JPH07110394A - Control rod-fuel support metal grasping tool and taking out method for the fuel support metal and control - Google Patents

Abstract

PURPOSE:To release and separate easily, surely and speedily the connection of CR (control rod) and CRD (control rod drive mechanism) connected detachablly with a bayonet coupling in a reactor pressure vessel and to simultaneously hang the CR and FS (fuel support metal) out of the reactor pressure vessel. CONSTITUTION:A grasping tool main body hung freely elevatably into a reactor pressure vessel, a fuel support metal grasping part provided at the lower part of the grasping tool main body to grasp the fuel support metal 6 and hang it up above the upper end of a control rod 4 and maintain it, and a control rod grasping part 40 hung from the grasping tool main body freely rotatably to grasp the handle 4d of the control rod 4 freely releasably and to release or connect the connection with a bayonet coupling 14 by rotating around an axis, are provided.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a boiling water reactor (hereinafter referred to as B
Control rods inside the reactor (hereinafter C
R) and a fuel support fitting (hereinafter referred to as FS), and then pulling them out of the reactor after removing them, and control rods and fuel support fittings used when these CR and FS are installed again in the core The present invention relates to a gripping tool, and more particularly to a control rod / fuel support fitting gripping tool for gripping both CR and FS and lifting them together outside a nuclear reactor.

[0002]

2. Description of the Related Art Generally, a core of a BWR is constructed as shown in FIG. 13, and a plurality of fuel assemblies 3 and CRs are provided in a cylindrical core shroud 2 contained in a reactor pressure vessel 1.
(Control rod) 4 is loaded.

The upper part of each of these fuel assemblies 3 is shown in FIG.
An upper part thereof is supported by an upper lattice plate 5 which is also indicated by 4, while a lower part thereof is supported by a core supporting plate 7 through an FS (fuel supporting metal fitting) 6.

As shown in FIG. 15, each FS 6 is supported by the core support plate 7 with its cylindrical lower part fitted in the FS supporting fitting hole 7a. As also shown, for example, the support fitting holes 6a, 6 for fitting and supporting the bottoms of the four fuel assemblies 3 respectively.
b, 6c, 6d and a cross-shaped insertion hole 4a through which the cross-shaped CR4 is inserted are formed.

Each of the supporting fitting holes 6a to 6d communicates with each of the orifices 6e, 6f, 6g and 6h on the side thereof, and is cooled from each of the orifices 6e to 6h through the supporting through holes 6a to 6d. The material is made to flow into each fuel assembly 3. Further, at one corner of the upper portion of the FS 6, a through hole 6i into which a fixing pin 7b planted on the core support plate 7 is fitted is formed to fix the FS 6 on the core support plate 7.

On the other hand, CR4 is a control rod drive mechanism (hereinafter referred to as C, which is provided by vertically penetrating the bottom of the reactor pressure vessel 1).
RD) 8 is detachably connected to each of the CRDs 8 and is moved up and down by the CRDs 8 to be inserted into and extracted from the core.

That is, CR4 passes through the inside of the control rod guide tube 9 connected to the core support plate 7, and the cross-shaped insertion formed between the four fuel assemblies 3, 3, 3, 3 supported by FS6. The hole 4a is moved up and down.

The conventional connecting mechanism of CR4 and CRD8 is of a spud type as shown in FIG.
This spud type coupling 10 has a lower end 4b of CR4.
In the outer circumferential gap of the lock plug 12 inserted in the fitting hole of the lock plug 12, a coupling claw-shaped coupling spud 11 having, for example, a notch in the circumferential direction is cut upward by a drive piston (not shown) of the CRD 8. The coupling spud 11 is clamped between the inner peripheral surface of the lower end portion 4b of the CR4 and the outer peripheral surface of the lock plug 12 by pushing up and strongly inserting the CR4 and CRD8.

Further, the lock plug 12 is pushed upward by the uncoupling rod 13 of the CRD 8 against the spring force of the spring 4c so that the connection between CR4 and CRD8 is released and cut off.

By the way, when the CR 4 is detached from the reactor pressure vessel 1 during the periodical inspection of the BWR and is hung outside the reactor, first, the fuel assembly 3 is pulled up from the inside of the core.

However, in the conventional BWR, since the lock plug 12 is strongly pushed upward by the uncoupled rod 13 to disconnect the connection between CR4 and CRD8 as described above, the lock plug 12 and the lock plug 12 should not be connected. If a foreign matter such as a clad is caught between the coupling spud 11 and the lock plug 12, it is difficult to push the lock plug 12 upward and it may be impossible to disconnect the CR4 and CRD8.

Therefore, in recent years, in order to solve such a problem, for example, the bayonet coupling 14 shown in FIGS. 18 (A) to 18 (C) may be adopted as a connecting means between the CR4 and the CRD8.

The bayonet coupling 14 is a lower end portion 4b of the CR 4 into which the coupling spud 11 is inserted.
On the inner peripheral surface of the fitting hole 15, the engaging projections 16 having a required width are provided so as to project in the circumferential direction at intervals of approximately 90 °, and as shown in FIG. 18B, the bayonet coupling 14, that is, the , CR
By rotating 4 in the circumferential direction by about 45 °, each engaging convex portion 16 is moved to the outer peripheral surface side of each coupling spud 11, thereby reducing the diameter of each coupling spud 11 and sandwiching the lock plug 17. CR by
4 and CRD8 are connected.

Further, as shown in FIG. 18C, the CR4 is further rotated by about 45 ° or returned to its original position to move the coupling spuds 11 into the recesses of the engagement holes 15 and to remove them. Expanded radially, CR4 and C
The connection with RD8 is released.

[0015]

In the CR4 using the bayonet coupling 14 as described above, foreign matter such as a clad between the lock plug 12 and the coupling spud 11 as in the conventional spud type coupling 10 is prevented. Since there is no biting, the connection between CR4 and CRD8 can be reliably released and cut off.

However, in order to release the connection with the CRD 8, the bayonet coupling 14, that is, CR4 must be rotated by about 45 ° around its axis, but CR4 is a fixed pin of the core support plate 7. Since it is inserted into the cross-shaped insertion hole 4a of the FS6 fixed by 7b, it cannot rotate, and when forcedly rotated, CR4
And FS6 may be damaged.

