JPH07181284A - In-core guide tube seal device - Google Patents

Abstract

PURPOSE:To make easy insertion and withdrawal from an in-core guide tube by providing an insertion part to be inserted in the in-core guide tube and a plurality of elastic seal of wedge shape with thin tip toward its insertion direction. CONSTITUTION:At an insertion part 27 to be inserted detachably in an in-core guide tube 2 provided on a core support plate 12, a seals 29 and 30 made of wedge shape elastic body with thin tip for water-sealing the guide tube are provided toward the insertion direction. These seals 29 and 30 are formed of natural rubber, synthetic rubber or other elastic body and the shaft seal 27b is put between a collar 28 and a stem 27c. As the seals 29 and 30 are formed in a wedge shape with thin tip downward, reactor water pressure works on the wedge upper surface. And thus, the seals 29 and 30 distorts to be enlarged in the diameter direction and the contact to the inner surface of the guide tube 2 increases and so the sealing function further improves. On the other hand, the seal 29 and 30 is wedge shape with thin tip, and therefore, insertion and withdrawal of the guide tube 2 to the insertion part 27 is easy and simplification and speedup of the work become possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-core guide for inserting a plurality of neutron measuring pipes arranged in the core of a boiling water nuclear reactor into an in-core guide pipe which has been removed and sealing the inside thereof in a water-tight manner. The present invention relates to a pipe sealing device, and more particularly, to an in-core guide pipe sealing device having an improved sealing member and the like.

[0002]

2. Description of the Related Art Generally, in a boiling water reactor, neutrons in the reactor are measured by a neutron measuring tube arranged in the core of the reactor, and power control in the reactor is controlled in a central control room based on the measured data. The reactor is being operated automatically.

As shown in FIG. 7, a neutron measuring tube 1 of this type has a neutron measuring device (not shown) for measuring neutrons therein, and a lower half of the neutron measuring tube 1 has an in-core guide tube. 2 and the in-core housing 3 are axially penetrated so as to extend outwardly below the lower bottom portion 4 of the reactor pressure vessel, and a plurality of lead wires 5 are provided from the lower end.
Is pulling out.

Further, the neutron measuring tube 1 is provided with a spindle 7 concentric with the upper part of the neutron measuring tube by means of a spring 6, and the upper end of the spindle 7 is connected to the upper lattice plate 8
They are supported by being fitted into the supporting recesses 9 on the lower surfaces of the intersecting portions 8a.

The neutron measuring tube 1 maintains its axial center position by the guide rings 10 and 11 provided in the portions accommodated in the in-core guide tube 2 and the in-core housing 3, respectively.

On the other hand, the upper end of the incore guide tube 2 is fixed by inserting it into the through hole 10a of the core support plate 12, and the lower end of the incore housing 3 is concentrically fixed by welding. . In the in-core housing 3, the in-core flange 13 is tightened with a tightening nut 14, and the lead wire 5 of the neutron measuring tube 1 is drawn out from the center hole of the tightening nut 14.

Each neutron measuring tube 1 thus constructed is replaced every time a periodic inspection is performed.
Further, during this work, it is also necessary to check and confirm the soundness of the incore guide tube 2 and the incore housing 3 which are traces of the neutron measurement tube 1 pulled out.

[0008]

To this end, an in-core guide tube sealing device is inserted into the in-core guide tube 2 from its open end to seal the inside of the in-core guide tube 2 in a watertight manner so that the reactor water is in-core. It is necessary to prevent water from entering the inside from the upper end of the opening of the guide tube 2 and the like, drain the water from the in-core housing 3 in the water-stop state, and then check the soundness and the like.

In this case, the most important point is that the sealing function of the in-core guide tube sealing device is high and reliable, and that the in-core guide tube 2 can be easily inserted and pulled out. It is also necessary to consider that the seal portion is less likely to be damaged or curled.

Further, the upper part from the insertion part inserted into the incore guide tube 2 of the incore guide tube sealing device to the upper lattice plate 8 should not interfere with other in-reactor devices below the upper lattice plate 8 as much as possible. It requires some ingenuity.

