JPH10153676A - Controller for reactor control rod drive mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the safety of a reactor by preventing the event of control rod falling due to loss-of-latch function of control rod in emergency insertion (scram) during reactor operation. SOLUTION: A control rod drive mechanism controller for inserting and withdrawing control rods 2 during normal operation of a reactor with an electric drive part 4 and separating the control rods 2 and the electric drive part 4 during such accidents as reactor pipe break and quickly inserting in the reactor by hydraulic pressure driver with a scram signal from a scram circuit is constituted of an ART valve 7 functioning to open by scram signal 10 and totally opening scram valves, PIP for detecting the insertion position of the control rods 2 in the reactor with a latch mechanism holding the control rods 2 separated after hydraulic scram in full insertion state and a control rod falling event detection means judging whether the whole control rods are at insertion based on the PIP signals 12 from PIP 3 with the input of scram signal and detecting the occurrence of control rod falling event in the case the whole control rods are not inserted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling a control rod drive mechanism having an electric / hydraulic drive unit in, for example, a nuclear reactor of a nuclear power plant, and particularly to an emergency insertion (scram) during operation of the nuclear reactor. The present invention relates to a control rod drive mechanism control device for preventing a control rod from falling due to a loss of a control rod latch function and improving the safety of a reactor.

[0002]

2. Description of the Related Art Conventionally, for example, in a nuclear reactor of a nuclear power plant, control rods are driven by an electric / hydraulic drive type control rod drive mechanism having an electric drive unit for normal operation and a hydraulic drive unit for emergency insertion. Control for insertion or withdrawal from the reactor is performed.

FIG. 4 is a schematic diagram showing an example of the configuration of a control device of this type of electric / hydraulic drive type control rod drive mechanism. FIG.
During the normal operation of the reactor, the reactor pressure vessel 1
The control rod 2 is inserted or withdrawn by the electric drive unit 4 connected to the control rod 2 to adjust the reactivity of the reactor.

In the event of an accident such as a pipe break, all control rods 2 are urgently inserted (scrum) into the reactor pressure vessel 1,
It is necessary to stabilize the power of the reactor. In this case, since the full insertion of the control rod 2 by the electric drive unit 4 is a low-speed operation and takes a long time, the emergency insertion is performed within a fixed time by a hydraulic drive for high-speed operation. In this hydraulic drive, the scram valve 6 is opened with a total scrum signal 10 from a scram circuit 9 for hydraulic scramming the control rod 2, and the high-pressure water stored in an accumulator of a hydraulic control unit (hereinafter, referred to as HCU) 5. The control rod drive mechanism 2
0, the control rod 2 is connected to the reactor pressure vessel 1
Insert quickly into.

[0005] As a backup of the scram valve 6, an alternative control rod insertion function valve (hereinafter, referred to as a "supply pressure source") which is a source of air pressure which is a driving source of the scrum valve 6 is provided by a scrum signal 10.
Opening the scrum valve 6 is possible by opening the ARI valve 7).

Further, by resetting the scrum signal 10 from the scrum circuit 9, the scrum valve 6 is closed and the HCU
The water pressure supply from 5 is cut off. On the other hand, a control rod position detection signal (hereinafter, referred to as a PIP signal) 12 from a control rod position detection sensor (hereinafter, referred to as a PIP) 3 that detects an insertion position of the control rod 2 into the reactor pressure vessel 1,
The entire insertion of the control rod 2 is detected.

When the control rod 2 is rapidly inserted into the reactor pressure vessel 1 during scram, the electric drive unit 4 separates from the control rod 2 and only the control rod 2 is fully inserted. Although this state is maintained by the scram water pressure from the HCU 5, the scram valve 6 closes and the water pressure disappears by a scrum reset after a certain time, and thereafter the control rod 2 descends and the latch mechanism 11 Holds the full insertion state.

