JPS6136636B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a position regulating device for a control rod drive mechanism exchanger (hereinafter abbreviated as CRD) of a reactor pressure vessel in a nuclear power plant.

Generally, in a boiling water nuclear power plant, a CRD exchanger 2 is installed in a cylindrical work chamber 1 at the bottom of a reactor pressure vessel (not shown) as shown in FIG. Control rod drive mechanism housing (hereinafter abbreviated as CRD housing) 3...
The control rod drive mechanism 4, which is attached by bolting to the CRD exchanger 2, is attached and replaced by the CRD exchanger 2.

Here, to briefly describe the CRD exchanger 2 with reference to FIGS. 1 to 4, a platform 6 is rotatably installed on an annular rail 5 attached to the inner peripheral wall of the cylindrical work chamber 1, and the platform 6 is located in the center. A rail 8 having a space 7 extending in the longitudinal direction and laid along both upper edges of the central space 7,
A traveling carriage 9 is installed on the carriage 8 so as to be able to run in a straight line.
is supported and configured. The attachment/detachment device 10
1 includes a vertically elongated beam 12 pivotally connected to the traveling truck 9 via a pin 11, and a beam drive mechanism that rotates the beam 12 from a vertical position to a horizontal position below the traveling truck 9. 13, a grip arm 14 provided on the beam 12 so as to be retractable, and a support stand 16 provided on the beam 12 so as to be reciprocated along the longitudinal direction by the drive of a chain 15. A bolt attachment/detachment mechanism conveyor 18 is installed next to the attachment/detachment device 10 via rails 17, 17 supported on both sides of the central space of the platform 6, and the beam 12 of the conveyance truck 18 and U-shaped recess 18a on the opposite side
A bolt attachment/detachment mechanism 19 is detachably suspended and on standby. Furthermore, a transport cart 21 for carrying in and out the control rod drive mechanism 4 enters and leaves the central space 7 of the platform 6 through a passage 20 opened in the peripheral wall of the work chamber 1. It is set up and ready for use.

Therefore, the CRD exchanger 2 having the above-mentioned configuration,
When removing the control rod drive mechanism 4 from the CRD housing 3, first hold the beam 12 of the attachment/detachment device 10 in a vertical position, move the support stand 16 to the lowest position, and move the carriage 18 close to remove the bolts. The mechanism 19 is positioned directly above the support stand 16. In this state, the support stand 16 is raised by a chain drive, and the bolt attachment/detachment mechanism 19 is floated away from and supported by the carriage 18, and the carriage 18 becomes empty and retreats. Next, by appropriately displacing the attachment/detachment device 10 by the rotational movement of the platform 6 and the linear movement of the traveling carriage 9, the support stand 1 is placed directly below the CRD housing 3 to which the control rod drive mechanism 4 to be removed is attached.
The bolt attachment/detachment mechanism 19 mounted on the control rod drive mechanism 6 is positioned, and then the support stand 16 is again raised high by chain drive to press the bolt attachment/detachment mechanism 19 into contact with the lower end of the control rod drive mechanism 4 for the purpose described above, and the control rod drive mechanism 19 is placed in position. The bolt between the mechanism 4 and the CRD housing 3 is removed by the action of the bolt attachment/detachment mechanism 19. Then, the lower end of the control rod drive mechanism 4 is attached to the bolt attachment/detachment mechanism 19.
The support stand 16 is lowered by chain drive while being supported by the support stand 16 and pulled out directly below. At this time, just before the upper end of the control rod drive mechanism 4 is completely removed from the CRD housing 3, the gripping arm 14 is protruded and held loosely from both sides as shown in FIGS. 1 and 2 to guide it so that it does not fall. In this state, it descends further and stops once at the place shown in FIG. 2, where it firmly holds the control rod drive mechanism 4 with the gripping arm 14, and moves the conveyance vehicle 18 closer to the bolt attachment/detachment mechanism 19 with its recess 18a. Take it and retreat. After that, the support stand 16 is raised to support the lower end of the control rod drive mechanism 4, and the grip arm 14 is loosened and the support stand 16 is lowered again to CRD the control rod drive mechanism 4.
Completely remove it from the housing 3 as shown in FIG. After this, the control rod drive mechanism 4 is strongly held again by the grip arm 14, and in this state, the beam drive mechanism 13 moves the beam 12 into a horizontal state in the central space 7 below the traveling carriage 9, as shown in FIG. The carriage 21 is inserted into the lower side of the carriage 21, and the control rod drive mechanism 4 is received onto the carriage 21 by the jack 21a on top of the carriage 21, and sent to a maintenance inspection room (not shown) through the passage 20. ). This completes the removal work of the control rod drive mechanism 4 at one location in the reactor pressure vessel, and the installation work of the control rod drive mechanism 4 to the reactor pressure vessel can be performed in the exact reverse order to the above. Become.

