JP2006317388A - Fuel assembly test system and fuel assembly test method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel assembly test system and fuel assembly test method capable of accurately measuring infinitesimal deformation of the fuel assembly due to radiation irradiation by avoiding deformation by pressing of contact probe in a contact type testing technique of fuel assemblies. <P>SOLUTION: An underwater test system 3 and a unit for process control 4 are provided. The underwater test system 3 comprises a sensor mechanism 8 for measuring the distance between a contact probe and a reference point member or the distance between two contact probes, a contact probe drive mechanism air cylinder 9, and a press pressure maintaining mechanism 10 for maintaining constant the press pressure of the contact probe 9. The unit 4 for process control has data of the press pressure which the press pressure maintaining mechanism 10 maintains and the deformation due to the press pressure of the test part of the fuel assembly 2. It also has a dimension correction means for outputting correction dimension in which the deformation due to the press pressure is removed from the distance that the sensor mechanism 8 of the underwater test system detected by inputting the distance that the sensor mechanism 8 of the underwater test system detected and by using the data of the press pressure and the deformation of the fuel assembly 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel assembly inspection system and a fuel assembly inspection method for inspecting dimensions of components of a nuclear power generation fuel assembly that has been irradiated with radiation.

  In particular, a fuel assembly inspection that can complete inspection in water and can inspect the exact dimensions by removing the influence of deformation of the component due to the pressing force of the contact using a contact type inspection method. The present invention relates to a system and a fuel assembly inspection method.

  First, the structure of the nuclear fuel assembly will be described.

  FIG. 13 shows the structure of the fuel assembly of the boiling water reactor.

  In the fuel assembly 100, a plurality of fuel rods 101 and a water rod 102 are bundled in a square lattice pattern with a plurality of spacers 103, and upper and lower ends are fixed with an upper tie plate 104 and a lower tie plate 105, and a rectangular tube channel box 106 is formed. Is fixed with a channel fastener.

  The fuel assemblies that have been exposed to radiation are periodically removed for repositioning and replacement, and inspected for health before being reloaded into the reactor and used. During regular inspections, the fuel rods are removed from the channel box and the integrity of the fuel rods is inspected.

  Generally, the outer width dimension of the spacer 103 increases due to irradiation and corrosion. The channel box 106 also grows by irradiation, causing bending and twisting.

  Before receiving radiation, there is a slight gap between the spacer 103 and the channel box 106.

  However, it is considered that the gap between the spacer 103 and the channel box 106 disappears due to the influence of the radiation irradiation, and the operation of removing the channel box 106 becomes difficult. For this reason, it is important to inspect the size of the spacer 103 of the fuel assembly during the periodic inspection.

  Japanese Patent Application Laid-Open No. 09-101390, Japanese Patent Application Laid-Open No. 2000-009880, and Japanese Patent Application Laid-Open No. 2000-009881 are techniques for measuring the outer width of the spacer 103, which is one of the constituent members of the fuel assembly, with a displacement sensor or an imaging device. Proposed by the publication. These inspection methods and apparatuses perform measurement under air conditions.

  On the other hand, as a method for measuring the outer width dimension of the spacer under water conditions, several techniques have been proposed by Japanese Patent Laid-Open Nos. 06-194491, 2001-108781, and US Pat. No. 6,125,160.

  Japanese Patent Laid-Open No. 06-194491 discloses a technique for automatically measuring dimensions such as length and outer width of a fuel assembly component member using visible light or infrared light.

  Japanese Patent Application Laid-Open No. 2001-108781 discloses a method and apparatus for measuring and calibrating a spacer and a gauge piece of a known size in a non-contact manner by an ultrasonic method.

  US Pat. No. 6,125,160 discloses an apparatus frame having a U-shaped opening in a horizontal direction, an apparatus fixing mechanism using an air cylinder as a drive source, a contact using an air cylinder as a drive source, and a contact of the contact An underwater inspection apparatus provided with a sensor for measuring the amount of movement is disclosed. The contactor and the sensor are arranged in two sets on the left and right.

In the technique described in US Pat.No. 6,125,160, when measuring the outer width dimension of the spacer, the outer width dimension measuring device is approached from the U-shaped opening side with respect to the fuel body suspended by a fuel exchanger or the like, The device is fixed to the fuel body by a device fixing mechanism at a predetermined position, and then the contact is pressed from both sides of the spacer, and the movement amount is measured by the sensor to measure the outer width dimension.
Japanese Patent Laid-Open No. 9-101390 JP 2000-9880 A JP 2000-9881 A JP-A-6-194491 JP 2001-108781 A US Pat. No. 6,125,160

(1) High-precision measurement is required to measure minute dimensional changes of spacers used in nuclear power plants. In addition, the measurement requires high-precision measurement in water, which is an inspection environment at the time of periodic inspection of the reactor.

  The techniques disclosed in Japanese Patent Laid-Open Nos. 06-194491 and 2001-108781 are so-called non-contact type inspection methods. The non-contact type inspection method is an inspection method using visible light, infrared light, ultrasonic method, or the like. These are advantageous in that the measurement is performed without affecting the dimensions of the inspection object, but the measurement error may increase due to a temperature change in the measurement environment, a minute inclination with respect to the spacer, or the like.