Further, the FS 6 is fixed to the fixing pin 7 of the core support plate 7.
When the CR4 and the FS6 are simultaneously rotated after being removed from b and freed, the upper part of the FS6 has a prismatic shape and hits the fuel assembly in the adjacent lattice, which damages the fuel assembly 3. There is a possibility to let.

That is, FIG. 19 (A) shows the control rod 4
FIG. 3 is a plan view of the fuel support fitting 6 and the fuel support fitting 6 viewed from above the upper lattice plate 5, showing a normal state. As shown in this figure, the control rods 4 are installed in the same direction as the upper lattice plate 5, and the fuel support fittings 6 are configured so that they can pass through the cells 5'formed in the upper lattice plate 5. There is. Further, a protrusion 6 ′ is formed on the fuel support fitting 6, and the protrusion 6 ′ holds the pin 7 b provided on the core support plate 7 to prevent the fuel support fitting 6 from rotating. . Further, the fuel assembly supporting fitting holes 6a, 6b formed in the fuel support fitting 6,
A fuel assembly having a square cross section is placed on each of 6c and 6d.

The four fuel assemblies thus arranged constitute one unit, and the reactor core is constructed by about 100 units.

Now, the fuel support fitting 6 and the control rod 4 arranged in the state shown in FIG. 19 (A) are grasped at the same time by using the respective grasping tools, and they are slightly raised and then rotated. Then, the above-mentioned projection 6'of the fuel support fitting 6 comes into contact with the surrounding fuel assemblies. FIG. 19 (B)
Shows this state, and shows the arrangement at the time when the fuel support fitting 6 and the control rod 4 are rotated by 45 ° from the state shown in FIG. 19 (A). In this state, the protrusion 6'protrudes to the upper cell shown in the figure, and this portion comes into contact with the fuel assembly arranged in the upper cell and damages it.

In order to avoid such a situation, as shown in FIG. 19 (C), in addition to the four fuel assemblies of the cell 5 ', a total of four cells 5 "in the upper, lower, left and right directions, hatched in the figure. The 16 fuel assemblies indicated by the above must be pulled up from the core and carried to the fuel storage pool provided on the upper outside of the reactor pressure vessel.

As described above, the above-mentioned method has a problem that it takes time and labor to carry 16 fuel assemblies out of the reactor pressure vessel.

Therefore, the present invention has been made in view of such circumstances, and an object thereof is to easily connect a CR and a CRD that are detachably connected by a bayonet coupling in a reactor pressure vessel. -To provide a control rod / fuel support metal fitting that can be reliably and quickly released and cut off, and that CR and FS can be removed from the reactor pressure vessel and simultaneously hung.

[0024]

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 is mounted on the core support plate below the upper lattice plate in the reactor pressure vessel, and the bottom portions of the plurality of fuel assemblies are fitted and supported. A fuel support fitting having a fuel assembly supporting fitting hole and a control rod insertion hole is detachably connected to a control rod drive mechanism by a bayonet coupling, and is vertically movable through the control rod insertion passage. A control rod / fuel support fitting gripping tool for gripping a control rod and a control rod driving mechanism, which are respectively lifted up and down in the reactor pressure vessel. A main body, a fuel support gripping mechanism provided at a lower portion of the main body, and a control rod gripping mechanism provided at a lower portion of the main body so as to be vertically movable and rotatable with respect to the main body. And this control rod Only mechanism is characterized in that a rotary drive source for rotating relative to the body.

The invention according to claim 2 of the present application is the grip according to claim 1, wherein the fuel support fitting of the grip body has a grip main body to the fuel support fitting. A seating detection mechanism that operates when seated is provided.

Further, the invention according to claim 3 of the present application is
The gripping tool according to claim 1 or 2, further comprising a mechanism for detecting when a rotation angle of the control rod gripping mechanism with respect to the main body becomes a predetermined value or more.

Further, in the invention according to claim 4 of the present application, an upper plate placed on the upper lattice plate is provided on the upper portion of the grip body with respect to the upper lattice plate. It is provided via an up-and-down drive mechanism in order to be able to move up and down.

Further, in the invention according to claim 5 of the present application, the control rod gripping portion is suspended by a rotating body rotatably attached to the upper plate so that the control rod gripping portion can be released freely. With a hook
A first drive source for gripping the control rod that causes the hook to perform a grasping operation and a releasing operation, a second drive source for raising and lowering the hook to raise and lower the control rod, and a forward / reverse rotation of the rotating body. A rotary mechanism that connects both ends of a wire attached to a rotary member that interlocks with both ends of a reciprocating piston rod of a third drive source to rotate the rotary body in a reversible manner. .

Further, the invention according to claim 6 of the present application is
The first drive source for gripping the control rod is urged in such a direction as to hold the gripping operation of the hook when the supply fluid is lost.

Furthermore, in the invention according to claim 7 of the present application, the first drive source for gripping the control rod is connected to the cord, and when the cord is pulled, the hook is opened. The release operation is forcibly performed.

Further, in the invention according to claim 8 of the present application, the fuel support fitting grip portion is provided in a pair of side holes that are in communication with the fuel assembly supporting fitting holes of the fuel support fitting and that face each other in the radial direction. First, a pair of first and second gripping plungers, each of which is capable of advancing and retracting from the inside, are projected so as to grip the fuel support fitting, and the fuel support fitting is gripped by the gripping plunger. And a second drive source for lifting and lowering.

Further, the invention according to claim 9 of the present application is
The fuel support metal gripping mechanism is a first mechanism for gripping the fuel support metal.
A lock mechanism that holds the first drive source for gripping in the gripping operation state and prevents the gripping from being released when the drive source is driven and gripped and then lifted by the lifting drive mechanism. Is characterized by.

Further, in the invention according to claim 10 of the present application, the first drive source for grasping has a grasping state holding mechanism for holding the grasping operation state of the fuel support fitting when the supply source is lost. It is characterized by being assembled.

The invention according to claim 11 of the present application is
The first drive source for gripping is connected to a line, and when the line is pulled, the pair of plungers are retracted inward from inside the pair of side holes of the fuel support fitting to release. It is characterized in that it is configured to be forced.

Further, according to the invention as set forth in claim 12, the first step of pulling up the fuel support fitting from the core supporting plate upward by a predetermined distance, and after the first step, the control rod is rotated by a predetermined angle to perform control. Fuel support fitting and control rod including a second step of separating the rod and the control rod drive mechanism, and a third step of pulling the fuel support fitting and the control rod from the upper part of the reactor pressure vessel after the second step Is the method of taking out.

