JPH03189508A - Inspection device for round rod body - Google Patents

Abstract

PURPOSE:To perform automatic and accurate inspection by irradiating the peripheral surface of the round rod body with laser light while rotating the round rod body, and inspecting a surface defect of the round rod body and its straightness with both the reflection position and quantity of reflected light. CONSTITUTION:A nuclear fuel rod 1 is set on a rotary driving roller 2 and irradiated with the laser light from a laser light projector 5 while rotated, and a position detection signal S1 and a light quantity detection signal S2 of each rotation of the fuel rod 1 are led out. Then the high frequency component and low frequency component of the signal S1 are inputted to frame memories 9 and 10 through an HPF 8 and an LPF 10. Further, a signal S2 is inputted to a frame memory 12. Then a defect extraction part 13 totalizes the high frequency component inputted to the memories 9 and 12 and the signal S2 and outputs a defect signal. This defect signal is corrected with correction data stored in a controller 17 and a defect decision part 14 decides the size and depth of the defect. Further, a straightness calculation part 15 finds the quantity of maximum displacement per rotation and the straightness decision part 16 decides the straightness of the fuel rod 1.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a round rod inspection device that inspects the shape of a round rod while rotating the rod around its axis, particularly for nuclear fuel rods. The present invention relates to an inspection device suitable for inspecting control rod guide tubes and control rod guide tubes.

[Prior Art] A round rod body, 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. Rods require strict quality control during the manufacturing process.

In particular, it is necessary to non-destructively inspect the presence or absence of surface defects that cannot be detected by visual inspection. It is also necessary to check the straightness of the nuclear fuel rods, that is, their bending with respect to their axis.

[Problems to be Solved by the Invention] Conventionally, automated inspection methods such as laser-based methods have been attempted as a method for inspecting defects on the surface of nuclear fuel rods, but the S/N and inspection speed have not been high enough to put them into practical use. I couldn't expect it.

Furthermore, there was no equipment to automatically check the straightness of nuclear fuel rods.

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

[Means for Solving the Problem] (+) The round bar inspection device according to the first claim is a round bar inspection device that inspects the shape of the round bar while rotating the bar about its axis. This is a bar inspection device that includes a laser beam projector that irradiates a laser beam from the outside in the radial direction toward the circumferential surface of the round bar, and a laser light projector that irradiates laser light from the circumferential surface of the round bar. , based on the reflection position of the reflected light, outputs a detection signal of the reflection position including a high frequency wave corresponding to the undulations of the surface of the round bar body and a low frequency wave corresponding to the straightness of the round bar body, and also outputs a detection signal of the reflection position including a high frequency wave corresponding to the undulation of the surface of the round bar body and a low frequency wave corresponding to the straightness of the round bar body, and also outputs a detection signal of the reflection position according to the light intensity of the reflected light. a high-pass filter that extracts a high frequency corresponding to the undulations on the surface of the round bar as a defect signal of the round bar from the detection signal of the reflection position output by the sensor; The present invention is characterized by comprising a defect determination unit that determines a defect in the round bar body based on a detection signal of the amount of reflected light outputted by the sensor and a defect signal of the round bar body taken out from the high-pass filter. .

(2) The round bar inspection device according to the second aspect of the present invention uses a low frequency signal corresponding to the straightness of the round bar as a straightness signal of the round bar from the detection signal of the reflection position outputted by the sensor. The present invention is characterized by comprising a low-pass filter to be taken out, and a straightness determination section that determines the straightness of the round bar body based on a straightness signal of the round bar body taken out from the low-pass filter.

[Operation] The round bar inspection device of the present invention rotates the round bar and irradiates the circumferential surface of the bar with a laser beam, and integrates the reflection position and amount of reflected light to inspect the round bar. Inspect for surface defects and straightness. As a result, the shape of the round bar over its entire length can be automatically and accurately inspected simply by rotating the round bar.

[Embodiment] Hereinafter, as an embodiment of the present invention, an inspection apparatus for inspecting nuclear fuel rods will be described based on the drawings.

In the figure, l denotes a nuclear fuel rod, which is placed on a plurality of rotary drive rollers 2 so that the axis in the front and back direction of the paper in FIG. 1 (left and right direction in FIG. 2) is horizontal. 2 in the direction of the arrow in FIG. 1, it is rotated about a horizontal axis. Furthermore, an axial feed roller 3 that feeds the nuclear fuel rod 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 this example) are provided above the nuclear fuel rods 1 on the rotary drive roller 2. This displacement/light amount sensor 4 has
A laser beam projector 5 that irradiates the circumferential surface of the nuclear fuel rod 1 with laser light from the radial direction, an imaging lens 6 that collects the reflected light from the circumferential surface of the nuclear fuel rod 1, and a laser beam that is reflected through the imaging lens 6. A light spot position sensor 7 for inputting light is incorporated.

The sensor 7 has the following two detection functions.