  On the other hand, the contact type inspection method is not affected by the temperature change of the measurement environment, and has an advantage that it is easy to prevent the inclination with respect to the inspection object because the inspection apparatus is fixed.

  However, in the contact type inspection method, it is inevitable to measure by pressing the contact against the inspection object. The object to be inspected is deformed by the pressing force of the contact, and in the measurement of a minute dimensional change, the deformation may not be negligible.

  The conventional inspection technique for contact-type fuel assemblies is to measure the deformation of the spacer by pressing the contact member in the deformation of the spacer by irradiation.

  Accordingly, one of the problems to be solved by the present invention is that in contact type fuel assembly inspection technology, deformation due to contact pressure can be eliminated, and minute deformation of the fuel assembly due to radiation irradiation can be accurately measured. Another object of the present invention is to provide a fuel assembly inspection system and a fuel assembly inspection method.

(2) For safety reasons, in-use fuel assemblies must be tested in water.

  In order to perform inspection in water, it is necessary to bring the inspection device close to the inspection site by remote control and fix the inspection device in a correct posture.

  Conventionally, there has been a demand for a technique that can freely control the movement of an inspection apparatus in water and correctly fix the inspection apparatus to an inspection site.

  Therefore, another problem to be solved by the present invention is to provide a fuel assembly inspection system and a fuel assembly inspection method that can easily operate an underwater inspection apparatus from the ground and have means for correctly fixing it to an inspection site. It is in.

(3) Conventionally, a special device was used to measure the surface products (oxide film) due to corrosion of the components of the fuel assembly that were exposed to radiation.

  However, measuring the oxide film separately from the measurement of the dimensions requires a lot of time and labor since the inspection cannot be performed continuously. For this reason, the technique which can perform a dimension measurement and an oxide film measurement continuously was calculated | required.

  In addition, it is desirable that the oxide film measurement can always measure a part having a certain positional relationship with the dimension measurement part. This is because the dimensional change and the change of the oxide film can be monitored over time by always measuring the dimension of the fixed part and simultaneously measuring the oxide film of the fixed part.

  Accordingly, another problem to be solved by the present invention is to provide a fuel assembly inspection system and a fuel assembly inspection method capable of measuring an oxide film in a portion in a certain positional relationship with respect to a dimension measurement portion in water. It is in.

(4) The oxide film measurement method using eddy current is
The method of measuring an oxide film using eddy current differs in the result of zero calibration between water and air. Further, the measurement result varies depending on the contact angle and pressure of the end face of the oxide film measurement sensor pressed against the oxide film.

  For this reason, it is important to perform zero-point calibration (calibration) on the measurement site in water under the same environment and measurement conditions.

  Another problem to be solved by the present invention is that a zero point calibration (calibration) is performed on the measurement site of the fuel assembly in water under the same environment and measurement conditions, and then the measurement site of the fuel assembly is determined. An object of the present invention is to provide a fuel assembly inspection system and a fuel assembly inspection method capable of measuring an oxide film.

A fuel assembly inspection system according to the present invention includes:
An underwater inspection device that inspects the dimensions of a predetermined inspection part of the fuel assembly in water, and a processing control unit that performs control and data processing of the underwater inspection device,
The underwater inspection device is:
A sensor mechanism for abutting a contactor or a contactor pair with an inspection site of the fuel assembly, and measuring a distance between the contactor and a reference point member or a distance between the two contactors;
A contact drive mechanism for driving the contact;
A pressing force holding mechanism for holding the pressing force of the contact constant,
The processing control unit has the pressing force held by the pressing force holding mechanism and the deformation data due to the pressing force of the inspection portion of the fuel assembly, and inputs the distance detected by the sensor mechanism of the underwater inspection device And a dimension correcting means for outputting a corrected dimension obtained by removing the deformation due to the pressing force from the distance detected by the sensor mechanism of the underwater inspection apparatus using the pressing force and the deformation data of the fuel assembly. It is characterized by that.

A fuel assembly inspection system according to the present invention includes:
An underwater inspection device that inspects the dimensions of a predetermined inspection part of the fuel assembly in water, and a processing control unit that performs control and data processing of the underwater inspection device,
The underwater inspection device is:
A sensor mechanism for bringing a contactor or a contactor pair into contact with an inspection site of the fuel assembly, and measuring a distance between the contactor and a reference point member or a distance between both the contactors;
A contact drive mechanism for driving the contact;
A pressing force detection mechanism for detecting the pressing force of the contact,
The processing control unit has a function or a table indicating the relationship between the pressing force by the contact and the deformation of the inspection portion of the fuel assembly, and the distance detected by the sensor mechanism of the underwater inspection device and the pressing force detection mechanism Is input, and the deformation due to the pressing force is removed from the distance detected by the sensor mechanism of the underwater inspection apparatus using a function or table indicating the relationship between the pressing force and the deformation of the fuel assembly. Dimension correction means for outputting a correction dimension is provided.