[0037]

First, the fuel assembly in the required lattice in the reactor pressure vessel is pulled out by a fuel exchanger or the like, and then the control rod / fuel support metal fitting main body is hung in the lattice and lowered. After the lower part of the main body is seated on the upper surface of the fuel support fitting, the fuel support fitting gripping mechanism is operated to grip the fuel support fitting. Similarly, the control rod gripping mechanism is operated to grip the control rod.

After that, either by driving an elevating drive mechanism provided in the main body or by driving a hoist installed in the upper part of the main body to pull up the whole main body through a lifting wire, the fuel is supplied by any means. Raise only the support bracket to the specified height. This predetermined height must be such that the lower end of the fuel support fitting is above the upper end of the control rod.

Thereafter, the rotary drive source for rotating the control rod gripping mechanism with respect to the main body is operated to rotate the control rod gripping mechanism. Since the control rod is fixed to the control rod gripping mechanism,
The control rod and the control rod drive mechanism are uncoupled by rotating simultaneously. During this rotation, the fuel support fitting is above the upper end of the control rod, so they do not come into contact with each other.

Next, the entire main body is lifted via a wire rope that suspends the main body, and is moved to a storage pool provided outside above the reactor pressure vessel for storage.

Therefore, according to the present invention, CR and FS in the reactor pressure vessel can be grasped together and then removed, and can be hung together outside the reactor pressure vessel. CR and FS in the reactor pressure vessel are removed and lifted as compared with the case where the CR and FS are sequentially grasped by separate grasping tools and then removed and then respectively hung outside the reactor pressure vessel. The work efficiency of the work can be significantly improved. As a result, the workability of the BWR regular inspection work can be significantly improved.

The configuration of the further preferred embodiment provides the following actions and effects.

The CR lifting air cylinder as the driving means for the CR (control rod) gripping portion can adjust the lifting height according to the pressure of the supply air. Therefore,
By increasing the pressure of the supply air from low pressure to high pressure, the hook and the C
The hook can be raised to the extent that the play between the R and the handle is eliminated, and then the hook can be further lifted. For this reason, since it is possible to mitigate the impact when the CRs are lifted all at once by the hooks, it is possible to improve both the soundness and the safety of the CR when the CRs are lifted.

Further, since the control rod rotating mechanism is connected to the rotating member for rotating the rotating body which hangs the hook for grasping the handle of the CR through the wire to the forward / reverse rotating air cylinder as the driving means, the rotating member is rotated. It is possible to reduce the burden of the rotational force.

If the supply of air to the control rod gripping air cylinder is interrupted while the CR is gripped by the hook driven by the control rod gripping air cylinder, control is performed by the spring force of the spring. The gripping operation of the rod gripping air cylinder is retained.

Therefore, even if the CR is grasped by the hook and the air supply to the control rod grasping air cylinder is interrupted due to breakage of the air hose or the like while the CR is being lifted, the hook releases the CR. Since it is not present, it is safe and can exhibit a fail-safe effect.

In the unlikely event that the CR release operation cannot be performed due to a failure of the control rod gripping air cylinder, the CR release operation can be forcibly executed by pulling the cord.

Since the pair of plungers are projected and supported in the existing pair of side holes of the FS, it is not necessary to perform any gripping processing on the FS side, and the plungers are opposed to each other in the radial direction of the FS. Since the pair of plungers are inserted into and supported by the pair of side holes, respectively, and suspended, the FS is supported and suspended in a stable state with a radial balance. And can be raised together.

When the FS is grasped and lifted by the FS grasping portion, the grasped state is locked by the lock mechanism, so that it is possible to prevent the FS from dropping and being damaged by the releasing operation of the FS. It is possible to improve both reliability and safety.

Further, if the supply of air to the FS gripping air cylinder is interrupted by the breakage of the air hose or the like while gripping the FS by the FS gripping air cylinder as the driving means, the spring will move. The spring force holds the gripping action of the FS gripping air cylinder.

Therefore, even if the supply of air to the FS grasping air cylinder is interrupted due to breakage of the air hose or the like while grasping and lifting the FS, the FS is not released, which is safe. Therefore, a fail-safe effect can be achieved.

If the FS releasing operation cannot be performed due to a failure of the FS grasping air cylinder or the like, the FS releasing operation can be forcibly performed by pulling the cord.

When the upper plate is seated on the upper lattice plate, and C
When the R grip portion is seated on the handle of the control rod and when the FS grip portion is seated on the FS, these seating positions are respectively detected by the seating detection devices.

Therefore, after confirming the presence or absence of these seats, it is possible to carry out a series of operations of gripping, removing and lifting CR and FS. As a result, the reliability of these series of operations can be improved and the operations can be smoothly performed.

Since the slack of the air hose or the cable is always absorbed by the slack absorbing mechanism such as the cable, it is possible to reduce the possibility that the slack of the air hose or the cable may be caught by other members and cause some trouble. You can improve your sex.

[0056]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 9, the same or corresponding parts are designated by the same reference numerals.

FIG. 1 is a schematic vertical sectional view showing the whole construction of an embodiment of the present invention suspended in the core of a reactor pressure vessel, and FIGS. 2 to 8 are detailed views of respective parts thereof. However, CR
The (control rod) 4 is detachably connected to a CRD (control rod drive mechanism) 8 by a bayonet coupling 14 shown in FIG.

The control rod / fuel support metal fitting 20 of one embodiment of the present invention is suspended in the reactor pressure vessel 1 at the time of periodic inspection of BWR and the like, and is installed in the core portion thereof. C
The R4 and the FS (fuel support metal fitting) 6 are detached and hung up to the outside of the reactor pressure vessel 1, and used again to be installed in the reactor core. For example, an auxiliary hoist of a fuel exchanger (not shown), etc. An upper plate 30 which is bound by a hanging rope or the like and moves up and down, a CR grip portion 40 which is hung on the upper plate 30 so as to be rotatable around an axis and movable up and down.
FS grip portion 50 that can be lifted up and down on the R grip portion 40
Have and.

