JPS59116097A - Incore neutron instrumentation device - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention mainly relates to an in-core neutron detection device for detecting the core operating state, that is, the power state, of a boiling water nuclear reactor.

[Technical background of the invention]

In general, detecting the number of neutrons due to nuclear fission within the core of a nuclear reactor is required to accurately grasp the operating state of a nuclear reactor and maintain the operating state appropriately.

One method for detecting this number of neutrons is a movable in-core probe drive mechanism (hereinafter referred to as TIP drive mechanism).
There is a method using

1 to 3 show a conventional in-core neutron detection device using a TIP drive mechanism.

In order to detect the number of neutrons in the reactor core (not shown) in the reactor pressure vessel 1, this in-reactor neutron detection device has approximately 40 neutrons installed through the reactor core and the bottom wall of the reactor pressure vessel 1. A neutron number measuring device 4 (FIG. 2) is inserted into and removed from the nuclear instrumentation tube 2 by means of TIP drive mechanisms 3a...3d.

To explain further, the 40 nuclear instrumentation tubes 2 are equally divided into four blocks, and each block is provided with a TIP mainframe movement mechanism 3a, 3d, respectively.

Each TIP drive mechanism 3a...3d is formed as shown in FIG. A large number of signal take-out cables 5, 5 are bundled with wires 6 and extend from the neutron number measuring device 4. This signal take-out cable 5.5 has flexibility and is wound around a winding reel 7, and a driving roll 9 is provided with retaining recesses 8, 8 at the same pitch as the leads of the wire 6 on the outer periphery.
and a driven roll 10, and is moved in and out by rotating the drive roll 9 in forward and reverse directions.

When measuring the number of neutrons in the reactor core, each TI
This is carried out by moving the neutron number measuring device 4 housed in the P drive mechanism 3a...3d through the pipe line 11 by rotating the drive roll 9 in the forward direction.

RO, the neutron number measuring device 4 that has exited each TIP drive mechanism 3a...3d is connected to the TIP drive mechanism chamber wall 12 and the shielding container 13.
&...13d1 Pulp assembly 14 a...1
4d1 Shea pulp 15a...15d1 Index mechanism 17a...17d via reactor containment vessel 16
reach the entrance.

At the exit side of each index mechanism 17a...17d, connecting pipes 18, 18 connected to ten nuclear instrumentation pipes 2, 2 are concentrically connected as shown in Fig. 3. . In each index mechanism 17a...17d, there are rotary distribution pipes 19a...19d that selectively guide the neutron number measuring device 4 entering from the inlet side to arbitrary continuous pipes 18, 18. Each is provided. Therefore, index mechanism 17 a...1
Each neutron number measuring device 4 that has reached the inlet of 7d enters the rotary distribution pipes 19a...19d, then enters one selected connecting pipe 18, then enters the nuclear instrumentation pipe 2, and enters the inside of the reactor core. When reaching a certain position, the drive roll 9 is stopped. Then, the number of neutrons is measured at that position, and the signal is sent to a measuring device (not shown) through signal extraction cables 5, 5. The measurement position of the neutron number measuring device 4 is changed by rotating the drive roll 9, and the position can be determined based on the number of rotations of the drive roll 9 and the like.

To measure the number of neutrons in the other nuclear instrumentation '#2, the drive roll 9 is reversed and the neutron number measuring device 4 is moved to the rotary distribution tube 19a of the index mechanism 17a...17d.
... Return to 19d, then rotate the rotating distribution pipe L9a...
・Turn 19d to match the position of the other connecting pipe 18,
Next, the driving roll 9 is rotated in the normal direction, and the neutron number measuring device 4 is inserted into the new nuclear instrumentation tube 2 through the newly selected connecting tube 18.

After the measurement of the number of neutrons in all ten nuclear instrumentation tubes 2 is completed, the neutron number measuring device 4 moves each TIP drive mechanism 3a...
It is pulled back to 3d.

[Problems with background technology]

Since the neutron number measuring device 4 used to detect the number of neutrons in the reactor core has a short lifespan, each part of the in-core neutron detection device is periodically inspected to ensure the accuracy of the detected neutron number.

However, the conventional device has four systems of the same device, and it takes a long time to inspect the small TIP drive mechanisms 3a...3d and the index mechanisms 17a...17d. This periodic inspection must also be performed inside the reactor containment vessel 16, and the longer the period, the greater the radiation exposure of the workers, which is dangerous. Therefore, especially the reactor containment vessel 1
It is necessary to reduce the number of parts to be inspected by reducing the number of parts of the equipment in 6.

