JPH10197239A - Method and device for measuring bend-amount of nuclear fuel rod - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve measuring precision in the bend-amount of a nuclear fuel rod and also to reduce labor of an inspector. SOLUTION: A nuclear fuel rod 1, in horizontal state, is placed on V-grooves 2a on three V-blocks 2. To each V-block 2, an axis position measuring device 3 which measures an axis position of the nuclear fuel rod 1 is attached, with each measuring data outputted to a bend-amount calculation device 4. At the bend-amount calculation device 4, a space coordinate indicating positions in three directions (x, y, z) is set on each V-block 2, and based on the measuring data from each axis position measuring device 3, a bend-amount of the nuclear fuel rod 1 in the space coordinate is calculated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring a bending amount of a long nuclear fuel rod.

[0002]

2. Description of the Related Art A nuclear fuel rod is a straight tubular member in which fuel pellets are sealed in a cladding tube. However, since its length is as long as about 4 m, deformation such as bending in a manufacturing process. That is, bending is likely to occur. On the other hand, the nuclear fuel rods are inserted into the cores of a plurality of spacers attached at predetermined intervals, and are arranged in the nuclear reactor in a state where a number of fuel rods are bundled. Therefore, if an attempt is made to assemble a nuclear fuel rod having a bend as it is as a fuel assembly, not only is it not possible to smoothly insert the nuclear fuel rod into the spacer, but also residual stress is generated in the nuclear fuel rod, It can cause damage to nuclear fuel rods during prolonged operation. Therefore, before disposing the nuclear fuel rods in the reactor, it is necessary to measure the amount of bending and to eliminate the nuclear fuel rods having a certain amount of bending.

Conventionally, the amount of bending of a nuclear fuel rod has been measured as follows. That is, first, an inspector puts a nuclear fuel rod to be inspected on a flat inspection table and rolls the nuclear fuel rod on this table. The inspector estimates the presence or absence of a bend from the state of rolling of the nuclear fuel rod at this time, picks up the suspicious nuclear fuel rod, and applies it to the straight edge. Then, by inserting a filler gauge into the gap, the bending amount of the nuclear fuel rod was measured.

[0004]

However, in the conventional bending amount measuring method described above, the inspector estimates the existence of the bending based on his own experience and intuition, and different inspection results are obtained depending on the difference of the inspectors. May cause. Also, there is a difference in how to apply the nuclear fuel rod to the straight edge and how to select the filler gauge depending on the skill of the inspector, so that the measured value of the bending amount tends to vary.

Further, most of the conventional methods for measuring the amount of bending rely on the judgment and manual work of the inspector, so that it cannot be said that the work efficiency is high, and the inspector is not a little. There were problems such as mental and physical fatigue.

The present invention has been made in view of the above circumstances, and provides a method and an apparatus for measuring the amount of bending of a nuclear fuel rod, which can improve the measurement accuracy and reduce the labor borne by an inspector. It is intended to be.

[0007]

Means for Solving the Problems As means for solving the above-mentioned problems, the invention according to the first aspect of the present invention uses a fuel rod of V
At least 3 parts, including both ends of the nuclear fuel rod and an intermediate part between the both ends, supported horizontally in the V groove of the block.
At more than one axial position, measure the axial position of the nuclear fuel rods in a plane perpendicular to the axial direction, and from the axial position of the intermediate portion to a straight line connecting the axial positions of the both ends. The length of the lowered perpendicular is calculated as the amount of bending.

According to a second aspect of the present invention, in the first aspect of the present invention, when two or more axial center measurement positions of the intermediate portion are set, the maximum value of the calculated bending amounts is calculated as a total length bending. Quantity.

According to a third aspect of the present invention, in the first aspect of the present invention, when three or more axial center measurement positions of the intermediate portion are set, three consecutive axial center measurement positions are set to one. As a group, the axial center measurement positions of all the intermediate portions are divided for each group, and the maximum value of the three bending amounts in the group is defined as the local bending amount.