Further, since the work is carried out in the reactor water in a narrow space in the nuclear reactor, it is required to carry out the work of mounting / removing the in-core guide tube sealing device safely, reliably and in a short time.

Therefore, the present invention has been made in consideration of such circumstances, and its purpose is to have a high sealing function, to be easily inserted into and withdrawn from an in-core guide tube, and to prevent interference with other in-core equipment. An object is to provide an in-core guide tube sealing device that does not occur.

[0013]

The present invention is configured as follows in order to solve the above-mentioned problems.

The invention according to claim 1 of the present application (hereinafter, referred to as the first
The invention) is an in-core guide tube sealing device that is removably inserted into an in-core guide tube provided in a core support plate below an upper lattice plate in a nuclear reactor to seal the inside of the in-core guide tube in a watertight manner. One or more seals, which are made of an elastic body and have a wedge shape that is tapered in the insertion direction, are provided at the insertion portion into the in-core guide tube to seal the inside of the in-core guide tube in a watertight manner.

Further, in the invention according to claim 2 of the present application (hereinafter referred to as the second invention), the insertion portion is connected to a holder protruding above the core support plate, and the insertion portion of the holder has an incore structure. It is characterized in that it is provided with a seating sheet which sits on the core support plate when inserted into the guide tube.

Further, in the invention according to claim 3 of the present application (hereinafter referred to as the third invention), a rod is connected to the holder, and the rod is suspended so as to straddle the intersection of the upper lattice plate. And a guide for guiding the insertion portion onto a predetermined in-core guide tube, and a handle that is erected on and suspended from the guide.

Furthermore, in the invention according to claim 4 of the present application (hereinafter referred to as the fourth invention), an axially expandable rod is connected to the holder, and the free end of this rod is connected to the holder.
The neutron instrumentation tube is characterized in that the neutron instrumentation tube is fitted and supported in the supporting recess of the upper lattice plate which is fitted and supported.

The invention according to claim 5 of the present application (hereinafter referred to as the fifth invention) is a rod which is connected to a holder and has a step portion, and the step portion of the rod is freely released. , And a gripping tool that can be lifted up and down in a nuclear reactor.

[0019]

[Action]

<First to Fifth Inventions> Since one or more tapered wedge-shaped elastic body seals are provided in the insertion portion of the in-core guide tube sealing device to be inserted into the in-core guide tube in the insertion direction, It is easy to insert into and pull out from the in-core guide tube.

Further, since the reactor water pressure is applied to the upper surface of the wedge-shaped elastic body seal, the seal is deformed so as to expand its diameter, the degree of close contact with the inside of the in-core guide tube is increased, and the sealing performance is improved.

<Second Invention> Since the holder of the insertion portion of the in-core guide tube sealing device is provided with the seating sheet which is seated on the core support plate when the insertion portion is inserted into the in-core guide tube, The amount of insertion of the insertion portion into the in-core guide tube can be adjusted to an appropriate amount.

<Third Invention> When the in-core guide tube sealing device is suspended by the handle and suspended in the reactor, and the guide is suspended above the intersection of the upper lattice plates, the in-core guide tube sealing device is provided. The insertion part is positioned on a predetermined in-core guide tube, and by further lowering of the in-core guide tube sealing device, the insertion part is inserted into the in-core guide tube to seal the inside in a watertight manner.

<Fourth Invention> Since the expandable rod of the in-core guide tube sealing device has substantially the same structure as the expandable spindle of the neutron measuring tube, the expandable rod of this in-core guide tube sealing device is By grasping with a handling tool for a neutron measuring tube and contracting it in the axial direction, it can be easily and surely attached to a predetermined position while being easily removed.

<Fifth Invention> The upper end of the in-core guide tube sealing device is terminated at the upper end of a rod having a step portion,
Since it does not extend to the upper lattice plate, it is possible to prevent interference with other devices above the rod of the in-core guide tube sealing device.

Further, in the in-core guide tube sealing device, since the step portion of the rod is grasped by the grasping tool and suspended in the reactor, the in-core guide tube sealing device can be easily and surely inserted into a predetermined in-core guide tube. On the other hand, it can be easily removed.

