JPS62228994A - Underwater pipe cutter - 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] [Object of the Invention] (Industrial Application Field) The present invention relates to a method for cutting underwater pipes used, for example, when cutting instrumentation pipes loaded in the core of a nuclear reactor when they are stuck. In particular, the present invention relates to an underwater pipe cutting machine which can cut easily and reliably by using water pressure, and can also easily take out a vibrator after cutting by remote control.

(Prior Art) For example, in a boiling water nuclear reactor, during periodic inspections, instrumentation pipes whose functionality tends to decline due to deterioration are replaced. For example, the dry tube of the instrumentation tube for monitoring the neutron source area is replaced every 5 years. This dry tube is installed through t1 above and below the reactor core, and has a total length of about 13 mm between the upper grid plate and the shield seat of the guide tube flange under the housing, which is temporarily attached to support the lower part of the reactor core.
It extends to m. The upper lattice plate is engaged by fitting the engagement piece at the upper end of the liftable spindle, which is supported by the sheath tube upwardly with a spring, into the recess of the upper lattice plate from below, and then disengaged by the spring. This is done by pushing up to the extent that it does not. That is, when replacing the dry duplex, the spindle is once pushed down to remove it from the upper grid plate, and then the dry duplex can be pulled out upward. Note that the downward extension of the sheath pipe is provided with a valve body that makes metallic contact with the guide link to the inside of the instrumentation pipe housing and the tapered seat of the guide pipe flange. By the way, corrosion, hardening, etc. of the material appear in the parts of the dry duplex where the irradiation effect is high, and this may cause the spindle to stick to the upper grid plate or the spindle to be unable to descend due to hardening of the spring, or the so-called stick phenomenon. There is. Note that upward handling difficulty 111 (housing error) may occur due to adhesion between the inner wall of the guide tube housing and the guide ring. In addition, leakage from the Taber seat of the guide pipe flange, flange error due to seizure) may occur in some cases. Therefore, when replacing the dry tube,
For the purpose of examining the above countries, a featured test called stick check is conducted. On the other hand, if a housing error or flange error occurs, push up the guide tube flange portion from outside the furnace bottom using a push-up tool. However, regarding the spring stick, if an inappropriate horn is applied due to pushing up, there is a possibility that the long sheath tube will break due to the buckling load. For this reason, it becomes necessary to increase the downward load on the spindle to remove it from the upper grid plate, and a weight for additional load is attached to a normal tool. If the spindle cannot be pushed down even with such an operation, the dry tube is cut at a position about 1 m below the grid plate to prevent it from being taken out.

This photopic action is generally achieved by, for example, an underwater arc cutter or a pressurized cutter 111ti equipped with a blade that utilizes water pressure. However, remote control of underwater arc cutting machines while suspended in a furnace is troublesome. Further, in the case of a pressure type cutter, a gripping tool is required for fixing the cutter to the cut portion of the dry tube, so the structure tends to be large-sized. Note that since the upper piece of the dry tube is small and light in weight, a separate gripping member is usually used to prevent it from being removed from the cut portion of the dry tube.

Since the lower part from the cut part is long, it is held up with a gripper attached to the VJ section, and then gripped with another upper and lower transport gripper on the upper lattice plate. Then, the sheath tube is moved at an angle so that it does not appear above the water surface, and the tube is divided into two parts on the ball side of the reactor to facilitate transfer. The thus cut dry tubes are transported to a fuel pool, temporarily stored, and then further cut at a predetermined time and transported to Ladbourg in a storage cask for storage.

Generally, the materials are eroded, shredded, solidified into plastic, packed into welded drum tubes, and stacked in a waste warehouse for permanent storage.

(Problems to be Solved by the Invention) For example, in the case of a dry tube, the wall pressure at the cut point is about 2.
Since it is a 4m thick walled pipe, tens of tons of force is required to press it with a pressure cutting machine to cut it.

Therefore, there is a possibility that the upper part of the dry tube may jump up or fall off due to the reaction during cutting. Therefore, since it is necessary to firmly grip the spindle portion, the structure of the dedicated gripping tool becomes complicated and installation becomes troublesome.