The electric drive unit 4 separated from the control rod 2 by a scrum supports the control rod 2 by following up with a scrum signal 10 from a scrum circuit 9 and controls only the latch mechanism 11 until the latch is released. The rod 2 is fully inserted and held.

Further, the separation detection switch 8 detects that the control rod 2 has been separated from the electric drive unit 4 and outputs a separation detection signal 13. However, in the control rod drive mechanism control device described above, while the electric drive unit 4 and the control rod 2 are separated during the scram, there is a case where some abnormality occurs in the latch mechanism 11 and the latch function is lost. In such a case, there is a problem that the control rod 2 falls and the reactivity is added to the inside of the nuclear reactor.

[0010]

As described above, in the conventional control rod drive mechanism control apparatus, when the latch function is lost while the electric drive section and the control rod are separated during scram, the control rod drive mechanism is controlled. However, there was a problem that the reactor fell and added reactivity into the reactor.

An object of the present invention is to prevent a control rod from falling due to a loss of a control rod latch function or the like at the time of emergency insertion (scram) during operation of a nuclear reactor, thereby improving the safety of the nuclear reactor. An object of the present invention is to provide a reactor control rod drive mechanism control device.

[0012]

According to a first aspect of the present invention, there is provided a control rod drive mechanism having an electric drive unit and a water pressure drive unit, wherein the electric power is supplied during normal operation of a nuclear reactor. The control rod is inserted into or pulled out of the reactor by the drive unit to adjust the reactivity of the reactor, and in the event of an accident such as a reactor pipe break, the scram valve is opened by the scram signal from the scram circuit to release high-pressure water. A control rod drive mechanism control device which is caused to flow into a control rod drive mechanism and urgently inserts a control rod into a reactor by a hydraulic drive unit to stabilize the output of the reactor, wherein a drive source for a scram valve is provided. An alternative control rod insertion function valve that is provided at the air pressure supply source and opens by the scrum signal from the scrum circuit to open the entire scrum valve, and the control rod separated after the hydraulic scram is fully inserted A control rod position detecting means for detecting an insertion position of the control rod into the reactor, and a detection from the control rod position detecting means when a scram signal is input from a scram circuit. Control rod drop event detecting means for determining whether or not all control rods are fully inserted based on the signal, and detecting that a control rod drop event has occurred if not all control rods have been fully inserted; Be prepared.

Therefore, in the control device for a nuclear reactor control rod driving mechanism according to the present invention, when a scram signal from the scram circuit is input, the whole after scram is detected by the detection signal from the control rod position detecting means. If the control rod has not been fully inserted, it can be detected that a control rod drop event has occurred.

According to a second aspect of the present invention, in the reactor control rod drive mechanism control device according to the first aspect of the present invention, when the control rod falling event detecting means detects a control rod falling event, Control rod fall prevention means for outputting a control rod fall prevention signal to the scrum circuit is added so that the scram circuit continues to output a scrum signal until the electric drive unit reaches the separated control rod.

Therefore, in the control rod drive mechanism control device according to the present invention, when the control rod falling event detecting means detects a control rod falling event, that is, when the control rod falling event is detected during a scram during the reactor operation. When the latch function is lost, by opening the scrum valve via the scram circuit, it is possible to prevent the control rods that could not be completely inserted from falling due to the water pressure of the high-pressure water.

Thus, the safety of the nuclear reactor can be improved. Furthermore, in the invention corresponding to claim 3,
In the control device for a reactor control rod drive mechanism according to the present invention, when a control rod drop event is detected by the control rod drop event detection means, the alternative control is performed until the electric drive unit reaches the control rod. Control rod fall prevention means for outputting a command signal for opening the rod insertion function valve to the alternative control rod insertion function valve as a control rod fall prevention signal is added.

