JPH0536729B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a system and apparatus for measuring the shape of a channel box of a nuclear fuel assembly, particularly a fuel assembly for a boiling water reactor, using ultrasonic waves.

(Prior Art) When reusing a channel box that has been irradiated once, it is necessary to inspect the amount of deformation such as bending, twisting, bulging, etc. of the channel box before reusing it to determine whether or not it can be reused. Therefore, the external dimensions of the channel box are measured using an underwater television device, etc., or the ultrasonic reflection method using ultrasonic waves is mainly used for measurement speed and accuracy. .

To measure the external dimensions of a channel box using this ultrasonic reflection method, an ultrasonic transducer installed in water emits ultrasonic waves to a target area on the surface of the channel box, and the reflected waves are received by the transducer. Then, the time from transmission to reception of the ultrasonic waves is converted from the speed of sound to distance, and after calculating the distance between each measuring part and the ultrasonic sensor, the amount of deformation of the aggregate is determined. Block diagram 1
An example is shown.

In this case, the following two methods can be considered depending on the installation method of the ultrasonic transducer constituting the ultrasonic sensor.

That is, one is a multi-point simultaneous measurement type, and the other is a multi-point sequential measurement type.

Below, we will explain both of these measurement types: (a) Multi-point simultaneous measurement type In this type, ultrasonic transducers (ultrasonic sensors) are installed at positions corresponding to all measurement points on the channel box, and all measurement data is simultaneously measured. As shown in FIGS. 5 to 8, a large number of ultrasonic sensors 14 and temperature correction sensors 15 are arranged on all four sides in a sensor frame 12 held on a lower mount 11, corresponding to all measurement sites. The installed equipment is used and the measurement data obtained is processed via a relay box 17 on an upper pedestal 16. In the figure, 13 is a cone guide.

(b) Multi-point sequential measurement type This measurement type installs one or more ultrasonic transducers in water, and receives and transmits ultrasonic waves while moving the channel box and the ultrasonic transducer relative to each other. In this data acquisition method, an ultrasonic sensor 14 consisting of an ultrasonic vibrator is placed on a control rod storage rack 18 as shown in FIG. 9 on the same horizontal plane, and a channel box A containing a fuel assembly is installed. A device is used to move it up and down.

(Problem to be Solved by the Invention) However, although the multi-point simultaneous measurement type can reduce measurement errors caused by shaking of channel box A, etc., the underwater equipment becomes large and cannot be installed in locations such as power plants. Considering that the space is narrow, there are problems in installing the equipment.

On the other hand, with the multi-point sequential measurement type, the underwater equipment can be made relatively compact, and there are no problems with equipment installation, but since measurements are performed sequentially, errors may occur due to swings of channel box A during measurement, etc. There are some difficulties that can easily occur.

That is, although it is desirable to downsize underwater equipment, there is a problem in that when the equipment is downsized, the measurement accuracy deteriorates, and that downsizing and high accuracy are not compatible.

The present invention deals with the above-mentioned actual situation and attempts to solve the above problems by skillfully combining the advantages of both of the above. The purpose is to provide systems and devices.

(Means for Solving the Problems) Therefore, the characteristics of the measurement system of the present invention that meets the above objectives are as follows: As an underwater measurement device, it has a base plate, 3 to 5 stages in the axial direction, and one or more points in the same horizontal plane. , it is assumed that a device consisting of a cylindrical sensor frame in which an ultrasonic sensor is arranged is used, and the channel box is moved within the sensor frame relative to the ultrasonic sensor, and three to five measurement points are set in one group. As, 2 of them
Simultaneous measurement of one group of measurement points is carried out sequentially so that some of the above points are measurement points at the same location, and from the data of the above specific one group to the data of the next one group, two or more overlapping points are measured. The purpose of this method is to correct a group of data so that the data of some points are at the same coordinates and at the same position as two or more points of the original data, and measure the shape of the cylindrical channel box over its entire length.

Further, the invention of claim 2 is an underwater measuring device of the above system, and the cylindrical sensor frame having the temperature correction sensor is specified to have a length of 2 m or less.

