JPH01116494A - Guide joint for mobile type internal core instrumentation system - Google Patents

Abstract

PURPOSE:To lock a sleeve positively at a connection holding position between a plug and a socket by locking a sleeve of a connection holding mechanism at a connection holding position between the plug and the socket with a lock pin and a lock member. CONSTITUTION:A lock member 46 being cylindrical is fitted rotatably and slidably into the circumferential side of a socket 35 and a small-dia. portion 46a thereof is inserted into a large-dia. hole section 43b of a sleeve 43 to abut a compression coil spring 45 while a flange 46b thereof abuts the sleeve 35. A pair of lock pins 49 engaged with grooves 47 and 48 of the lock member 46 is protruded onto the circumferential surface of the socket 35. When connecting guide pipes 11a and 11b, with a deep groove 48 of the member 46 engaging the pin 49, the sleeve 43 is moved axially against an energizing force of the spring 45 and a plug 33 is inserted into the socket 35 up to a position where a ball 42 is inserted and retained into a hollow 36 of the plug 33 and then, the sleeve 43 is released.

Description

DETAILED DESCRIPTION OF THE INVENTION (Objective of the invention) (Industrial application field) The present invention is directed to an output*tlt neutron detection system for monitoring in-reactor neutron flux installed in, for example, a van water reactor (hereinafter referred to as 3WR). Mobile in-core instrumentation system (Tr
aversing Incore Probe 5ys
tes, hereinafter referred to as TIP), relates to a guide pipe joint that connects a guide pipe for neutron detector insertion below the reactor.
In particular, the present invention relates to a guide pipe joint that can reliably maintain a locked state in a connected position.

(Prior Art) FIGS. 6 and 7 show the overall configuration of a TIP provided in a BWR.

As shown in FIG. 6, in a BWR, a reactor pressure vessel 1 is mounted and fixed on a reactor pressure vessel pedestal 3 in a reactor containment vessel 2, and a heat shielding wall 4 is erected on this pedestal 3.
is surrounded by. A coolant and a reactor core are housed in the reactor pressure vessel 1, and the reactor core is composed of a plurality of fuel assemblies, control rods, and the like.

A plurality of power range detector assemblies 5 are installed in the reactor pressure control unit 111, and a calibration 116 is inserted into the power range detector assemblies 5. A mobile neutron detector is inserted into this calibration tube 6 in order to calibrate the output region neutron flux detector. This neutron detector is a detection V! installed outside the reactor containment vessel 2. It is wire driven by the J drive device 7. That is, the wire is led from the detector drive device 7 via the shielding vessel 8 and the valve assembly 9 to the index 1fflO in the reactor containment vessel 2'. Index device 10
A plurality of guide tubes 11 are provided with openings, and each of the guide tubes 11 is led to the lower part of the reactor pressure vessel 1 and connected to the calibration tube 6, respectively.

FIG. 7(A) shows an enlarged view of the arrangement of the guide tube 11 inside the pedestal 3. That is, within the pedestal 3, the guide pipe 11 is connected near the exit side of the indexing device W110 and near the lower end of the output area detector assembly 5 by guide pipe joints 12, respectively. FIG. 7(B) shows an enlarged view of the connecting portion.

Note that the selection of which output area detector assembly 5 the TIP neutron detector is inserted into is determined by switching in the indexing device 10. Furthermore, the inner circumferential surfaces of the guide tube 11 and the guide tube joint 12 are coated with dry fllfl material to reduce frictional resistance with the neutron detector.

By the way, during periodic inspections of nuclear reactors, the guide pipe 1' inside the pedestal 3 is
1 is being removed. That is, this guide tube 1 is removably connected to the calibration tube 6 and the indexing device 10 via guide tube joints 12 in the vicinity of each of them, and each of the guide tube joints 12 has a one-touch joint structure and can be removed and removed. This allows work and restoration work to be carried out quickly.

FIG. 8 shows a conventional example of such a guide pipe joint.