According to the inventor's study, dry tubes may develop cracks near the cut points due to iso-bu corrosion, so the dry tube should be treated not only locally but over a wide range of areas near the cut points. It is thought that it is desirable to hold it by hand.

The present invention has been developed in view of these circumstances, and has a compact configuration that eliminates the need to install a separate gripping tool.
To provide a pressurized underwater pipe cutting machine capable of preventing the risk of an upper piece jumping up or falling during cutting, and also preventing cracks from forming in a pipe to be cut during cutting.

[Structure of the invention]

(Means for Solving the Problems) An underwater vibrator cutting machine according to the present invention includes a cylinder provided in a main body block that can be suspended along an underwater pipe, a piston having a blade section housed in the cylinder, and a piston having a blade section housed in the cylinder. It has a two-chamber configuration that applies water pressure in the reciprocating direction of the piston, and has a control clamp that holds one part of the pipe cutting part installed in the main body block so that it can be driven simultaneously with the piston, and a grip that grips the other part of the pipe cutting part. The tool is installed in the main body block as a cylinder-driven type, and these control tools and grippers are arranged over a wide range from the pipe cutting section, and the pipe is placed on the opposite side of the pressure side, facing the blade, control tool, and grip tool. A support for holding from the side is provided integrally with the main block.

(Function) Since the blade, the handle and the handle are integrally provided, there is no need for special parts to grip each cut part of the pipe, and the handle and grip can be placed over a wide range from the cut part. Because of this, concentrated loads are not applied to the pipes and the occurrence of cracks in the pipes can be effectively prevented.

Furthermore, by providing a gripping tool that utilizes water pressure, etc., the structure is simple and the pipe can be prevented from jumping up, and the pipe can be moved after cutting with only a small amount of bI and TJ1gi, improving work efficiency. .

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. This embodiment concerns a dry duplex cutting machine for a neutron t1 tube in a nuclear reactor.

1 to 4 show the overall configuration of the cutting machine h'4.

In the dry tube 1 serving as an underwater pipe to be cut, engaging pieces 1b provided on a spindle 1a at the upper end are engaged with four parts 2a of an upper grid plate 2. In order to support the device on this dry tube 1, 1. L]; A pair of nabots 3 are provided. As shown in FIGS. 3 and 4, each of these one-piece boats 3 has a vertically stub-shaped b shape with a cross section facing in the opposite direction, so that the U-shaped brackets 1 to 3 protrude from the main body block 4. 5 with a bolt 6 or the like. Thereby, each support 3 supports the dry shaft from two directions.

A cylinder chamber 7 is formed in the main body block 4 facing the bracket 5, and a piston 8 is housed in the cylinder chamber 7 via an O-ring 9.10. Note that a flange portion 8a is provided on one end side of the piston 8, and the cylinder chamber is divided into two parts.
It is divided into chambers 7a and 7b. Reference numeral 11 denotes a sealing cover that closes off the cylinder chamber 7 at one end of the piston 8, and is sealed by an O-ring 12. This cover 11 has
A guide pin 13 is integrally protruded by welding or the like, and is slidably fitted into an engagement hole 14 of the piston 8 to prevent the piston 8 from rotating.

Further, a chevron-shaped cutting blade 15 is connected to the other end of the piston 8 with a flange 17 by bolts 16. The flange 17 extends upward, and a support 18 is integrally attached to the extended portion. The support 18 is in the form of a vertical rod with an L-shaped cross section, and a holding cylinder 19 is provided at its base parallel to the axis of the piston 8, as shown in FIG. A control member 20 is provided within the holding cylinder 19 and is biased to a certain degree of protrusion by a compression coil spring 21, and has the function of holding down the dry tube 1. Note that the guide rod 20 is supported by a guide rod 21 on the inside.

This guide rod 21 is fixed to a frame 22 fixed to the main body block 4. A lifting eye 23 is provided at the tip of the frame 22 at the center of gravity of the main block 4 and fixed by welding, bolts, or the like.

Note that 24 is a first water supply pipe for applying driving water pressure for pressurizing the blade 15, and is open to the cylinder chamber 7a on the rear side of the piston 8. Further, 25 is a second water supply pipe for applying driving water pressure for returning the blade 15, and is open to the cylinder chamber 7b on the front side of the piston 8.

