JPS632078B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In the CRD replacement work of a nuclear reactor, the present invention provides that when an operator installs a CRD in a CRD exchanger and operates it, the CRD installed in the CRD exchanger due to an erroneous operation causes the instrumentation piping containing measuring equipment to be damaged. Relates to a CRD exchanger protection device for preventing contact with the CRD exchanger.

Generally, in a boiling water reactor, a control rod drive mechanism CRD for driving the control rod CR is installed at the bottom of the pressure vessel. This CRD is typically
It is scheduled to be removed and inspected during the annual periodic inspection. The removal of the CRD during this inspection and the installation of the CRD in its original position after inspection are performed using a dedicated CRD replacement machine that can be operated remotely automatically or manually at the CRD replacement site.

Figure 1 is a block diagram of the CRD exchanger, which is installed at the bottom of the reactor. The platform 1 pivots on rails 3 installed on the side walls 2 at the bottom of the reactor. The traveling carriage 4 reciprocates on the platform 1 in the radial direction, and as the platform 1 rotates, the CRD exchanger moves in the horizontal direction.

The rotating frame 5 is supported by the traveling carriage 4 at a support point 6, and can rotate from horizontal to vertical and from vertical to horizontal about this point. The lifting cart 7 moves up and down along the rotating frame 5. Desorption machine 8
It is used to attach and detach the bolts that fix the CRD to the CRD housing 10, and is transported vertically by the lifting truck 7, and is mounted on the detacher truck 9 when not in use. The desorption machine trolley 9 runs under the platform 1, and the desorption machine 8 is moved between it and the lifting trolley 7.
The delivery will take place. With a CRD exchanger like this
The case of removing the CRD will be explained below. First, where should the operator be located from the approximately 200 CRD housings 10 installed at equal intervals at the bottom of the reactor?
Decide whether to remove the CRD from the CRD housing 10. Then, the platform 1 is rotated, the traveling trolley 4 is run, and the target CRD housing 1 is
Move the rotating frame 5 directly below 0. The rotating frame 5 is kept vertical at this time. Next, the demounting machine cart 9 is placed adjacent to the rotating frame 5, and the elevating cart 7 is raised, and the demounting device 8 is mounted on the elevating cart 7. Thereafter, the lifting cart 7 is raised along the rotating frame 5 and connected to the CRD housing 10. Then, the CRD at the bottom end of the CRD housing 10
The eight bolts fixing the CRD are warmed by the demounting machine 8, and the lifting cart 7 is lowered while mounting the removed CRD on the demounting machine 8. As a result, the CRD is removed from the CRD housing 10, fixed to the rotating frame 5, and then moved to a predetermined position using the platform 1 and the traveling carriage 4. Then, level the CRD and move the traveling trolley 4.
Then, run platform 1 and take out the CRD from the CRD exit for inspection. CRD
When attaching to the housing 10, the operation is completed by following almost the reverse procedure described above.

However, at the bottom of the reactor, along with the CRD housing, there are more than a dozen instrumentation pipes that house measurement equipment for measuring neutron flux inside the reactor, so when operating the CRD exchanger, the lifting cart 7 is installed. When operating the platform 1 and traveling trolley 4 with a CRD mounted on the platform, it is necessary to operate so that a part of the CRD does not come into contact with this instrumentation piping and damage each other's equipment. In other words, the operator is on the lifting trolley 7.
When driving with a CRD installed, it was necessary to pay close attention to the driving route, making it difficult to operate the CRD exchanger.

Therefore, an object of the present invention is to provide a CRD exchanger protection device that prevents a CRD exchanger equipped with a CRD from coming into contact with instrumentation piping due to an operator's erroneous operation, and enables safe operation of the CRD exchanger. It's about getting.

An embodiment of the present invention will be described below. Figure 3 is
1 is a block configuration diagram in which a CRD exchanger protection device 19 of the present invention is provided in an operation control system of a CRD exchanger 15. FIG. Operation commands to the CRD exchanger 15 by an operator are given via the control device 13 and the drive device 14. That is, the operator drives the drive device 14 via the control device 13, and the CRD exchanger 15 operates according to the operation by the operator. The current location of each device of the CRD exchange 15 is platform 1 of the CRD exchange 15,
The position is detected by the position detector 16 installed on the traveling truck 4, and is input to the control device 13, thereby notifying the operator. The operator continues to operate the CRD exchanger 15 via the control device 13 while checking the current position obtained in this manner.