  The pressing force holding mechanism includes a spring connected to the contact and a spring deformation adjusting member that adjusts a deformation amount of the spring after the contact is pressed against an inspection site of the fuel assembly. can do.

  The pressing force detection mechanism may include a pressure sensor that is connected to the contact and detects a pressing force after the contact is pressed against an inspection site of the fuel assembly. .

  When the sensor mechanism has a contact pair, the contact pairs are arranged so as to face each other on the same line.

  The underwater inspection apparatus includes a pair of clamp pads arranged to face each other and having a shape that can be fitted to a fuel rod disposed on the outer periphery of the fuel assembly, and a clamp pad drive mechanism that drives the clamp pad. It has the means.

  The underwater inspection apparatus includes at least one buoyancy body.

  The underwater inspection apparatus includes an oxide film measurement sensor for measuring an oxide film thickness, and an oxide film measurement sensor driving mechanism that drives the oxide film measurement sensor and contacts the inspection portion of the fuel assembly with a predetermined pressing force. It is characterized by having.

  The underwater inspection apparatus includes a test piece for performing zero point calibration of the oxide film measurement sensor in water.

  The zero point calibration test piece is provided so that the surface thereof is included in the same plane as the plane of the inspection site of the fuel assembly.

The underwater inspection apparatus includes a visual monitoring camera,
The processing control unit includes a monitor that displays an image from the visual monitoring camera.

A pole for holding the underwater inspection device, and a holding frame for holding the pole attached to a channel attaching / detaching machine platform;
The holding frame is
It has horizontal movement means for moving the pole in the horizontal direction while holding the pole, vertical movement means for moving in the vertical direction, and inclination means for inclining the pole.

The fuel assembly inspection method of the present invention comprises:
Contacting a contactor or a contactor pair with a predetermined pressing force against a predetermined inspection site of the fuel assembly in water;
Measuring the distance between the contact and the reference point member, or the distance between the two contacts;
Outputting a corrected dimension obtained by removing the deformation due to the pressing force from the measured distance based on the predetermined pressing force and the deformation data due to the pressing force of the inspection portion of the fuel assembly. Features.

The fuel assembly inspection method of the present invention comprises:
Contacting the contactor or contactor pair with a predetermined inspection site of the fuel assembly in water;
Detecting the pressing force of the contactor or contactor pair;
Measuring the distance between the contact and the reference point member in the state where the pressing force is applied, or measuring the distance between the two contacts.
Outputting a correction dimension obtained by removing the deformation due to the pressing force from the measured distance using a function or a table indicating the relationship between the pressing force by the contact and the deformation of the inspection portion of the fuel assembly. Features.

  According to the present invention, in a contact-type fuel assembly inspection system, it is possible to eliminate the deformation of the inspection site due to the pressing force of the contactor from the measured dimensional deformation while enjoying environmental stability by the contact-type, and accurate. The deformation of the examination site can be measured.

  Further, according to the present invention, the zero point calibration is performed under the same conditions as the actual measurement by providing the oxide film measuring device and providing the zero point calibration test piece in the same plane as the inspected part of the fuel assembly. In addition, the measurement of the outer dimensions and the measurement of the oxide film can be performed by a series of operations, and the time and labor for the measurement can be greatly reduced.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing the configuration of a fuel assembly inspection system according to an embodiment of the present invention.

  As shown in FIG. 1, the fuel assembly inspection system 1 of the present embodiment includes an underwater inspection device 3 that inspects a fuel assembly 2 immersed in water, and control and data processing of the underwater inspection device 3. And a processing control unit 4 arranged on the ground.

  The underwater inspection device 3 and the processing control unit 4 are connected by a power cable and a data communication cable.

  The processing control unit 4 is not limited to a physically integrated device, and may be composed of separate devices such as a data processing device, a control device, and a display device.

  The processing control unit 4 has a dimension correcting means to be described later. In addition, even if it equips the underwater inspection apparatus 3 with a dimension correction | amendment means, it is in the scope of the present invention.

  A power cable is a cable which provides the motive power of the underwater inspection apparatus 3, and there exist various things according to motive power, such as an electric power cable and an air hose.

  The data communication cable is a cable for transmitting a control signal to the underwater inspection apparatus 3 or an output signal from the underwater inspection apparatus 3. The power cable and the data communication cable may be bundled together in a single cable.

  FIG. 2 is a plan view of the underwater inspection apparatus 3 according to the embodiment of the present invention.

  The underwater inspection device 3 according to the present embodiment includes a base plate 5 having a notch for introducing the fuel assembly 2.

  On the base plate 5, a pair of dimension measuring devices 6 are arranged to face each other.

  The dimension measuring device 6 has a sensor mechanism 8 for bringing the contact 7 into contact with the inspection site of the fuel assembly and measuring the amount of movement of the contact 7.

  Reference numeral 9 denotes an air cylinder which is an example of a contact drive mechanism for driving the contact 7. As the contact drive mechanism, a hydraulic cylinder, an electric drive device or the like may be used.