Therefore, in the electric / hydraulic drive type control rod control device in the nuclear reactor according to the invention according to claim 3,
When a control rod drop event is detected by the control rod drop event detection means, that is, when the latch function is lost during a scram during the operation of the reactor, the supply source of the air pressure that is the driving source of the scram valve without passing through the scram circuit By opening the scram valve by opening the alternative control rod insertion function valve, the control rods that could not be completely inserted can be prevented from falling due to the water pressure of the high-pressure water.

Thus, the safety of the nuclear reactor can be improved. On the other hand, according to a fourth aspect of the present invention, in the control device of a nuclear reactor control rod drive mechanism according to the first aspect of the present invention, the separation detecting means for detecting that the electric drive unit and the control rod are separated during the hydraulic scram. And, based on the detection signal from the control rod position detecting means, detect all the control rods that have not been inserted, and based on the detection signal from the separation detecting means, detect the control rods that have not been separated from the electric drive unit. By detecting the control rod, only the control rod that has not been held at the full insertion position by the latch mechanism after being separated from the electric driving unit during the hydraulic scram is specified as the control rod in the falling event, the control rod falling event It is added to the detection means.

Therefore, in the reactor control rod drive mechanism control device according to the present invention, after the scram, the separation detection means detects that each control rod is separated from the electric drive unit by the water pressure of the high-pressure water. By detecting control rods that have not been fully inserted, which control rod is in a falling event (only control rods that are separated from the electric drive unit and that are not fixed without operating the latch means) and latching Only the event of the total insertion failure due to the loss of the latch function by the means can be limited to the control rod falling event.

According to a fifth aspect of the present invention, in the control device for a reactor control rod driving mechanism according to the fourth aspect of the present invention, when the control rod falling event detecting means detects a control rod falling event, Control rod fall prevention means for directly outputting a control rod fall prevention signal only to the target scrum valve specified as a control rod in a fall event is added.

Therefore, in the reactor control rod drive mechanism control device according to the invention of claim 5, the physical quantity is small in the reactor control rod drive mechanism control device of the invention according to claim 2 or 3. However, opening all scrum valves may reduce the reliability of the scrum system, whereas when the control rod fall event detection means detects a control rod fall event, only the target scrum valve By directly outputting the control rod fall prevention signal, the control rod can be prevented from falling.

According to a sixth aspect of the present invention, in the control device for a reactor control rod driving mechanism according to the fourth aspect of the present invention, the control rod specified by the control rod falling event detecting means as being in a falling event. When it is confirmed that the control rod has once reached the full insertion position based on a detection signal from the control rod position detecting means, it is determined that there is some abnormality in the latch mechanism of the control rod and the "latch A latch mechanism abnormality detection function for notifying the operator of "mechanism abnormality" is added to the control rod drop event detection means.

Therefore, in the control device for controlling a reactor control rod driving mechanism according to the invention, the control rod falls once again from the full insertion position after reaching the full insertion position by the control rod falling event detecting means. This can be detected by the detection signal from the control rod position detecting means, so that the operator can be notified that there is some abnormality in the latch mechanism of the control rod.

According to a seventh aspect of the present invention, in the reactor control rod drive mechanism control device of the fourth aspect of the present invention, the control rod falling event detecting means includes:
When it is confirmed that there is a control rod that has not been separated from the electric drive unit during the hydraulic scram based on a detection signal from the separation detection unit, it is determined that there is some abnormality in a coupling portion between the control rod and the electric drive unit. Then, a control rod separation abnormality detecting function for notifying the operator of "control rod separation abnormality" is added to the control rod drop event detecting means.

Therefore, in the control device for a reactor control rod driving mechanism according to the present invention, the control rod which is not separated from the electric drive unit even though the scram signal is output from the scram circuit is separated and detected. By detecting by means, it is possible to notify the plant operator that there is some abnormality in the joint between the electric drive unit and the control rod.

According to an eighth aspect of the present invention, there is provided the reactor control rod drive mechanism control device according to the first aspect of the present invention, wherein the scram signal is generated from the scram circuit. When an event occurs in which the control rod cannot be fully inserted, the operator is notified of the occurrence of a control rod fall event, and the control rod is prevented from falling by fully inserting the control rod using control rod fall prevention means. The function of notifying the operator of the fact is given to the control rod drop event detecting means.