The CRD exchanger protection device 19 of the present invention is for preventing the CRD exchanger equipped with a CRD from coming into contact with instrumentation piping, and is composed of a prohibited area detection device 17 and an operation stop device 18. .

The prohibited area detection device 17 detects that the CRD exchanger 15 approaches the instrumentation piping, and this detection is performed as follows. That is,
As shown in FIG. 4, an instrumentation pipe 20 is provided at the bottom of the reactor separately from the CRD housing 10. When the lifting cart 7 of the CRD exchanger 15 carries a CRD and runs, the CRD 21 and the instrumentation pipe There may be cases where they come into contact with each other. Therefore, the projection of the location where the instrumentation piping 20 is provided onto the floor of the CRD replacement work site (pedestal) is set as an operation prohibited area, and the CRD exchanger 15 is prevented from intruding into this operation prohibited area.

Figure 2 shows the distribution of part of the prohibited operation area due to the presence of instrumentation piping at the bottom of the reactor. 11 in the diagram is
It represents the CRD housing (+ mark), and 12 represents the prohibited operation area (○ mark). Forbidden area detection device 1
7 detects that the CRD exchanger has entered the operation prohibited area 12.

Next, the prohibited area detection device 17 is composed of a reed switch 22 and a permanent magnet 23, as shown in FIGS. 4 and 5a. First, an annular permanent magnet 23 having a constant width larger than the diameter of the instrumentation pipe 20 is provided at the location where the instrumentation pipe 20 is projected onto the pedestal floor surface, as shown in FIG. 5b. A reed switch 22 is arranged and buried at the bottom of the rotating frame 5 as shown in FIG. 5c. Then, when the CRD exchanger 15 runs and one of the reed switches 22 of the reed switch group installed at the bottom of the rotating frame 5 approaches the permanent magnet 23 installed on the pedestal floor, the reed switch 22 The CRD exchanger 15 operates and detects that the CRD exchanger 15 has entered the operation prohibited area 12. As mentioned above, the diameter of the permanent magnet 23 is larger than the diameter of the instrumentation piping 20, so the CRD exchanger 1
The intrusion signal A from the prohibited area detection device 17 is input to the operation stop device 18 immediately before the CRD 21 mounted on the CRD 5 comes into contact with the instrumentation piping 20.

Next, the intrusion signal A from the prohibited area detection device 17 and the mounting signal B of the CRD 21 onto the lifting truck 7 from the control device 13 are input to the operation stop device 18 . Then, the operation stop signal C is outputted from the operation stop device 18 to the control device 13 under the AND condition of the intrusion signal A from the prohibited area detection device 17 and the mounting signal B for mounting the CRD 21 on the lifting truck 7.

This means that the lifting cart 7 of the CRD exchanger 15 is
21 is not installed, CRD exchanger 1
5 and the instrumentation piping 20 do not come into contact with each other,
This is because even if the CRD exchanger 15 enters the operation prohibited area 12, there is no need to stop the operation of the CRD exchanger 15. In other words, in the present invention, the driving prohibited area, which is originally shown in three dimensions, is represented as a two-dimensional driving prohibited area projected on the pedestal floor surface, and by taking into account whether or not a CRD is installed,
This system is designed to determine three-dimensional driving prohibited areas.

Now, assume that the operator operates the control device 13 to operate the drive device 14 and start operation of the CRD exchanger 15 equipped with the CRD 21. The CRD installed in the CRD exchanger 15 due to an operator's error, etc.
21 is operated in such a way that it approaches the instrumentation piping 20 unnecessarily, the vehicle enters the prohibited operation area 12.
A situation occurs in which the CRD exchanger 15 enters, and in the prohibited area detection device 17, one of the reed switches 22 of the reed switch group is located in the space above the permanent magnet 23. Therefore, the contact point of the reed switch 22 is closed before the CRD 21 comes into contact with the instrumentation pipe 20. Due to the closing operation of this reed switch 22, the prohibition detection device 1
7 outputs the intrusion signal A to the operation stop device 18.

