JPH1152089A - Checking method for fuel rod dimension inspection device and reference gauge for calibration used for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the lowering of load factor of a fuel rod dimension inspection device by making simply performing the check of measurement accuracy possible. SOLUTION: A reference gauge 9 for calibration is mounted on a fuel dimension inspection device and such measuring items as total length, bend and the parallelism of end plug fixing is measured similarly to the ordinary work of fuel rod dimension inspection. Then, a displacement gauge for calibration 10 is mounted on the fuel rod dimension inspection device and such measuring items as total length, bend and the parallelism of end plug fixing is measured similarly. When the measurement of each measuring item for the reference gauge 9 for calibration and the displacement gauge for calibration 10 is completed in this manner, whether or not the deviation between each of the measured values is within a specified range is judged. By this, good or bad of measuring accuracy for each sensor and scale of the fuel rod dimension inspection device is checked.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for checking the measurement accuracy of a fuel rod size inspection apparatus and a reference gauge for calibration used in the method.

[0002]

2. Description of the Related Art A nuclear fuel rod is a straight tubular member in which fuel pellets are filled inside a cladding tube, end plugs are attached to both ends of the cladding tube, and the fuel pellets are sealed. Since this nuclear fuel rod is a long member having a total length of about 4 m, errors in the total length increase in the manufacturing process, bending such as bending occurs, or end plugs at both ends are attached. There is a possibility that an error such as an increase in the parallelism error occurs.

If such problems are overlooked, not only does it hinder the installation of the nuclear fuel rods in the nuclear reactor, but also cause damage to the nuclear fuel rods during the long-term operation of the nuclear reactor. It could be. Therefore, the fuel rods whose end plugs have been attached to both ends of the cladding tube are mounted on a fuel rod dimensional inspection device, and a dimensional inspection of a predetermined item is performed by this device to prevent the above-mentioned problem from occurring.

FIG. 3 is an explanatory view showing the configuration of the fuel rod size inspection device. As shown in this figure, the present inspection apparatus comprises a linear scale 3 for measuring the total length L of a fuel rod 1 having an upper end plug 2a and a lower end plug 2b attached to both ends, and a bending amount of the fuel rod 1. And a plurality of laser sensors 5 for measuring the parallelism of the mounting of the end plug 2.

FIGS. 4A and 4B are a side view and a front view showing a mounted state of the contact type displacement sensor 4. FIG. The displacement sensor 4 is attached to a V block 6 on which the fuel rod 1 is placed. A contact 7 is attached to the tip of a movable rod 8 that moves forward and backward with respect to the fuel rod 1. Then, the position of the center of the cross section of the fuel rod 1 is calculated from the position where the contact 7 comes into contact with the outer peripheral surface of the fuel rod 1. The amount of bending is calculated.

[0006]

As the dimensional inspection of a large number of fuel rods 1 is performed by the above-described fuel rod dimensional inspection apparatus, each sensor and the scale caused by aging, vibration, etc. The measurement accuracy gradually decreases due to a change in the mounting position of the sensor and the scale. Therefore, it is necessary to check the measurement accuracy of each sensor and scale every fixed period. The check of the measurement accuracy has been conventionally performed individually by removing each sensor and scale from the fuel rod size inspection device.

However, such a conventional measuring accuracy check method requires a considerable amount of time and effort to remove and attach each sensor and scale, and furthermore, the operation of the apparatus must be stopped during that time. In addition, problems such as a decrease in the operation rate have occurred.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and enables a simple check of the measurement accuracy to be performed, thereby suppressing a decrease in the operation rate. It is an object of the present invention to provide a method and a calibration reference gauge used for the method.