As shown in FIGS. 1 and 2, the upper plate 30 is hung on a required lattice of the upper lattice plate 5 so that the entire load of the control rod / fuel support fitting gripping tool 20 is loaded on the upper lattice plate 30. An upper plate seating detection lever 30a is swingably provided on the bottom surface of one corner portion of the upper plate 30 by being loaded on the upper plate so as to prevent rotation.

When the upper plate 30 is seated on the upper lattice plate 5, the swinging end of the upper plate seating detection lever 30a swings to move the upper plate seating detection limit switch 30b. When the switch is turned on, the upper plate seating detection signal is output to a fuel exchanger or the like via a cable (not shown).

The upper plate 30 has a support tube 31 of a rectangular tube shape fixed to the center thereof by penetrating in the vertical direction in the figure, and a square stud 32 is pinned on the center of the upper end of the support tube 31. Three
It is swingably erected by 2a so that it cannot easily cope with the long control rod / fuel support fitting gripping tool 20 from a horizontally stored state to a vertically suspended state.

The square stud 32 has a screw hole 32b formed at the upper end thereof as shown in FIGS. Connect to the screw hole 32b by screwing a bolt attached to the tip of a wire rope such as a torqueless wire for preventing rotation of an auxiliary hoist of a fuel exchanger (not shown),
The entire control rod / fuel support fitting gripping tool 20 is hung up and down without rotating.

The support cylinder 31 is internally provided with a CR grip portion 40, and this CR grip portion 40 has a cylindrical inner and outer double cylinder 41, 4.
2 is housed concentrically in the support cylinder 31, and the outer cylinder 42 is fixed to the support cylinder 31, while the rotary cylinder 41 of the inner cylinder is rotated around the axial center of the outer cylinder 42 by the thrust bearing 43a and the radial bearing 43b. It is attached to be freely rotatable.

The rotary cylinder 41, as shown in FIGS. 1 and 4,
A hook 44 for gripping or releasing the grip 4d of the CR 4 is attached to the lower end portion thereof, while the CR rotation mechanism 45 shown in FIGS. 2 and 6 rotates in both forward and reverse directions around the axis.

In the CR rotation mechanism 45, a rotary gear 45a is provided on the side of an axially intermediate portion of the rotary cylinder 41 so as to be interlocked with the rotary cylinder 41, and both ends of a wire 45b wound around the rotary gear 45a are provided. Further, after being respectively wound around the pulleys 45c and 45d, the pair of left and right air cylinders 45e and 45f for rotational driving are connected to the upper and lower ends of the piston rod 45g, respectively, and the rotary cylinder 41 is rotated by the reciprocating movement of these piston rods 45g. It is designed to rotate in the forward and reverse directions around the heart.

The rotary cylinder 41 is moved up and down by a CR lifting air cylinder 46. When low-pressure air is supplied to the rising chamber side (lower chamber side) in this air cylinder 46, CR4 is applied. The hook 44 which holds the handle 4d with a little play is raised a little, and the hook 44 is raised so as to eliminate the play with the handle 4d and is brought into close contact with the handle 4d. It is designed to absorb shocks. Further, when the supply air has a high pressure, the CR lifting air cylinder 46 is configured to raise the position by, for example, several tens of millimeters to a position higher than the lifting height when the supply air has a low pressure.

As shown in FIG. 4, the rotary cylinder 41 has a CR gripping mechanism 47 built in the lower end thereof. The CR gripping mechanism 47 links the piston rod 47b of the hook opening / closing air cylinder 47a to the swinging end of the hook 44 via the link mechanism 47c to supply air to the hook opening / closing air cylinder 47a. And the lower chamber side, the hook 44 is opened or closed to grip or release the grip 4d of the CR4. Further, a hook opening detection limit switch 47d for detecting the opening of the hook 44, and the hook 4
Hook detection limit switch 47e for detecting closing of 4
And a CR seating detection limit switch 47f for detecting seating of the hook 44 on the grip 4d of the CR4.

The rotary cylinder 41 has a guide protrusion 4 on its bottom surface.
7g is projected. The guide protrusion 47g has a guide groove formed on the bottom surface thereof and adapted to the cross-shaped central portion of the cross-shaped handle 4d. As the hook 44 descends toward CR4, the cross-shaped guide groove is formed. The hook 44 is guided into the optimum gripping position of the grip 4d by gradually fitting it inside.

Further, an air cylinder 47a for opening and closing the hook
As a countermeasure against such a failure, when the air supplied to the air cylinder 47a is interrupted due to breakage of the air hose or the like, the piston rod 47b is moved to the gripping operation side so as to hold the gripping operation. Assembling the holding spring 47i for urging the piston rod 4
By connecting the release operation wire 47h to 7b and pulling the wire 47h strongly against the spring force of the holding spring 47i, the hook opening / closing air cylinder 47a is forcibly released. There is.

On the other hand, in the FS grip portion 50, as shown in FIG. 3, the lower half of the double cylinder of the support cylinder 31 and the rotary cylinder 41, which is a square cylinder, has a larger diameter than the support cylinder 31. Lifting angle cylinder 51
7A and 7B, the up-and-down angle tube 51 is attached to the inner support tube 31 so as to be able to move up and down with a shift of approximately 45 ° C. around the axis.

That is, the FS elevating air cylinder 52 is fixed to the outer surface of the intermediate portion in the axial direction of the support cylinder 31 having a rectangular tube shape, and the FS elevating air cylinder 52 is elevated and lowered by the piston rod 52a. The rectangular tube 51 is suspended so that it can be raised and lowered.

Further, as shown in FIG. 8, a plurality of guide rollers 53, 53 ... Rotating the outer surface of each corner portion of the outer surface of the support tube 31 in the shape of a rectangular tube is provided inside the elevating angle tube 51. ing. On the other hand, as shown in FIG. 4, the up-and-down angle cylinder 51 has a cross-shaped insertion hole 51b through which the cross-shaped grip 4d of the CR4 is inserted in the bottom surface 51a, and each corner portion of the bottom surface 51a as shown in FIG. Corner pins 54, which come into contact with the guide pins of the core support plate 7, are provided on the outer surface so as to project vertically downward.

Further, as shown in FIG. 4, a pair of plate-shaped guides 55, 55 are provided on the bottom surface 51a of the up-and-down angle tube 51 at a pair of corner portions opposed to each other in a diagonal direction thereof. , FS6 shown in FIG. 13 are inserted into a pair of diametrically opposed fuel supporting fitting holes, for example, 6b and 6d, and guide the hook 44 to the grip 44d of the CR44.

