JPH02271299A - Driving device for detector - Google Patents

Abstract

PURPOSE:To decrease operators' radioactive exposure and to enable a detector damage by an operation error to be preventable by controlling a winding reel in a winding direction of a driving cable during the detector is being driven and by fixing the winding reel during the detector is halted. CONSTITUTION:When a driving cable 23 of a detector is inserted from a driving unit 26, a winding reel 22 are rotatingly activated in a pulling-out direction of the cable 23 not so as to loosen the cable 23 and not to derail the detector. As a torque of the reel 22 is smaller than a pulling-out force of a driving wheel, the reel 22 rotates in an inserting direction. Also, when the cable 23 is pulled out, a torque motor 19 is used and the motor 19 is able to rotate for winding a longer length of the cable than a length that the driving wheel pulls out the cable 23. The motor 19 is equipped with an electromagnetic brake and when the motor 19 stops, the reel is fixed by the brake. Meanwhile, a connector at a detector end is connected to a rotary connector 18 attached to the reel 22. An end of the connector 18 rotates together with the connector at the detector end, and another end is fixed to a support of a fixture reel and is connected to a lead-out cable 24 of a detector output.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a mobile reactor core for calibrating a power range neutron east detector for in-core neutron east monitoring of a nuclear reactor such as a boiling water reactor. Regarding the internal instrumentation system, especially the detector drive device of the mobile in-core instrumentation system.
Regarding.

(Prior Art) A nuclear reactor such as a boiling water reactor is equipped with a power range neutron detector (hereinafter referred to as an LPRM detector) in the core of the reactor to monitor the neutron flux within the reactor. A mobile in-core instrumentation system (Travers) is used to calibrate the
ing Incore Probe System (hereinafter referred to as TIP) will be installed.

The conventional TIPI is configured as shown in Figure 2.
A reactor pressure vessel 3 housed within the reactor containment vessel 2 is supported on a support pedestal 4 and surrounded by a heat shielding wall 5. A plurality of power range detector assemblies 6 are installed inside the reactor pressure vessel 3, and the TI
A P detector calibration tube 7 is housed.

TIPI includes the calibration tube 7, an indexing device 8 installed outside the reactor pressure vessel support pedestal 4, a valve assembly 9 installed outside the reactor containment vessel 2, a shielding vessel IO, and a detector drive device. 11, and guide tubes 12a and 12b that interconnect these.

The number of guide tubes 12a and 12b is one from the detector driving device 11 to the indexing device 8, and a plurality of guide tubes 12a, 12b are provided from the exit side of the indexing device 8, for example, 10.
A plurality of output area detector aggregates 6 correspond to each of the output area detectors b.

A drive cable (not shown) is guided so as to be inserted into the guide tubes 12a and 12b, and a mobile in-core instrumentation system detector (sensor) is attached to the tip of the drive cable. Which power range detector assembly 6 this drive cable is inserted into is determined by switching the indexing device 8 .

The inner peripheral surfaces of guide tubes +2a and 1.2b are coated with dry lubricant, and the drive cable and guide tube 12a are coated with dry lubricant.

This is intended to alleviate the frictional resistance of 12b. However, as the dry lubricant coating becomes thinner due to aging,
Frictional resistance between the drive cable and the guide tubes 12a, 12b increases, resulting in damage to the drive cable. Therefore, the frictional resistance between the drive cable and the guide tubes 12a, 12b is regularly monitored by measuring the torque when the drive cable is inserted.

- The conventional detector drive device for driving the right drive cable is constructed as shown in Figs.
The figure is a side view of the detector driving device with the case 40 and side covers 41 and 42 removed, and FIG. 4 is a plan view.

The detector drive device connects the reactor side to a clean area 44 by a partition wall 43 provided in the center of the case 40 of the detector drive device.
, and the other side is the dust area 46. In the clean area 44, single-door doors 41 attached with hinges are provided on both sides of the case 40, and a drive motor 50 and a reducer 51 are installed in the inner space formed by the case 40, the partition wall 43, and the two doors 41. ．． A sprocket 52 for transmitting the rotation, a chain 53, a control panel 33 for controlling the stop and drive of the drive shaft 31 and drive motor 50 are arranged, and further,
Insert and pull out the detector drive cable 28 into the partition wall 43. Attach the closed container 45 containing the drive unit 26. Pass the guide tube I2 through the reactor side of the case 40 of the detector drive device and connect it directly to the closed container 45. I'm here.