[0026]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 7, the same or corresponding parts are designated by the same reference numerals.

First Embodiment FIG. 1 is a longitudinal sectional view of the incore guide tube sealing device 21 according to the first embodiment of the present invention, in which the incore guide tube 2 is inserted into the incore guide tube 2 shown in FIG. FIG.
As shown in FIG. 2, the in-core guide tube sealing device 21 has a guide 22 that is suspended so as to straddle the intersection 8 a between the upper lattice plates 8 and the handle 23 is provided on the guide 22.
Is erected.

The handle 23 is gripped by an ordinary dedicated grapple and moved up and down in the reactor.

The guide 22 is a pair of leg portions 2 which are bifurcated.
2a and 22b are provided, and the crossing portion 8a of the upper lattice plate 8 is inserted into the crotch portion of the leg portions 22a and 22b so as to be suspended, and a relatively long rod 24 is fixed. . The rod 24 extends downward in the vertical direction and is slightly bent at a bent portion 24a in the middle thereof.

That is, as shown in FIG. 7, the neutron measuring tube 1 and the in-core guide tube 2 intersect at the intersection 8a of the upper lattice plates 8 with each other.
Since the rod 24 is located below the perpendicular of the central portion of the rod 24, the rod 24 is bent at a bent portion 24a at an intermediate portion in the axial direction so that its axial center coincides with the central portion of the intersecting portion 8a, and then is concentrically formed on the tubular holder 25. It is fixed.

The holder 25 has a shaft-shaped insertion portion 27 at its lower end in the drawing with a seating sheet 26 having a larger diameter disk than the holder seat 25 interposed therebetween.
Are fixed concentrically with each other, and when the insertion portion 27 is inserted into the in-core guide tube 2, the seating sheet 26 is attached to the core support plate 1
It is designed to sit on the upper surface of 2.

The insertion portion 27 connects a shaft 27a fixed to the lower surface of the seating seat 26 to a stem 27c concentrically with a shaft-shaped joint 27b, and a hook-shaped head 27d is pinned to the tip of the stem 27c. 1 by connecting with 27e
It is formed on the axis of the book.

As shown in FIG. 3, the insertion portion 27 has a collar 28 on the outer periphery of the stem 27c, and an upper inner seal 29 and a lower inner seal 30 located above and below the collar 28.
Are attached respectively.

The upper and lower inner seals 29, 30 are made of natural rubber, synthetic rubber, or other elastic material, and are formed in a tapered wedge shape downward, and the outer peripheral surfaces thereof are the inner circumference of the in-core guide tube 2. It adheres to the surface in a watertight manner to seal the reactor water. In FIG. 1, reference numeral 27f is a shaft seal, which is an elastic seal material such as an O-ring interposed between the collar 28 and the stem 27c.

Therefore, according to this embodiment, since the upper and lower inner seals 29 and 30 are formed in a tapering wedge shape that is tapered downward in FIG. 1, the reactor water pressure is applied to the upper surface of the wedge shape. To be done.

To this end, these inner seals 29, 30
Is deformed so as to expand in the diameter direction, and the in-core guide tube 2
Since the degree of close contact with the inner peripheral surface of is increased, the sealing function is further improved.

On the other hand, since the inner seals 29, 30 are wedge-shaped tapering toward the insertion direction, it is easy to insert and pull out the insertion portion 27 into and from the in-core guide tube 2, and to simplify these operations. It is possible to work together with speeding up.

Second Embodiment FIG. 4 is a partially cutaway vertical sectional view of an in-core guide tube sealing device 41 according to a second embodiment of the present invention. It is characterized in that a retractable spindle 42 similar to the spindle 7 is assembled in a part so that it can be attached and detached by a conventional handling tool 43 for the neutron measuring tube 1 shown in FIG.

That is, the in-core guide tube sealing device 41 is the in-core guide tube sealing device 2 of the first embodiment shown in FIG.
Rod 24 connected to the holder 25 of No. 1, guide 22,
The handle 23 is omitted, and the holder 25 has a straight rod 4
An extendable and retractable spindle 42 is concentrically connected via the connector 4.