Therefore, in the control device for a nuclear reactor control rod drive mechanism according to the present invention, when an event occurs in which the control rods cannot be fully inserted after the generation of the scram signal from the scram circuit, the control rod drive mechanism is controlled. Is in a falling state to the operator, and the operator can be notified that the control rod falling prevention means has prevented the control rod falling event.

As described above, it is possible to prevent the control rod from falling due to the loss of the control rod latch function or the like at the time of emergency insertion (scram) during the operation of the reactor, thereby improving the safety of the reactor.

[0029]

Embodiments of the present invention will be described below in detail with reference to the drawings. (First Embodiment) FIG. 1 is a schematic diagram showing a configuration example of a reactor control rod drive mechanism control device according to the present embodiment. The same parts as those in FIG. Detailed description is omitted, and only different portions will be described here.

That is, as shown in FIG. 1, the reactor control rod drive mechanism control device of the present embodiment comprises a control rod fall event detection circuit 15, a control rod fall prevention circuit 16, and a display device 19. The configuration is added to FIG.

Here, the control rod drop event detection circuit 15
When the scrum signal 10 from the scrum circuit 9 is input, it is determined whether or not all the control rods 2 are in the full insertion based on the PIP signal 12 from the PIP 3, and when all the control rods 2 are not fully inserted. Detects that a control rod drop event has occurred.

The control rod drop event detection circuit 15
When an event occurs in which the control rod 2 cannot be completely inserted after the generation of the scrum signal 10 from the scrum circuit 9, an alarm signal 18 is output to the display device 19 to indicate that the control rod drop event has occurred. It also has a function of notifying the operator and notifying the operator that the control rod 2 has been fully inserted by the control rod drop prevention circuit 16 to prevent the control rod from falling.

On the other hand, when the control rod drop event detection circuit 15 detects a control rod drop event, the control rod drop prevention circuit 16 operates until the electric drive unit 4 reaches the separated control rod 2 until the electric drive unit 4 reaches the separated control rod 2. The control rod drop prevention signal 17 is sent to the scrum circuit 9 so that the scrum circuit 9 continues to output the scrum signal 10.
Is output.

Further, the display device 19 includes, for example, a display lamp 19A and a CRT 19B, and displays the presence or absence of the alarm signal 18 from the control rod drop event detection circuit 15 and the content thereof.

Next, the operation of the reactor control rod drive mechanism control device of the present embodiment configured as described above will be described. Here, only the portions different from the operation of the above-described conventional control device for driving a nuclear reactor control mechanism will be described.

In FIG. 1, a control rod drop event detection circuit 1
In 5, when the scrum signal 10 from the scrum circuit 9 is received at the time of occurrence of the scrum event, it is determined from the PIP signal 12 whether or not all the control rods 2 are in the fully inserted state.

As a result, if the control rod 2 is not fully inserted, the control rod fall prevention circuit 16 is instructed to output a control rod fall prevention signal 17 and the control rod fall prevention event 16 is generated. Is issued to the display device 19.

The scram circuit 9 outputs a scram signal 10 to the scram valve 6 and the ARI valve 7 in order to scram the reactor at the time of a reactor accident or the like. It is also output to the circuit 15. The scrum signal 10 is reset by the operator after 10 seconds.

On the other hand, in the control rod drop prevention circuit 16, after the scrum signal 10 is reset, the control rod drop event detection circuit 15 which detects the control rod full insertion from the PIP signal 12 causes the control rod 2 not fully inserted to be completely inserted. Is detected, a control rod fall prevention signal 17 is output to the scrum circuit 9.

Then, the scrum circuit 9 receives the stiffness control rod fall prevention signal 17 as a scrum event occurrence signal,
By outputting the scrum signal 10, the scrum valve 6
Will be reopened.