Further, since the neutron number measuring device 4 is extremely expensive and has a short lifespan, it is desirable to reduce the number of neutron number measuring devices used.

However, the conventional index mechanism 17a
In this configuration, if the 40 connecting pipes 18 were selected by one index mechanism, there was an inconvenience that the index mechanism itself would become unnecessarily large.

In addition, if one of the devices in the four systems breaks down in the conventional equipment mentioned above (in this case), parts that cannot be identified will be created. There was an inconvenience that it had to be done.

[Purpose of the invention]

The present invention has been made in view of these points, and it is possible to selectively insert neutron number measuring instruments into all nuclear instrumentation tubes using one small index mechanism, thereby reducing the number of old components and parts. In addition, by installing preliminary Ia equipment that can be replaced immediately, even if a measuring instrument fails, there is no need to shut down the reactor. An object of the present invention is to provide an in-core neutron detection device that can reduce radiation exposure.

[Summary of the invention]

The present invention provides two T-engine P drive @ mechanisms and is formed so that they can be selectively connected to the path of a neutron number measuring device using a switch.
Two index mechanisms are provided to be connected to the ends in the traveling direction of the neutron number m111 determiner of one path output from the switching device, and are configured to be selectively connectable to the ends in the traveling direction by a switching mechanism, Each of these indexing mechanisms is provided with a distribution tube having an inlet end directly opposite said forward end and an outlet end moved along a vortex trajectory, each of said continuums connected to said respective nuclear instrumentation tube. The inlet ends of the tubes are arranged on the vortex flow locus of the outlet end of the distribution pipe of the index mechanism, and a neutron number measuring device is selectively connected to all the nuclear 1f equipment by one small index mechanism, Another feature is that the index mechanism and the TiP drive mechanism can be switched even during operation of the nuclear reactor in the event of a failure or calibration.

[Embodiments of the invention]

The present invention will be described below with reference to embodiments shown in FIGS. 4 to 24.

FIG. 4 shows the overall configuration of the present invention, in which the same parts as in the prior art are given the same reference numerals.

This embodiment is configured so that the measurement of the number of neutrons is performed by one system.

That is, the neutron number measuring device 4 is moved forward and backward along one course 20 by one TIP drive #J mechanism 3a.

The neutron number measuring device 4 that has exited the TIP drive mechanism 3a is
It passes through the chamber wall 12, the shielding vessel 13a1 switch 21, the valve assembly j4a, the share valve 15a, and the reactor containment vessel 16 in this order and enters the index mechanism 22a. Due to the distribution α23 of this index mechanism 22, the neutron number measuring device 4
The connecting pipes 18 and 1.8 are selectively inserted and removed one after another.

Further, in this embodiment, another TIP drive mechanism 3b and a shielding container 13 are provided, and are configured to be switchable and connectable to one route 20 via a switch 21 with another TIP drive mechanism 3a, etc. . Since the two TIP drive mechanisms 3a and 3b are made switchable in this way, if one breaks down, simply by changing the connection state of the switch 21, the number of neutrons can be measured using the other one immediately. By measuring the number of neutrons in the same nuclear instrumentation tube 2,
Measurements can be calibrated.

In addition, in this embodiment, another index mechanism 22b is provided, and one
The indexing mechanism 22a is configured to be switchable and connectable to the other indexing mechanism 22a. In addition, even if one index mechanism fails, it is possible to switch to the other index mechanism and continue measuring the number of neutrons without stopping the reactor operation.

To further explain, Figures 5-8 show one index mechanism 22a-Q of the same structure.

This index mechanism 22a has a distribution 'u23 housed in a hollow housing 24. The front wall 24a of this housing 24 is connected to the pipe 2 forming the course 20.
5, and is fitted into a protrusion 26a that protrudes annularly from the partition wall 2b.
It is formed in contact with the ring 27 to prevent radiation leakage from the connecting portion. Also, after the housing 24
24b faces the back of the bulkhead that supports the inlet ends of all connections VL8.18, and like the front wall 24a, the O-ring 29
is in contact with A guide groove plate 31 is fixed to this rear wall 24b by a fixing plate 30.

