection light, and the detection of the reflection position output by the sensor From the signal, a high-pass filter that extracts a high frequency corresponding to the undulations of the surface of the round bar as a defect signal of the round bar, a detection signal of the amount of reflected light output by the sensor, and a round bar extracted from the high-pass filter. The round bar is missing based on the defect signal. An inspection device for a round rod, comprising: a defect determination unit for determining a pit. 2. A low-pass filter that extracts a low frequency corresponding to the straightness of a round rod as a straightness signal of the round rod from the detection signal of the reflection position output by the sensor, and a circle extracted from the low-pass filter. The round rod inspection apparatus according to claim 1, further comprising a straightness determination unit that determines the straightness of the round rod based on the straightness signal of the rod.