The up-and-down angle cylinder 51 has a pair of left and right FS gripping mechanisms 56 and FS gripping locking mechanisms 57 in its lower end portion.
And an FS seating detection device 58. Note that FIG.
Then, only one of the pair of left and right FS gripping mechanisms 56 is shown and the other is omitted.

Each FS gripping mechanism 56 projects in a pair of diametrically opposed orifices of the FS 6, for example, 6f and 6h, and a pair of plungers 56 that grip the FS 6 respectively.
The FS gripping air cylinder 56c for moving the a through the ring mechanism 56b and the FS gripping air cylinder 5c.
6c has an FS grip detection limit switch 56d for detecting a gripping operation of the FS 6 and an FS release detection limit switch 56e for detecting a release operation of the FS 6.

The FS gripping air cylinder 56c is provided as a measure against the failure of the FS gripping air cylinder 5c.
When the FS 6 is being gripped by the 6c, if the air supplied to the FS gripping air cylinder 56c is interrupted due to breakage of the air hose, etc., the piston rod 56f is attached in a direction to hold the gripping operation. It has a built-in grip holding spring 56g.

Further, a wire rope 56h for release operation is connected to the FS gripping air cylinder 56c, and the wire rope 56h is pulled up against the spring force of the gripping holding spring 56g to pull up the FS gripping wire. The grasping operation of the air cylinder 56c is forcibly switched to the releasing operation, and the pair of plungers 56a, 56a are retracted inward from the pair of orifices 6f, 6h of the FS6 to forcibly FS.
It is designed to release 6.

The FS grip lock mechanism 57 is a lifting / lowering rectangular tube 51.
A lock lever 57a is provided on the bottom surface 51b of the FS so as to be swingable, and is biased so as to be always engaged in the engagement hole 56i of the connecting rod 56f of the link mechanism 56b of the FS gripping mechanism 56. , The connecting rod 56f is constrained, and when the bottom surface 51a of the ascending / descending angle cylinder 51 is seated on the upper surface of the FS 6, the lock lever 57a swings to cause the connecting rod 56f to swing.
The link mechanism 56b can be operated by releasing the restraint of the connecting rod 56f by being disengaged from the engaging hole 56i of f.

Therefore, when the bottom surface 51a of the up-and-down angle tube 51 is separated from the upper surface of the FS 6, the lock lever 57a swings to be engaged in the engaging hole 56i of the connecting rod 56f and release the connecting rod 56f. By restraining, the gripping operation of the FS 6 is locked.

In the FS seating detection device 58, a seating detection lever 58a is swingably provided on the bottom surface 51a of the up-and-down angle cylinder 51.
When the seating detection lever 58a is seated on the upper surface of the FS 6, its oscillating end turns the FS seating detection limit switch 58b on and off to output or stop the FS seating signal.

As shown in FIGS. 1 and 3, an absorbing mechanism 59 such as a cable is provided on the inner surface of the upper portion of the elevating / lowering angle cylinder 51. This is each air cylinder 45e, 45f, 46, 4
The ropes 59a, 59b and the spring 59c absorb the cords 60 such as the air hoses and cables connected to the cables 7a, 52, 56c, the operating wires 45h, 47h, 56h, and the trouble caused by the slack of the cords 60. This is to prevent the occurrence.

Next, by using the control rod / fuel support fitting gripping tool 20 having the above-mentioned structure, at the time of periodic inspection of the BWR,
A case where the CR4 and the FS6 are pulled up from the water-filled reactor pressure vessel 1 will be described.

First, as shown in FIG. 9 (A), in order to maintain the subcriticality of four fuel assemblies 3, 3, 3, 3 which are adjacent to each other in one lattice, CR4 is entirely placed in the core. After being inserted, the two fuel assemblies 3 and 3 which are diagonal to each other in that state are pulled out from the core by a fuel exchanger or the like.

Next, as shown in FIG. 9B, a blade guide (a pair of simulated channels 61a, 61b is connected diagonally with a handle 61c at the trace of the two fuel assemblies 3, 3 being pulled out). Insert the control rod guide device) 61. Thereafter, as shown in FIG. 9C, the remaining two fuel assemblies 3 and 3 are pulled out from the core.

Next, as shown in FIG. 9 (D), CR4 is guided by a blade guide 61 and moved below the core by CRD8 to a fully drawn state, and then further shown in FIG. 9 (E). The blade guide 61 is pulled out from the core.

Then, the bolt of the wire rope of the auxiliary hoist (not shown) of the fuel exchanger is screwed into and suspended in the screw hole 32b of the rectangular stand 32 of the control rod / fuel support fitting grip 20 of this embodiment. , 1 into the reactor pressure vessel. Thereafter, as shown in FIG. 1, the upper plate 30 of the control rod / fuel support fitting grip 20 is seated on the upper surface of the upper grid plate 5, and almost the entire load of the control rod / fuel support fitting grip 20 is set. Is moved from the wire rope to the upper lattice plate 5.

When the upper plate 30 is seated on the upper surface of the upper lattice plate 5 in this way, the upper plate seating detection lever 30a contacts the upper surface of the upper lattice plate 5 and swings, thereby moving the upper plate seating detection limit switch 30b. When the switch is turned on, the upper plate seating detection signal is output to a fuel exchanger or the like through a cable not shown.

At this time, the bottom surface 51a of the up-and-down angle tube 51 is
Seats on the upper surface of the FS 6 and the upper surface of the handle 4d of the CR 4 substantially simultaneously, so that both seating signals are output from the CR seating detection limit switch 47f and the FS seating limit switch 58b.

Furthermore, at this time, the lock lever 57a is disengaged from the engaging hole 56i of the connecting rod 56f, and the lock mechanism 5
The restraint of 7 is released.

Then, next, the FS gripping air cylinder 56.
When air is supplied to c, the pair of left and right plungers 56a and 56a project into the pair of orifices 6f and 6h of the FS6 via the ring mechanism 56b whose restraint is released.
Grab 6 At this time, the FS grip detection limit switch 56
A grip signal for detecting the grip state of the FS6 is output from d.

Similarly, when air is supplied to the grip side of the hook opening / closing air cylinder 47a, the hook 44 moves to C
CR4 is gripped by closing the grip 4d of R4 while holding it with some play in the vertical direction. At this time, the hook closing detection limit switch 47e outputs a hook closing signal.