The other dust area 46 is covered with a cover 42 with sealing material 47 on both sides of the case 40, and detected inside a closed room made of the case 40, the cover 42, and a partition wall 43 in the center of the case 40. A device drive cable 28 and a take-up reel 54 that feeds out the cable 28 when it is inserted and winds it up when it is pulled out are arranged. That is, the detector driving device 11
In this case, a partition wall 43 is provided in the center of one case 40, and the case 40 is divided into two, with the reactor side serving as a clean area 44 and one side serving as a dust area 46, each having a total of four doors on both sides. .

Detector currently stored in shielded container 10 (not shown)
When inserted and driven by rotating the drive wheel of the detector drive device 11, the detector drive cable 23 and the detector at its tip are pushed out of the shielding container 10, pass through the valve assembly 9, and enter the indexing device 8. As a result, the peak of the calibration tube 7 of the selected predetermined output area detector assembly 6 is reached.

At this point, by rotating the drive wheel of the drive device 11 in the reverse direction, the drive is pulled out, and the detector at the tip of the detector drive cable 23 measures the neutron flux and returns to the shielding container 10.

Furthermore, as mentioned earlier, the detector drive cable 23 is exposed to radiation on three sides of the reactor pressure vessel, activating the dry lubricant on the inner surface of the guide tube 12, and discharging the dry lubricant each time the insertion and withdrawal drive is repeated. The drive unit 26 is peeled off little by little and attached to the detector drive cable up to the detector drive device 11 and then pulled back, but the drive unit 26 that comes into direct contact with this detector drive cable inside the detector drive device 11 is placed in a closed container. Since the guide tube 12 is directly connected to the guide tube 12, the fine powder of the dry lubricant activated in the clean area 44 will not be spilled or suspended. A drive cable 23 is also wound around it. The take-up reel 54 has two types of spring springs; one type is a spring spring that is used when the detector drive cable 23 is pulled out from the take-up reel 54 by the drive unit 26 when the detector is inserted and driven. Since the handle 54 rotates in the insertion direction, the spring spring 48 is wound around it, and this winding causes the drive cable 23
A winding force is generated in the spring spring 48, and is a force capable of winding the pull drive cable 23 when the detector is pulled out.

Another type of spring spring 49 has a detector output connector (not shown) at the end of the drive cable 23 fixed to the take-up reel 54, and rotates together with the take-up reel 54 in the insertion direction and the withdrawal direction. Therefore, a pulley 56 is used to prevent the detector output take-out cable 55 from being twisted and disconnected, and a pulley mechanism is provided on the take-up reel 54, and the pulley 56 is rotated to follow the take-up reel 54 for detection. This prevents the device output take-out cable 55 from being twisted.

The rotational force of this pulley 56 also causes the take-up reel 54 to rotate in the insertion direction when the detector is inserted and to pull the detector output take-out cable 55.
, the pulley 56 rotates in the insertion direction and winds the spring spring 49.

Therefore, the detector output extraction cable 55 is connected to the pulley 56.
Since it is constantly pulled by the rotational force of the spring spring 49, its lifespan is shortened and it must be replaced periodically.

When performing this replacement work, since the first take-up reel 54 is located in the dust area 46, there are fine powders of activated dry lubricant, resulting in poor workability and increased radiation exposure for regular inspection workers.

Also, when measuring torque to monitor the lifespan of the dry lubricant coated on the guide tube 2, the drive shaft is rotated with a torque wrench instead of the drive motor 50.
The detector drive cable 23 is pulled out from the take-up reel 54 and the spring spring 48 is wound thereon. At this time, if the worker accidentally releases his hand from the torque wrench, the first take-up reel 54 rotates in the take-up direction due to the take-up force of the spring spring 48, pulling the detector drive cable 23 in the pull-out direction. The momentum builds up quickly, and there is a possibility that the detector with a high radiation plate will be pulled all the way to the drive device 11, and the radiation exposure of the workers will increase.