That is, as shown in FIG. 8, the guide pipe joint 12 has a hollow cylindrical plug 14, which is provided at the end of one of the guide pipes 11a to be connected via a nut 13, and has a small diameter plug 14 at the end of the guide pipe 11a. The socket 16 is provided at the end of the other guide tube 11b via a nut 15, and has a hollow cylindrical shape with an open end and into which the end of the plug 14 is removably inserted. The plug 14 and the socket 16 are locked by a one-touch connection holding mechanism 17 that locks the plug 14 and the socket 16 in a removable manner at a predetermined mating position. This connection holding mechanism 17 includes a spherical locking tool, for example, a pole 18, which is removably provided on the plug-fitting surface of the socket 16, and a recess 19, which is provided on the socket-fitting surface of the plug 14, and in which the ball 18 is engaged. and a different diameter which is provided on the outer circumferential side of the socket 16 so as to be slidable within a certain range along the axial direction (direction of arrow a), and allows or prevents the retracting movement of the ball 18 toward the socket 16 depending on the movement position. The sleeve 20 has inner surfaces 20a and 20b, and a spring 21 that constantly biases the sleeve 20 to a position where the ball 18 is prevented from entering (the position shown in the figure).

The plug 14 is attached to the socket 16 by moving the sleeve 20 in the axial direction (direction of arrow a) against the elastic force of the spring 21 to free the ball 18, and in that state, the plug 14 is attached. Ball 1 in depression 19
The plug 14 is held in the socket 16 via the ball 18 by inserting the plug 14 to the position where the sleeve 8 is fitted, and then releasing the sleeve 20 and moving it in the opposite direction of arrow a using the spring 21.

Further, when the guide pipe joints 12 are to be separated from each other, the sleeve 20 is moved in the direction of the arrow a in the same manner as described above, and the ball 18 is set free so that the plug 14 is pulled out from the socket 16.

By the way, for example, in the case of a nuclear reactor with an output of 1100 MWe,
There are 43 guide tubes 11a and 11b between the lower part of the output range detector assembly 5 and the inner wall side of the pedestal 3, and each of them is cut to a length at the site and then piped.

Therefore, the length of the guide tube 11 may be longer or shorter, and a tensile force or a pressing force acts on the guide tube joint 12. Shortly cut guides 1! 11a, 11b
In this case, a tensile force acts on the guide pipe joint 12. At this time, if a force is applied to the sleeve 20 of the socket 16 in the direction of the arrow a, the plug 14 will come off the socket 16 from the crown. During periodic inspections, please be sure not to interfere with the inspection of other machines.

11b will be removed, but since there are many devices inside the pedestal 3 and many inspection items, even after reinstalling the guide tubes 11a and 11b, there will be a lot of work in and out of other machines, and the tools on hand are in the socket 16. A malfunction such as the plug 14 coming off due to contact with the sleeve 20 of the plug 14 may occur. Therefore, as a final check, the person in charge of the TIP system checked the 43 guide pipe joints at the bottom of the output area detector assembly 5 and the 43 guide pipe joints 12 on the inner wall side of the pedestal 3, a total of 86 pieces. You must reinstall and check each piece one by one. In this way, it is easy to find the completely removed φ joint when reinstalling it, but
This is because if the ball 18 of the socket 16 comes off the recess 19 of the plug 14 and is incompletely connected, it is difficult to detect. Moreover, the number of confirmed locations was 86,111, which resulted in poor work efficiency.

Furthermore, although the inner peripheral surfaces of the guide tubes 11a, 11b and the guide tube joint 12 are coated with a dry lubricant, this coating material gradually peels off due to contact with the TIP detector, and the guide tubes 11a, 11b and the guide tube joint 12 are coated with dry lubricant. It accumulates together with dust at the bottoms of large diameter holes a[I21a, 21b formed at the connection portions with the pipe joint 12 and at the bottoms 22 of large diameter holes formed at the connection portions between the sockets 16 and the plugs 14. Large diameter hole bottom 21a, 21b
, 22, the coating material and dust accumulated on the plug 14
When the O-ring 2311! is removed, the O-ring 2311! l! There is a possibility that the O-ring 23 may be damaged when the plug 14 is installed, or the O-ring 23 may be damaged by entering the matching groove 24 and reducing the sealing performance. For this reason, 0
The frequency of ring replacement increases, and it becomes necessary to clean the O-rings 24 of the socket 16.

However, in the conventional type, since the O-ring 24 is formed deep within the socket 16, cleaning the accumulated coating material and dust is time consuming and requires a large number of man-hours. Similarly, the O-ring 23 deteriorates quickly due to the influence of radiated tI4 radiation, so it needs to be replaced periodically, but the O-ring 23 must be installed and removed at a deep position within the socket 16, which also reduces work efficiency. was decreasing.