As shown in FIG. 4, the telescopic spindle 42 has a spring cylinder 45 fixed concentrically on the upper end of the straight rod 44 in the figure. A coil-shaped spring 46 and a piston 47 mounted on the spring 46 are concentrically built in the spring cylinder 45, and the piston 47 has a shaft center portion at the upper end portion in the drawing vertically above and below. The lower end of the spindle body 48 penetrating in the direction is fixed concentrically.

A disc-shaped ring 49 having a larger diameter than the spindle body 48 is concentrically fixed to the lower portion of the spindle body 48. The spindle body 48 is kept in contact with the outer surface of the upper end of the spring cylinder 45 in the figure. The lower end portion of 48 is retracted into the spring cylinder 45 and contracts.

On the other hand, the head 48a of the spindle body 48 is fitted in the supporting recess 9 of the intersection 8a between the upper lattice plates 8 and the spindle body 48 is elastically supported by the spring 46.

The telescopic spindle 42 constructed in this way
As described above, since it expands and contracts in the same configuration as the expandable spindle 7 shown in FIG. 7, the inside of the in-core guide tube 2 of the in-core guide tube seal device 41 is handled by the handling tool 43 for the neutron measuring tube 1 shown in FIG. It can be inserted into and removed from.

That is, as shown in FIG. 5, the handling tool 43, which is hung up and down by the wire rope 50, is hung so that the upper grid plate 8 can be inserted into the guide rod 51, and supported by the roller 52. Excuse me. Next, the slider 53 is moved forward (to the right in FIG. 5) to move the fork 54.
Holds the spindle 42 by.

In this gripped state, when the roller 52 is moved backward by a roller operating cylinder (not shown), the support by the roller 52 is lost and the entire in-core guide tube seal device 41 is slightly lowered, and its own weight is expanded and contracted. 42 is loaded to cause the spring 46 to contract.
As a result, the head 48a of the spindle 42 can be removed from the supporting recess 9 of the upper grid plate 8.

Therefore, according to the present embodiment, the in-core guide tube sealing device 4 is provided by the handling tool 43 for the neutron measuring tube 1.
It is possible to surely and quickly insert and withdraw 1 into and from the predetermined in-core guide tube 2.

Third Embodiment FIG. 6 is a partially cutaway vertical sectional view of an in-core guide pipe sealing device 61 according to a third embodiment of the present invention, which is an expansion / contraction of the in-core guide pipe sealing device 41 shown in FIG. Spindle 4
2 is omitted, and a conical gripping head 62 having a diameter larger than this and tapering upward in the drawing is integrally formed on the upper end portion of the straight rod 44. Is formed so that it can be grasped by the grasping tool 63.
Is not extended to the upper lattice plate 8 by terminating at the head portion 62, so that a space above the head portion 62 can be secured, and the working space in the furnace can be expanded correspondingly. is there.

The grasping tool 63 has a structure similar to that of a collet chuck and allows the grasping head 62 of the straight rod 44 to be freely released, and has a bottomed circular tubular piston shaft 65 in an operating cylinder 64. Built-in slidable in any direction,
Wire rope 6 coupled to the bottom shaft center of piston shaft 65
6 is hung up and down freely by an auxiliary hoist or the like of a fuel exchanger (not shown) on the reactor.

The operation cylinder 64 has a finger 67 having its upper end fixed to the lower end by bolts or the like.
The finger 67 has a plurality of claws 67a formed in the lower portion of the cylindrical body by forming a plurality of axial slits that reach the lower end of the cylindrical body at required intervals in the circumferential direction.
The lower end of is slightly curved inward.

Further, the operation cylinder 64 has a descending air supply port pipe 69a and an ascending air supply port pipe 69b.
And the piston shaft 65 is lowered by supplying air of a predetermined pressure into the operation cylinder 64 from the descending air supply port pipe 69a, while the piston is formed by supplying air from the ascending air supply port pipe 69b. The shaft 65 is raised.