(Problem to be solved by the invention) In the conventional detector drive device of the mobile in-core instrumentation system, it is necessary to replace the detector output cable every few years during periodic inspections.
If it is carried out once, the periodic inspection work wave @ amount for that year will increase by that amount.

Furthermore, if workers accidentally let go of the torque wrench during torque measurement work, which is carried out every year, the detector with its high radiation plate may be pulled out to the drive device, increasing the radiation exposure of workers.

Also, at this time, the detector is pulled back vigorously, so
It is also conceivable that it may hit the drive unit case and cause damage.

The present invention was made considering the above-mentioned 9x1 circumstances,
It is an object of the present invention to provide a movable in-core instrumentation system detector drive device that reduces radiation exposure of workers and prevents damage to the detector due to an operational error.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above-mentioned object, the detector drive mechanism of the mobile in-core instrumentation system according to the present invention has a detector drive cable that is inserted from the drive unit and taken up once. When being pulled out from the reel, a rotational force is applied to the take-up reel in the pull-out direction to prevent it from being pulled out excessively and sagging in the drive device and coming off the take-up reel and derailing, and this rotational force of the take-up reel is The take-up reel rotates in the insertion direction since it is smaller than the pull-out force of the drive wheel. Furthermore, when pulling out the detector drive cable, a torque motor is used that generates a rotation speed that allows the drive wheel to wind a length greater than the length to which the detector drive cable is pulled out.

This torque motor is equipped with an electromagnetic brake, and the take-up reel is fixed by the brake when the torque motor is stopped.

The connector at the end of the detector is connected to a rotary connector attached to the shaft center at the rotation center of the take-up reel.

One of the rotary connectors rotates together with the connector at the end of the detector, and the other is fixedly attached to the support of the mounting reel and connected to the detector output extraction cable. This prevents the detector output cable from getting twisted.
This eliminates the need for constant tension.

(Function) In this mobile in-core instrumentation system detector drive device, the drive motor rotates the drive unit in the insertion direction, and at the same time, the electromagnetic brake of the take-up reel is released and the torque motor is powered on. The take-up reel receives rotational force in the pull-out direction, but since the pull-out force of the drive unit is stronger, the take-up reel rotates in the insertion direction. Therefore, the rotational force of the take-up reel in the pulling direction does not cause the detector drive cable to slacken.

When the detector enters the reactor core and reaches the neutron east measurement position, the drive motor and torque motor stop, the electromagnetic brake operates, and the detector and take-up reel stop.

The output of the neutron flux measured by the detector is extracted from the detector capacity via a rotary connector from the connector at the end of the detector.

After measuring neutrons, the detector is driven to withdraw.

At this time, the drive motor rotates the drive unit in the pulling direction, and at the same time the electromagnetic brake of the take-up reel is released and power is turned on to the torque motor, so that the take-up reel obtains rotational force in the pulling direction.

The rotation speed of the take-up reel has the ability to wind up more cable than the length of the drive cable to be pulled out by the drive unit, so the drive cable will not become loose.

At the same time as the extraction completion drive motor stops, the torque motor and electromagnetic brake operate to fix the take-up reel.

In addition, when performing torque measurement, remove the lid from the window of the case of the detector drive device of the mobile in-core instrumentation system.
A torque measuring device is inserted through this window, and the torque measuring device is connected to the drive shaft of the drive unit, and while the internal air is exhausted from the exhaust port formed in the case, the inside of the case is maintained at negative pressure to drive the drive unit. It is detected by a shaft torque measuring device, and the driving torque associated with the movement of the mobile in-core instrumentation system detector is measured.

(Example) Hereinafter, an example of the present invention will be described with reference to the accompanying drawings.

A mobile in-core instrumentation system (TI
The overall arrangement of P) is the same as that shown in FIG. 3, so a description thereof will be omitted.

As shown in FIG. 1, the mobile in-core instrumentation system includes a detector drive device 20 that drives a mobile in-core needle system detector (not shown). This detector drive bag [20 rotatably accommodates a take-up reel 22 in a box-like case 21, and a drive cable 23 is wound around this take-up reel 22.

The drive cable 23 wound around the take-up reel 22 is inserted into the guide tube 12 through the drive unit 26 of the cable drive mechanism 25, and a mobile in-core instrumentation system detector (hereinafter referred to as a sensor) (not shown) is installed at the tip of the drive cable 23. is attached.

