JP2991984B2 - Method and apparatus for measuring bending amount of nuclear fuel rod - Google Patents

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.
The axial center position of the nuclear fuel rod in a plane perpendicular to the axial direction is measured at the axial position or more, and a straight line connecting the axial center positions of both ends of the nuclear fuel rod is measured. The length of the perpendicular line lowered from the axial center position of the intermediate portion is calculated as a bending amount, and the maximum value of the calculated bending amounts is defined as the total length bending amount, and the continuous length of the nuclear fuel rod is calculated. The three axis center measurement positions located in the same position as one group, all the axis center measurement positions are divided into groups, and the maximum value of the amount of bending of each group is defined as the local amount of bending. I do.

According to a second aspect of the present invention, there is provided a nuclear fuel rod having at least three portions including both ends thereof and an intermediate portion between the both ends.
A V-block having a V-groove that can be supported horizontally at more than three axial positions, and disposed inside the V-block near the V-groove, and perpendicular to the axial direction at the three or more axial positions. And measuring the axial center position of the nuclear fuel rod in a simple plane, and perpendicularly to two support surfaces formed by the V-grooves, which are in contact with the outer peripheral surface of the nuclear fuel rod. An axial position measuring device having a movable contact that can move forward and backward, and measuring the axial position based on the amount of protrusion of the movable contacts; and an axial center in the axial direction and in the plane. Spatial coordinates capable of specifying a position are set in advance, and based on the input of the measurement value of the axial center position measuring device, the middle portion of the intermediate portion is defined with respect to a straight line connecting the axial center positions of the both ends in the spatial coordinates. The length of the perpendicular that is lowered from the axis position is the amount of bending A bending amount computing unit to to operation,
Wherein the nuclear fuel rods are horizontally supported in the V-groove of the V-block, and at least three or more axial positions of the nuclear fuel rods in a plane perpendicular to the axial direction. The axial position is measured, and the length of the perpendicular drawn from the axial position of the intermediate portion between the both ends to the straight line connecting the axial positions of both ends of the nuclear fuel rod is calculated as the amount of bending, Moreover, the maximum value of the calculated bending amounts is defined as a total bending amount, and three consecutively measured axial centers of the nuclear fuel rods are defined as one group.
All the axis center measurement positions are divided for each group, and the maximum value of the bending amounts of each group is calculated as the local bending amount.

[0009]

[0010]

[0011]

[0012]

[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 device for performing a measuring method according to an embodiment of the present invention ,
Shows the case where three V blocks are used as the basic configuration
ing. In this figure, a nuclear fuel rod 1 in a horizontal posture is mounted on V grooves 2a of three V blocks 2. In the vicinity of the V groove 2a of each V block 2, a nuclear fuel rod 1
An axial center position measuring device 3 for measuring the axial center position is attached, and each measurement data is output to a bending amount calculating device 4. In the bending amount calculating device 4, the axial direction of the nuclear fuel rod 1 is defined as the z direction, and directions orthogonal to each other in a plane perpendicular to the axial direction are defined as x and y.
Spatial coordinates indicating positions in three directions x, y, and z are set as directions. 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. A fuel rod delivery device and a fuel rod dispensing device (not shown) are installed near the three V blocks 2, and the nuclear fuel rods 1 are automatically placed in the V grooves 2 a of the V block 2. To be sent out. 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 amount of protrusion 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
Block 2 (intermediate V block) becomes more, but so that the plurality of bending amount is obtained, the ends V block 2
And any of the intermediate V-blocks that indicate the maximum value
The maximum amount of bending due to the inter-V block is "the total amount of bending"
It will be specified. In addition, a plurality of intermediate V blocks 2 are divided into groups with three consecutive V blocks as one group, and the maximum bending amount among the bending amounts indicated by the three V blocks in the group is referred to as “local bending”. amount"
It will be specified. This will be explained more specifically
And if the measuring device has n V blocks
In this case, for these V blocks, 1, 2, 3,
Numbering such as 4,..., N−2, n−1, n
V block at the end of 1 and n and any V block in the middle
Is used to calculate the “full-length bending amount”. Also continuous
1, 2, and 3 V blocks to the first group, 2, 3,
4 V block into the second group, 3, 4, 5 V block
Group as the third group, and grouping in the same way
From the V block of each group
The amount of bending is calculated. And these songs
The value of the group that indicates the maximum value of the
Amount ". Thus, the amount of bending of the nuclear fuel rod 1 is
Length and the total length of nuclear fuel rod 1
Divided into "local bend amount" for a part of area
If it is determined, the suitability of assembling the nuclear fuel rod 1 as a fuel assembly can be determined from multiple aspects, and a detailed analysis of the tendency and characteristics of bending is performed, and the analysis result is used in the manufacturing process. Can also be reduced to

