JPH11190790A - Welding bevel inspection device of reactor shroud - Google Patents

Abstract

PROBLEM TO BE SOLVED: To confirm integrity of a welding bevel part by measuring the root gap size of the welding bevel part of a shroud and a shroud support set in a reactor pressure vessel and the crossing size of a welding joint face. SOLUTION: A duct for welding bevel drying 12 is provided inside a shroud 1, a turn rail 13 is provided on the duct 12, and a bevel inspection device body 10 is attached through a turn device 11 on the rail 13. The bevel inspection device body 10 is provided with a laser type shape measuring sensor 14 and a laser range finder 15. In addition, the bevel inspection device body is connected through the electric cable 17 of a controller 16, which is set on an operation floor, and calculator processing of measured data and display of a measured result are performed by remote control.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for inspecting a groove of a shroud in a reactor for automatically and remotely measuring a groove size of a welding portion between a new shroud and a shroud support when replacing the shroud in the reactor.

[0002]

2. Description of the Related Art In a boiling water reactor, a shroud for holding a core support plate and an upper lattice plate in a reactor pressure vessel and surrounding the entire fuel assembly to form a core is provided. The shroud has a cylindrical shape and includes upper, middle and lower shroud bodies.

In a reactor that has been used for many years, a defect such as a crack may occur in a welded portion of a shroud in the reactor or in a material in the vicinity thereof, and the shroud having the defect needs to be replaced with a new shroud depending on circumstances. come. When the shroud is replaced, welding is performed between the new shroud and the shroud support on which the new shroud is mounted, and a groove dimension inspection must be performed to check the soundness of the weld groove before starting the welding operation.

Using the conventional technique, the route interval, ie, the gap between the grooves, is measured from the inside of the shroud using a mechanical measuring instrument, and the gap between the joint faces, ie, the joint surface is measured using another mechanical measuring instrument. I had to measure the steps.

FIGS. 3 and 4 are schematic cross-sectional views when a conventional groove inspection device is used. In FIG. 3, shroud 1
The route interval of the welding groove portion 8 composed of the groove and the shroud support 2 is visually inspected with the underwater television 5 by inserting the thickness gauge 4 attached to the route interval inspection device 3 into the groove portion. The route interval inspection device 3 is hung on the mast 9 from above the reactor pressure vessel, and is accessed near the welding groove 8.

In FIG. 4, the difference between the upper and lower joint surfaces of the welding groove portion 8 composed of the shroud 1 and the shroud support 2 is determined by using two linear gauges 7 attached to the difference inspection device 6 to the inner surface of the shroud 1. And the inner surface of the shroud support 2, and the inspection is performed based on the difference between the measured values of the linear gauges 7. The misalignment inspection device 6 is suspended from above the reactor pressure vessel on the mast 9, and the welding groove 8 is provided.
Is accessed in the vicinity of

[0007]

However, since the replacement work of the shroud 1 is performed under high radiation, the inspection time must be shortened. However, in the case of FIGS. 3 and 4, the thickness gauge 5 or the like is required. Since the inspection position by the linear gauge 7 is discontinuous, it takes time to change over to another inspection position, and there is a problem that it is difficult to shorten the inspection time.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to perform necessary dimension measurement at a time with one type of inspection apparatus at a time, and to continuously perform inspection positions, and furthermore, it is possible to obtain measurement responsiveness. An object of the present invention is to provide a groove inspection apparatus and a method thereof that have a good short inspection time.

[0009]

A first aspect of the present invention is a laser type shape measuring instrument for measuring the dimension of a welding groove between a shroud and a shroud support installed in a reactor pressure vessel, and a laser type distance measuring apparatus. It is characterized in that it is connected to a groove inspection device main body containing a gauge and a controller installed on an operation floor connected to the groove inspection device main body.