The drive unit 26 is connected to a reduction mechanism 29 from the drive motor 28 via an electromagnetic clutch 30, and by the clutch action of the electromagnetic clutch 30, 11 power from the 1 Todo motor 28 is transferred to the drive shaft 31 of the drive unit 26 as necessary. Communicating. The reduction mechanism 29 is, for example, a worm reduction gear. A torque motor 22 is attached to the winding wheel 22.
and a rotary connector I8 are attached, and the torque motor 22 serves as a drive source for the winding loop.The rotary connector 18 connects a connector (not shown) below the detector drive cable, and connects the detector output take-out cable 24. The detector output is relayed to.

On the other hand, a circular window 34 is formed on the side surface of the case 21 in correspondence with the drive shaft 31 of the cable drive mechanism 25, and this circular window 34 is removably closed by a lid 35.

This lid body 35 is removed when measuring the torque of the TIP detector, and the torque wrench 36 is attached to the drive shaft 31 through the circular window 34.
A torque detector such as the following is connected.

Further, the case 2I of the detector driving device 20 has an exhaust port 27 formed at the top, for example, and an exhaust pipe 39 is provided at the exhaust port 27. This exhaust pipe 32 is connected to exhaust equipment such as an exhaust duct 38 that air-conditions the storage chamber 37 housing the detector drive mechanism 20.

Further, reference numeral 33 is a field control panel for the detector drive device 20, and this control panel 33 includes an electric circuit including a motor controller, an electromagnetic switch, a relay, a timer, a transformer, and a motor wattmeter (all not shown). is built-in.

Next, the operation of the detector driving device will be explained.

Select the detector drive device 20 connected to the LPRM detector assembly 6 to be calibrated from among the plurality of detector drive devices 20 installed in the nuclear power plant of the boiling water reactor, and perform the drive operation from the central operation room. When this is done, the drive motor 28 and the torque motor 19 operate, and at the same time the electromagnetic brake (not shown) of the torque motor 19 is released, the fixation of the take-up reel 22 is released, and the torque motor 19 applies rotational force to the take-up reel 22 in the pulling direction. However, since the pull-out force of the take-up reel 22 is smaller than the insertion driving force of the drive unit 26, the take-up
The lever 22 rotates in the insertion direction. Therefore, drive cable 2
The detector drive cable 23 is smoothly inserted and driven by the drive unit without loosening the cable 3.

When the detector enters the reactor core and reaches the neutron flux measurement position, the drive motor 28 and torque motor 19 stop, the electromagnetic brake operates, and the detector and take-up reel 22 stop. The output of the neutron flux measured by the detector is taken out from a detector output take-out cable 24 from a connector (not shown) at the end of the detector through a rotary connector. After the zero-order neutron east measurement, the detector is driven to pull out.

At this time, the drive motor 28 rotates the drive unit 26 in the pulling direction, and at the same time, the torque motor 19 attached to the take-up reel 22 and the electromagnetic brake are removed, and the torque motor 19 is turned on, so that the take-up reel 22 is rotated in the pulling direction. get.

The number of rotations of the take-up reel 22 is such that it can take up more detector drive cables 23 than the length of the detector drive cable 23 that the drive unit 26 pulls out, so the drive cable 23 is not loosened. The detector drive cable 23 is wound up at any time without being derailed from the reel 22. When the extraction is completed, the drive motor 28 stops and at the same time the torque motor 19 and the electromagnetic brake operate to fix the take-up reel.

In addition, when measuring the driving torque accompanying the movement of the mobile in-core instrumentation system detector during periodic inspection, the lid body is 35, and insert the torque wrench 3 through this circular window 34.
6 is inserted to connect the torque wrench 36 to the 1 drive shaft 31 of the drive unit 26, and while exhausting the air inside from the exhaust port 32 formed in the case 21, the inside of the case is maintained at negative pressure and the drive is performed. It is detected with a torque wrench on the shaft 31, and the driving torque associated with the movement of the movable in-core instrumentation system detector is determined.

