JPS60144695A - Method and device for cutting and treating used nuclear reactor internal instrumentaion pipe - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to a boiling water nuclear reactor (hereinafter simply referred to as a nuclear reactor).
This invention relates to a method for cutting and processing used in-reactor instrumentation tubes (hereinafter simply referred to as instrumentation tubes) and an apparatus therefor.

[Technical background of the invention]

The conventional method for cutting instrumentation pipes and its equipment are shown in Figures 1 and 2.
The diagram will be explained.

FIG. 1 shows a cutting tool 1 forming an instrumentation tube cutting device.

A disk-shaped fixed pedestal 3 is fixed to one end of a support body 2 made of a plate material of the cutting tool 1.

At the other end of the support body 2, a cutter head support 4 having a circular outer peripheral cross section is fixed to the outer wall with its central axis aligned with the fixed pedestal 3 and facing the fixed pedestal. The cutter head support base 4 forms a fluid cylinder, and a stepped cylindrical cutter head 5 is provided with a piston at the right end (not shown).
is supported so as to be movable in the direction of the central axis of the cutter head 5 and prevented from rotating by a known structure (not shown), and together with the cutter head 5 constitutes a moving mechanism. One end of the cutter head support 4 is connected to a pressure fluid source (not shown), and the other ends of fluid conduits 6 and 7 are connected to a pressure fluid source (not shown). At one end of the cutter head 5 facing the fixed pedestal 3, a push-cutting cutter 8 has its cutting blade fixed to the pedestal 3.
It is fixed perpendicularly to the central axis of the support body 2 and parallel to the upper and lower surfaces of the support body 2. Hanging hands 9°lO are fixed to the support body 2 in directions perpendicular to each other.

The instrumentation tube 11 is supported in the middle core part 13 of the reactor pressure vessel 12 at its upper end by an upper grid plate 14 and at its lower middle part by a core support plate 15, and its lower end is supported from the bottom of the reactor pressure vessel 12. It is inserted vertically with 1 protruding downward.

To cut the instrumentation pipe 11, first, the upper end of the instrumentation pipe 11 is grasped with an instrumentation pipe handling tool (hereinafter simply referred to as a handling tool) 16 suspended from the lower end of a wire rope of a cargo speculator (not shown). , as shown in Figure 2, its lower end is the core part 1.
3 until the instrumentation tube 11 reaches a position higher than the upper grid plate 14.
Fish and fry.

At this time, the reactor well 17 in and above the reactor pressure vessel 12, the nuclear fuel storage pool 18 adjacent to the reactor well 17, and the in-reactor equipment storage pool 19 are opened for communication and filled with cooling water 20. ing. The instrumentation tube 11, whose upper end is gripped by the handling tool 16, is then gripped horizontally or diagonally in the cooling water 20 by a wire port of a cargo speculator (not shown), and is transferred to the nuclear charge storage boot 1.゛Moved to the 8 side.

Next, the cutting tool 1 suspended from the lower end of the wire rope of a speculator (not shown) via the hanging handle 10 is attached to its fixed pedestal 3,
Place the instrumentation tube 11 so that the desired lengthwise position of the instrumentation tube 1.2 is between the push-cut cutters 8, and feed pressure fluid into the cutter head support 4 through the fluid conduit 6. For example, the instrumentation pipe 11 is sandwiched between the fixed pedestal 3 and the push cutter 8, and then cut at that point. The force ahead 5, which switches the pressure fluid inlet line from the fluid line 6 to the fluid line 7, returns to its original position relative to the cutter head support base 4. The cut piece of the instrumentation tube 11 is attached to the instrumentation tube grip 21 or 2.
2, the nuclear fuel is stored in a storage container 23 installed in the nuclear fuel storage pool 18. The length of the instrumentation tube 11 is usually about 1
However, due to transportation needs, it is necessary to cut the instrumentation pipe 11 at three points according to the length of 4m or less, and the instrumentation pipe 1
In order to further cut the longer remaining portion of the instrumentation tube 11, the positions of the instrumentation tube grip 21 or 22 and the cutting tool 1 are moved along the length of the instrumentation tube 11.