Further, a holding hole 26 parallel to the axis of the cylinder chamber 7 is formed in the lower part of the main body block 4 .

In this holding hole 26, a cylinder 27 for gripping the tube is attached to the threaded portion 2.
They are screwed together and held through 8. This cylinder 27 is provided with a piston shaft 29, and this screw shaft 29 is moved forward toward the dry chew 71 by a spring 30. Further, a third water supply pipe 32 is connected to the auxiliary cylinder chamber 31 in the cylinder 27 for supplying water pressure in the backward direction to the two piston shafts. NaJ3.3
3 is a support for the rear end of the two piston shafts, and 34 is an O-ring.

A tube gripper 35 is screwed onto the tip of the piston shaft 29.
It is tightened into a double nut shape by tightening nuts 1 to 36. This tube gripping shell 35 has a nabo 1-37 integrally projecting therefrom. As shown in FIG. 3, this support 37 has a protruding portion 37a having an angular cross-section.

Further, a blade pressure receiver seat 38 and a grip shell pressure receiver seat 39 are screwed onto the bracket 5 as supports facing the blade 15 and gripping tool 35, respectively.

In addition, the U-shaped space of the bracket 5 is for the blade 15 and the writhing tool 3.
In addition to being a moving space for the dry tube 5, it also serves as a receiving opening for the dry tube 1.

Figure 6 shows the water supply line system. 1st, 2nd,
The third water supply pipe 24.25.32 connects a pair of tanks 40.
41 pumps 42, 43 with removable joints 44. /1.5. In addition, 4
6. /17 is a check valve that prevents return due to back pressure. Further, 48°/19 is a pressure word and indicates the pressure of discharged water. Further, reference numeral 50.51 is a valve that allows the discharge system to be disconnected and allows return water from each water supply pipe 24, 25, and 32 to be introduced into the tank. 52 indicates the water surface of raw F reactor water J0 Next, the operation will be explained.

During periodic inspection, plan to replace several dry duplexes 1. Then, before starting the replacement work, a stick test is performed.In this case, first, a normal lifting tool is used to engage the spindle 1a, then the spindle 1a is lowered by the weight of the tool, and the Just make sure it comes off.

In this case, what is considered a spring stick additionally imposes a limiting load on the lower edge of the tool. Even at this stage, if the spindle 1a does not move, it is defined as a spring stick, and preparations are made for cutting and removal.

It goes without saying that it is necessary to confirm in advance that there is no external damage to the sheath tube of the dry tube 1 due to irradiation effects.

When cutting, first attach the mounting bracket of the auxiliary hoist on the platform for traveling above the reactor to the lifting eye 23, and suspend it into the reactor core. Then, the upper lattice plate 2 is lowered and the cutting machine of this embodiment is stopped at a cutting position of about 1 m from the lattice plate. In this case, first, the third water supply pipe 32 is connected to the pump 43 to apply water pressure, and the piston shaft 29 is moved backward against the spring 30. In addition, the second water supply line 2
5 is connected to the pump 42 in advance to apply water pressure. As a result, the blade 15 is in a retracted state, and the support 37 with respect to the main body block 4 is also in a retracted state. Then, when the cutting position is positioned at a predetermined cutting position, the valve 51 is opened to release the water pressure.

As a result, the gripping tool 35 is brought into contact with the dry duplex 1 by the elasticity of the spring 30. At that time, as shown in FIG. 6, the third water supply pipe 32 is removed from the pump 43.