A rotary shaft 33 is formed substantially in the center of the rear wall 24b and the groove guiding plate 31 so as to project into the housing 24 via bearings 32, 32 in a cantilevered manner. As shown in FIG. 6, a vortex groove 34 centered around the rotating shaft 33 is carved in the guide groove plate 31, and all connecting pipes are formed on the rear wall 24b at positions that match the vortex groove 34. 18. The same number of through holes 35 and 35 as the number of holes 18 are arranged and bored. The inlet end of each connecting pipe 18, 18 is connected to a storage hole 35.
, 35 with their axes aligned and facing each other.

Further, a rotary plate 16 is fixedly mounted on the inner end of the rotary shaft 33. This rotating plate 36 has a radial vertical groove 37 centered around the rotating shaft 33, and a driven gear 40 that meshes with a driving gear 39 rotated by a motor 38 is provided on the outer peripheral surface of the rotating plate 36. . This vertical groove 37 is formed to have a length ranging from the minimum radius to the maximum radius of the swirl groove 34. Further, the inlet end of the distribution pipe 23 is rotatably supported via a bearing 42 on a support wall 41 erected from the bottom of the housing 24, and the axis of the inlet end is concentric with the axis of the pipe 25. It is supported by. A through hole 43 through which the neutron number measuring device 4 passes is provided in the front wall 24a of the fuzzy housing 24.

On the other hand, the outlet end of the distribution pipe 23 is penetrated by bearings 44 and 45 which are movably installed inside the vertical groove 37 of the rotary &36 and the vortex groove 34 of the guide groove plate 31, respectively, and are rotatably supported. . Moreover, the middle part of this distribution pipe 23 has a center hole 47 of a curvature 4b support 46 provided between the ceiling and the floor of the housing 24,
Abnormal deformation is prevented.

Next, the operation of this index mechanism 22a will be explained.

Neutron d 1111 fixed device 4 made to advance to the front end of the piping 25 by either TIP drive* isostructure 3a or 3b
The connecting pipe ■ passes through the through hole 43 in the front wall 24a of the housing 24, the distribution pipe 23, and the through hole 35 in the rear wall 24b in this order.
8, and then reaches the nuclear instrumentation tube 2 inside the reactor pressure vessel 1 to measure the number of neutrons in the reactor core.

After this measurement, the neutron number measuring device 4 is inserted into the through hole 3 of the rear wall 24b.
It is returned to the distribution pipe 23 before 5. Next, motor 38
is energized, the drive gear 39 rotates, and the rotating plate 36 slowly rotates around the rotating shaft 33. At this time, distribution pipe 2
The outlet end of No. 3 passes through bearings 44 and 45 movably housed in valleys No. 34 and 37 in the vertical groove 37 of the rotating plate 36 and in the vortex groove 34 of the guide groove plate 31. Therefore, as the rotating plate 36 rotates, it moves along the vortex groove 34 toward the next through hole 35. And its distribution/
When the outlet end of 123 reaches the next through hole 35, the contact 48 of the limit switch 48 provided on the upper circumferential surface of the groove guide plate 31
a comes into contact with a protrusion 49 protruding from the outer peripheral surface of the rotary plate 36 and is turned off (see FIG. 8), and the flow to the motor 18 is stopped and the rotary plate 36 is stopped.

As a result, the outlet end of the distribution pipe 23 is positioned coaxially with the next through hole 35, that is, the next connecting pipe 18. The bale and the neutron number measuring device 4 are moved forward again and inserted into the next nuclear H1 suspension 2 to measure the number of neutrons.

By repeating this operation, all the nuclear d1 tubes 2.2
The number of neutrons is measured within the space.

As shown in FIG. 6, the through holes 35, 35 are arranged on the radiation +m50, 50 equally divided around the rotating shaft 33, and the protrusion 4 controls the operation of the limit switch 48.
9 and 49 are also arranged at equal pitches.

In this way, in this embodiment, all the connecting pipes 18 and 18 are provided along the swirl groove 34, so that the small guide groove plate 31,
The neutron number counter 4 is connected to each nuclear instrumentation tube 2 by rotation &, 36.
2 can be led in order. That is, one small indexing mechanism 22a (thereby all the nuclear instrumentation tubes 2
, 2 can be measured.

Further, as shown in FIG. 9, the index mechanism 22
In a, the rotary shaft 36 is hung between the rear wall 14a and the guide groove plate 31 in a manner such that it is supported on both sides. A notch 51 is provided to avoid the motor 38.

Further, FIG. 10 shows another embodiment in which the rotary plate 36 is fed one step at a time using a sticky gear type. That is, the rotary plate 36 is used as a driven wheel, and the rotary plate 36 is driven step by step by one pivot pin 54 of a driving wheel 52 rotating around a rotating shaft 54. The contact 48a of the limit switch 48 is pushed down with a protrusion 54 protruding from the drive wheel 52 to turn the motor 38 on and off.
It is designed to allow

11 to 20 show specific examples of the distribution pipe 23.