On the other hand, a cylindrical guard 70 is attached to the bottom of the piston shaft 65 to cover substantially the entire outer circumference of the finger 67, and the inner peripheral surface of the lower end of the guard 70 slightly protrudes inward. A convex stepped portion 70a that slidably contacts the outer peripheral surface of the shaft 67 in the axial direction is integrally provided.

Therefore, the rising air supply port pipe 6
By supplying a predetermined pressure of air into the operating cylinder 64 from 9b to raise the piston shaft 65 upward, the guard 70 is raised above the upper end portion of the finger 67, and each claw 67a of the finger 67 is lifted. The grip 63 is hung free, and in this state, the grip 63 is suspended from the gripping head 62 of the straight rod 44.

Then, the tips of the claws 67a of the fingers 67 of the grip 63 contact the tapered surface of the gripping head 62 and are gradually expanded by being guided by the tapered surface, and the grip 63 further descends. Thus, the curved lower end of each claw 67a is caught on the lower surface of the gripping head 62.

Then, next, the piston shaft 65 is lowered by supplying air from the lowering air supply port pipe 69a into the operation cylinder 64.

Then, as shown in FIG. 6, the guide 70 descends to the outside of the finger 67, and the convex stepped portion 7 of the guide 70.
The gripping head 62 is grasped by the fingers 67 because 0a tightens the claws 67a from the outside to the inside.

Therefore, with the gripping head 62 of the straight rod 44 gripped by the gripper 63 in this way, the in-core guide tube sealing device 61 is suspended on the predetermined in-core guide tube 2 in the reactor and lowered. By doing so, the insertion portion 27 of the in-core guide tube sealing device 61 can be inserted into the in-core guide tube 2 and the inside thereof can be sealed.

After that, by supplying air of a predetermined pressure into the operating cylinder 64 from the lifting air supply port pipe 69b of the grip 63, the guide 70 is lifted together with the piston shaft 65, and the finger 67 by the guide 70 is lifted.
Release the restraint of.

In this state, the grip 63 is attached to the wire rope 6
When the finger 67 is lifted by being wound up, the finger 67 is disengaged from the gripping head 62 and separated, only the grip 63 is lifted, and the insertion portion 27 of the in-core guide tube sealing device 61 is inserted into the in-core guide tube 2. It remains as it is, and the inside of the in-core guide tube 2 is sealed in a watertight manner.

Therefore, predetermined work such as inspection of the incore guide tube 2 and the incore housing 3 is performed. At this time, since the grip 63 has already been pulled up from above the in-core guide tube sealing device 61, the space above the gripping head 62 of the in-core guide tube sealing device 61 greatly expands, and the workability in various furnace operations is improved. improves.

After the completion of these in-furnace operations, the gripping tool 63 is used to grip the gripping head 62 again and the in-core guide tube sealing device 61 is pulled out from the in-core guide tube 2.

[0061]

As described above, according to the first to fifth aspects of the present invention, the wedge-shaped elastic body seal tapering in the insertion direction is inserted into the insertion portion of the in-core guide tube sealing device which is inserted into the in-core guide tube. Since at least one is provided, the insertion and the withdrawal of this insertion portion into the in-core guide tube are facilitated.

Further, when the insertion portion of the in-core guide tube sealing device is inserted into the in-core guide tube, the reactor water pressure is applied to the upper surface of the wedge-shaped elastic body seal, so that this seal is deformed to expand its diameter. As a result, the degree of adhesion to the inner surface of the in-core guide tube is increased and the sealing property is improved.

The second invention of the present application is that the holder of the insertion portion is
Since the seat for seating on the core support plate is provided when the insertion portion is inserted into the incore guide tube, the insertion amount of the insertion portion inserted into the incore guide tube can be adjusted to an appropriate amount.

In the third invention of the present application, when the in-core guide tube sealing device is suspended by the handle and suspended in the reactor, and the guide is suspended above the intersection of the upper lattice plates, the in-core guide tube sealing device is suspended. The insert of the tube seal device is positioned over a predetermined in-core guide tube and further lowering of the in-core guide tube seal device inserts the insert into the in-core guide tube for sealing.

