JP2783633B2 - Control rod position monitoring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a control rod position monitoring device for a power reactor.

(Prior art) Nearly 200 control rods are installed in a power reactor,
The reactor power is controlled and the power distribution is adjusted by pulling it out or inserting it from the reactor core. The position of the control rod is controlled by being driven by hydraulic pressure or a magnetic jack.

The actual insertion or withdrawal of the control rods is confirmed by detecting the position of a reed switch that operates when each control rod passes.

This reed switch is provided for each control rod,
Nearly 30 control rods are installed per control rod from the full withdrawal position to the full insertion position. Usually, any one control rod is selected by an operator to perform a pull-out or insertion operation. This operation is controlled by the control rod driving device such that the position of the reed switch is moved backward or forward by one operation. Therefore,
If the position of the reed switch does not change during operation, it is expected that the control rod drive system will be damaged by water pressure or a magnetic jack during the failure of the reed switch and the failure of the drive circuit.
Generally, the drive circuit is provided with a self-diagnosis circuit, and the control rod drive system is provided with a failure detection circuit such as a pressure switch.If no failure is detected by the self-diagnosis circuit or the failure detection circuit, the failure of the reed switch itself will occur. it is conceivable that. In particular, in the case of a contact failure of the reed switch contact, the control rod position signal becomes non-signal and the current position cannot be determined, so that such a failure must be immediately notified.
In this case, the control rod position monitoring device detects which of the control rod reed switches has failed, outputs an alarm, and displays an individual display on the display panel. Conventionally, in this control rod position monitoring device, the alarm output and the individual display on the display panel are continued until the faulty part is recovered, and the fault recovery work is notified.

A conventional example of such a control rod position monitoring device will be briefly described with reference to FIGS. 3 and 4. FIG.

In FIG. 3, a large number of control rods 2 installed in a nuclear reactor 1 are driven by respective control rod drive systems 3.
A reed switch signal a (ON or OFF signal) of a plurality of reed switches 4A to 4D that operate according to the position of one control rod 2 is led to a reed switch matrix 5A, and converted into an 11-bit binary signal b. 6 and sent to the central monitoring device 7 via the transmission line as a control rod position signal c having an address. Such an operation is sequentially repeated for each control rod at a constant period, and control rod position signals for all control rods are transmitted to the central monitoring device 7. In the central monitoring device 7, while displaying on all the control rod status indicators 8,
The position of each control rod is monitored, and if there is a failure, a failure display panel 9
The upper individual display lamp 9A is turned on. When the operator selects an arbitrary control rod from the control rod selection panel 10 and then selects the insertion or withdrawal function, a control rod selection signal d is guided to the central drive unit 11 and an electromagnetic valve having an address via a transmission line. The drive signal e is transmitted to the local drive device 12. The on-site driving device 12 outputs a solenoid valve driving signal f to drive a corresponding control rod, and in accordance with insertion or withdrawal, a withdrawal supply valve 13,
The insertion / discharge valve 14, the insertion / supply valve 15, and the extraction / discharge valve 16 are appropriately excited to supply water from the hydraulic unit 17 to the control rod drive system 3.
Or the drainage water is discharged from the control rod drive system 3 to drive the control rod 2.

FIG. 4 shows a detailed circuit of the control rod position failure detecting section inside the central monitoring device 7. The control rod position signal c having the address transmitted from the terminal device 6 is received by the transmission receiving circuit 7A and sent to the all control rod state display 8 as the state display signal k via the transmission transmitting circuit 7B, It led to the fault detection circuit 7C _1. The position failure detection circuits 7C ₁ , 7C ₂ … are provided for each control rod, and when any of the reed switches does not operate and the position is unknown, the position failure detection outputs i ₁ , i ₂
... is output. The position failure detection outputs i ₁ , i ₂ … of each control rod are O
The R output is output to the failure display panel 9 as a failure display signal l. When the display reset switch 9B set on the failure display panel 9 is turned on, the display reset command m is guided into the central monitoring device 7.