The above operations are repeated for the desired number of lines of the instrumentation tube.

[Problems with background technology]

In the conventional method of cutting an instrumentation tube using the conventional instrumentation tube cutting and treatment apparatus, there is a problem in that there is a shortage.

(1) In order to extract and cut one of the instrumentation tubes 11 from the reactor core 13, the handling tool 16, the instrumentation tube grip 21.2
2, it is necessary to change the grip in the cooling water 20 at least three times in total, and this work is difficult and requires skill.

(2) When moving the instrumentation pipe 11 laterally, there is a risk that the instrumentation pipe 11 will be exposed above the water surface of the cooling water 20 by mistake; in this case, the instrumentation pipe 11
is highly radioactive, and there is a risk that nearby workers may be exposed to large amounts of radiation.

(3) When cutting the instrumentation tube 11 at three locations with the cutting tool 1, it is necessary to change the instrumentation tube grip 21 or 22 and move the cutting tool 1 each time the cutting location changes.

Above (1)? For the reasons stated in (3) above, the work of cutting instrumentation pipes using conventional equipment and methods is complicated, difficult, and requires a lot of man-hours, and it also causes radiation exposure to workers near the work site. The risk of exposure to radiation becomes even greater.

[Purpose of the invention]

This invention was made in order to solve the above-mentioned problems of the conventional method and device for cutting instrumentation pipes, and it is possible to cut instrumentation pipes easily and easily, reducing the number of man-hours involved. An object of the present invention is to provide a method and device for cutting an instrumentation tube, which can reduce radiation exposure and reduce the risk of radiation exposure to workers.

[Summary of the invention]

The method and device for cutting an instrumentation tube according to the present invention include a cutting device that is attached to an open bottom cylindrical storage container into which an instrumentation tube can be vertically inserted; The cutting device has a lower end equipped with a cutting tool capable of cutting an instrumentation tube inserted into a storage container, and is configured in a shape that can be removably inserted into a fixed position in the core of a reactor pressure vessel. First, install it in place in the reactor core,
Grasp the upper end of the instrumentation tube in the reactor core with a handling tool, move it directly above the lifting and cutting equipment, and suspend the instrumentation tube until the lower end of the instrumentation tube reaches the desired depth in the storage container. Lower it and hold it in that position, operate the cutting tool to cut the instrumentation tube at that location, repeat the lowering and cutting of this instrumentation tube the required number of times, and release the upper end grip by the instrumentation tube handling tool. After the cut pieces for one instrumentation tube are stored in the total number storage container, the above-mentioned operations are repeated for the desired number of other instrumentation tubes, and then the cutting processing device stores the cut pieces of the instrumentation tube. The above purpose is achieved by moving the fuel to a predetermined location in the nuclear fuel storage pool.

[Embodiments of the invention]

A third embodiment of the cutting device for instrumentation pipes according to the present invention will be described below.
This will be explained using figures.

The cutting device 50 includes a storage container 60 in the shape of a rectangular cylinder with an open bottom and a cutting tool 70 assembled to the upper end of the storage container 60. The cutting tool 70 differs from the cutting tool 1 (MfJI drawing) only in a few parts, and most of the other parts have the same structure as the cutting tool 1, and the same part has 8 tons! In FIG. 3, the same reference numerals as in FIG. 1 are given, and the explanation thereof will be omitted, and instead of the above explanation for FIG. 1, only the different parts will be explained next.

In place of the handles 9 and 10 in the cutting tool 1, a cutting tool 70 is used.
In this case, there are two handles 71 on the upper surface of the support body 2.
72 is fixed upright, and when the cutter head 5 of the cutting tool 70 is in the most retracted state with respect to the cutter head support 4, the midpoint on the central axis between the fixed pedestal 3 and the push-cut cutter 8 is retracted. Attachment bolts 7 with bent corners are screwed into three locations on the outer wall of the upper end of the storage container 6° so that the vertical central axes of the container 60 are approximately located and these central axes intersect at right angles.
3, two end faces of the support body 2, and the cutter head support base 4.
It is detachably attached to the storage container 60 by a support leg 74 fixed to one location on the outer surface. The funnel-shaped guide member 75 through which the instrumentation pipe 11 can be easily inserted has its central axis almost overlapping the upper extension of the vertical central axis of the storage container 60, and is located somewhat above the fixed pedestal 3 and the cutter head support 4. It is fixed to the support body 2 via the mounting legs 76 so as to be positioned in the same position.