  Reference numeral 10 denotes a pressing force holding mechanism that holds the pressing force of the contact 7 constant.

  In FIG. 2, reference numeral 11 indicates a fuel rod, reference numeral 12 indicates a water rod, and reference numeral 13 indicates a spacer for bundling the fuel rod 11 and the water rod 12.

  In the following description, the dimension measurement of the spacer 13 and the oxide film measurement will be described. However, it is apparent that the present invention is not limited to the spacer 13 for measuring the dimension and the oxide film.

  The underwater inspection apparatus 3 of this embodiment is a form which keeps the pressing force of the contactor 7 constant and excludes the deformation corresponding to the pressing force from the measured deformation.

  Hereinafter, the pressing force holding mechanism 10 that holds the pressing force constant will be described.

  FIG. 3 is a diagram showing a comparison between the state before and during the measurement of the dimension measuring device 6 having the pressing force holding mechanism 10. 3, the same parts as those in FIG. 2 are denoted by the same reference numerals as those in FIG.

  On the left side of FIG. 3, two dimension measuring devices 6 are shown on the upper and lower sides. The upper left dimension measuring device 6 shows a state before measurement, and the lower left side shows a state during measurement. The same examination site is measured. The reference numerals of the lower left member are omitted for simplicity of the drawing, but are the same as those of the upper left member.

  The contact 7 is integrally connected to the intermediate member 14, and the pressing force holding mechanism 10 and the sensor mechanism 8 are connected to the intermediate member 14. The pressing force holding mechanism 10 transmits a force to the contact 7 through the intermediate member 14, and the sensor mechanism 8 detects the movement amount of the contact 7 by the movement of the intermediate member 14.

  The pressing force holding mechanism 10 includes a spring 15 that is connected to the contact 7 via the intermediate member 14 and a spring deformation that adjusts the amount of deformation of the spring 15 after the contact 7 is pressed against the inspection site of the fuel assembly 2. And an adjustment member 16.

  The spring 15 can be replaced with a known elastic body.

  The spring deformation adjusting member 16 of the present embodiment is formed of a nut that can adjust the amount of contraction of the spring 15 by rotating, but any known member or structure may be used as long as the amount of contraction can be adjusted. Can do. The rotation driving mechanism of the nut is not shown for simplicity of the drawing.

  Before the measurement, the spring 15 has a natural length, and the contact 7 is separated from the measurement site of the fuel assembly 2.

  When the measurement is performed, the intermediate member 14 is advanced by a predetermined distance by the air cylinder 9 as shown in the lower left part of FIG. 3 so that the contact 7 comes into contact with the measurement site of the fuel assembly 2. Next, the spring deformation adjusting member 16 is moved back and forth so that the spring 15 is adjusted to a predetermined length (the length at which the spring 15 generates a predetermined pressing force).

  The adjustment of the spring length by the spring deformation adjusting member 16 is repeated a plurality of times because the deformation amount of the spacer 13 changes correspondingly every time the spring length is adjusted, and the adjustment amount of the spring length is a predetermined value. The adjustment is finished when the value becomes smaller.

  By adjusting the spring deformation amount as described above, the contactor 7 under measurement can create a state in which the spacer 13 is pressed with a predetermined pressing force.

  The amount of movement of the contact 7 at this time includes deformation due to the pressing force of the contact 7 together with the change of the spacer 13 with time.

  Next, dimension correction will be described.

  FIG. 4 is a graph showing the relationship between the pressing force of the contact 7 and the deformation amount of the spacer 13 due to the pressing force.

When the contact 7 is pressed against the spacer 13, a pressing force is applied to the spacer 13, and the spacer is elastically deformed up to a certain pressing force (F ₁ in FIG. 4).

Becomes above a certain pressing force (large pressing force than F _1), modified by the fuel rods and water rods that are loaded inside the spacer is limited, deformation of the spacer is reduced, it becomes almost flat state.

As apparent from FIG. 4, the relationship between the pressing force of the contact 7 and the deformation amount of the spacer 13 is measured in advance, so that the pressing force F _x of the contact 7 is between zero (F ₀ ) and F ₁ . By setting (F ₀ <F _x <F ₁ ), the deformation amount ΔW _x of the spacer 13 due to the pressing force F _x can be predicted in advance.

In the dimension measuring device 6 of this embodiment, the pressing force holding mechanism 10 holds the pressing force of the contact 7 at a predetermined pressure F _x (F ₀ <F _x <F ₁ ). The amount of movement is detected by the sensor mechanism 8.

Next, the dimension correcting means of the present embodiment subtracts the deformation amount ΔW _x of the spacer 13 due to the pressing force F _x from the movement amount of the contact 7 detected by the sensor mechanism 8, thereby The net deformation amount is output.

  In FIG. 2, a pair of dimension measuring devices 6 are provided, and the contact pairs are arranged on the same line so as to face each other. The reason why the contact pairs are provided so as to face each other on the same line is to prevent torque from being generated by the pressure of the contacts.