[0009]

As means for solving the above-mentioned problems, the invention according to claim 1 is directed to a linear scale for measuring the entire length of a fuel rod, and for measuring the bending of a fuel rod. Contact type displacement sensor for bending measurement,
In the measurement accuracy check method of the fuel rod size inspection device provided with a parallelism measuring laser sensor for measuring the parallelism of the end plug mounting of the fuel rod, first, the overall length of the fuel rod, the bending, and the parallelism of the end plug mounting A calibration reference gauge formed in a shape having a predetermined reference value for each measurement item of the degree is attached to the fuel rod size inspection device, and the measurement for each measurement item is performed on the calibration reference gauge, Then
A calibration displacement gauge formed in another dimension different from the predetermined reference value is mounted on the fuel rod size inspection device, and the calibration displacement gauge is measured for each of the measurement items. Determining whether or not the deviation between the respective measured values of the calibration reference gauge and the calibration displacement gauge is within a predetermined range, thereby checking whether the measurement accuracy of the fuel rod size inspection device is acceptable or not. And

According to a second aspect of the present invention, there is provided a calibration reference gauge formed in a shape having a predetermined reference value with respect to each measurement item of the total length, bending, and end plug mounting parallelism of the fuel rod, and the predetermined reference value. And a displacement gauge for calibration formed in another size different from the above.

According to a third aspect of the present invention, in the second aspect of the present invention, the calibration displacement gauge is formed such that sections having the same diameter as the diameter of the calibration reference gauge and a different diameter are alternately formed. The position where the section having the different diameter is formed corresponds to the installation position of the bending displacement contact type displacement sensor for measuring the bending of the fuel rod.
It is characterized by the following.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1A and 1B show a calibration reference gauge used in the measurement accuracy checking method according to the present embodiment, and a pair of calibration reference gauges 9 and a calibration reference gauge 9 for calibrating the calibration reference gauge. It is a perspective view showing each shape of displacement gauge 10. As shown in these figures, the calibration reference gauge 9 includes a portion corresponding to the fuel rod 1 having a total length L0 and a diameter φA0, one end corresponding to the lower end plug 2b (diameter φB0), and an upper end plug. 2a (the diameter φC0). In addition, displacement gauge for calibration 1
0 also has a portion corresponding to the fuel rod 1, one end corresponding to the lower end plug 2b, and the other end corresponding to the upper end plug 2a, similarly to the calibration reference gauge 9. However, the total length is L1, which is a value shorter than L0, and the diameters of one and the other ends are also φB1, φC1, which are smaller than φB0 and φC0.

In the displacement gauge 10 for calibration, a portion having the same diameter as the diameter φA0 of the reference gauge 9 for calibration and a portion having a diameter φA1 smaller than φA0 are alternately arranged at regular intervals within the range of the total length L1. Is formed. The position of the section where the portion having the diameter φA1 is formed corresponds to the installation position of the contact displacement sensor 4 shown in FIG.

When the calibration reference gauge 9 is mounted on the fuel rod size inspection device, the entire length of the fuel rod 1 is measured.
It is formed so as to have a predetermined reference value for each measurement item of bending and end plug attachment parallelism. Similarly, when the calibration displacement gauge 10 is mounted on the fuel rod size inspection device, the predetermined length from the above-mentioned predetermined reference value is determined by a predetermined amount with respect to each measurement item of the fuel rod 1 in total length, bending, and end plug mounting parallelism. It is formed to have a displaced value.

Next, a method of checking the measurement accuracy of the fuel rod size inspection apparatus according to the embodiment of the present invention, which is performed using the above-described calibration reference gauge 9 and calibration displacement gauge 10, will be described. The inspector first attaches the calibration reference gauge 9 to the fuel rod size inspection device, and, like the normal fuel rod size inspection work, makes the calibration reference gauge 9 full length, bend, and end plug attachment parallelism. Measure each measurement item.

Next, the calibration reference gauge 9 is removed, and the calibration displacement gauge 10 is mounted on the fuel rod size inspection device. Then, similarly to the calibration reference gauge 9, the measurement items of the total length, the bending, and the parallelism of the end plug attachment are measured for the calibration displacement gauge 10. As described above, when the measurement of each measurement item with respect to the calibration reference gauge 9 and the calibration displacement gauge 10 is completed, it is determined whether or not the deviation between these measurement values is within a predetermined range, thereby determining the fuel. The pass / fail of the measurement accuracy for each sensor and scale of the rod size inspection device is checked.