The control rod fall prevention signal 17 is held by the control rod fall prevention circuit 16 during the completion of the scrum follow by the electric drive unit 4. Thereby, H
When the high-pressure water stored in the accumulator of the CU 5 flows into the control rod 2, it is possible to prevent the control rod 2 that could not be completely inserted from falling due to the water pressure.

As described above, the reactor control rod drive mechanism controller of the present embodiment receives the scrum signal 10 from the scram circuit 9 when the scram signal 10 is input to the conventional reactor control rod drive mechanism controller described above. , PIP signal 12 from PIP3
It is determined whether all control rods 2 are in full insertion based on
If all the control rods 2 are not fully inserted, the function of detecting that a control rod drop event has occurred, and the event that the control rods 2 could not be fully inserted after the generation of the scrum signal 10 from the scrum circuit 9 When it occurs, an alarm signal 18 is output to the display device 19 to notify the operator that a control rod drop event has occurred, and the control rod 2 is fully inserted by the control rod fall prevention circuit 16 to control the control rod. A control rod drop event detection circuit 15 having a function of notifying an operator that the fall has been prevented;
When the control rod drop event detection circuit 15 detects a control rod drop event, the scrum circuit 9 continues to output the scrum signal 10 until the electric drive unit 4 reaches the separated control rod 2. A control rod fall prevention circuit 16 that outputs a control rod fall prevention signal 17 to the scrum circuit 9 and a display device 19 that displays the presence / absence of an alarm signal 18 from the control rod fall event detection circuit 15 and the contents thereof are added. It was done.

Therefore, when the scrum signal 10 from the scrum circuit 9 is input, the PIP signal 1 from the PIP 3
In the case where all the control rods 2 have not been fully inserted after the scram due to 2, it is possible to detect that a control rod drop event has occurred.

When the control rod drop event detection circuit 15 detects a control rod drop event, that is, when the latch function is lost during scram during reactor operation, the scram valve 6 is opened via the scram circuit 9. This makes it possible to prevent the control rods 2 that could not be completely inserted from falling due to the water pressure of the high-pressure water.

Further, if an event occurs in which the control rod 2 cannot be completely inserted after the generation of the scrum signal 10 from the scrum circuit 9, the operator is notified that the control rod 2 is in a falling state, and the control is performed. The operator can be notified by the display device 19 that the control rod drop event has been prevented by the rod drop prevention circuit 16.

As a result, it is possible to prevent a control rod falling event due to a loss of the latch function of the control rod 2 during a scram during the operation of the reactor, thereby improving the safety of the reactor.

(Second Embodiment) FIG. 2 is a schematic diagram showing an example of the configuration of a reactor control rod drive mechanism control device according to the present embodiment, and the same parts as those in FIG. The detailed description is omitted, and only different parts are described here.

That is, as shown in FIG. 2, when the control rod drop event detection circuit 15 detects a control rod drop event, the electric drive unit 4 controls the reactor control rod drive mechanism control device of this embodiment. Until the control rod 2 is reached, a command signal for opening the ARI valve 7 is directly output to the ARI valve 7 as the control rod fall prevention signal 17 by the control rod fall prevention circuit 16 without passing through the scram circuit 9. And

Next, the operation of the reactor control rod drive mechanism control device of the present embodiment configured as described above will be described. Here, only the parts that are different from the operation of the reactor control rod drive mechanism control device of the first embodiment described above will be described.

In FIG. 2, the control rod drop event detection circuit 1
5, when the control rod 2 that is not fully inserted during the scrum is detected, the control rod fall prevention signal 16 is sent from the control rod fall prevention circuit 16 to the AR without passing through the scrum circuit 9.
It is output directly to the I valve 7.

Then, the ARI valve 7 once closed after the scrum reset is reopened in response to the control rod fall prevention signal 17, and all the scrum valves 6 are opened. The control rod fall prevention signal 16 is held by the control rod fall prevention circuit 16 while the electric drive unit 4 completes the scrum follow.