Then, the CR lifting air cylinder 46 is next.
When low-pressure air is supplied to the rotary cylinder 41, the rotary cylinder 41 is slightly raised, so that the hook 44 comes into contact with the lower surface of the handle 4d of the CR4.

That is, since the pressure of the air supplied to the CR lifting air cylinder 46 is low, the hook 44 and the C
Only the gap (play) between R4 and the handle 4a rises, and the hook 44 comes into close contact with the handle 4d.

Next, when air is supplied to the ascending chamber side (lower chamber side) of the FS elevating / lowering air cylinder 52, the ascending / descending angle cylinder 51
Rises. For this reason, the FS6 grasped by the FS grasping mechanism 56 is slightly lifted up from the core support plate 7 and removed, and the bottom surface of the FS6 is raised to a height slightly higher than the upper surface of the handle 4d of the CR4. Once held at that height.

When the elevating and lowering cylinder 51 is raised, a plurality of guide rollers 53, 53 provided on the inner surface thereof rotate on the outer surface of the support cylinder 31 in the shape of a rectangular cylinder, so that the elevating and lowering cylinder 51 and its F
It is possible to prevent the FS 6 gripped by the S gripping mechanism 56 from rotating around the axis. Therefore, it is possible to prevent interference such as the FS 6 hitting the fuel assemblies 3 loaded in the adjacent lattices.

Thereafter, in order to further raise the CR gripping mechanism 47 by several tens of millimeters to rotate the CR 4, high pressure air is supplied to the rising chamber side (lower chamber side) of the CR lifting air cylinder 46.

As a result, all the loads of the connecting members of the CR4 and CR8 bayonet couplings 14 are received by the control rod / fuel support fitting gripping tool 20, and the loads are loaded and supported by the upper lattice plate 5. .

When air is supplied to one of the CR rotation driving air cylinders 45e, 45f, for example, 45e, in such a suspended state of the CR4, the rotation gear 45a is rotated in the forward direction, and the rotation cylinder 45 is substantially rotated by the rotation gear 45a. The bayonet coupling 14 of CR4 and CRD8 can be disconnected by rotating it by 45 °. When air is supplied to the other CR rotation driving air cylinder 45f to rotate the rotation cylinder 41 in the reverse direction by about 45 °, CR4 and CRD8 are connected to the bayonet coupling 14 again.
Can be connected by.

After removing CR4 from CRD8 in this way, CR4 and FS6 are lifted toward the upper core by winding a wire rope such as an auxiliary hoist of the fuel exchanger.

Then, these CR4 and FS6 are passed through the upper lattice plate 5 to be pulled up from the inside of the reactor pressure vessel 1 to the reactor well above it, and further, the fuel communicating with this reactor well in water. After moving it into the storage pool in water, the CR and CS gripping mechanisms 47 and 56 are released at a predetermined position to release CR4 and FS6, and the work is completed. However, if these gripping mechanisms 47, 56 cannot be released for some reason, the release operation wires 47h, 56h are pulled strongly to force CR4 and FS.
6 and can be released.

Further, once the CR4 and FS6 are gripped by the CR and FS gripping mechanisms 47 and 56, the gripping operation is held by the holding springs 47g and 56g and the lock mechanism 57, so that CR and FS are held. While the CR4 and FS6 are being gripped by the two gripping mechanisms 47 and 56, these CR4 and FS6 can be released to prevent an unexpected situation from occurring.

According to the present embodiment, CR4 and FS
6 and 6 can be grasped and removed together by the control rod / fuel support fitting grasping tool 20, and these CR4 and FS6 can be hung from the reactor pressure vessel 1 to the outside at substantially the same time. The work can be performed easily, surely and quickly, and the workability of the BWR regular inspection can be significantly improved.

FIG. 10 shows a second embodiment of the present invention.

In this second embodiment, the gripping tool body 10
0 drives the hoist which is not illustrated via wire rope 101, and is hung in the reactor pressure vessel. Hanging hand 10
Reference numeral 2 is attached to the upper portion of the grip body, and has a role of attaching the wire rope 101 to the grip body 100. At the bottom of the grip body 100, a fuel support metal grip 1
03 is provided, and the fuel support fitting 6 placed on the core support plate 7 can be grasped. In the grip body 100, a control rod grip 106 for gripping the head of the control rod 111 is provided on the shaft 107 and the shaft 1.
It is attached via a support plate 108 that supports 07. The shaft 107 is attached to a support plate 108 so as to be vertically movable, and a control rod rotating unit 109 that drives the shaft 107 to rotate with respect to the support plate 108 is provided near this attachment portion.
Is provided. . A stopper 110 is formed on the upper end of the shaft 107 to prevent the control rod grip 106 and the shaft 107 from falling off the support plate 108 when the grip body is raised. The upper lattice plate 5 shown in the upper part of the figure horizontally supports the head of a fuel assembly (not shown), and one cell 113 in which the grip body 100 is installed has an ordinary nuclear reactor. In operation, four fuel assemblies are arranged. Further, the horizontal cross-sectional shape of the grip body 100 is a regular square that is slightly smaller than the regular cell 113, so that the grip body 100 or the cell 113 does not rotate. A method for taking out the control rod 111 and the fuel support fitting 104 to the outside of the reactor pressure vessel by using the grip body 100 configured as described above will be described with reference to FIGS. 10 and 11.

The state before the operation is shown in FIG. The fuel support fitting 6 is installed on the control rod guide tube 114 supported by the core support plate 7. The fuel support fitting 6 is prevented from rotating by a pin 115 fixed to the core support plate 7. The control rod 4 penetrates the inside of the fuel support fitting 6 and has a head protruding upward. In this state, the gripping tool main body 100 is suspended from above using the wire rope 101 and placed on the fuel support fitting 6. Figure 10 at this point
The state becomes as shown in. From this state, the fuel support fitting grip 1
03 is operated to grasp the fuel support fitting 6. Further, the control rod gripper 106 is operated to grip the control rod 111.

Then, the wire rope B is pulled up to pull up the grip body 100. At this time, the fuel support fitting 6 rises at the same time as the grip body 100, but the control rod grip 106 does not rise because the shaft 107 slides. FIG. 11B shows a state in which the fuel support fitting 6 is raised.