  Even if only one dimension measuring device 6 is provided and the spacer 13 is sandwiched between one contact and a reference point member (not shown), the same effect can be obtained.

  The above is an embodiment in which the pressing force of the contactor 7 is made constant, and the deformation amount due to the pressing force is subtracted from the movement amount of the contactor 7 detected by the sensor mechanism 8. Instead, the relationship between the pressing force and the deformation may be measured in advance, the pressing force of the contact 7 may be detected, and the deformation amount corresponding to the pressing force may be subtracted.

  FIG. 5 shows the configuration of the dimension measuring device 6 for detecting the pressing force of the contact 7. 5, the same parts as those in FIG. 3 are denoted by the same reference numerals as those in FIG. FIG. 5 shows only the dimension measuring device 6 during measurement.

  This embodiment has a pressing force detection mechanism for detecting the pressing force of the contact 7 in place of the pressing force holding mechanism 10 of the dimension measuring device 6 in FIG. 3, that is, the spring 15 and the spring deformation adjusting member 16. is there.

  The pressing force detection mechanism may be, for example, a pressure sensor 17 disposed between the drive shaft of the air cylinder 9 and the intermediate member 14.

  In the present embodiment, since the pressing force by the contact is not constant, the dimension correcting means has a function or table indicating the relationship between the pressing force by the contact and the deformation of the inspection portion of the fuel assembly.

  The dimension correction means inputs the pressing force of the contact 7 detected by the pressing force detection mechanism, acquires the deformation amount due to the pressing force using the function or table, and moves the contact 7 detected by the sensor mechanism 8. The amount of deformation of the spacer 13 due to the pressing force is subtracted from the amount, and the net amount of deformation of the spacer due to radiation irradiation is output.

  As described above, according to this embodiment, by adopting a contact-type measurement method, it is easy to position the measurement region without being affected by the measurement environment, and eliminates deformation due to the pressing force of the contact. The dimension of the measurement site can be accurately measured.

  Next, another embodiment of the present invention having an oxide film measuring apparatus will be described.

  FIG. 6: has shown the top view of one Embodiment of the underwater inspection apparatus which comprises an oxide film measuring apparatus.

  In FIG. 6, the same parts as those in FIG.

  The underwater inspection device 3 according to the present embodiment includes an oxide film measuring device 18 on the base plate 5.

  The oxide film measuring device 18 includes an oxide film measuring sensor 19 that measures the thickness of the oxide film, and an oxide film measuring sensor driving mechanism 20 that drives the oxide film measuring sensor to contact the inspection portion of the fuel assembly with a predetermined pressing force. And have.

  The oxide film measurement sensor drive mechanism 20 includes a vertical direction drive unit 20a that drives the oxide film measurement sensor 19 perpendicularly to the inspection surface of the fuel assembly 2, and a parallel direction that drives the oxide film measurement sensor 19 parallel to the inspection surface of the fuel assembly 2. The oxide film measuring sensor 19 can be freely driven on the plane of the base plate 5.

  The oxide film measurement sensor drive mechanism 20 is preferably controlled so as to press the oxide film measurement sensor 19 against the inspection surface of the fuel assembly 2 with a predetermined pressing force.

  Reference numeral 21 denotes a cable for controlling the oxide film measurement sensor 19.

  Reference numeral 22 denotes a zero-point calibration test piece 22 for performing zero-point calibration of the chemical film measurement sensor 19 in water.

  The zero point calibration test piece 22 is provided so that the surface thereof is included in the same plane as the plane of the inspection site of the fuel assembly 2.

  FIGS. 7 and 8 are diagrams for explaining the reason why the zero point calibration test piece 22 is provided in the same plane as the surface of the inspection portion of the fuel assembly 2.

  As shown in FIG. 7, an oxide film measurement sensor generally uses eddy current, but an oxide film measurement sensor using eddy current has different zero points in air and in liquid.

  In the present embodiment, since the zero point calibration test piece 22 is in the liquid like the fuel assembly 2, if the zero point calibration is performed using the zero point calibration test piece 22, the oxide film thickness and the eddy current voltage are correct. Can respond.

  In the oxide film measurement using the eddy current voltage, the eddy current voltage varies depending on the inclination of the sensor end face of the oxide film measurement sensor 19 and the surface of the inspected part.

  In the present invention, tilting of the underwater inspection device 3 and the fuel assembly 2 is prevented by fixing means described later. However, when the fixing means is not provided, the sensor end surface of the oxide film measurement sensor 19 and the surface of the part to be inspected may be inclined.

  In this case, as shown in FIG. 8A, the inclinations of the sensor end face of the oxide film measuring sensor 19 and the surface of the inspected part are the same θ. When the inclination θ is in this way, the zero point calibration by the zero point calibration test piece 22 does not become a correct value, or when it is small, θ is the same condition on the surface to be inspected of the fuel assembly 2 and has a considerable accuracy. Can measure the thickness of the oxide film.