(2) A function of detecting the position of the surface of the nuclear fuel rod 1 directly below the laser beam projector 5 from a change in the light receiving position corresponding to the reflection position of the laser beam in the nuclear fuel rod 1, and outputting a position detection signal St.

■Detecting the amount of laser light reflected from nuclear fuel rods,
Function to output light amount detection signal S2.

A large number of sensors 7 having such two detection functions are provided in each displacement/light amount sensor 4 in close proximity along the axial direction of the nuclear fuel rod l, and are located at multiple points on the surface of the nuclear fuel rod l. is targeted for detection. For example, total length 25
In the displacement/light amount sensor 4 on the order of cm, 0! 5-0
, 4000 sensors 7 are arranged at intervals of about 2 ff1 m. Therefore, in this case, the number of measurement points per displacement/light amount sensor 4 is 4000. In addition, in the case of this embodiment, the large number of sensors 7 in the four displacement/light quantity sensors 4 rotate once at the position where the nuclear fuel rod l is shown by the solid line in FIG. By making one rotation at this position, the light reflected from the circumferential surface over the entire length of the nuclear fuel rod 1 can be received.

The high frequency component of the position detection signal Sl output from the sensor 7 is passed through a high-pass filter 8, converted into a digital signal, and then taken into the first frame memory 9. At the same time, the low frequency component of the position detection signal Sl is passed through a 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. Each of the frame memories 9, 11, and 12 is configured to store data during one rotation of the nuclear fuel rod 1.

The high frequency component data taken into the first and third frame memories 9 and 12 is transferred from the defect extraction section 13 to the defect determination section 1.
4 is input. The functions of the defect extraction section 13 and the defect determination section 14 will be described later along with their actions. On the other hand, the low frequency component data taken into the second frame memory 11 is input from the straightness calculation section 15 to the straightness determination section 16 . The functions of the straightness calculating section 15 and the straightness determining section 16 will also be described later.

In FIG. 1, reference numeral 17 denotes a controller, and this controller 17 controls the timing of data acquisition in the frame memories 9, 11 and 12, and also transfers predetermined correction data to the defect extraction section 13 and the straightness calculation section 15. It is designed to output to . This controller 1
Function 7 will also be described later.

Next, the effect will be explained.

First, prior to inspecting the nuclear fuel rod l, correction data is obtained using a dummy nuclear fuel rod. Then, the nuclear fuel rods are automatically set and inspected. In the following, the former operation will be explained as a preparation operation A, and the latter operation will be explained as an automatic inspection operation B.

A: Preparatory operation First, a dummy nuclear fuel rod (hereinafter referred to as "dummy rod") having an ideal shape of the nuclear fuel rod 1, that is, no defects on the surface and no bending with respect to the axis, is set on the rotary drive roller 2. Then, while the dummy rod is rotated by the rotary drive roller 2 at the position indicated by the solid line in FIG. Take out the light amount detection signal S2.

Originally, these signals Sl and S2 are data for measuring defects and straightness of the nuclear fuel rod I. Here, we will use a dummy rod with no defects or bends, and use correction data due to the characteristics of the equipment. taken out to seek.

Therefore, the original position detection signal Sl and light amount detection signal S2 in the case where the nuclear fuel rod 1 is targeted will be explained.

"About position detection signal S1" This position detection signal S1 includes a high frequency component and a low frequency component as shown in FIG.

(1) High-frequency component This high-frequency component is caused by fine undulations on the circumferential surface of the nuclear fuel rod I, and its size corresponds to the size of the defect on the circumferential surface, especially when the depth of the defect increases. Effective as measurement data.

(11) Low Frequency Component This low frequency component is caused by the bending of the nuclear fuel rod 1 with respect to its axis, and increases in size depending on the straightness.

"About the light amount detection signal S2" The light amount detection signal S2 is caused by the degree of diffuse reflection on the circumferential surface of the nuclear fuel rod 1, and is particularly effective as measurement data for the size of a defect.

Here, such detection signals Sl and S2 are extracted for the dummy rod. Then, the former position detection signal Sl
The high frequency component (i) of is filtered by a high pass filter similar to 8 in FIG. 1 and then digitally converted, and the low frequency component (ii) is filtered by a low pass filter similar to IO in FIG. , and then digital conversion. The light amount detection signal 82 is also converted into digital data. Then, based on the digitally converted high-frequency component (1) and the light intensity detection signal S2, a defect signal corresponding to the size and depth of the defect on the circumferential surface of the dummy rod (originally, there are no defects on the dummy rod, so the device ) is extracted and stored as correction data for defect determination. On the other hand, the straightness of the dummy rod is determined based on the digitally converted low-frequency component (11) (as the dummy rod does not have any bends, the data is due to the characteristics of the equipment), and this is used to determine the straightness. stored as correction data.

In this way, after rotating the dummy rod once at the position indicated by the solid line in Figure 2, the dummy rod is sent to the position indicated by the two-dot chain line in the same figure and rotated one more time, and the above-mentioned operation is performed. repeat. As a result, correction data over the entire length of the dummy rod is obtained and stored.