Conventionally, there was one problem when installing and removing the control rod drive mechanism 4 using the CRD exchanger 2 as described above. That is, generally, a large number of reactor neutron instrumentation device cables 22 are suspended from the bottom of the reactor pressure vessel. Moreover, those cables 22 are the fifth
As shown in the figure, the control rod drive mechanism 4 is attached and detached.
It is arranged near the CRD housing 3 and extends further downward from the lower end of the housing 3. Therefore, the beam 12 of the CRD exchanger 2 does not come into contact with the cable 22 no matter how it moves, but the control rod drive mechanism 4 is supported vertically by the attachment/detachment device 10 during the attachment/detachment work by the exchanger 2. When the control rod drive mechanism 4 is moved to its destination, there is a risk that the upper end of the control rod drive mechanism 4 and the cable 22 may interfere with each other and be damaged. This requires workers to perform inspections in special locations under high-level radiation control, which poses many health and safety problems, requires a large number of workers, and lengthens inspection times. Such inconveniences may occur. Therefore, when the control rod drive mechanism 4 is supported,
It was necessary to operate the CRD exchanger 2 extremely carefully, and there was a problem in which the efficiency of the removal and replacement work could not be avoided because it was extremely difficult.

This invention was made in view of the above circumstances, and its purpose is to connect the neutron instrumentation cable at the bottom of the reactor pressure vessel and the CRD exchanger's attachment/detachment device to vertically support the platform and traveling bogie. The positional relationship with the control rod drive mechanism that moves during operation is displayed on a mock display board in a remote operator's cab, etc., so that the operator can easily operate the CRD exchanger without making mistakes while monitoring it. In addition, even if the control rod drive mechanism approaches the neutron instrumentation cable due to incorrect operation, the limit switch will detect this and automatically stop the operation of the exchanger and restrict its position, preventing further operation. It is an object of the present invention to provide a device that can prevent inconveniences such as damage caused by interference between the two by blocking their approach.

An embodiment of the present invention will be described below with reference to FIGS. 6 to 8. Note that the same components as those shown in FIGS. 1 to 5 described above are designated by the same reference numerals, and detailed explanation thereof will be omitted. However,
In FIG. 6, position detection sensors 23 and 24 are provided on the platform 6 and the traveling truck 9 of the CRD exchanger 2 installed in the lower cylindrical working chamber 1 of the reactor pressure vessel (not shown), respectively. One of the position detection sensors 23 is for detecting the rotational movement position of the platform 6, and is connected to a synchro transmitter 23a attached to the outer end of the platform 6.
The drive mechanism 25 of the platform 6 consists of a pinion 23b attached to the shaft end of the synchro transmitter 23, and a rack 23c laid parallel to the ring rail 5 so that the pinion 23b meshes with the pinion 23b. As the pinion 23b rotates, the synchro transmitter 23a rotates.
It is designed to emit a position signal. The other position detection sensor 24 detects the linear movement position of the traveling vehicle 9, and includes a synchronizing transmitter 24a attached to one end of the traveling vehicle 9, and a pinion attached to the shaft end of the synchronizing transmitter 23a. 24b and
The drive mechanism 2 of the traveling bogie 99 consists of a rack 24c laid parallel to the rail 8 on the platform 6 to be engaged with the pinion 24b.
6, the pinion 24b rotates and rotates the synchro transmitter 24a, so that the synchro transmitter 24a outputs a position signal of the traveling carriage 9.