A method according to the invention for cutting instrumentation tubes using a cutting apparatus 50 according to the invention will now be described with reference to FIG. 3 in conjunction with FIG.

First, the cutting device 50 is placed at a predetermined position in the reactor core 13 under the reactor pressure G1112, with its storage container 60 facing downward, and the lifting handles 71.72 are placed using an appropriate cargo handling device (not shown).
Insert it by suspending it through. It is vertically inserted into the reactor core 13 with its upper end supported by an upper grid plate 14 and its lower middle part supported by a core support plate 15, with its lower end protruding below the reactor pressure vessel 12. The upper end of the instrumentation pipe 11 is held by a handling tool 16 suspended from the lower end of a wire rope of a speculator (not shown), and the instrumentation pipe 11 is held so that its lower end is slightly above the upper end of the cutting device [50]. The cutting tool 70 is lifted up until the cutting tool 70 is located in the cooling water 20 of the reactor well 17, and moved to be directly above the guide member 75 of the cutting tool 70. Next, the instrumentation tube 11 is lowered and held in that position through the guide member 75 until the lower end of the instrumentation tube 11 reaches a desired depth in the storage container 60, and the pressure fluid is supplied to the cutter head support via the fluid conduit 6. 4, the cutter head 5 protrudes from the cutter head support 4, the push-cut cutter 8 firmly presses the instrumentation tube 11 against the pedestal 3, and cuts the instrumentation tube 11. It is stored in a storage container 60. Subsequently, the inlet line for the pressurized fluid sent to the cutter head support base 4 is switched from the fluid line 6 to the fluid line 7, and the cutter head 5 is pulled into the cutter head support base 4 and returned to its original position. . The instrumentation pipe 11 having a length of 14 tn is usually cut into pieces having a length of 4 m or less due to transportation needs. The cutting operation and the operation of returning the cutter head 5 to its original position are repeated until all of the instrumentation tubes 11 are cut into pieces of 4 m or less, and finally the upper end of the instrumentation tube 11 is released from the grip by the handling tool 16. That part is also stored in the storage container 60.

Subsequently, the instrumentation pipe 1 is also applied to other instrumentation pipes (not shown).
When the same work operations as those for 1 are repeated and all the desired number of instrumentation tubes are cut and stored in the storage container 60, the cutting processing device 50 is used to transfer the cut pieces of the instrumentation tubes into the storage container 60. While stored in the reactor well 17, it is lifted from the reactor core 13 by a known means (not shown) and moved laterally through the cooling water 20 into a nuclear fuel storage pool (not shown) adjacent to the reactor well 17 (corresponding to the nuclear fuel storage pool 18 in FIG. 2). Lower it and set it in place to finish the work.

〔Effect of the invention〕

According to the method and device for cutting an instrumentation tube according to the present invention, the cutting device includes a cylindrical storage container with an open bottom into which an instrumentation tube can be inserted vertically, and a storage container that is attached to the upper end of the storage container. It is equipped with a cutting tool whose lower end can cut the instrumentation tube inserted into the storage vessel, and is configured in a shape that can be removably inserted into a fixed position in the core of the reactor pressure vessel. First, the processing equipment is attached to the foot position of the reactor core, and the upper end of the instrumentation tube in the reactor core is grasped with a handling tool, lifted into the cooling water of the reactor well, and moved directly above the cutting processing equipment. Lower the instrumentation tube until the lower end of the instrumentation tube reaches the desired depth in the storage container, hold it in that position, and operate the cutting mechanism.The instrumentation tube will be cut at that point, and the instrumentation tube will be suspended After repeating the lowering and cutting the required number of times, the upper end grip of the instrumentation tube handling tool is released, and the instrumentation tube is cut into short pieces and all the cut pieces are stored in the storage container, allowing the desired number of instrumentation tubes to be installed. After repeating the pipe cutting and storage work, the work is completed by moving the cutting processing device, which contains all the cut pieces of the instrumentation pipe in the storage container, to a predetermined location in the nuclear fuel storage pool. There is no need to change the grip during the entire work process, the cutting tool remains stationary and does not need to be moved, and the cut piece of instrumentation pipe is automatically stored in the storage container by its own weight, making the work extremely easy. It is easy and simple and has the effect of significantly reducing the number of work steps. Furthermore, since the instrumentation tube before cutting is moved through the cooling water in a vertical position with only its upper end held by a handling tool, the highly radioactive instrumentation tube is exposed to the surface of the cooling water. There is no risk, and in combination with the remarkable reduction in the number of work hours, there is an effect of preventing radiation exposure of workers.