On the other hand, the first water supply pipe 24 is connected to the pump 43 and the valve 5
1 is opened and water pressure is applied, and the second water supply pipe 25 switches the valve 50 to the return water direction. This pressurizes the piston 8 and moves the blade 15 forward. At this time, the support 18 moves forward together with the blade 15 via the flange 17,
The controller 20 also moves forward and comes into contact with the dry tube 1. As a result, support 3, management 20, grip 35 J:
The dry tube 1 is solidified in all directions. Until the cutting by the blade 15 is completed, the first water supply pipe 24 is used for supplying water on the pressurizing side, and the second water supply f125 is used for returning water to the tank 40. After cutting g7i, first water supply pipe 2
The valve 51 of No. 4 is opened to reduce the pressure. Further, the second water supply pipe 25 is separated from the pump 42. As a result, the blade 15 remains as it is, resulting in upper and lower support 3 and management 2.
0 and the gripper 35 continue to hold the dry tube 1 under F after cutting. From this state, the third water supply pipe 32
is connected to the pump 42 and pressurized, and the gripper 35 is pulled back against the spring 3o to release the lower long dry tube, ie, the lower piece. (After that, the cutting machine is moved and the upper short dry tube, that is, the upper piece is taken out onto the grid plate 2 together with the cutting machine.Then, the platform is moved and the cutting machine is transferred to the fuel pool, and inside the same pool. The cut piece of the dry tube is grasped with another tool, the second water supply pipe 25 of the cutting machine is pressurized, the first water supply pipe 24 is depressurized, the blade 15 and the support 18 are pulled back, and the cut piece is freed. The grabbed cut pieces are transferred to a basket (not shown), etc., and stored temporarily.Then, the cutting machine is moved on the platform and headed for the next stick dry tube, and the upper piece is cut again as described above. The remaining length of the cut dry tube, that is, the lower part, is taken out using a special gripping tool and gripped on the grid plate with a new special gripping tool.

It is then transported to the pole deck side of the reactor core, made into a state that is easy to handle, and sent to the fuel pool for temporary storage, whereupon any necessary treatment will be carried out.

According to the underwater tube cutting machine according to the J: eel embodiment, the sabot 1 of the dry tube 1 is attached to the opposing portion of the gripping shell 35 and the blade 15.
-3 is in step [), and the nabot 3 of the dry tube 1 is also provided in the opposite part of the control 20, and these are arranged vertically over a wide range, so that local stress is not generated around the cutting when cutting. There is no. Therefore, it is effective in preventing cracks from occurring in the dry tube 1. In addition, after cutting, the upper part of the spindle 1a can be removed without using any other special tools.
It can be moved along with the blade, giving it an excellent ability. Furthermore, even if there are a plurality of sticks, the cutting operation can be performed successively on other stick dry tubes, making the cutting operation easier. Further, since the long remaining portion is held upright within the housing and guide tube by taking advantage of its rearward feature, it can be smoothly pulled up in the same way as the dry tube is taken up when other normal items are replaced.

Therefore, continuous drawing is achieved and workability is improved.

Furthermore, by adopting remote control by attaching and detaching the pump to the pump installation surface on land, work can be carried out in clean conditions.

〔Effect of the invention〕

As described above, according to the present invention, both sides of the pipe cut section in the axial direction are gripped over a wide range, so a separate gripping tool dedicated to each cut section is not required, and the configuration can be made more compact. This not only simplifies the work, but also prevents the pipe from breaking during cutting, and also ensures the prevention of cracks during cutting.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a vertical sectional view showing the entire cut-off [17i aircraft], Fig. 2 is a left side view of Fig. 1, and Figs. 3 and 4 are respectively the same as Fig. 1. ■-■ line and IV
-IV line sectional view, FIG. 5 is an enlarged dimensional drawing of a part of FIG. 1, and FIG. 6 is a diagram showing an operating hydraulic system. 1... Underwater piping (dry tube), 4... Main body block, 7a, 7b... Cylinder (cylinder chamber), 8
...Piston, 20...Manage, 21...Gripper, 3°38.39...Support.

Claims (1)

[Claims] 1. A cylinder is provided in the main body block that can be suspended along the underwater piping, a piston having a blade is housed in the cylinder, and the cylinder has two chambers that apply water pressure in the reciprocating direction of the piston. A pipe holder for holding one part of the pipe cutting part is provided on the main body block so as to be able to be driven at the same time as the piston, and a cylinder-driven grip for gripping the other part of the pipe cutting part is provided on the main body block. The presser foot and the gripper are arranged over a wide area from the pipe cutting part, and a support is provided integrally with the main block to face the blade, the tube footer, and the gripper and hold the pipe from the side opposite to the pressurizing side. This underwater pipe cutting machine is characterized by: 2. The underwater pipe cutting machine according to claim 1, wherein the underwater pipe is a neutron instrumentation pipe of a nuclear reactor.