  Further, since the surface of the zero point calibration test piece 22 and the surface of the inspected part of the fuel assembly 2 are included in the same surface, the oxide film measurement for the zero point calibration test piece 22 and the surface of the inspected part is performed. The pressing force of the sensor 19 is also the same, and the change in eddy current voltage due to the change in pressing force can be prevented. FIG. 8B shows a case where the oxide film measurement sensor 19 correctly contacts the zero point calibration test piece 22 and the inspection part of the fuel assembly 2.

  Thus, in the present invention, the thickness of the oxide film of the fuel assembly 2 is arranged by arranging the surface of the zero point calibration test piece 22 so as to be the same surface as the surface of the inspected portion of the fuel assembly 2. Can be measured correctly.

  As described above, according to the present embodiment, the zero point calibration is performed in the underwater environment where the actual inspection is performed, and the zero point calibration is performed with the same sensor angle and pressing force as when the actual inspection is performed. Can be measured.

  Further, since the dimensional measurement and the oxide film measurement can be performed simultaneously, the dimensional deformation and the oxide film thickness of the fuel assembly can be measured by a series of measurement operations, and the time can be greatly shortened.

  Further, since the positional relationship of the oxide film measurement site with respect to the dimension measurement site can be accurately specified, it is very convenient for observation of the change with time.

  Next, another embodiment of the present invention including a clamp pad and a buoyancy body will be described.

  FIG. 9 is a view of an embodiment of the underwater inspection apparatus 3 as viewed from the bottom.

  As shown in FIG. 9, the underwater inspection apparatus 3 according to the present embodiment includes fuel rods 11 arranged on the outer periphery of the fuel assembly 2 on both sides of a notch for introducing the fuel assembly 2 below the base plate 5. The fixing means 25 includes a pair of clamp pads 23 arranged to face each other and a clamp pad driving mechanism 24 for driving the clamp pads 23. The clamp pad drive mechanism 24 can be an air cylinder.

  In addition, at least one buoyancy body 26 is provided on the bottom surface of the base plate 5. In the embodiment of FIG. 9, three buoyancy bodies 26 are provided.

  The buoyancy body 26 may have a certain buoyancy that reduces the weight of the underwater inspection apparatus 3, or may change the buoyancy when gas is supplied from a compressed gas source.

  As the buoyant body having a certain buoyancy, a container that is sealed with gas, or a solid having a low specific gravity, or a liquid that tightly seals the outer periphery of a solid having a low specific gravity, such as those that can be appropriately used by those skilled in the art, is used. be able to.

  As a buoyancy body that changes buoyancy, a container connected to a compressed gas source or the like can be used. When the buoyancy is simply increased to facilitate the operation of the underwater inspection apparatus 3, only one buoyancy body 26 with variable buoyancy is provided, and in addition to the buoyancy, the inclination of the underwater inspection apparatus 3 is controlled by the buoyancy body 26. The buoyancy body 26 can be provided.

  When a plurality of buoyancy bodies 26 with variable buoyancy are used, it is possible to control the posture of the underwater inspection apparatus 3 by independently changing the buoyancy by adjusting the amount of gas in each buoyancy body by remote control.

  According to the fixing means 25 of the present embodiment, since the clamp pad 23 has a shape that can be fitted to the plurality of fuel rods 11, if the clamp pad 23 is clamped from both sides of the fuel rod 11, The angle of the inspection device 3 with respect to the fuel rod 11 is correctly adjusted to be vertical, and the contactor 7 and the oxide film measurement sensor 19 can be brought into perpendicular contact with the measurement site of the spacer 13.

  Next, the operation of the underwater inspection apparatus 3 in the present invention will be described.

  FIG. 10 shows a configuration for operation of the fuel assembly inspection system 1 in one embodiment of the present invention.

  As shown in FIG. 10, the underwater inspection device 3 usually has a plurality of connected poles 27 and is used by being submerged in the spent fuel pool 200.

  The processing control unit 4 includes a data processing device 4a, a control device 4b, and a display device 4c.

  In the present embodiment, the data processing device 4a has a dimension correcting means.

  Reference numeral 28 denotes a power cable (air hose 28 in the present embodiment), which is attached along with the data communication cable 29 along the pole 27.

  The data communication cable 29 is connected to the data processing device 4a via the control device 4b, and the air hose 28 is connected to the compressed gas source 30 via the control device 4b.

  The data processing device 4a has a dimension correcting means, inputs measurement data from the underwater inspection device 3, and truly irradiates radiation from the relational data of the pressing force and the outer width displacement of the spacer measured in advance. The dimensional change of the received fuel assembly is corrected and output.

  The air supplied from the compressed gas source 30 is switched by the control device 4b, and each part of the underwater inspection device 3 is operated via the plurality of air hoses 28.

  When adjusting the balance of the underwater inspection device 3 in water by the amount of air of the buoyancy body buoyancy body 26, an air hose to the buoyancy body is also provided.

  The connecting metal fitting between the pole 27 and the underwater inspection device 3 can also have a flexible structure.

In addition, it has a pole 27 for holding the underwater inspection device 3 and a holding frame 33 that is attached to the platform 32 of the channel attaching / detaching machine 31 and holds the pole.
The holding frame 33 includes horizontal moving means for moving the pole 27 in the horizontal direction while holding the pole 27, vertical moving means for moving in the vertical direction, and tilting means for inclining the pole 27.