Next, the control rod rotating portion 109 is driven to rotate the control rod gripping tool 106 and the control rod 4 by 45 ° to control the control rod 4.
And the control rod drive mechanism are uncoupled. The state before rotation is shown in FIG.

Then, the control rod 4 and the fuel support fitting 104 are taken out of the furnace by lifting the grip body 100 with the wire rope 101. The state before pulling up the control rod is shown in FIG. When the gripping tool main body 100 is raised, the control rod gripping tool 106 does not slide down because of the stopper 110, and the control rod 4 ascends together with the fuel support fitting 6.

As described in the above two embodiments, in the present invention, as shown in FIG. 12 (B), the fuel support fitting 6 is not rotated in the horizontal direction from the installed state shown in FIG. 12 (A),
Uncouple by rotating only control rod 4. Therefore, the control rod and the fuel support fitting can be taken out of the reactor at the same time without moving the fuel assemblies around.
The fuel assembly 116 shown in FIG. 12C is the fuel assembly that is currently being pulled out in order to install a television camera that is installed in order to monitor all working states of the gripping tool. It is expected that the fuel assembly 116 will not need to be pulled out when the reliability of the fuel assembly 116 is confirmed by the accumulated use results of the gripping tools in the future.

[0110]

As described above, according to each of the inventions in the claims of the present application, the control rod and the fuel support fitting in the reactor pressure vessel are grasped together and then removed, and the control rod and the fuel support fitting are removed to the outside of the reactor pressure vessel. Since it can be lifted, when the control rod and the fuel support fitting inside the reactor pressure vessel are sequentially gripped by separate gripping tools and then removed before being respectively hung outside the reactor pressure vessel. Compared with the above, the work efficiency of the work of removing and hoisting the control rods and fuel support fittings in the reactor pressure vessel can be significantly improved. As a result, the workability of the BWR regular inspection work can be significantly improved.

Further, in the conventional method for taking out using the simultaneous grasping tool (shown in FIG. 19), it is necessary to combine the peripheral fuel assemblies with 20 pieces.
It was necessary to remove the fuel assembly of the body, but according to the invention of the present application, only seven bodies are needed, and it is expected that this will be reduced to four in the future. That is, the amount of removal work can be significantly reduced. Further, it is possible to obtain an effect that the storage space in the storage pool, which is required when using the conventional separate gripping tools, can be reduced to 1/2.

According to the fifth aspect of the present invention, the control rod rotating mechanism has the air cylinder for forward / reverse rotation via the wire to the rotating member for rotating the rotating body that suspends the hook for holding the handle of the control rod. Since it is connected to and rotated, the burden of the rotational force can be reduced.

According to the sixth aspect of the invention, while the control rod is being held by the hook driven by the first control rod holding drive source, the first control rod holding drive source is held. When the supply of motive power to the control rod is interrupted, the grasping operation of the control rod grasping first drive source can be maintained by the spring force of the spring.

Therefore, hold the control rod with the hook,
Even if the motive power supply to the control rod gripping first drive source is interrupted due to breakage of the motive power line during lifting, the hook does not release the control rod, so it is safe and fails. A safe effect can be achieved.

Further, according to the invention described in claim 7, if the control rod cannot be released due to a failure of the control rod gripping first drive source, the control is performed by pulling the cord. You can force the release of the stick.

Further, according to the invention of claim 8, since the pair of plungers are projected and supported in the existing pair of side holes of the fuel support fitting, the processing for grasping on the fuel support fitting side. In addition, it does not need to be provided, and since a pair of plungers are inserted and supported in a pair of side holes facing each other in the radial direction of the fuel support fitting and are suspended, the fuel support fitting is balanced in the radial direction. Since it is supported and hoisted in a stable state, the reliability and safety of these hoists or hoists can be improved.

Further, according to the invention of claim 9, when the fuel support fitting is gripped by the fuel support fitting grip portion and is lifted, the gripping state is locked by the lock mechanism. It is possible to prevent the fuel support fitting from dropping and being damaged by the releasing operation, and it is possible to improve both reliability and safety.

According to the tenth aspect of the present invention, while the fuel support fitting is being held by the first drive source for gripping the fuel support fitting, the first drive source for gripping the fuel support fitting is moved to the first drive source. When the supply of motive power is interrupted due to breakage of the supply line, etc., the spring force of the spring causes the fuel holding metal fitting first
The gripping operation of the drive source is retained.

Therefore, even if the supply of the motive power to the first drive source for grasping the fuel support fitting is interrupted by the motive power supply line or the like while the fuel support fitting is being grasped and lifted, the fuel support fitting is stopped. Is safe,
A fail-safe effect can be achieved.

Further, according to the invention described in claim 11, if the release operation of the fuel support fitting cannot be performed due to a failure of the first drive source for grasping the fuel support fitting, the cord is pulled. Thus, the release operation of the fuel support fitting can be forcibly performed.

[Brief description of drawings]

FIG. 1 is a schematic partially cutaway vertical cross-sectional view showing the overall configuration of a first embodiment of a control rod / fuel support fitting gripping tool according to the present invention in a state of being suspended in a core of a reactor pressure vessel.

2 is a detailed view of the upper part of the embodiment shown in FIG.

FIG. 3 is a detailed view of an intermediate portion of the embodiment shown in FIG.

FIG. 4 is a detailed view of the lower portion of the embodiment shown in FIG.

5 is a partial cross-sectional view taken along the line VV of FIG.

6 is a view taken along the line VI-VI of FIG.

7 (A) is a sectional view taken along the line VIIA-VIIA in FIG.
FIG. 7B is a sectional view taken along the line VIIB-VIIB in FIG.

8 is a sectional view taken along the line VIII-VIII in FIG.

9A to 9E are plan views showing steps of pulling out a fuel assembly from a required lattice.

FIG. 10 is a schematic partially cutaway vertical cross-sectional view showing the overall configuration of a second embodiment of the control rod / fuel support fitting gripping tool according to the present invention when it is suspended in the core of a reactor pressure vessel.

11A to 11D are schematic views showing an uncoupling step from the CR side in the embodiment shown in FIG.

12 (A) to 12 (C) are plan views showing a process of pulling out a fuel assembly from a required lattice.

FIG. 13 is a partially cutaway vertical sectional view of a core portion of a general BWR.