(Problems to be Solved by the Invention) In the conventional guide pipe joint of the mobile in-core instrumentation system, the sleeve, which serves as the connection holding structure 1a between the plug and the socket, is pushed against the spring from the connection holding position. Since the locking member is relatively easy to come off when the joint is removed, there is a problem in that a large number of joints must be reinstalled after inspection and a holding state check must be performed.

The present invention was made in view of the above circumstances, and the sleeve can be reliably locked in the position where the plug and socket are connected, thereby reducing the amount of time and effort required for checking and improving work efficiency during inspection. The purpose of this invention is to provide a guide pipe joint for a mobile in-core instrumentation system.

[Structure of the invention]

(Means for Solving the Problems) The present invention is a joint for a guide tube for neutron detector insertion that connects a calibration tube and a traction device below a nuclear reactor, in which a tube provided in one of the guide tubes to be connected is provided. a cylindrical socket provided on the other guide tube into which the plug is removably inserted; a spherical locking tool inserted into the recess; and a spherical locking tool provided on the outer circumference of the socket so as to be slidable within a certain range in the axial direction, and pressing the locking tool to an insertion position in the recess according to the sliding position,
or a sleeve that releases the pressure, and a spring that urges the sleeve toward the pressed position of the locking device, wherein the connection holding mechanism is arranged on the outer periphery of at least one of the plug and the socket. The locking member is characterized in that it has a locking pin that protrudes from above, and a locking member that engages with the locking pin and locks the sleeve in the pressing side position of the spherical locking device.

(Function) According to the present invention, by locking the sleeve of the connection holding mechanism in the connection holding position between the plug and the socket using the lock pin and the locking member, the locking can be prevented even if the sleeve is inadvertently abutted. There is no risk of the tool coming off.

In addition, since the lock pin and locking member are exposed on the outer periphery of the plug or socket, it is possible to visually confirm the lock status, which simplifies checking of the connection status and improves work efficiency. will be able to achieve this.

(Example) An example of the present invention will be described below with reference to FIGS. 1 to 3.

Note that the connection arrangement of the guide tubes, etc. is the same as that shown in the conventional example, so Figs. 6 and 7 (A),
See also (B).

Figure 1 is a longitudinal sectional view showing the guide tube connection state, Figure 2 is the first
It is a sectional view along ■-■ of the figure.

As shown in FIGS. 1 and 2, the guide pipe joint 31 of this embodiment has a nut 3 attached to one of the guide pipes 11a to be connected.
2, and a cylindrical socket 35 that is attached to the other guide pipe 11b to be connected via a nut 34 and into which the tip of the plug 33 is removably inserted. .

The outer circumferential surface of one end 33a of the plug 33 for insertion into the socket 35 gradually becomes smaller in diameter through a tapered portion, and a spherical depression 36 is formed in the circumferential direction on the outer circumferential surface of the large diameter portion of the one end 33a. It is formed at intervals. Further, a ring-shaped groove 37 is provided on the outer peripheral surface of the small-diameter tip portion of the one end side 33a of the plug 33, and a seal ring 38 for sealing the fitting portion with the inner peripheral surface of the socket 35 is attached to this groove 37. ing. Further, a threaded portion 39 is provided on the outer peripheral surface of the other end side 33b of the plug 33.
The threaded portion 39 and the nut 32 are screwed together to clamp the end of the guide tube 11a whose diameter has been expanded. In addition,
On the outer circumferential surface of the central part of the plug 33, there is a square flange 4 for rotational operation.
0 is set protrudingly. Further, a detector insertion hole 41 formed in the center of the plug 33 is enlarged in diameter at both ends of the plug 33 so as not to obstruct the movement of the detector.