  These horizontal moving means, vertical moving means, and tilting means can adopt any known structure. In FIG. 11, the holding frame 33, horizontal moving means 34, vertical moving means 35, and tilting means are used. An example of 36 is shown.

  FIG. 11A shows the holding gantry 33 viewed from the top, and FIG. 11B shows the viewing from the side.

  A holding frame 33 is attached to the handrail of the platform 32 of the channel attaching / detaching machine 31 and fixed with a handrail clamp.

  The pole 27 to which the underwater inspection device 3 is connected is fixed by attaching a detachable flange-shaped metal fitting called a "warikara" to the upper part of the pole, and the warrikara is placed in the recess at the tip of the arm. Furthermore, the pole 27 is prevented from being detached from the arm by pressing and fixing the upper surface of the warrikara with a presser plate and a clamp lever.

  When aligning the underwater inspection device 3 with the spacer 13, the underwater inspection device 3 is moved closer to the fuel assembly 2 by operating the up / down movement handle, the left / right movement handle, and the forward / backward movement handle, and the position where the positioning device can be installed Secure the arm so that it does not move with the left and right movement stopper and the front and rear movement stopper. Further, when the tip of the underwater setting device is inclined upward or downward, the level is adjusted by setting the angle of the pole with the angle adjustment knob. When fine adjustment of the position of the spacer 13 and the height position of the underwater inspection apparatus 3 is necessary, fine adjustment of the height position is performed by operating the vertical movement handle.

  When adjustment beyond the vertical movement stroke of the vertical movement handle is necessary, the underwater inspection device 3 is once moved away from the fuel body 2 and then adjusted by operating the channel attaching / detaching device 31. The holding frame 33 is an example using a handrail of the platform 32 of the channel attaching / detaching machine, but the same function can be obtained even if it is arranged on the channel attaching / detaching machine platform 32.

  Since the underwater inspection device 3 is fixed close to a predetermined position of the fuel assembly 2, a visual monitoring camera can be used.

  The camera for visual monitoring can be supported by a pole similar to the pole 27 and submerged in the spent fuel pool 200 to monitor the positioning of the underwater inspection apparatus 3. However, preferably, a visual monitoring camera is attached on the base plate 5 so that the positioning of the underwater inspection apparatus 3 can be monitored from the ground.

  By providing a camera for visual monitoring on the base plate 5 of the underwater inspection apparatus 3, the inspection site can be directly visually confirmed.

Finally, FIG. 12 shows a series of operations of the underwater inspection apparatus 3.

1 is a configuration block diagram showing a configuration of a fuel assembly inspection system according to an embodiment of the present invention. The top view of the underwater inspection apparatus 3 of one Embodiment of this invention. The figure which compared and showed the state before a measurement of the apparatus for dimension measurement which has a pressing force holding | maintenance mechanism, and a measurement. The graph which showed the relationship between the pressing force of a contactor, and the deformation amount of the spacer by this pressing force. The figure which showed the structure of the apparatus for dimension measurement which detects the pressing force of a contactor. The top view of one Embodiment of the underwater inspection apparatus which comprises an oxide film measuring apparatus. The figure for demonstrating the reason for providing the test piece for zero point calibration in the same surface as the surface of the inspection part of a fuel assembly. The figure for demonstrating the reason for providing the test piece for zero point calibration in the same surface as the surface of the inspection part of a fuel assembly. The figure which looked at one Embodiment of the underwater inspection apparatus 3 from the bottom face. The figure which showed the whole structure of the fuel assembly inspection system in one Embodiment of this invention. The figure which showed the structure of the holding stand of the fuel assembly inspection system in one Embodiment of this invention. The flowchart which showed the flow of operation of the underwater inspection apparatus by this invention. The perspective view which shows the structure of a fuel assembly.

Explanation of symbols

1 Fuel Assembly Inspection System of the Present Embodiment 2 Fuel Assembly
3 Underwater inspection device 4 Processing control unit 4a Data processing device 4b Control device 4c Display device 5 Base plate 6 Dimensional measurement device 7 Contact 8 Sensor mechanism 9 Air cylinder 10 Pressure holding mechanism 11 Fuel rod 12 Water rod 13 Spacer 14 Intermediate member 15 Spring 16 Spring deformation adjusting member 17 Pressure sensor 18 Oxide film measurement device 19 Oxide film measurement sensor 20 Oxide film measurement sensor drive mechanism 20a Vertical direction drive means 20b Parallel direction drive means 21 Oxide film measurement sensor control cable 22 Zero point Calibration specimen 23 Clamp pad 24 Clamp pad drive mechanism 25 Fixing means 26 Buoyant body 27 Pole 28 Air hose 29 Data communication cable 30 Pressed gas source 31 Channel attaching / detaching machine 32 Platform 33 Holding stand 34 Horizontal moving means 35 Vertical moving means 3 Tilting means 200 spent fuel pool

Claims (14)