(Function) According to the measuring system of the present invention using the above-mentioned measuring device, the channel box and the ultrasonic sensor are moved relatively, and first, one or more points in the horizontal direction are measured at 3 to 5 positions in the axial direction of the channel box. Measure simultaneously as a group. Next, the two are moved relative to each other again and the next measurement is performed in the same manner. At this time, for the first time,
Among the measurement points of the first group, 2 to 4 points on the upper side in the axial direction and 2 to 4 points on the lower side of the second measurement are set to measure the same position. In this way, while partially overlapping measurement points, the channel box and the ultrasonic sensor are moved relative to each other and sequentially performed over the entire length of the channel box, but the measurement data at the overlapping points must match in the two measurements. 2nd time (same thereafter)
The coordinates of the repeated measurement points are transformed to match the first measurement position.

Through such processing, it is possible to obtain the same accuracy as in the case of simultaneous multi-point measurement even for points that are not overlapping points in the second measurement data.

In addition, the underwater measurement device has 3 to 5 points in the axial direction and is 2 m or less in length, so it does not span almost the entire length of the channel box, so it can be miniaturized.

(Example) Next, an example of the present invention will be described based on the accompanying drawings.

Figure 1 A and LO are configuration examples of the measurement device used in the measurement system of the present invention. In these figures, 1 is a control rod storage rack, 2 is a base plate, 3 is a sensor frame, 4 is an ultrasonic sensor, and 5 is a temperature correction 6 indicates a guide pin, and as is clear from the figure, the measuring device of the present invention is used by being placed on, for example, a control rod storage rack 1, and consists of a base plate 2 and a sensor frame 3. , the length of sensor frame 3 is less than 2m,
Usually, it is around 125cm and is less than 1/2 of the length of the channel box A containing the fuel assembly, and is arranged in 3 to 5 stages in the vertical axis direction (in the figure, 3 stages) to generate 4 ultrasonic waves on each of the four sides in the same horizontal plane. Sensors 4a, 4b,
4c is provided. Therefore, in the illustrated example, the measurement is performed by repeatedly carrying out simultaneous three-point measurements while gradually lowering channel box A from above.

That is, when performing measurements using the above measuring device, first, three axial positions and four horizontal positions of channel box A are simultaneously measured as one group, and then channels including channel box A and a sensor including an ultrasonic sensor are measured simultaneously. Measurement is performed at the next position by relatively moving the frame 3, and this is repeated several times in order to measure the entire length of the channel box. At this time, out of the three measurement points on the initial side, two on the upper side In the next second measurement, the same position as the two points on the lower side is to be measured overlappingly.

Measurement at this overlapping point is one of the important features of the present invention. Since the channel box is originally supposed to have the same posture and shape in the axial direction as a rectangular cylinder, the measurement data at the overlapping point is Aggregation,
In other words, if the two measurements do not match due to minute rotation or displacement of channel box A, the coordinates of the second repeated measurement point are transformed to match the previous measurement position.

This processing is another feature of the measurement system of the present invention, and as a result, among the second measurement data,
Even for points that are not overlapping points, the same accuracy can be obtained compared to the case of simultaneous multi-point measurement.

Figure 2 shows the basic aspect of the above measurement system, and when there is simultaneous measurement data at points a to h shown in figure A, the first measurement data group is as shown in figure B, and the second measurement data group is as shown in figure B. If it is like C, coordinate transformation (described later) is performed to set the points f and g to the initial values, and the coordinates of e are determined to determine the shape of h to e.

Figure 3 shows the procedure for coordinate transformation in this case, where A is the first measurement data group, B is the second measurement data group, and the procedure for combining the second measurement data group with the first data group is as follows. .

(b) The second data group is (g′) (x ₁ ′, y ₁ ′) is (g
)
Translate to the (x ₁ , y ₁ ) position.

Here, x ₁ =x ₁ +α, y ₁ =y ₁ ′+β. (However, α and β are constants determined for each measurement.) (b) The above parallel second measurement data group is expressed as (θ ₁ −
θ ₂ ) and (f) (x ₂ , y ₂ ) and (f′) (x ₂ ′,
y ₂ ′).