FIG. 14 is a partially cutaway perspective view of the upper lattice plate shown in FIG.

15 is a partially cutaway perspective view of the CR, FS and core support plate shown in FIG.

16 is an enlarged perspective view of the FS shown in FIG. 15 and the like.

FIG. 17 is a partial enlarged view of a CR and CRD coupling portion shown in FIG.

18 (A) to (C) are schematic cross-sectional views of bayonet couplings that are a connecting mechanism between CR and CRD.

19 (A) to 19 (C) are plan views showing steps of pulling out a fuel assembly from a required lattice based on the conventional technique.

[Explanation of symbols]

 1 Reactor Pressure Vessel 2 Core Shroud 3 Fuel Assembly 4 Control Rod 5 Upper Lattice Plate 6 Fuel Support Bracket 7 Core Support Plate 8 Control Rod Drive Mechanism 20,100 Control Rod / Fuel Support Bracket 30 Upper Plate 30a Upper Plate Seating detection lever 30b Upper plate seating detection limit switch 31 Support tube 32 Square tube stud 40,106 Control rod gripping section 41 Rotating tube 42 Outer tube 43a Thrust bearing 43b Radial bearing 44 Hook 45,109 CR rotating mechanism 45a Rotating gear 45e, 45f Air cylinder for rotation drive 45g Piston rod 46 CR Air cylinder for lifting / lowering 47 CR gripping mechanism 47a Hook opening / closing air cylinder 47b Piston rod 47c Link mechanism 47d Hook open detection limit switch 47e Hook closed detection limit switch 47f CR seating detection limit switch Chi 47i Holding spring 47h Release operation wire 50, 103 FS grip portion 51 Lifting angle cylinder 51a Bottom surface 51b Cross opening 52 FS lifting air cylinder 53 Cide roller 54 Corner pin 55 Guide 56 FS gripping mechanism 56a A pair of plungers 56b Link mechanism 56c FS grip air cylinder 56d FS grip detection limit switch 56e FS release detection limit switch 56f piston rod 56g holding spring 56h release operation wire 56i engagement hole 57 FS lock mechanism 57a lock lever 58 FS seat Detection device 58a FS seating detection lever 58b FS seating detection limit switch 61 Blade guide 61a, 61b Simulated channel

Claims (12)

[Claims] 1. A fitting hole for supporting a fuel assembly, which is placed on a core support plate below an upper lattice plate in a reactor pressure vessel to support the bottom portions of a plurality of fuel assemblies by being fitted therein. And a fuel support fitting having a control rod insertion hole,
A control rod which is detachably connected to the control rod drive mechanism by a bayonet coupling and is vertically inserted through the control rod insertion passage is grasped and detached from the core support plate and the control rod drive mechanism, respectively. In the control rod / fuel support fitting gripping tool, a gripping tool main body that can be lifted up and down in the reactor pressure vessel, a fuel support gripping mechanism provided at the bottom of the main body, and A control rod gripping mechanism, which is provided in a lower portion, is provided so as to be vertically movable and rotatable with respect to the main body, and a rotary drive source for rotating the control rod gripping mechanism with respect to the main body. A control rod / fuel support metal fitting gripping tool. 2. The control rod / fuel support according to claim 1, wherein the fuel support fitting of the grip body is provided with a seating detection mechanism which is activated when the grip body is seated on the fuel support fitting. Hardware gripping tool. 3. The control rod / fuel support metal gripping tool according to claim 1, further comprising a mechanism for detecting when a rotation angle of the control rod gripping mechanism with respect to the main body becomes a predetermined value or more. . 4. An upper plate, which is placed on an upper grid plate, is mounted on an upper part of the grip body via an elevating and lowering drive mechanism so that the upper body can be moved up and down with respect to the upper grid plate. The control rod / fuel support fitting gripping tool according to claim 1, wherein 5. The control rod gripping portion is hung by a rotating body rotatably attached to an upper plate, and a hook for freely gripping the handle of the control rod is provided. Attached to a first drive source for gripping the control rod for performing a releasing operation, a second drive source for raising and lowering the hook for raising and lowering the hook, and a rotating member that interlocks with the rotating body so as to rotate forward and backward. 2. The control rod according to claim 1, further comprising: a rotating mechanism that connects both ends of the wire to both ends of a reciprocating piston rod of a third drive source to rotate the rotating body in a reversible manner. -Fuel support metal grip tool. 6. The first drive source for gripping the control rod is urged in a direction for holding the gripping operation of the hook when the supply fluid is lost. Control rod and fuel support metal fittings. 7. The first drive source for gripping the control rod is connected to a cord, and when the cord is pulled, the hook is opened to force a releasing operation. The control rod / fuel support fitting gripping tool according to claim 2 or 3, which is configured. 8. The pair of fuel support fitting grips is movable inward and backward from a pair of radially facing side holes communicating with the fuel assembly supporting fitting holes of the fuel support fitting. A first drive source for grasping the fuel support fitting by projecting each of the grasping plungers, and a second drive source for raising and lowering after grasping the fuel support fitting by the grasping plunger and lifting. The control rod / fuel support fitting gripping tool according to claim 1, which has. 9. The first support drive mechanism for gripping, when the fuel support support gripping mechanism is driven by a first drive source for gripping the fuel support support and then lifted by a lifting drive mechanism. 9. The control rod / fuel support fitting gripping tool according to claim 1, further comprising a lock mechanism for holding the power source in the gripping operation state to prevent the gripping from being released. 10. The gripping first drive source is equipped with a gripping state holding mechanism for holding the gripping operation state of the fuel support fitting when the supply source is lost. The control rod / fuel support fitting gripping tool according to item 9. 11. The first drive source for gripping is connected to a line, and when the line is pulled, the pair of plungers are retracted inward from the pair of side holes of the fuel support fitting. The control rod / fuel support fitting grip according to any one of claims 9 and 10, wherein the control rod / fuel support fitting gripping tool is configured so as to forcibly perform a releasing operation. 12. A first step of pulling a fuel support fitting upward from a core support plate by a predetermined distance, and a second step of separating the control rod and the control rod drive mechanism by rotating the control rod by a predetermined angle after the first step. And a third step of, after the second step, pulling up the fuel support fitting and the control rod from the upper portion of the reactor pressure vessel, a method of taking out the fuel support fitting and the control rod.