Thus, as in the case described above, the HCU
When the high-pressure water stored in the accumulator 5 flows into the control rod 2, it is possible to prevent the control rod 2 that could not be completely inserted from falling due to the water pressure.

As described above, the reactor control rod drive mechanism controller of the present embodiment is different from the reactor control rod drive mechanism controller of the first embodiment in that the control rod drop event detection circuit 15 When a control rod drop event is detected,
Until the electric drive unit 4 reaches the control rod 2, the ARI valve 7
Is output directly to the ARI valve 7 as a control rod fall prevention signal 17 without passing through the scram circuit 9 by the control rod fall prevention circuit 16.

Therefore, it is possible to obtain the same operation and effect as in the case of the reactor control rod drive mechanism control device of the first embodiment described above, and the latch function of the control rod 2 during scram during reactor operation. A control rod falling event due to loss or the like can be prevented, and safety of the reactor can be improved.

(Third Embodiment) FIG. 3 is a schematic diagram showing a configuration example of a reactor control rod drive mechanism control device according to the present embodiment, and the same parts as those in FIG. The detailed description is omitted, and only different parts are described here.

That is, as shown in FIG. 3, the reactor control rod drive mechanism control device of the present embodiment uses the control rod 2 that has not been completely inserted based on the PIP signal 12 from the PIP 3.
By detecting the control rod 2 that has not been separated from the electric drive unit 4 based on the detection signal from the separation detection switch 8, by the latch mechanism 11 separated from the electric drive unit 4 during the hydraulic scram. A function of specifying only the control rods 2 not held at all the insertion positions as the control rods 2 in the drop event, and a function of the control rods 2 specified as being in the drop event by the control rod drop event detection circuit 15 , When it is confirmed based on the PIP signal 12 from the PIP 3 that the control rod 2 has reached the full insertion position once, it is determined that there is some abnormality in the latch mechanism 11 of the control rod 2 and “Latch mechanism abnormality And a control rod drop event detection circuit 15 to notify the operator of the fact that the separation detection signal 1 from the separation detection switch 8
3, when it is confirmed that there is a control rod 2 that has not been separated from the electric drive unit 4 during the hydraulic scram, it is determined that there is some abnormality in the joint between the control rod 2 and the electric drive unit 4. A control rod separation abnormality detection function for notifying the operator of the "control rod separation abnormality" is added to the control rod drop event detection circuit 15.

Further, when a control rod drop event detection circuit 15 detects a control rod drop event, a control rod drop prevention signal 17 is sent to only the target scrum valve 6 identified as the control rod 2 in the drop event. The control rod drop prevention circuit 16 directly outputs the signal without passing through the scram circuit 9.

Next, the operation of the reactor control rod drive mechanism control device of the present embodiment configured as described above will be described. Here, only the parts that are different from the operation of the reactor control rod drive mechanism control device of the first embodiment described above will be described.

In FIG. 3, the control rod drop event detection circuit 1
5, when the scram signal 10 is input to the control rod 2, the control rod 2 separated from the electric drive unit 4 by the input of the separation detection signal 13 from the separation detection switch 8 is determined.
The control rod 2 that is not completely inserted is specified by the P signal 12.

Then, from the control rod drop event detecting circuit 15, the data of the control rod 2 which is separated from the electric drive unit 4 and not fully inserted is output to the control rod drop prevention circuit 16. Then, the control rod fall prevention circuit 16 outputs the control rod fall prevention signal 17 only to the control rods 2 that have not been fully inserted, but has output destinations to the scrum valves 6 of the total number of control rods. Only the targeted scrum valve 6 will be opened.