Here, θ ₁ = tan−1 (y ₂ −y ₁ /x ₂ −x ₁ ), θ ₂ = tan ⁻¹ (y ₂ ′−y ₁ ′/x ₂ ′−x ₁ ′), θ ₃ = tan ^-1 (y ₃ ′−y ₁ ′/x ₃ ′−x ₁ ′) (c) Find the e(x ₃ , y ₃ ) coordinate after parallel translation and rotation.

x ₃ = Rcos (θ ₁ − (θ ₂ − θ ₃ )) + (x ₁ − x ₀ ) y ₃ = Rsin (θ ₁ − (θ _{2 −} θ ₃ )) + (y ₁ − y ₀ ) where , R=√( ₃ ′- ₁ ′) ² + ( ₃ ′- ₁ ′
) ² Thus, the correction is made as described above, and this is repeated to achieve the measurement system according to the present invention.

(Effects of the Invention) The present invention uses the above-described underwater measuring device to repeatedly measure the channel box simultaneously at 3 to 5 points while gradually lowering it from above, thereby measuring the shape over the entire length of the channel box. By measuring at multiple points, converting the coordinates of the data at the overlapping points, and correcting the data, it is possible to obtain high-precision measurements similar to those of conventional simultaneous measurements, and without having to cover the entire length of the channel box. By using a small underwater measurement device, it can be used even in places such as nuclear power plants where there is not enough space to install the device, and shape measurement achieves both miniaturization and high precision, which were previously considered difficult. It is a highly practical system.

Further, the apparatus according to claim 2 is extremely effective as an underwater measuring apparatus that achieves the above measuring system.

The measuring system and apparatus of the present invention can be used to measure the shape of a rectangular tube or cylinder similar to that of a channel box, and the same effects can be obtained.

[Brief explanation of the drawing]

FIG. 1 shows the device used in the measurement system of the present invention, where A is a front schematic view, B is a sectional view taken along line X-X, and FIG.
Figures 2A to 2D show the basic aspects of the measurement system of the present invention, where A is simultaneous measurement data, B is the first data group, C is the second measurement data group, and D is composite data. 3A and 3B are explanatory diagrams showing the procedure of coordinate transformation, FIG. 4 is a block diagram of the shape measuring device, and FIGS. 5 to 8 show conventional multi-point simultaneous measurement devices. The figure is a front view, Figure 6 is a side view with the channel box inserted, and Figure 7 is a side view with the channel box inserted.
The figure is a sectional view taken along the Y-Y line in Figure 6, and Figure 8 is a cross-sectional view taken along the line Z-Z in Figure 6.
FIG. Furthermore, FIG. 9 is a schematic diagram of the main parts of a conventional multi-point sequential measurement type device. A...Channel box, 2...Base plate, 3...Sensor frame, 4, 4A, 4
B, 4C... Ultrasonic sensor, 5... Temperature correction sensor.

Claims (1)

[Claims] 1. When measuring the shape of a channel box using an ultrasonic sensor installed underwater, the ultrasonic sensor is attached to a cylindrical sensor frame in the axial direction.
~ Arrange one or more points in 5 stages and within the same horizontal plane,
While moving the channel box relative to the ultrasonic sensor within the sensor frame, set 3 to 5 measurement points as one group, and set them so that two or more of them measure the same location. Simultaneous measurement of the measurement points of the groups is carried out sequentially, and from the data of the specific one group mentioned above, the data of some points of two or more overlapping points of the data of the next one group are measured at the same coordinates as the two or more points of the original data. A channel box shape measuring system characterized by correcting a group of data so that they are at the same position and measuring the shape of a cylindrical channel box over its entire length. 2 Consists of a base plate and a cylindrical sensor frame in which ultrasonic sensors are arranged in 3 to 5 stages in the axial direction and at one or more points in the same horizontal plane, the cylindrical sensor frame has a length of 2 m or less, and the sensor frame The channel box shape measuring device is further equipped with a temperature correction sensor for correcting the sound speed and temperature of the measurement data.