When the normal failure display signal 1 is turned ON, when the display reset command m is OFF, the NOT output m 'is ON, and the display output self-holding signal n continues to be ON. While any _{one of the} position failure detection outputs i ₁ , i _2, ... Is ON, the failure display signal 1 does not turn OFF even if the display reset switch 9B is turned ON and the display output self-holding signal n is turned OFF. When the failure of the reed switch is recovered and the position failure detection outputs i ₁ , i ₂ … all turn OFF,
By turning on the display reset switch 9B, the failure display signal 1 can be turned off.

(Problems to be Solved by the Invention) As described above, in the conventional control rod position monitoring device, the failure display output cannot be reset until the failure cause is not recovered. However, when a failure such as a contact failure actually occurs in one reed switch, the following problems occur in the above-described conventional device.

That is, since the operation of the reactor is performed by comprehensively monitoring various parameters including the position of the control rod, even if the reed switch of the control rod is broken, the operation of the reactor can be stably continued. However, if a second failure of the reed switch is superimposed on this failure in addition to the failure, the occurrence of the second failure is not notified to the operator because the failure output is already ON.

Therefore, the present invention reports a failure when the first failure occurs in the control rod position detecting reed switch, interrupts the failure display output as necessary after the failure is confirmed by the operator, and It is an object of the present invention to provide a control rod position monitoring device capable of notifying the occurrence of a failure even when a failure occurs in the second reed switch while the failure continues.

[Means for Solving the Problems] The present invention relates to a monitoring device that detects a failure in a control rod position and continues to output a failure display while the failure continues, and displays a display reset PB operation information of an operator. A means for inputting a display output prohibition signal and interrupting the fault display output even when the fault continues, and individual fault detection to enable detection of another fault while the fault continues. Means for adding a circuit for detecting a state change when the output changes from normal to abnormal, releasing the display output prohibition signal when a state change occurs, and enabling a failure display output again. .

(Operation) With the configuration described above, the failure display output can be interrupted even if the first failure cause is not recovered, and if the second failure occurs while the first failure continues, the failure display output will be performed. Since the suspension is released and the output is enabled, the operator can be notified of the occurrence of the second failure.

(Embodiment) FIGS. 1 and 2 show the configuration of a central monitoring apparatus according to an embodiment of the present invention. The overall configuration of the control rod position monitoring device is the same as that of the conventional embodiment shown in FIG. 3, and FIG. 1 shows the circuit configuration in the central monitoring device 12 in detail. In the figure, the same reference numerals as those in FIG.
Differs from the structure of figures, the position fault detection output i _2, i ₂ ... OR ₁ a
To obtain the position fault signal p by taking the logical sum
The fault signal l is a signal obtained by ANDing the position fault signal p and the NOT ₁ output, which is the negative signal of the display output prohibition signal q, to AND ₁ , and the position fault detection outputs i ₁ , i ₂ … Are input to the state change detectors 7E ₁ , 7E ₂ … and the state change detector outputs v ₁ , v ₂ … are input to the OR ₂ to obtain a state change signal u. The NOT ₂ output, which is a negative signal of u, and the display output inhibit signal q are input to AND ₂ to obtain a display reset self-holding signal v, which is the logical product of them.
And lies in that to obtain the the display reset self-holding signal v, a display output disable signal q takes a logical sum by OR ₃ of the display reset command m.

FIG. 2 shows a detailed circuit of the state change detector 7E _1. This state change detector 7E ₁ has a current value area 7F ₁ that always stores the latest detection output, and a previous value area that stores the detection output when the previous control rod position scan signal is input.
7G ₁ and has, for storing data which has been held until now for each new data in a certain scan cycle to the current value area 7F ₁ is inputted to the value area 7G _1. Also the current value, and a negative NOT ₃ Output of the value as a configuration in which a logical sum with the AND _3, this value is ON i.e. failure and, only the state change detector output v ₁ when the previous value is OFF i.e. normal and ON I am trying to become. The other state change detectors 7E ₂ have the same configuration.

Next, the operation of the above-described embodiment of the present invention will be described.