On the other hand, in the control rod falling event detecting circuit 15,
If the control rod 2 separated from the electric drive unit 4 has once reached the full insertion position but has once again deviated from the full insertion position, it is considered that there is some abnormality in the latch mechanism 11 and the "latch The alarm signal 18 to the effect that "the mechanism is abnormal"
Emitted to the display device 19.

If the control rod 2 is not separated from the electric drive unit 4 after the generation of the scrum signal 10,
The warning signal 18 indicating “control rod separation failure” is displayed on the display device 1.
Issued at 9.

As described above, the reactor control rod drive mechanism control device of the present embodiment is based on the PIP signal 12 from the PIP 3 in the reactor control rod drive mechanism control device of the first embodiment. The control rod 2 that has not been completely inserted is detected, and the control rod 2 that has not been separated from the electric drive unit 4 based on a detection signal from the separation detection switch 8.
Of the electric drive unit 4 during the hydraulic scram.
A function of specifying only the control rod 2 that has not been held at the full insertion position by the latch mechanism 11 after being separated from the control rod 2 as the control rod 2 in the falling event, and a control rod falling event detecting circuit 15 detects the falling event. Control rod 2 identified as
Among them, when it is confirmed that the control rod 2 has reached the full insertion position once based on the PIP signal 12 from the PIP 3, it is determined that there is some abnormality in the latch mechanism 11 of the control rod 2 and the "latch" is determined. A latch mechanism abnormality detection function for notifying the operator of "mechanism abnormality" and a control rod drop event detection circuit 15 are separated from the electric drive unit 4 during the hydraulic scram based on the separation detection signal 13 from the separation detection switch 8. When it is confirmed that there is no control rod 2 that is not present, it is determined that there is some abnormality in the joint between the control rod 2 and the electric drive unit 4, and the operator is notified of the "control rod separation abnormality". The control rod separation abnormality detection function is added to the control rod drop event detection circuit 15, and the control rod drop event detection circuit 15
When the control rod fall event is detected by the control rod fall prevention signal 17 for only the target scrum valve 6 specified as the control rod 2 in the fall event, the control rod fall prevention circuit 1
6 directly outputs the signal without passing through the scrum circuit 9.

Accordingly, it is possible to obtain not only the same operation and effect as in the case of the reactor control rod drive mechanism control device of the first embodiment, but also the following operation and effect. It becomes possible.

That is, after the scram, the separation detection switch 8 detects that the control rods 2 have been separated from the electric drive unit 4 by the water pressure of the high-pressure water, and detects the control rods 2 that could not be fully inserted. In addition to specifying which control rod 2 is in the falling event (only the control rod 2 which is separated from the electric drive unit 4 and is not fixed because the latch mechanism 11 does not work),
Only the event of the total insertion failure due to the loss of the latch function by the latch mechanism 11 can be limited to the control rod drop event.

In the reactor control rod drive mechanism control device of the first embodiment, although the physical quantity is small, opening all the scram valves 6 may reduce the reliability of the scram system. On the other hand, in the present embodiment, when the control rod falling event detection circuit 15 detects a control rod falling event, the control rod It is possible to prevent the control rod 2 from falling.

Further, the control rod falling event detecting circuit 15
By detecting from the PIP signal 12 from the PIP 3 that the control rod 2 has once reached the full insertion position and then deviated from the full insertion position once again, the latch mechanism 1 of the control rod 2 is detected.
It is possible to notify the operator that there is some abnormality in 1.

Further, despite the output of the scrum signal 10 from the scrum circuit 9, the electric drive unit 4
By detecting the control rod 2 that is not separated from the control rod 2 by the separation detection switch 8, it is possible to notify the plant operator that there is some abnormality in the joint between the electric drive unit 4 and the control rod 2.