As shown in FIG. 6, the operation stop device 18 processes intrusion signals A corresponding to the number of reed switches 22 in the reed switch group using an OR circuit. At the same time, a signal B for mounting the CRD 21 on the lifting cart 7 is received from the control device 13, and these two signals are processed by the AND circuit. Therefore, the operation stop device 18 outputs the operation stop signal C to the control device 13 when the lifting cart 7 carries the CRD 21 and the CRD 21 approaches the instrumentation piping 20 at the same time. This operation stop signal C blocks the output signal from the control device 13 to the drive device 14, causing the CRD exchanger 15 to stop driving.

Of course, the CRD exchanger 15 is the operation stop device 1.
It goes without saying that after the operation is stopped in step 8, the operator continues the operation via the control device 13 while avoiding the operation prohibited area.

Another embodiment of the present invention will now be described. An ultrasonic transmitter is installed at the bottom end of the rotating frame 5.
Rotate at high speed using the CRD diameter. Ultrasonic waves are transmitted toward the pedestal floor. The area of the floor surface that corresponds to the operation-prohibited area is set at a slight height difference from other floor parts, and the operation-prohibited area is determined based on the time difference in the emitted ultrasonic waves caused by this, and the operation of the CRD exchanger is stopped.

Additionally, a limit switch is installed at the bottom end of the rotating frame 5, and a height difference is created between the area corresponding to the prohibited operation area and other parts on the pedestal floor surface, and the limit switch is opened and closed based on this height difference. The operation may be stopped by determining the driving prohibited area. It is also possible to use a combination of a photoelectric section and a light receiving section instead of the ultrasonic transmitter. That is, as described above, the gist of the present invention is a procedure for detecting approach, and it is clear that it is applicable not only to reed switches but also to other procedures.

As described above, the present invention has the following effects because it stops the CRD exchanger before a situation in which the CRD comes into contact with the measurement pipe due to an erroneous operation or the like occurs during the CRD exchange operation.

(1) Damage caused by equipment collision, etc. can be prevented.

(2) Safe operation of equipment and highly efficient work are possible.

(3) The load on the operator can be reduced.

(4) Work time and periodic inspection process can be shortened.

(5) Radiation exposure for operators can be reduced.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of the CRD exchanger, Figure 2 is a distribution diagram of prohibited operation areas, Figure 3 is a configuration diagram of the CRD exchanger protection device, Figure 4 is an installation diagram of the prohibited area detection device,
Figures 5a, b, and c are explanatory diagrams of the prohibited area detection device;
FIG. 6 is a circuit diagram of the operation stop device. 1...Platform, 4...Traveling trolley, 5...
... Rotating frame, 7 ... Lifting truck, 8 ... Detachment machine, 9 ... Detachment machine cart, 10, 11 ... CRD housing, 12 ... Operation prohibited area, 13 ... Control device, 14 ... Drive device, 15...CRD exchange machine,
16...Detector, 17...Prohibited area detection device, 1
8... Operation stop device, 19... CRD exchanger protection device, 20... Instrumentation piping, 21... CRD, 22
... Reed switch group, 23 ... Permanent magnet, A1
-n...Intrusion signal from reed switch, B...
CRD installed signal, C...operation stop signal.

Claims (1)

[Claims] 1. In a nuclear power plant equipped with a CRD exchanger that attaches and detaches a CRD that drives the control rods of a nuclear reactor, and a control device for operating this CRD exchanger, the CRD exchanger is operated by the operation of the control device. a prohibited area detection device that outputs an intrusion signal when the vehicle enters a predetermined driving prohibited area; and a CRD-equipped device that indicates the intrusion signal from the prohibited area detection device and that the CRD exchanger is equipped with the CRD. A CRD exchanger protection device comprising: an operation stop device that outputs an operation stop signal to the control device to stop running of the CRD exchanger under an AND condition with a signal.