Furthermore, as shown in FIGS. 7 and 8, a mock display board 27 is installed in a location that is easy for the driver to see, such as a driver's cab (not shown) located at a remote location from the work room 1. This simulated display board 27 is made of a transparent or semi-transparent disk such as a plastic board, and its surface is used for a plurality of CRD housings 3 and neutron instrumentation devices arranged at the bottom of the reactor pressure vessel as shown in FIG. Position indicators 3a and 22a are attached to the cables 22 in the same positional relationship as the cables 22, respectively. Further, on the back surface of the simulated display board 27, limit switch strikers 28 are provided to protrude, corresponding to the neutron instrumentation cable position display 22a. Further, the back side of the simulated display board 27 is supported by a box-shaped frame 29, and a simulated operation mechanism 30 is mounted inside the frame 29 on the back side of the simulated display board 27. This is configured so that the platform 6 of the CRD exchanger 2 and the traveling trolley 9 move in the same way as the signals from the position detection sensors 23 and 24. is received by the receiver 31, and the received signal is sent to the amplifier 32.
The amplified signal causes the servo motor 33 fixed to the bottom of the frame 29 to rotate, and the rotation of the servo motor 33 causes the shaft 3 supported on the bearing 34 to rotate.
5, transmission is transmitted via transmission gears 36 and 37 to a central shaft 39 supported by a bearing 38 on an intermediate frame 29a of the frame body 29, and rotation of the central shaft 39 causes a rotating disk 40 fixed to this shaft 39 to rotate as described above. It is designed to rotate in the same manner as platform 6.
Further, a position signal from the synchro transmitter 24a of the other position detection sensor 24 is received by the synchro receiver 41, and the received signal is amplified by the amplifier 42. A servo motor 43 fixed to the servo motor 43 rotates, and this rotation causes a ball screw 46 provided on the rotating disk 40 via bearings 44 and 45 to rotate, and a ball nut 47 screwed onto the ball screw 46 rotates. Due to the feeding action, it can move in a straight line in the same way as the traveling carriage 9 described above. A support frame 48 is attached to the ball nut 47 of the simulated operation mechanism 30, and an indicator lamp 49 and a limit switch 50 are attached to the upper and lower portions of this support frame 48. The display lamp 49 and the limit switch 50 are moved to the rear side of the simulated display board 27 by the simulated operation mechanism 30 operated by the position signals from the position detection sensors 23 and 24 as described above.
Both control rod drive mechanisms 4 are held vertically in the attachment/detachment device 10 of the CRD exchanger 2 and moved.
and the display lamp 4 always moves in the same manner as
9 lights up to display the position of the movement of the control rod drive mechanism 4 on the simulated display board 27, and the limit switch 50 turns on the striker 28 when the control rod drive mechanism 4 approaches the neutron instrumentation cable 22. When this occurs, the switch is turned ON to issue a signal to stop the operation of the CRD exchanger 2, that is, to stop the drive mechanism 25 of the platform 6 and the drive mechanism 26 of the traveling truck 9.

Therefore, in the position regulating device of this invention, the CRD
When the control rod drive mechanism 4 is attached or replaced by the operating operation of the exchanger 2, the movement position of the control rod drive mechanism 4 is projected on the simulated display board 27 in the driver's cab etc. by the light of the display lamp 49, and the situation is shown. CRD housing position display 3a and neutron instrumentation cable position display 22 attached to the mock display board 27
By looking at the neutron instrumentation cable position indicator 22a, the light of the indicator lamp 49 is shown to prevent the light from approaching the neutron instrumentation cable position indicator 22a, that is, the control rod drive mechanism 4 does not touch the neutron instrumentation cable. Board 2
The CRD exchanger 2 is operated while being remotely monitored on the CRD exchanger 7, and the control rod drive mechanism 4 is connected to the target CRD while controlling its position to prevent damage due to interference between the control rod drive mechanism 4 and the cable 22. It becomes possible to easily move it to the housing and attach it, or conversely, remove it and take it away.