According to a fourth aspect of the present invention, there is provided a V-block having a V-groove capable of horizontally supporting a nuclear fuel rod at at least three axial positions including both end portions and an intermediate portion between both end portions. And an axial position measuring device disposed inside the V-block near the V-groove and measuring the axial position of the nuclear fuel rod in a plane perpendicular to the axial direction at the three or more axial positions. And space coordinates capable of specifying the axial position in the axial direction and the plane, and based on the input of the measurement value of the axial position measuring device, the two end portions in the spatial coordinates. And a bend amount calculating means for calculating, as a bend amount, a length of a perpendicular line lowered from the axial position of the intermediate portion to a straight line connecting the axial positions.

According to a fifth aspect of the present invention, in the invention of the fourth aspect, the axial center position measuring device is provided on two support surfaces formed by the V-shaped grooves, which are in contact with the outer peripheral surface of the nuclear fuel rod. On the other hand, each of the movable contacts has a movable contact that can move forward and backward in the vertical direction, and the axial center position is measured based on the amount of protrusion of the two movable contacts.

The invention according to claim 6 is characterized in that the shaft center position measuring device measures the shaft center position in a non-contact manner with the nuclear fuel rod.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a measuring apparatus for performing a measuring method according to an embodiment of the present invention.
In this figure, a nuclear fuel rod 1 in a horizontal posture is mounted on V grooves 2a of three V blocks 2. An axial position measuring device 3 for measuring the axial position of the nuclear fuel rod 1 is attached near the V groove 2a of each V block 2, and each measurement data is output to the bending amount calculating device 4. It has become. In the bending amount calculation device 4,
Spatial coordinates indicating positions in three directions of x, y, and z, where the axial direction of the nuclear fuel rod 1 is the z direction, and the directions orthogonal to each other in a plane perpendicular to the axial direction are the x and y directions. Is set. The bend amount calculating device 4 calculates the axial position of the nuclear fuel rod 1 in the space coordinates based on the measurement data from each axial position measuring device 3. In the vicinity of the three V blocks 2,
A fuel rod delivery device and a fuel rod delivery device (not shown) are provided, and the nuclear fuel rod 1 is automatically delivered into the V groove 2a of the V block 2. After the measurement is completed, the nuclear fuel rods 1 in the V groove 2a are automatically paid out to the side of the V block 2.

FIG. 2 shows an axial center position measuring device 3 shown in FIG.
It is sectional drawing which shows the attachment state of. In this figure, a mounting member 5 is disposed below a V groove 2a of a V block 2 on which a nuclear fuel rod 1 is mounted, and a pair of right and left linear gauges 6 is mounted on the mounting member 5. I have. Also,
The V groove 2a of the V block 2 forms an angle of 90 ° with each other.
It is formed by two support surfaces 2a1 and 2a2, and holes 2b1 and 2b2 are provided in a direction perpendicular to these support surfaces. Each linear gauge 6 passes through the holes 2b1 and 2b2, and the two support surfaces 2a1 and 2b.
It has a movable bar 7 that moves back and forth in a direction perpendicular to a2. A contact 8 having a flat surface parallel to the support surface is provided at a tip end of the movable rod 7. When the movable rod 7 moves forward with respect to the nuclear fuel rod 1, the contact 8 has a flat surface. The movable rod 7 stops when it comes into contact with the outer peripheral surface of the rod 1, and retreats to the original position after the measurement of the axis position. Then, measurement data on the position where each of the left and right contacts 8 comes into contact with the outer peripheral surface of the nuclear fuel rod 1, that is, the protrusion amount of both contacts 8 is output to the bending amount calculation device 4.