According to the first aspect of the present invention, there is provided an apparatus for remotely and automatically inspecting from the inside of a shroud, comprising a laser type shape measuring sensor head and a controller for measuring a groove dimension. The shape of the groove portion is measured in a short time by the high-speed scanning operation of the laser beam and the optical position detection element, the required route interval and the joint surface are checked at the same time, and the controller performs the computer processing of the measurement data and the measurement result Display.

According to a second aspect of the present invention, the groove inspection device main body is attached to a turning device that turns around the inner periphery of the shroud, and the turning device runs while being suspended on a turning rail. It is characterized in that it is provided in a drying duct.

According to the second aspect of the present invention, when the shroud is replaced, the welding groove drying duct which is necessary in the shroud and extends along the entire circumference of the welding groove is used, and a rail is provided below the drying groove. Is installed, the groove inspection device main body and the turning device are attached to the rail, and the groove inspection device is turned around the entire inside of the shroud.

According to a third aspect of the present invention, the distance between the sensor head of the shape measuring device and the welding groove portion is prevented from being reduced in the groove inspection device main body, thereby preventing the accuracy of the shape measurement data from being reduced. A laser beam is emitted from the shape measurement sensor head to the inner wall of the new shroud to detect a change in distance and automatically correct the shape measurement data.

Next, according to the invention corresponding to claim 3,
In order to prevent the distance between the shape measurement sensor head and the groove part from changing in the laser type shape measurement, the accuracy of the shape measurement data is reduced, the laser beam is emitted from the shape measurement sensor head to the inner wall of the shroud and the change in distance is detected. And automatically corrects the shape measurement data.

[0015]

1 and 2, an embodiment of a groove inspection apparatus for a shroud in a nuclear reactor according to the present invention will be described. FIG. 1 is a longitudinal sectional view partially showing a groove inspection device according to the present embodiment in a block diagram. FIG. 2 is a diagram illustrating a groove shroud and a shroud obtained by installing the groove inspection device according to the present embodiment in a reactor pressure vessel. This shows a state where the groove with the support is being inspected.

That is, in FIG. 1, a laser type shape measuring device 14 for measuring the dimensions of a welding groove 8 between the shroud 1 and the shroud support 2 and a laser type distance meter
A groove inspection device main body 10 having a built-in groove 15 is disposed in front of the welding groove 8. A turning device 11 is attached to the groove inspection device main body 10, and the turning device 11 turns by being fitted into a turning rail 13 attached to a groove drying duct 12.

The laser type shape measuring device 14, the laser type distance meter 15 and the turning device 11 of the groove inspection device main body 10 are connected to a controller 16 via an electric cable 17.
The controller 16 is installed on an operation floor (not shown) and remotely controls the groove inspection device. Shape measuring instrument 14
Preferably, the sensor head is configured to face the welding groove 8 and a plurality of sensor heads are provided.

Next, a method of inspecting the weld groove 8 of the shroud in the reactor by the groove inspection apparatus having the above-mentioned configuration will be described with reference to FIG. In FIG. 2, reference numeral 18 denotes a reactor pressure vessel with an upper lid removed. Reference numeral 19 denotes an overhead crane, which is suspended from a refueling machine (not shown) running on an operation floor (not shown).
A shroud holder 20 for hanging the shroud 1 into the reactor pressure vessel 18 is attached to the overhead crane 19. The shroud holder 20 allows a groove inspection device to access the welding groove 8. Mast 9 is attached.
The mast 9 has a groove drying duct 12 attached thereto.

In FIG. 2, reference numeral 21 denotes a jet pump,
22 is a diffuser, 23 is a baffle plate, 24 is a riser tube, 25 is a riser brace arm, 26 is a water supply nozzle,
27 is a main steam nozzle and 28 is a control rod guide tube group.