Additionally, if the control rod drive mechanism 4 accidentally comes close to the neutron instrumentation cable 22 during the above operation, the limit switch 50, which is moved to simulate this, hits the striker 28 and turns ON. The signal automatically stops the operation of the CRD exchanger 2, that is, the drive mechanism 25 of the platform 6 and the drive mechanism 26 of the traveling trolley 9 automatically stop, thereby stopping further approach and preventing the two from moving toward each other. Inconveniences such as damage caused by interference can be prevented.

Since this invention was made as detailed above,
When installing and removing the control rod drive mechanism from the CRD housing using the CRD exchanger, monitor the positional relationship between the control rod drive mechanism and the neutron instrumentation cable on a simulated display board in a remote operator's cab, etc. This allows you to easily operate the CRD exchanger while controlling its position so that the two do not interfere and cause damage, and even if you make a mistake in operation, the limit switch will not operate. This system automatically stops the operation of the CRD exchanger and regulates its position, thereby preventing inconveniences such as damage caused by interference between the control rod drive mechanism and the neutron instrumentation cable.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing the schematic configuration of the CRD exchanger in the work chamber, Figures 2 to 4 are side views showing the operation of the CRD exchanger in order, and Figure 5 is the CRD housing at the bottom of the reactor pressure vessel. 6 to 8 show an embodiment of the present invention, and FIG.
FIG. 7 is a side view showing the position detection sensor attached to the CRD exchanger, FIG. 7 is a front view of the simulated display board, and FIG. 8 is a cross-sectional view showing the simulated display board and the mechanical part on the back side thereof. DESCRIPTION OF SYMBOLS 1... Working room, 2... Control rod drive mechanism exchanger, 3... Control rod drive mechanism housing, 4... Control rod drive mechanism, 6... Platform, 9... Traveling trolley, 10... Detachment device, 22... Cable for neutron instrumentation device, 23, 24... Position detection sensor, 25, 26... Drive mechanism, 27... Simulated display board, 3a... Control rod drive mechanism housing position display, 22a... Neutron meter Cable position display for equipment, 28... Striker for limit switch, 4
9...Display lamp, 50...Limit switch.

Claims (1)

[Claims] 1. A platform installed rotatably in the lower working chamber of the reactor pressure vessel, a traveling truck installed on the platform so as to be able to travel in a straight line, and the reactor pressure is controlled by the traveling truck and by the traveling of the traveling truck and the rotation of the platform. A device for controlling the position of a control rod drive mechanism exchanger, which is comprised of an attachment/detachment device that comes below the control rod drive mechanism housing of the container and attaches/detachs the control rod drive mechanism to the housing, and that is connected to the platform of the exchanger and travels with the control rod drive mechanism. The control rod drive mechanism housing position display and the neutron instrumentation cable are installed in a remote location such as the operator's cab and located at the bottom of the reactor pressure vessel with the same positional relationship. A transparent or translucent simulated display board with a position indication; a limit switch striker protruding from the back side of the simulated display board in correspondence with the cable position indication for the neutron instrumentation device; and the back side of the simulated display board. a simulated movement mechanism that moves in the same way as the platform of the exchanger and the traveling truck in response to a signal from the position detection sensor, and a control rod that is supported by the simulated movement mechanism and held vertically in the attachment/detachment device of the exchanger. 1. A position regulating device for an exchanger in a control rod drive mechanism, comprising an indicator lamp that can be moved in the same manner as the drive mechanism, and a limit switch for stopping operation of the exchanger.