Further, the timing of capturing the detection data from the sensor 7 is stored in the controller 17 in relation to the operation of rotating the dummy rod around its axis and the operation of sending it in the direction of its axis. Hereinafter, this 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 as in the case of stacked dummy rods, the nuclear fuel rod 1 is rotated once at the position indicated by the axis line in FIG. A laser beam is irradiated, and a position detection signal St and a light amount detection signal S2 per rotation of the nuclear fuel rod I are taken out.

The high frequency component (1) included in the position detection signal S1 is filtered by a high pass filter 8 and then digitally converted, and the low frequency component (11) is filtered by a low pass filter 1O and then digitally converted. Then, these data per rotation of the nuclear fuel rod 1 are taken into the frame memory 911. In addition, the light amount detection signal S2 per rotation of the nuclear fuel rod l is
After digital conversion, it is taken into the frame memory 12.

When importing these data, the controller 17
Utilizing the timing data stored in , data acquisition is started in relation to the operation of rotating the nuclear fuel rod 1 once.

Then, the defect extracting unit 13 extracts the high frequency component captured into the first frame memory 9 and the third frame memory 1.
A defect signal corresponding to the size and depth of the defect in the nuclear fuel rod l is output by synthesizing the light quantity detection signals S2 taken into the nuclear fuel rod l. The defect signal is corrected by correction data stored in the controller 17 and then sent to the defect determination section 1.
Enter 4. The defect determination unit 14 determines the size and depth of defects on the circumferential surface of the nuclear fuel rod 1 based on the input data. Further, the straightness calculation unit 15 calculates the maximum displacement amount per rotation of the nuclear fuel rod 1 from the low frequency component (ii) captured in the second frame memory 11. The obtained value is corrected using correction data stored in the controller 17 and then input to the straightness determining section 16.

The straightness determination unit) 6 determines the straightness of the nuclear fuel rod 1 based on the input data.

Next, the nuclear fuel rod 1 is sent to the position indicated by the two-dot chain line in FIG. 2, rotated one more time, and the above-described operation is repeated. This allows inspection of defects and straightness over the entire length of the nuclear fuel rod.

Thereafter, after the inspected nuclear fuel rod 1 is sent out, the next nuclear fuel rod 1 is automatically set, and the inspection of the nuclear fuel rods 1 is carried out one after another in the same manner.

In this example, the nuclear fuel rod l is rotated twice in total to inspect its shape over its entire length. If 4 is deployed, one rotation is sufficient. Also,
It can also be completed by one rotation by rotating the nuclear fuel rod l and feeding it in the axial direction.

[Effects of the Invention As explained above, the round bar inspection device of the present invention has the following advantages:
The round rod is rotated and a laser beam is irradiated onto its circumferential surface, and the reflection position and amount of reflected light are combined to inspect the surface defects and straightness of the round rod. By simply rotating the rod, its shape over its entire length can be automatically and accurately inspected.

[Brief explanation of drawings]

The drawings are diagrams for explaining one embodiment of the present invention, and FIG. 1 is a block diagram of the main parts, and FIG. 2 is a side view of a nuclear fuel rod during inspection. ■... Nuclear fuel rod (round rod body), 2... Rotating drive roller, 3... Axial feed roller, 4... Displacement/light amount sensor, 5... Laser beam projector, 7... Light spot position sensor, 8... High pass filter, 9.11.12... Frame memory, 10...
. . . Low pass filter, 15 . . . Defect determination section, 16 . . . Squareness determination section. 6...imaging lens,

Claims (2)

[Claims] (1) A round bar inspection device that inspects the shape of a round bar while rotating the bar about its axis, and which inspects the circumferential surface of the bar from the outside in the radial direction of the bar. A laser beam projector that emits laser light toward the round rod, a high frequency wave that receives reflected light from the circumferential surface of the round rod, and responds to the undulations of the surface of the round rod based on the reflection position of the reflected light. A sensor that outputs a reflection position detection signal including a low frequency corresponding to the straightness of the body and also outputs a reflection position detection signal based on the amount of reflected light; and a sensor that outputs a reflection position detection signal based on the amount of reflected light. , a high-pass filter that extracts a high frequency corresponding to the undulations on the surface of the round rod as a defect signal of the round rod, a detection signal of the amount of reflected light outputted by the sensor, and a defect signal of the round rod extracted from the high-pass filter. 1. An inspection apparatus for a round bar body, comprising: a defect determining section that determines defects in the round bar body based on the above. (2) From the detection signal of the reflection position output by the sensor,
A low-pass filter that extracts a low frequency corresponding to the straightness of the round bar body as a straightness signal of the round bar body, and based on the straightness signal of the round bar body taken out from the low-pass filter,
The inspection device for a round bar body according to claim 1, further comprising a straightness determining section for determining the straightness of the round bar body.