The distribution pipes 23 of FIG. 11 and the twelfth factor are respectively
3N and a ball shaft 56a with a drum-shaped cross section carved with a ball with a center hole 55 in the center through which the neutron number measuring device 4 passes, as shown in FIG. The ball shafts 56a and 56b are arranged alternately with a slight gap between them, and the ball shafts 56a and 56b are connected by a bar-shaped ball shaft 57.57 and a ball shaft 758.58 with a spherical tip. be.

The distribution pipe 23 in Fig. 15 has ball shafts 56c carved in a scale-like manner, which are connected with a slight gap between balls 57, 57 and bottles 58°. 58.

15 and 17, every other ball shaft 56a, 56b, 56c is connected by a ball support 57, and the distribution pipe in FIG. 16 is connected to every second ball shaft 5.
6a and 56b are joined by a ball support 57.

As shown in Figure gg16, the spherical portion 58a at the tip of the bottle 58 is housed in the spherical recess 59 of each ball shaft, so each ball shaft can rotate around the bottle 58. and,
The installation of 758 and 758 is because the position and phase are changed by 90 degrees (
(See FIG. 17), each distribution front 23 with connected ball shafts has tjj contact.

Further, the arrangement of the ball support 57 with respect to the ball shaft may be such that the circumference is divided into three equal parts as shown in FIG. 18, or may be divided into five equal parts.

m 19 j:<l within the distribution ball shafts 56a and 5
6b are arranged alternately, and these ball shafts 56a
, outside of 56b (1111) is spirally wound by a band-shaped elastic phase 59 to increase flexibility.In this case, a plurality of elastic phases 59 are formed so as to cross each other. It is best to roll it up.

Self” 12J figure self/white is ball shaft 56a and 56b
These are arranged alternately and then broken with an elastic vibro-0 to provide attractability. In this case, if mutual unevenness is formed on the ball shafts 56a and 56b of the elastic vibro 0 in advance, its flexibility will be increased.

FIG. 21 specifically shows two switching devices, and the number of neutrons from the valley shielding containers 13a and 13b is 61! It connects the pipes 161a and 61b that send out the J-quantizers 4, respectively, and one pipe 25, and a limit switch 62a detects which of the pipes 61 the neutron number measuring device 4 is passing through. , 62b are provided.

Further, FIGS. 4j and 8-3 show an embodiment of a switching mechanism for switching and connecting each index mechanism 22 a p 22 b to the dijj regular position.

Two index mechanisms 2'2 a F 22 b
is fixed on a long frame 63. This multi-frame frame 63 is placed on support frames 64 and 64 so as to be able to freely reciprocate via rollers 65 and 65, CIiI'.

This movable frame 63 is caused to reciprocate and Fjb by rotating a pinion 67 which meshes with a rack 6G set at 1α1 on the lower surface in forward and reverse directions by an AAJ motor 68. The center f of this binion 67, QIi G 9 i is the binion 67
ring 7iJ to prevent it from coming off the rack 66,
70 are solidly layered with a pinion 67 interposed therebetween, and are also connected to a drive motor G8+ via a group of six reduction gears 71. Further, limit switches 72 and 72 are provided at the front and rear ends of the rack 66, respectively, and operate together with a stopper (not shown) to control each index mechanism 22a.
12b reaches the 7% constant measurement position, and the drive motor 68 is stopped.

Next, the operation of this switching device will be explained.

For example, in FIG. 4 (here, if some kind of failure occurs in one of the index mechanisms 22a,
Reverse the drive roll 9 of f43a and set the neutron number measuring device 4
is pulled out from the index mechanism 22a into the piping 25, this drawing is confirmed by the proximity switch 73 (FIG. 4), and then passed to the drive motor 68 of the temporary switching device, and then passed through the reduction gear group 71 to the pinion 67. is rotated at a low speed, and both index mechanisms 22a and 22b placed on the movable frame 63 are moved in the direction of arrow 8 in Fig. F4. As this movement progresses, the limit switch 72 attached to the front end of the rack 66 comes into contact with a stopper, the drive motor 68 stops, and the other index mechanism 22b moves to a constant d.
llll is switched and connected to the home position.