In the shroud replacement operation, the shroud 1 is placed in the reactor pressure vessel 18 as shown in FIG.
And is installed on the end face of the shroud support 2. As shown in FIG. 1, the groove inspection device body 10 and the turning device are used to inspect the welding groove 8 of the shroud 1 and the shroud support 2. 11 for welding groove drying duct
Attach it to the turning rail 13 attached to the lower surface of 12. It is necessary to previously incorporate a laser-type shape measurement sensor 14 and a laser distance meter 15 for automatic correction into the groove inspection device body 10.

Next, an inspection method will be described. The groove inspection device main body 10 is moved on the inner periphery of the shroud 1 along the turning rail 13 by the turning device 11. While moving, the laser type shape measuring sensor 14 measures the shape of the welding groove 8 of the shroud 1 and the shroud support 2 in a short time, and sends data to the controller 16 which also functions as a display.

The laser distance meter 15 for automatic correction measures the distance between the shroud 1 and the groove inspection apparatus body 10 in a short time while moving, and sends data to the controller 16. The controller 16 performs computer processing on both data, and continuously displays and stores the exact dimensions of the weld groove 8 with the distance corrected, that is, the inspection results of the route interval and the misalignment of the joint surface over the entire circumference.

The turning device 11 has a built-in potentiometer and can detect the position. If the dimensional tolerance deviates from the preset dimensional tolerance, it is also possible to display that fact. These operations are performed by remote control, and the measurement positions on the entire circumference can be continuously measured. Since the measurement response is good, the inspection time can be shortened.

[0024]

According to the present invention, the integrity of the weld groove can be inspected by remote control regardless of whether it is in the water or in the air. By incorporating a laser type shape measuring sensor, the route interval and the joint surface can be checked. Can be measured simultaneously in a short time,
The swirl device allows the inner circumference of the shroud to be inspected continuously over the entire circumference. Therefore, the inspection work is easy and the inspection time can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a groove inspection apparatus for a shroud in a nuclear reactor according to the present invention by partial blocks.

FIG. 2 is a schematic view for explaining a method of installing and inspecting a groove inspection apparatus according to the present invention in a reactor pressure vessel.

FIG. 3 is a vertical cross-sectional view showing a first example of a conventional groove inspection device in partial blocks.

FIG. 4 is a longitudinal sectional view showing a second example of a conventional groove inspection device in a partial block.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Shroud, 2 ... Shroud support, 3 ... Route interval inspection device, 4 ... Thickness gauge, 5 ... Underwater television, 6 ...
Discrepancy inspection device, 7: linear gauge, 8: groove, 9
… Mast, 10… groove inspection device body, 11… turning device, 12…
Groove drying duct, 13 turning rail, 14 laser shape measuring device, 15 laser range finder, 16 controller, 17 electric cable, 18 reactor pressure vessel, 19 overhead crane, 20 shroud Holder, 21: Jet pump, 22: Diffuser, 23: Baffle plate, 24: Riser tube, 25: Riser brace arm, 26: Water supply nozzle, 27: Main steam nozzle, 28: Control rod guide tube group.

Claims (3)

[Claims] 1. A groove inspection apparatus main body including a laser type shape measuring device and a laser type distance meter for measuring a dimension of a welding groove portion between a shroud and a shroud support installed in a reactor pressure vessel; A welding groove inspection apparatus for a shroud in a nuclear reactor, wherein the apparatus is connected to a controller installed on an operation floor connected to the groove inspection apparatus body. 2. The groove inspection device main body is attached to a turning device that turns around the inner periphery of the shroud, and the turning device runs while being suspended on a turning rail. The turning rail is connected to a groove portion drying duct. The welding groove inspection device for a shroud in a nuclear reactor according to claim 1, wherein the welding groove inspection device is provided. 3. The distance between the sensor head of the shape measuring instrument and the welding groove portion changes in the groove inspection device body,
Prevents the accuracy of the shape measurement data from deteriorating, and has a function of emitting a laser beam from the shape measurement sensor head to the inner wall of the new shroud, detecting a change in distance, and automatically correcting the shape measurement data. The welding groove inspection device for a shroud in a nuclear reactor according to claim 2.