If a fault in the reed switch 4A in situ nuclear reactor 1 has occurred, the control rod position signal c having an address is inputted to the central monitoring unit 7 without position data, the position fault detection circuit 7C ₁ corresponding to the address, position signal failure is detected, the position fault detection output i ₁ is turned ON. Before a failure occurs, the display reset command m from the display reset switch 9B is not input, and the display output prohibition signal q is OFF, so the NOT ₁ output is ON, and the position failure signal p is a failure display signal. 1 is output externally, the individual display lamp 9A on the failure display panel 9 is turned on, and the operator is notified by an alarm output or the like.

After the operator confirms the failure content, if the operator presses the display reset switch 9B to suspend the recovery of the failure of the reed switch 4A and interrupt the individual display lamp 9A and the alarm output, the display reset command m is 7 is input. On the other hand, the output v ₁ of the state change detector 7E _1, the position fault detection output i
Turns on when ₁ turns on, but turns off during the next control rod position scan cycle. Therefore, the condition detector output v ₁ is OFF
At that point, once the display reset command m is input,
Even if this disappears, unless the state change signal u is turned on, the display output prohibition signal v will be turned on, and the self-holding signal will continue to be turned on. Therefore, the NOT ₁ output will be kept off and the position fault signal p will be turned on.
, The failure display signal 1 is turned off, and the individual display lamp 9A and the alarm output are turned off.

If fault in the read switch for another control rod in this state occurs, the position fault detection circuit 7C ₂ corresponding to the address, the position fault detection output i ₂ failure is detected location signal turned ON. When the position failure detection output i ₂ turns ON,
The state change detector 7E ₂ outputs the state change detecting output v _2, and the state change signal u is ON, the display reset self-holding signal v is turned OFF, so also OFF display output inhibit signal q, the position fault signal p can be externally output again as the failure indication signal l.

As described above, the display output prohibition signal is ANDed with the fault display output of the control rod position signal, so that when the display output prohibition signal is established, even if the failure of the control rod position signal does not recover, the external display of the fault display output can be performed. Output can be interrupted. Also, a circuit is provided to detect a change in the state of the output of the fault detector of the control rod position signal, and the display output prohibition signal is released by this state change output signal. The display can be resumed.

Although the above embodiment has been described with reference to the case where the present invention is applied to a control rod position fault detecting circuit, the same effect can be obtained with a similar configuration by applying the present invention to a fault detecting circuit of another on-site limit switch or sensor. . In addition, although the example in which one display reset switch is configured has been described, the same effect can be obtained by configuring the display reset switch for each type of failure detection.

[Effect of the Invention] As described above, according to the present invention, the failure display output can be interrupted without the first failure cause being recovered, and the second failure can be continued during the first failure. When a fault occurs, the suspension of the failure display output is canceled and output is enabled.
The operator can be notified of the occurrence of the second failure.

[Brief description of the drawings]

1 is a detailed view of a central monitoring device according to an embodiment of the present invention, FIG. 2 is a configuration diagram of a state change detector of FIG. 1, FIG. 3 is an overall configuration diagram of a control rod position monitoring device, FIG. The figure is a detailed view of a central monitoring device of a control rod position monitoring device showing a conventional example. 7A: Transmission reception circuit, 7B: Transmission transmission circuit, 7C, 7D ...
Position failure detection circuit, 7E, 7F ... State change detector.

Claims (1)

(57) [Claims] A plurality of reed switches for detecting the positions of control rods provided on a plurality of control rods disposed in a nuclear reactor, and the position of each control rod received by inputting a signal from the reed switch. A terminal device for transmitting a signal at regular intervals and a position signal of each control rod from the terminal device are input,
A control rod position monitoring device comprising: a central monitoring device that monitors a position state of each control rod to detect and display a failure, wherein a control rod position failure detection that detects each control rod position failure is provided in the central monitoring device. A state change detection circuit for detecting that one of the control rod position signals has changed from normal to abnormal according to an output of the control rod position failure detection circuit and outputting a state change signal; Signal to release the fault display output prohibition condition and output the fault display signal,
A control rod position monitoring device, wherein a failure display output prohibition condition is satisfied by input of a failure display reset command, and a circuit for interrupting the control rod position failure display output is provided.