In this way, in this embodiment, two index mechanisms 2 are used.
2a and 22b are provided, and one can be used as a spare, so even if the other breaks down during reactor operation, it can be immediately replaced with one and the number of neutrons can be measured. This eliminates the need to stop the operation of the nuclear reactor as in the past, and increases the operating efficiency of the reactor.

FIG. 24 shows another embodiment of the switching mechanism, in which the movable frame 63 is reciprocated by an air cylinder 74 and its plunger 75 instead of the rack binion. In this embodiment, in order to accurately reciprocate the movable pedestal 63, air cylinders 74 and the like are provided on both sides of the movable pedestal 6(5) so as to face each other.

Air for movement is supplied to and discharged from the air cylinder 74 through an air supply and discharge pipe 76 . In order to finely adjust the moving distance, a fine adjustment valve 77 or a vent valve 78 may be installed in the middle of the supply/discharge pipe 76. It is preferable that a stopper 79 for stopping the movable frame 63 at an appropriate position is provided protrudingly on the support frame 64, or that a limit switch, a proximity switch, etc. (both not shown) are provided.

〔Effect of the invention〕

Since the in-reactor neutron detection device of the present invention is configured and operates in this way, the neutron number measuring device can be selectively inserted into all the nuclear instrumentation tubes using one small indexing mechanism, and the component equipment and By reducing the number of parts, periodic inspection periods and failure points can be reduced, periodic inspection periods can be shortened, space between walls within the reactor containment vessel has been increased, workability has been improved, and index We have prepared spares for the mechanism and TIP drive mechanism that can be replaced immediately, so even if these fail, measurements can be continued without shutting down the reactor, thereby increasing the operating rate of the reactor. is possible,
Furthermore, the effects of reducing the radiation exposure of workers are diminished.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing an example of a conventional in-core neutron detection device, Fig. 2 is a principle diagram of the TIP drive mechanism, Fig. 3 is an explanatory diagram showing the connection state of the connecting pipe of the conventional index mechanism,
Figures 4 to 24 show an embodiment of the in-core neutron detection device of the present invention, with Figure 4 being a system diagram, Figure 5 being a longitudinal sectional side view of the index mechanism, and Figure 6 being a front view of the guide groove plate. Fig. 7 is a front view of the rotary plate, Fig. 8 is a view in the direction of Fig. , FIG. 10 is a front view showing another drive type of the rotating plate, and FIGS. 11 and 12 are plan views showing the distribution pipe, respectively. Figures 13 and 14 are longitudinal sectional views showing the ball shaft, respectively, Figure 15 is a plan view showing another example of the distribution pipe, and Figure 1
Figure 6 is a cross-sectional view taken along the line AVI-XVI in Figure 11;
Figure 17 is a left side view of Figure 11, Figure 18 is a side view similar to Figure 17 showing another example, Figure 19 is a plan view showing another example of the distribution pipe, and Figure 20 is the distribution pipe. Fig. 21 is a cross-sectional plan view of the switching device, Fig. 22 is a front view of the switching mechanism, Fig. 23 is a bottom view of Fig. 22, and Fig. 24 is a partial cross-sectional plan view showing another example in the history of FIG. 7 is a plan view showing another switching mechanism. 1... Reactor pressure vessel, 2... Nuclear instrumentation tube, 3a, 3
b...'f' IP drive mechanism, 4... Neutron number measuring device, 18... Connecting pipe, 20... Course, 21...
Switch, 22a, 22b...index mechanism,
Imperial edict...distribution pipe. Applicant's agent Kiyomoto Otsu Inomata Figure 7r2J Evaporation δ diagram: EJ-q Figure Iq & 70 diagram

Claims (1)

[Claims] The TIP drive mechanism moves the neutron number measuring device forward and backward along the course, and in the middle of the course, the index mechanism moves the neutron number measuring device to a plurality of plate stands inserted into the reactor pressure vessel through connecting pipes. In an in-core neutron detection device that sequentially selects and guides the neutron measuring device into and out of the nuclear instrumentation tube to detect the number of neutrons in the reactor core.
1. Two of the TIP drive mechanisms are provided and can be selectively connected to the path by a switch, and one path extending from the switch is connected to the end in the traveling direction of the neutron measuring device. Two of the index mechanisms are provided and can be selectively connected to the end in the direction of travel depending on the width of the switching device. A distribution pipe is provided along which the pipe is moved along, and the inlet end of each connecting pipe connected to each of the plate-assembled pipes is arranged on the vortex trajectory of the outlet end of the distribution pipe of the index mechanism. Characteristic in-core neutron detection equipment.