On the other hand, on the inner peripheral surface of the opening end side 35a of the socket 35,
A step is formed to fit with the outer circumferential surface of one end 33a of the plug 33, and a ball 42 as a spherical locking device that is inserted and locked into the recess 36 of the plug 33 moves in the radial direction of the socket 35 on the open end side. It is possible to keep it. This ball 42 has a diameter larger than the thickness of the peripheral wall of the one end side 35a of the socket 35, and can protrude and retract from the inner and outer peripheral sides of the peripheral wall. socket 3
A sleeve 43 that locks the ball 42 is fitted onto the outer peripheral surface of the sleeve 5 so as to be slidable in the axial direction. That is, on the inner peripheral surface of the sleeve 43, a protrusion 43a that presses the ball 42 from the outer circumferential side of the socket 35 is formed at a portion located on the open end side of the socket 35, and the protrusion 43a is formed in a portion located on the open end side of the socket 35, and the protrusion 43a presses the ball 42 from the outer circumferential side of the socket 35. The portion 43a is disengaged from the ball 42, and the ball 42
is pressed against or released from the recess 36 of the plug 33. A stopper ring 44 is provided on the outer peripheral surface of one end 35a of the socket 35 to limit the movement of the sleeve 43 toward the front end of the socket 35. Further, a square flange portion 35c for rotational operation is provided protruding from a position near the other end of the outer circumferential surface of the socket 35. A threaded portion 35d is formed on the outer circumferential surface of the other end side 35b of the socket 35, and the threaded portion 35d and the nut 34 are screwed together to open the guide tube 1 with an enlarged diameter.
The ends of 1b are sandwiched.

By the way, the large diameter hole 4 formed on the inner peripheral surface of the sleeve 43
A compression coil spring 45 is inserted into 3b, and the tip side of this compression coil spring 45 is inserted into the protrusion 43 of the sleeve 43.
a, and the proximal end side is in contact with the locking member 46. The locking member 46 has a cylindrical shape and is rotatably and slidably fitted to the outer circumferential side of the socket 35, with a small diameter portion 46a on one end of the locking member 46 extending into the large diameter hole 143 of the sleeve 43.
b, so that it comes into contact with the compression coil spring 45, and a flange 46b protruding from the outer peripheral surface near one end of the sleeve 43 can come into contact with the sleeve 43.

Further, on the other end side of the locking member 46, a pair of shallow grooves 47 and a deep groove 48 are formed at different positions in the circumferential direction and are recessed along the axial direction from the other end surface. The shallow grooves 47 and the deep grooves 48 are each 18
The shallow grooves 47 and the deep grooves 48 are opposed to each other at 0° intervals, and are adjacent to each other at 90° intervals.

On the other hand, a pair of lock pins 49 that engage with these pins 47 and 48 are provided protruding from the outer peripheral surface of the socket 35. A pair of these lock pins 49 are arranged at 90° intervals in the circumferential direction of the stud 35.

When the deep groove 48 of the locking member 46 engages with the lock pin 49, as shown in FIG.
is in contact with. That is, in the state shown in FIG. 1, the locking member 46 is pressed by the compression coil spring 45 and has slid to the maximum extent toward the other end of the socket 35. The compression coil spring 45 biases the sleeve 43 and the locking member 46 in opposite directions, so that the other end surface of the sleeve 43 and the flange 46b of the locking member 46 are spaced apart from each other. In this case, when the sleeve 43 is pushed against the elastic force of the compression coil spring 45, the sleeve 43 can move toward the other end in the axial direction of the socket 35, and the ball 42 is moved toward the outer circumference by the protrusion 43. The pressing force from the plug 33 is released, and the plug 33 is allowed to be removed from the socket 35.

On the other hand, the lock member 46 is once slid to the front end side of the socket 35 to release the engagement with the lock pin 49,
After that, when the shallow end 47 of the lock member 46 is engaged with the lock pin 49 by rotating 90 degrees in the circumferential direction,
As shown in FIG. 3, the other end surface 46G of the locking member 46 is removed from the m section 35C of the socket 35, and the collar portion 46b on one end side of the locking member 46 comes into contact with the other end surface of the sleeve 43. In this case, the sleeve 43 is locked in the position where the ball 42 is pressed by the locking member 46, and does not move even if the sleeve 43 is pushed toward the other end in the axial direction. That is, the plug 33 is held in a locked state with the socket 35 via the ball 42 and the recess 36, and will not come off.