For example, the pass / fail of the measurement accuracy of the contact type displacement sensor 4 will be described with reference to FIG. 2. The measured value of the diameter of the portion of the calibration reference gauge 9 corresponding to the fuel rod is φA 0, Since the value of the portion obtained by displacing φA0 by a predetermined amount is φA1, the actual displacement x of the contact 7 of the displacement sensor 4 is x = (φA0−φA1) / 2. On the other hand, the correct value of (φA0−φA1) / 2 is obtained in advance by another measurement method for the calibration reference gauge 9 and the calibration displacement gauge 10. Therefore, (φA
With respect to the value of (0−φA1) / 2, it is determined whether or not a deviation between a correct value obtained in advance by another method and a value measured by the displacement sensor 4 is within a predetermined range. Pass / fail of the measurement accuracy can be checked. In this case, portions having different diameters of φA0 and φA1 are alternately formed on the calibration displacement gauge 10 at regular intervals, and the positions of the sections where the portions having the diameter φA1 are formed are in contact with each other. Since it corresponds to the installation position of the displacement sensor 4, it is possible to individually check whether or not the measurement accuracy is satisfactory for all of the plurality of displacement sensors 4 arranged along the axial direction. it can.

The measurement accuracy of the linear scale 3 for measuring the entire length of the fuel rod size inspection apparatus and the laser sensor 5 for measuring the parallelism of the end plugs can be checked for pass / fail by the same method as described above. Since such a checking method can be performed by the same operation as that of a normal fuel rod size inspection, it is not necessary to remove each sensor and scale from the fuel rod size inspection device and individually perform them.
Further, according to such a checking method, it is possible to check the measurement accuracy for all of the linear scale 3, the displacement sensor 4, and the laser sensor 5 almost simultaneously.
Therefore, it is possible to prevent the operating rate of the fuel rod size inspection device from being reduced due to the work of checking the measurement accuracy.

[0019]

As described above, according to the present invention, since it is not necessary to remove each sensor and scale from the fuel rod size inspection device and perform them individually, it is possible to easily check the measurement accuracy. This makes it possible to suppress a decrease in the operating rate of the fuel rod size inspection device.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a shape of a gauge used in an embodiment of the present invention. FIG. 1 (a) is a perspective view of a calibration reference gauge, and FIG. 1 (b) is a perspective view of a calibration displacement gauge.

FIG. 2 is an explanatory diagram illustrating a measurement accuracy check method of a contact displacement sensor for bending measurement according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a configuration of a conventional fuel rod size inspection device.

4A and 4B are explanatory views showing a mounting state of the contact displacement sensor in FIG. 3, wherein FIG. 4A is a side view and FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel rod 2 End plug 3 Linear scale 4 Displacement sensor 5 Laser sensor 6 V block 7 Contact 8 Moving rod 9 Calibration reference gauge 10 Calibration displacement gauge

Claims (3)

[Claims] 1. A linear scale for measuring the entire length of a fuel rod, a contact displacement sensor for measuring a bend of the fuel rod for measuring a bend of the fuel rod, and a parallelism for measuring the parallelism of the end plug of the fuel rod. In a measurement accuracy check method of a fuel rod size inspection device provided with a laser sensor for parallelism measurement, first, a shape having a predetermined reference value for each measurement item of the overall length, bending, and end plug attachment parallelism of the fuel rod The calibration reference gauge formed in the above is mounted on the fuel rod size inspection device, and the measurement is performed for each of the measurement items with respect to the calibration reference gauge, and then the measurement is performed to another dimension different from the predetermined reference value. The formed displacement gauge for calibration is attached to the fuel rod size inspection device, and the measurement for each of the measurement items is performed on the displacement gauge for calibration. By determining whether or not the deviation between the respective measured values of the calibration displacement gauge is within a predetermined range, it is checked whether or not the measurement accuracy of the fuel rod size inspection device is acceptable. A method for checking the measurement accuracy of an inspection device. 2. A calibration reference gauge formed in a shape having a predetermined reference value for each measurement item of the total length, bending, and parallelism of end plug mounting of a fuel rod, and another dimension different from the predetermined reference value. A calibration reference gauge used for a measurement accuracy check method of a fuel rod size inspection device, comprising: a formed displacement gauge for calibration; 3. The displacement gauge for calibration has sections having the same diameter as the diameter of the reference gauge for calibration and sections having different diameters are alternately formed, and the position where the section having the different diameter is formed is 3. The calibration method according to claim 2, wherein the sensor corresponds to a position of a contact displacement sensor for measuring the bending of the fuel rod for measuring the bending of the fuel rod. Reference gauge.