When the lid 35 is removed, the circular window 34 opens, and air outside the detector driving device 20 is sucked into the case 21 through the circular window 34. The sucked air is guided from the exhaust port 27 to the exhaust duct 30 through the exhaust pipe 32, and is exhausted from the exhaust duct 38. At this time, the detector drive bag 512
The dust in the air is carried by the air flow to the exhaust duct 38.
It will not leak out from the circular window.

After confirming this air flow, worker 9 inserts a torque detector such as a torque wrench through the circular window 34 and sets it on the drive unit drive shaft 31 of the cable drive mechanism 25.

Next, operate the switch on the field control panel 33 to activate the m-magnetic latch 30, and the clutch action disconnects the output shaft of the deceleration mechanism 29 from the drive shaft 31 of the drive unit 26, freeing the drive shaft 31. Make it. When the electromagnetic brake of the torque motor 19 attached to the take-up reel 22 is released by a switch on the field control panel 33 and the torque motor 19 is turned on, the take-up reel 22 receives rotational force in the pulling direction. In this state, rotate the torque wrench 36,
The drive cable 23 is driven in a direction to be inserted into the core of the reactor pressure vessel. As a result, the drive cable 23 is pulled out from the take-up reel 22, passes through the guide tube 27, and is inserted into an arbitrary power range detector assembly (see FIG. 4) in the reactor pressure vessel. At the time of insertion, the load torque of the drive shaft 31 is measured at any time using a torque detector such as a torque wrench 36.

For example, if the worker accidentally removes his hand from the torque wrench 36 at this time, the detector drive cable 23 will be pulled back toward the detector drive device 20 by the pulling force of the torque motor 19. Since the rotational speed of the torque motor 19 is constant, the speed at which the detector drive cable 23 is pulled out is constant at a certain speed.In addition, the torque motor 19 is turned off with a switch on the field control panel 33, and the electromagnetic brake is operated, and the detector drive cable 23 is pulled out at a certain speed. It is possible to stop the extraction of the

When the measurement of the load torque is completed, the drive cable 23 is pulled out from the output range detector assembly and inserted into the next output range detector assembly, and the load torque of the drive unit drive shaft 31 is similarly measured. This switching is performed by an indexing device (see FIG. 4). The indexing device undergoes a switching operation once the drive cable 23 is pulled out to the indexing device, and the drive cable 23 is switched and reinserted. When all the load torque measurements are completed in this way, the next detector drive device 20 is shifted to the next one, and the torque is measured by the worker. a+1 is determined.

〔Effect of the invention〕

As described above, in the present invention, the cable for taking out the detector output is simply attached to the rotary switch and is not subjected to rotational force from the pulley, resulting in a longer life and eliminating the need for replacement. Therefore, the radiation exposure of regular inspection workers can be reduced accordingly.

It is also nearby even if a regular inspection worker accidentally removes his/her hand from the torque wrench when measuring the drive torque associated with the movement of the mobile in-core instrumentation system detector. By simply operating a switch on the field control panel, the detector can be stopped without damaging it, and there is no need to return the detector to the detector drive device where operating tools are located. Therefore, there is no possibility of being exposed to radiation generated from the detector.

(Other Embodiments) If we consider only the case where a worker accidentally removes his hand from the torque wrench during torque measurement, it is effective to simply attach a brake to the take-up reel.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the detector driving device of the present invention, Fig. 2 is a sectional view showing the mobile in-core instrumentation system, and Fig. 3 is a side view of the conventional detector driving device with the cover removed. FIG. 4 is a plan view of FIG. 3. Agent Patent Attorney Noriyuki Ken Yudo Daishimaru Ken Figure 1 Figure 3

Claims (1)

[Claims] 1) A mobile in-core instrumentation system detector is housed in a case, including a take-up reel around which the attached drive cable is wound, and a cable drive mechanism that takes in and out the drive cable wound around this take-up reel. , in the detector drive device for the mobile in-core instrumentation system that drives the mobile in-core instrumentation system detector to be inserted into and pulled out of the reactor core, the drive cable is constantly connected while the detector is being driven by the motor attached to the take-up reel. A detector drive device for a mobile in-core instrumentation system, which controls a take-up reel in the direction of winding the detector, and fixes the take-up reel with an electromagnetic brake when the detector is stopped.