Further, according to the fourth invention of the present application, since the expandable rod of the in-core guide tube sealing device has almost the same structure as the expandable spindle of the neutron measuring tube, the expandable rod of the in-core guide tube sealing device can be expanded and contracted. By grasping the rod with a handling tool for a neutron measuring tube and reducing the rod in the axial direction, the rod can be easily attached to a predetermined position and easily removed.

Furthermore, in the fifth invention of the present application, the upper end of the in-core guide tube sealing device is terminated at the upper end of the rod having the step portion and does not extend to the upper lattice plate.
A large space above the rod of the in-core guide tube sealing device can be secured, and interference with other devices can be prevented.

Further, since the in-core guide tube sealing device is grasped by the step part of the rod and is suspended in the reactor, the in-core guide tube sealing device can be easily and surely inserted into a predetermined in-core guide tube. On the other hand, it can be easily removed.

[Brief description of drawings]

FIG. 1 is a first of the in-core guide tube sealing device according to the present invention.
The partial notch partial longitudinal cross-sectional view of an Example.

FIG. 2 is a view taken along the line II-II of FIG.

FIG. 3 is an external front view of the main part shown in FIG.

FIG. 4 is a partial cutaway vertical sectional view of a second embodiment of the present invention.

FIG. 5 is a partial vertical sectional view of a handling tool for a neutron measuring tube.

FIG. 6 is a partially cutaway vertical sectional view of a third embodiment of the present invention.

FIG. 7 is a partially cutaway vertical sectional view showing a state in which a neutron measuring tube is attached to an in-core guide tube of a core.

[Explanation of symbols]

 1 Neutron Measuring Tube 2 Incore Guide Tube 3 Incore Housing 4 Lower Bottom of Reactor Pressure Vessel 5 Lead Wire 6 Spring 7 Spindle 8 Upper Lattice Plate 8a Intersection of Upper Lattice Plate 9 Recess 12 Support Core Plate 21, 41, 61 In-core guide pipe sealing device 22 Guide 23 Handle 24 Rod 24a Bending portion 25 Holder 26 Seating seat 27 Inserting portion 27a Shaft 27b Joint 27c Stem 27d Head 28 Collar 29 Upper inner seal 30 Lower inner seal 42 Telescopic spindle 43 Handling tool for neutron measuring pipe 44 Straight rod 45 Spring cylinder 46 Spring 47 Piston 48 Spindle body 48a Body 51 Gite rod 52 Roller 53 Slider 54 Fork 62 Grip head 63 Grip 64 Operating cylinder 65 Piston shaft 66 Wye Yarope 67 Finger 67a Claw 68 Guide 69a Descending air supply port pipe 69b Ascending air supply port pipe 70 Guard

Claims (5)

[Claims] 1. An in-core guide tube sealing device that is removably inserted into an in-core guide tube provided in a core support plate below an upper lattice plate in a nuclear reactor to seal the inside of the in-core guide tube in a watertight manner. An in-core guide tube sealing device comprising at least one seal, which is made of an elastic body and has a wedge shape that is tapered toward the insertion direction, and which seals the inside of the in-core guide tube in a watertight manner. 2. The insert portion is connected to a holder projecting above the core support plate, and the holder is a seat for seating on the core support plate when the insert portion is inserted into an in-core guide tube. The in-core guide tube sealing device according to claim 1, further comprising: 3. A rod is connected to the holder, and the rod is suspended so as to straddle the intersection of the upper lattice plate,
A guide for guiding the insertion portion onto a predetermined in-core guide tube,
The in-core guide tube sealing device according to claim 2, further comprising: a handle which is erected on the guide and suspended. 4. An axially expandable rod is connected to the holder, and a free end portion of the rod is fitted into a supporting concave portion of an upper lattice plate for supporting by fitting an upper end portion of a neutron instrumentation tube. The in-core guide tube sealing device according to claim 2, wherein the in-core guide tube sealing device is configured so as to be supported. 5. A rod, which is connected to the holder and has a step portion, and a gripping tool that freely holds the stepped portion of the rod and that is vertically hung in the reactor. The in-core guide tube sealing device according to claim 2.