According to the configuration of this embodiment, when connecting the guide pipe 118.11b using the guide pipe joint, the deep groove 48 of the lock member 46 is engaged with the lock pin 49, as shown in FIG. Compress the sleeve 43 with the coil spring 45
The ball 42 is moved in the axial direction (in the direction of the arrow) against the urging force of the ball 42, thereby setting the ball 42 in a free state. In this state, the plug 33 is inserted into the socket 35 until the ball 42 is inserted and locked into the recess 36 of the plug 33. When the sleeve 43 is released, the compression coil spring 4
5 and the open end side of the socket 35 (in the direction of arrow C)
, and comes into contact with the stopper ring 44 and stops. At the same time, the ball 42 locks into the recess 36 of the plug 33, thereby holding the plug 33 in the socket 35.

However, as it is, when a force greater than the elastic force of the compression coil spring 45 acts on the sleeve 43 in the direction indicated by the arrow, the sleeve 43 moves in the direction indicated by the arrow.
The plug 33 comes off easily.

Therefore, after moving the locking member 46 in the direction of arrow C against the force of the compression coil spring 45, it is rotated 90'' to engage the locking pin 49 in the shallow groove 47, resulting in the state shown in FIG. Good. This allows the flange 4 of the locking member 46 to
6b comes into contact with the other end surface of the sleeve 43, and the sleeve 43 can no longer move in the direction indicated by the arrow, resulting in the aforementioned locked state.

In addition, when removing the plug 33, move the lock member 46 slightly in the direction of arrow C against the force of the compression coil spring 45, rotate the lock member 46 90 degrees, and attach it to the lock pin 49. Deep groove 48 is engaged. As a result, the lock member 46 is moved in the direction of the arrow by the elastic force of the compression coil spring 45, returning to the state shown in FIG. Therefore, by releasing the sleeve 43 under the elastic force of the compression coil spring 45 and moving it in the direction of the arrow, the ball 42 is set in a free state, and in that state, the plug 3
It can be easily removed by pulling 3. As described above, a so-called safety lock can be achieved simply by moving the locking member 46 in the axial direction and rotating it by 90 degrees.

In addition, even if a worker working on the guide tube connection or another TL device comes into contact with the sleeve 43 of the socket 35 at the end of a periodic inspection, the locking function will be activated. If the state shown in FIG. 3 is maintained, the engagement between the plug 33 and the socket 35 will not come off. Therefore, when making a final check of the guide pipe joint, it is only necessary to confirm that it is in the state shown in FIG. 3 in which the locking function is exerted. This can be easily confirmed by visual inspection. That is, as shown in FIG.
8 are engaged and in the unlocked state, a large gap is formed between the flange 46b of the locking member 46 and the other end surface 43c of the sleeve 43. On the other hand, as shown in Figure 3,
When the lock pin 49 engages with the shallow groove 47 of the lock member 46 and is in the locked state, the flange 47 of the lock member 46
b and the other end surface 43G of the sleeve 43 come into contact with each other, with almost no gap. Therefore, the presence or absence of these gaps can be visually inspected, and the final inspection can be completed in an extremely short time.

Note that the flange 46 of the locking member 46 that occurs in the state shown in FIG.
If the outer peripheral surface of the locking member 46 located in the gap between the sleeve 43b and the other end surface 43c of the sleeve 43 is colored, the presence or absence of a gap can be clearly determined, making final inspection even easier. .

In addition, the guide tube 11a, which was slightly peeled off during TIP operation,
Even if dry lubricant and dust inside the guide tube fitting 31 accumulates on the enlarged diameter bottom of the connection between the socket 35 and the plug 33, there is no groove on the inner peripheral surface of the socket 35 for attaching the seal ring. It can be easily cleaned with a cloth, etc.

Furthermore, since the seal ring 38 is attached to the outer circumferential surface of the plug 33, the workability at the time of replacement is good, and it can be replaced in a short time.

In addition, in the embodiment described above, both the shallow groove 47 and the deep groove 48 were provided in the lock member 46, but only the deep groove 48 was provided,
The shallow groove 47 may be omitted. That is, the sleeve 43 may be locked by bringing the lock pin 49 into contact with the other end surface of the lock member 46. Also,
Of course, the number and spacing of the deep rR48 or the shallow grooves 478 of the locking member 46 can be set to various values other than those in the embodiments described above.

Further, in the above embodiment, the lock pin 49 is connected to the socket 35.
Although the lock pin 49 is configured to protrude from the side, the lock pin 49 is connected to the plug 3.
It is also possible to have a configuration provided on the third side.