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.

[0022]

As described above, according to the present invention, the nuclear fuel rod is supported horizontally in the V groove of the V block, and at least three fuel rods including both ends of the nuclear fuel rod and an intermediate part between the both ends are provided. The axial center position of the nuclear fuel rod in a plane perpendicular to the axial direction is measured at the axial position or more, and a straight line connecting the axial center positions of both ends of the nuclear fuel rod is measured. The length of the perpendicular line lowered from the axial center position of the intermediate portion is calculated as a bending amount, and the maximum value of the calculated bending amounts is defined as the total length bending amount, and the continuous length of the nuclear fuel rod is calculated. The three axis center measurement positions
As a group, all the axis measurement positions are divided for each group, and the maximum value of the bending amounts of each group is defined as the local bending amount. Therefore, this bending amount is determined by the axis position measuring means and the bending. It can be automatically obtained by using the quantity calculating means, so that the measurement accuracy can be improved and 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

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-50-96252 (JP, A) JP-A-63-246607 (JP, A) JP-A-59-92309 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) G01B 7/00-7/34 G01B 21/00-21/32

Claims (2)

(57) [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 from the axial position of the intermediate portion between the both ends with respect to a straight line connecting the axial positions of both ends of the nuclear fuel rod. The length of the lowered perpendicular is calculated as the amount of bending , and the maximum value of the calculated amounts of bending is calculated as the total length.
In addition to the amount of bending, three axial center measurement positions continuously located on the nuclear fuel rod
Position as one group, all axis center measurement positions are grouped
The maximum value of the amount of bending in each group
The amount of bend of the nuclear fuel rod. 2. A V-block having a V-groove capable of horizontally supporting a nuclear fuel rod at at least three axial positions including both ends and an intermediate portion between the both ends, and the V-groove. And measuring the axial center position of the nuclear fuel rod in a plane perpendicular to the axial direction at the three or more axial positions in the vicinity of the V block. A movable contact in contact with the outer peripheral surface of the V-groove, the movable contact being able to advance and retreat in a vertical direction with respect to each of two support surfaces formed by the V-grooves. An axis position measuring device for measuring the center position, and space coordinates capable of specifying the axis position in the axial direction and the plane in the plane are set, and input of the measured value of the axis position measuring device is performed. Based on the two ends in this spatial coordinate A bending amount calculation unit with respect to a straight line connecting the axial center position calculated as the amount of bending the length of the perpendicular drawn from the axis position of the intermediate portion, the provided, the nuclear fuel rods in the V-grooves of the V block Horizontal support
And at least three axial positions of the nuclear fuel rod in the axial direction.
And the axis of the nuclear fuel rod in a plane perpendicular to the axial direction
Measure the position, with respect to the straight line connecting the axial center position of both ends of the nuclear fuel rod
Perpendicular line lowered from the axial center position of the middle part between these two ends
Is calculated as the amount of bending, and the maximum value of the calculated amounts of bending is calculated as the total length.
In addition to the amount of bending, three axial center measurement positions continuously located on the nuclear fuel rod
Position as one group, all axis center measurement positions are grouped
The maximum value of the amount of bending in each group
And calculating a local bending amount of the nuclear fuel rod.