Next, a description will be given of a measuring method according to the present embodiment using the measuring apparatus configured as described above. FIG.
When the nuclear fuel rod 1 is fed from a fuel rod feeding device (not shown) and the nuclear fuel rod 1 is placed on the V groove 2a of the V block 2, the axial center position measuring device 3
The movable rods 7 of the pair of linear gauges 6 advance with respect to the nuclear fuel rod 1, and the flat surface of each contact 8 comes into contact with the outer peripheral surface of the nuclear fuel rod 1. At this time, the measurement data on the contact position of each contact 8 on the flat surface is obtained by the bending amount calculating device 4.
The bending amount calculating device 4 calculates the axial position of the nuclear fuel rod 1 on each V block 2 based on the measurement data. The position of this axis is determined by the positions P1 (x1, y1, z1) and P2 (x2,
y2, z2) and P3 (x3, y3, z3).

FIG. 3 shows the three positions P1, P2, P
FIG. 3 is an explanatory diagram showing 3 in the z direction, that is, in the axial length direction of the nuclear fuel rod 1. In this figure, positions P1 and P3 indicate the axial center positions of the V blocks 2 on both ends on the V groove 2a.
The position P2 indicates the axial position of the intermediate V block 2 on the V groove 2a. The bending amount calculating device 4 calculates the positions P1, P
A perpendicular 10 is drawn from the position P2 to a straight line 9 formed by connecting the three, and the intersection point is defined as P, and the distance between P2 and P, that is, the length h of the perpendicular 10 is calculated. The length h of the perpendicular 10 is treated as the amount of bending of the nuclear fuel rod 1. In this case, since the nuclear fuel rods 1 are mechanically sent out onto the V-grooves 2a of the V-block 2 by the above-mentioned fuel rod feeding device, even if the same nuclear fuel rods 1 are sent out, To the position P excluding the z direction
1 (x1, y1,), P2 (x2, y2,), P3 (x3
, Y3,) have different values each time. However, regardless of the values of these positions, the length h
Is immutable.

The bend amount calculated by the bend amount calculating device 4 is displayed on a display device (not shown) so that an inspector can check a specific numerical value of the bend amount. In this case, a warning message or the like may be displayed for a bend amount that is equal to or greater than a certain value to alert the inspector.

After the display device displays the amount of bending, a fuel rod dispenser (not shown) dispenses the nuclear fuel rods 1 in the V-groove 2a of the V-block 2, and then delivers the fuel rods. The apparatus feeds the next nuclear fuel rod 1 into the V groove of the V block 2. And the next nuclear fuel rod 1
Is measured.

In the above-mentioned measuring method, the setting of the nuclear fuel rods 1 to be inspected, the measurement of the amount of bending, and the display of the measured values are automatically performed, so that the work involving the inspector is very small. Has become. Therefore, as compared with the conventional measurement method, the measurement accuracy is improved, and the labor of the inspector is significantly reduced. Furthermore, since the operation can be performed in a few seconds on one nuclear fuel rod 1, the operation time is greatly reduced.

Incidentally, in the above embodiment, three V
Having described the simplest example using block 2,
In order to obtain a more accurate bending amount over the entire length of the nuclear fuel rod 1, it is preferable to further increase the number of V blocks 2. In this case, V excluding V blocks 2 at both ends
There are a plurality of blocks 2 (intermediate V blocks), and a plurality of bend amounts can be obtained. The maximum bend amount is defined as "full length bend amount". In addition, a group of three consecutive V blocks constitutes a plurality of intermediate V blocks.
Block 2 is divided into groups, and 3
The maximum bend amount of one bend amount is referred to as “local bend amount”.
It will be specified. As described above, if the amount of bending of the nuclear fuel rod 1 is obtained by dividing it into the “total bending amount” and the “local bending amount”, the suitability of assembling the nuclear fuel rod 1 as a fuel assembly becomes more diverse. It is also possible to perform a detailed analysis on the tendency and characteristics of the bending, and to return the analysis result to the manufacturing process.