An underwater inspection device that inspects the dimensions of a predetermined inspection part of the fuel assembly in water, and a processing control unit that performs control and data processing of the underwater inspection device,
The underwater inspection device is:
A sensor mechanism for abutting a contactor or a contactor pair with an inspection site of the fuel assembly, and measuring a distance between the contactor and a reference point member or a distance between the two contactors;
A contact drive mechanism for driving the contact;
A pressing force holding mechanism for holding the pressing force of the contact constant,
The processing control unit has the pressing force held by the pressing force holding mechanism and the deformation data due to the pressing force of the inspection portion of the fuel assembly, and inputs the distance detected by the sensor mechanism of the underwater inspection device And a dimension correcting means for outputting a corrected dimension obtained by removing the deformation due to the pressing force from the distance detected by the sensor mechanism of the underwater inspection apparatus using the pressing force and the deformation data of the fuel assembly. A fuel assembly inspection system characterized by that. An underwater inspection device that inspects the dimensions of a predetermined inspection part of the fuel assembly in water, and a processing control unit that performs control and data processing of the underwater inspection device,
The underwater inspection device is:
A sensor mechanism for bringing a contactor or a contactor pair into contact with an inspection site of the fuel assembly, and measuring a distance between the contactor and a reference point member or a distance between both the contactors;
A contact drive mechanism for driving the contact;
A pressing force detection mechanism for detecting the pressing force of the contact,
The processing control unit has a function or a table indicating the relationship between the pressing force by the contact and the deformation of the inspection portion of the fuel assembly, and the distance detected by the sensor mechanism of the underwater inspection device and the pressing force detection mechanism Is input, and the deformation due to the pressing force is removed from the distance detected by the sensor mechanism of the underwater inspection apparatus using a function or table indicating the relationship between the pressing force and the deformation of the fuel assembly. A fuel assembly inspection system, comprising: a dimension correcting means for outputting a corrected dimension.   The pressing force holding mechanism includes a spring connected to the contact and a spring deformation adjusting member that adjusts a deformation amount of the spring after the contact is pressed against an inspection site of the fuel assembly. The fuel assembly inspection system according to claim 1, wherein:   The pressure detection mechanism includes a pressure sensor that is connected to the contact and detects a pressure after the contact is pressed against an inspection site of the fuel assembly. Item 3. The fuel assembly inspection system according to Item 2.   3. The fuel assembly inspection system according to claim 1, wherein, when the sensor mechanism includes a contact pair, the contact pairs are arranged to face each other on the same line. 4. .   The underwater inspection apparatus includes a pair of clamp pads arranged to face each other and having a shape that can be fitted to a fuel rod disposed on the outer periphery of the fuel assembly, and a clamp pad drive mechanism that drives the clamp pad. The fuel assembly inspection system according to claim 1, further comprising means.   The fuel assembly inspection system according to any one of claims 1 to 6, wherein the underwater inspection apparatus includes at least one buoyancy body.   The underwater inspection apparatus includes an oxide film measurement sensor for measuring an oxide film thickness, and an oxide film measurement sensor driving mechanism that drives the oxide film measurement sensor and contacts the inspection portion of the fuel assembly with a predetermined pressing force. The fuel assembly inspection system according to claim 1, wherein the fuel assembly inspection system is provided.   The fuel assembly inspection system according to claim 8, wherein the underwater inspection device includes a test piece for performing zero point calibration of the oxide film measurement sensor in water.   10. The fuel assembly inspection system according to claim 9, wherein the zero-point calibration test piece is provided so that a surface thereof is included in the same plane as a surface of the inspection portion of the fuel assembly. The underwater inspection apparatus includes a visual monitoring camera,
The fuel assembly inspection system according to any one of claims 1 to 10, wherein the processing control unit includes a monitor that displays an image obtained by the visual monitoring camera. A pole for holding the underwater inspection device, and a holding frame for holding the pole attached to a channel attaching / detaching machine platform;
The holding frame is
The horizontal movement means for moving the pole in the horizontal direction while holding the pole, the vertical movement means for moving in the vertical direction, and the inclination means for inclining the pole. The fuel assembly inspection system according to any one of 1 to 11. Contacting a contactor or a contactor pair with a predetermined pressing force against a predetermined inspection site of the fuel assembly in water;
Measuring the distance between the contact and the reference point member, or the distance between the two contacts;
Outputting a corrected dimension obtained by removing the deformation due to the pressing force from the measured distance based on the predetermined pressing force and the deformation data due to the pressing force of the inspection portion of the fuel assembly. A fuel assembly inspection method. Contacting the contactor or contactor pair with a predetermined inspection site of the fuel assembly in water;
Detecting the pressing force of the contactor or contactor pair;
Measuring the distance between the contact and the reference point member in the state where the pressing force is applied, or measuring the distance between the two contacts.
Outputting a correction dimension obtained by removing the deformation due to the pressing force from the measured distance using a function or a table indicating the relationship between the pressing force by the contact and the deformation of the inspection portion of the fuel assembly. A fuel assembly inspection method.

Images