[Brief explanation of the drawing]

Figures 1 and 2 are a perspective view of a conventional cutting processing device for used in-reactor instrumentation pipes, and an implementation diagram of a cutting processing method, and Figs. 3 and 4 are used in-reactor instrumentation pipes. FIG. 1 is a perspective view of a cutting device and an implementation diagram of a cutting method according to the present invention, respectively. 2... Support body, 3... Fixed pedestal, 4... Cutter head support stand, 5... Cutter head, 8... Push cutter, 11... Used reactor instrumentation Tube, 12...
・Reactor pressure vessel, 13...Reactor core, 16...Instrumentation tube handling tool, 17...Reactor well, 18...Nuclear fuel storage pool, 20...Cooling water, 50...Cutting process Device, 60... Storage container, 70... Cutting. (7317) Agent Patent attorney Kensuke Norichika (and 1 other person) Figure 3

Claims (3)

[Claims] (1) A used reactor instrumentation tube cutting device, in which a storage container and a cutting device are integrated with the cutting tool upward, is removably attached to a fixed position in the core of the reactor pressure vessel; A used reactor instrumentation tube inserted vertically into the reactor core is held at its upper end by an instrumentation tube handling tool, and the instrumentation tube is placed in the cooling water of the pressure vessel and the reactor well above it. Lift the tube until its lower end is above the cutting device and move it laterally so that it is directly above the storage container, and then move the instrumentation tube until its lower end reaches the desired depth in the storage container. The instrumentation tube is lowered and held at that position, and the cutting tool is operated to cut the instrumentation tube at a desired position in the length direction, and the lower part to be cut is stored in the storage container, and the instrumentation tube is cut at a desired position in the length direction. After repeating the lowering cutting and storing operation a predetermined number of times, the remaining upper end of the instrumentation tube is released from the grip of the handling tool and stored in the storage container, and the desired number of the remaining instrumentation tubes are removed from other used reactor reactors. Repeating each of the operations for the internal instrumentation tube from gripping it with the handling tool to storing it in the storage container,
lifting and removing the cutting device in which a desired number of cut instrumentation tubes are stored, from the reactor core;
A method for cutting a used nuclear reactor instrumentation pipe, which is moved through the cooling water of the reactor well and a nuclear fuel storage pool adjacent to the reactor well, and is lowered into the nuclear fuel storage pool and stored therein. (2) A cylindrical storage container with an open bottom and a used nuclear reactor that is attached to the upper end of the storage container and is inserted into the storage container from above along the vertical central axis direction of the storage container and held vertically. A cutting device for a used nuclear reactor instrumentation tube, which is equipped with a cutting tool capable of cutting an instrumentation tube at a predetermined position, and has a shape that can be detachably inserted into a predetermined position in a reactor core in a reactor pressure vessel. (3) The cutting tool includes a support body, a fixed pedestal and a cutter head support base that are attached to the support body so as to sandwich the vertical center axis of the storage container and face each other in a substantially horizontal direction; The head support is fixed to one end facing the fixed pedestal with a push-cut cutter capable of pushing off a used reactor instrumentation pipe held vertically between the cutter head support and the fixed pedestal. The used cutter head according to claim 2, wherein the used cutter head is supported movably in a direction toward and away from a fixed pedestal, and is provided with a moving mechanism for this movement. A cutting device for instrumentation tubes inside a nuclear reactor.