The V-block used in the above-described embodiment is assumed to be a tool normally used as a measuring tool. However, a dedicated V-block for measuring the amount of bending is manufactured and used. It may be. For example, if a V-block having a length approximately equal to the length of a nuclear fuel rod is manufactured and the holes 2b1 and 2b2 are formed as long holes along the axial direction, one axial center position measuring device 3 can be used. It can be easily arranged in the V block and at any position in the axial direction.

Further, in the above embodiment, an example is described in which a pair of linear gauges 6 having movable contacts 8 are used as the axial center position measuring means. For example, a non-contact type axial center such as a laser gauge is used. A position measuring means may be used. When this laser gauge is used, it is possible to move the laser gauge little by little over the entire length of the nuclear fuel rod 1 to further shorten the measurement interval of the amount of bending.

[0023]

As described above, according to the present invention, the nuclear fuel rod is supported on the V-block in a horizontal state, and the axial position of the intermediate portion is defined with respect to the straight line connecting the axial positions of both ends. Since the length of the lowered perpendicular is calculated as the amount of bending, the amount of bending can be automatically obtained using the axis position measuring means and the amount of bending calculating means, and the measurement accuracy is improved, The labor borne by the inspector can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a measuring device for performing a measuring method according to an embodiment of the present invention.

FIG. 2 is a sectional view showing an attached state of the shaft center position measuring device 3 in FIG.

FIG. 3 is an explanatory diagram of calculation contents of a bending amount calculation device 4 in FIG. 1;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 nuclear fuel rod 2 V block 2 a V groove 2 a 1, 2 a 2 support surface 2 b 1, 2 b 2 hole 3 axis center position measuring device 4 bending amount calculation device 5 mounting member 6 linear gauge 7 movable rod 8 contact 9 straight 10 perpendicular

Claims (6)

[Claims] 1. A nuclear fuel rod is horizontally supported in a V-groove of a V block, and at least three or more axial positions including both ends of the nuclear fuel rod and an intermediate portion between the both ends, The axial position of the nuclear fuel rod in a plane perpendicular to the axial direction is measured, and the length of the perpendicular drawn from the axial position of the intermediate portion to the straight line connecting the axial positions of the both ends is bent. A method for measuring the amount of bending of a nuclear fuel rod, characterized in that: 2. The method according to claim 1, wherein when the axial center measurement position of the intermediate portion is two or more, the maximum value of the calculated bending amounts is the full length bending amount. A method for measuring the amount of bending of a nuclear fuel rod. 3. When three or more axial center measurement positions of the intermediate portion are set, three axial center measurement positions that are continuously located are regarded as one group, and the axial center measurement positions of all intermediate portions are grouped. 2. The method according to claim 1, wherein a maximum value of the three bending amounts in the group is defined as a local bending amount. 4. A V-block having a V-groove capable of supporting a nuclear fuel rod horizontally at at least three or more axial positions including both ends and an intermediate portion between both ends thereof, and a vicinity of the V-groove. An axial position measuring device disposed inside the V-block and measuring an axial position of the nuclear fuel rod in a plane perpendicular to the axial direction at the three or more axial positions; And, spatial coordinates capable of specifying the axial position in the plane are set, and based on the input of the measured value of the axial position measuring device, the axial positions of the both ends in the spatial coordinates are connected. A bending amount calculating device for calculating, as a bending amount, a length of a perpendicular line lowered from an axial center position of the intermediate portion with respect to the straight line, a bending amount measuring device for a nuclear fuel rod. 5. The axial center position measuring device includes a movable contact that is capable of moving back and forth in a vertical direction with respect to two support surfaces formed by the V-grooves, which contact the outer peripheral surface of the nuclear fuel rod. 5. The bending amount measuring apparatus for a nuclear fuel rod according to claim 4, wherein the axial center position is measured based on the amount of protrusion of the two movable contacts. 6. The bending of a nuclear fuel rod according to claim 4, wherein the axial position measuring device measures the axial position in a non-contact manner with the nuclear fuel rod. Quantity measuring device.