FIG. 4 shows an example, in which the lock pin 49 is connected to the plug 33.
The lock member 46 protrudes from the outer peripheral surface of the sleeve 4.
3 itself. In this example,
The sleeve 43 is made rotatable, and an L-shaped groove 50 is provided on the distal end side of the sleeve 43 to which the lock pin 49 is engaged, and the lock pin 49 is detachably engaged with the groove 50.

Further, FIG. 5 shows another example, in which a rotatable sleeve 43
A hook 51 is provided protruding from the distal end side, and a lock pin 49 is removably engaged with the hook 51.

According to such another embodiment shown in FIG. 4 or FIG. 5, the sleeve 43 can be directly locked in the locking tool pressing position, and substantially the same effect as the above embodiment can be achieved. .

〔Effect of the invention〕

As described above, according to the present invention, it is possible to reliably lock the sleeve in the position where the connection between the plug and the socket is maintained, and the locked state can be easily controlled from the outside, thereby reducing the time and effort required for checking. This has the effect of improving work efficiency during reactor inspection.

4. Drawing lI! FIG. 1 is a sectional view of an embodiment of a guide pipe joint for a mobile in-core instrumentation system according to the present invention in an unlocked state, and FIG.
FIG. 3 is a sectional view showing the locked state of the guide pipe joint, FIG. 4 is a side view showing another embodiment of the present invention, and FIG. 5 is still another embodiment. Figure 6 is the overall layout of the mobile in-core instrumentation system, Figure 7 (A)
7(B) is an enlarged view of part 8 of FIG. 7(A), and FIG. 8 is a cross-sectional view of a conventional guide pipe joint.

6... Calibration tube, 10... Indexing device, 118.11b
... Guide pipe, 31 ... Guide pipe joint, 33 ... Plug, 35 ... Socket, 38 ... Seal ring, 4
2...Ball, 43...Sleeve, 45...Compression coil spring, 46...Lock member, 49...
lock pin.

Applicant’s agent Hisashi Hatano” ■ Figure 1 Figure 2

Claims (1)

[Claims] 1. A cylindrical plug provided in one of the guide tubes to be connected, which is a joint for a guide tube for neutron detector insertion that connects a calibration tube and an indexing device below the reactor; a cylindrical socket provided on the other guide tube into which the plug is removably inserted, and a spherical socket that protrudes from the socket and is inserted into a recess on the outer peripheral surface of the plug as a connection holding mechanism between the plug and the socket; a locking tool; a sleeve that is provided on the outer periphery of the socket so as to be slidable within a certain range in the axial direction and presses the locking tool to an insertion position in the recess or releases the pressure depending on the sliding position; and a spring that biases the sleeve toward the pressing position of the locking tool, the connection holding mechanism includes a lock pin protruding from the outer periphery of at least one of the plug and the socket, and the lock pin A guide pipe joint for a mobile in-core instrumentation system, comprising: a locking member that removably engages with the spherical locking member to lock the sleeve in the pressing side position of the spherical locking member. 2. The lock pin is located on the side opposite to the plug of the sleeve and protrudes toward the outer periphery of the socket, and the locking member is a cylindrical member fitted to the outer periphery of the socket so that it can rotate and slide in the axial direction. One end of the locking member is in contact with the sleeve and the spring, and a shallow groove is formed along the axial direction from the other end of the locking member, or a deep groove is formed at a circumferential position different from that groove. The mobile in-core instrumentation system according to claim 1, wherein the sleeve is held in contact with the pressing position of the spherical locking tool so as to be able to move toward and away from it by selectively engaging the lock pin. Guide pipe fitting. 3. The lock pin protrudes toward the outer circumferential side of the plug, while the lock member is the sleeve itself of the connection holding mechanism, and an L-shaped groove or hook that engages with the lock pin is formed on the tip side of this sleeve. The mobile in-core instrumentation according to claim 1, wherein the sleeve is removably hooked to the pressing side position of the spherical locking device by hooking a groove or a hook to the lock pin. System guide pipe joint. 4. The plug has a ring-shaped groove on the outer circumferential surface of the tip, and a seal ring is inserted into this groove to seal the fitting part with the inner circumferential surface of the socket. Guide pipe joint for mobile in-core instrumentation system.