[0069]

As described above, according to the invention corresponding to claim 1, in the control rod drive mechanism having the electric drive unit and the hydraulic drive unit, the control rod is controlled by the electric drive unit during normal operation of the nuclear reactor. The reactor by adjusting the reactivity of the reactor by inserting or withdrawing it from the reactor, and in the event of an accident such as a reactor pipe break, open the scram valve with a scram signal from the scram circuit to supply high-pressure water to the control rod drive mechanism. And a control rod drive mechanism control device for stabilizing the output of the reactor by urgently inserting a control rod into the reactor by a water pressure drive unit, and supplying a pneumatic pressure which is a driving source of a scram valve. An alternative control rod insertion function valve that is provided at the base and opens the scram valve by opening the scram signal from the scrum circuit, and a latch mechanism that holds the control rod separated after the hydraulic scram in the fully inserted state In that and a control rod position detection means for detecting the insertion position of the reactor control rods,
When the scrum signal from the scrum circuit is input, it is determined whether or not all the control rods are in the full insertion based on the detection signal from the control rod position detecting means. Has a control rod falling event detecting means for detecting that a control rod falling event has occurred, so that if all the control rods have not been fully inserted after the scram, it is detected that a control rod falling event has occurred. A control rod drive mechanism control device for a nuclear reactor can be provided.

According to the invention corresponding to claim 2,
In the control rod drive mechanism control device according to the first aspect of the present invention, when a control rod drop event is detected by the control rod drop event detection means, the control unit is driven until the electric drive unit reaches the separated control rod. In addition, control rod fall prevention means for outputting a control rod fall prevention signal to the scram circuit is added so that the scram circuit continues to output the scram signal. Prevents control rod falling due to loss of control rod latch function, etc.
A reactor control rod drive mechanism control device capable of improving the safety of a reactor can be provided.

According to a third aspect of the present invention, in the control device of a nuclear reactor control rod drive mechanism according to the first aspect of the present invention, the control rod falling event detecting means detects a control rod falling event. Until the electric drive reaches the control rod, a control rod drop prevention means that outputs a command signal to open the alternative control rod insertion function valve to the alternative control rod insertion function valve as a control rod fall prevention signal is added. Reactor control that can improve the safety of the reactor by preventing the control rod from falling due to loss of the control rod latch function during emergency insertion (scram) during operation of the reactor A bar drive mechanism controller can be provided.

On the other hand, according to the invention corresponding to claim 4,
The reactor control rod drive mechanism control device according to the first aspect of the present invention further includes a separation detection unit that detects that the electric drive unit and the control rod are separated during the hydraulic scram, and further includes a control rod position detection unit. By detecting the control rods that have not been fully inserted based on the detection signal of the electric drive unit and detecting the control rods that are not separated from the electric drive unit based on the detection signal from the separation detection unit, the electric drive unit during the hydraulic scram The function of specifying only control rods that have not been held at all insertion positions by the latch mechanism after being separated from the control rods as control rods in a drop event is added to the control rod drop event detection means. After that, while identifying which control rod is in the falling event (only the control rod which is separated from the electric drive unit and is not fixed without operating the latch means),
A reactor control rod drive mechanism control device capable of limiting only an event of total insertion failure due to loss of a latch function to a control rod drop event can be provided.

According to the invention corresponding to claim 5,
In the control rod drive mechanism control device of the invention according to claim 4, when the control rod drop event detecting means detects the control rod drop event, the scrum valve specified as the control rod in the drop event A control rod drop prevention means that directly outputs a control rod fall prevention signal is added only to the control rod, which prevents the target control rod fall event and improves the safety of the reactor. A furnace control rod drive mechanism control device can be provided.

According to a sixth aspect of the present invention, in the reactor control rod drive mechanism control device according to the fourth aspect of the present invention, the control rod falling event detecting means specifies that a falling event has occurred. Of the control rods, when it is confirmed that the control rod has once reached the entire insertion position based on the detection signal from the control rod position detecting means, it is determined that there is some abnormality in the latch mechanism of the control rod. A latch mechanism abnormality detection function that notifies the operator of the "latch mechanism abnormality" is added to the control rod drop event detection means, so that the operator is notified that there is some abnormality in the control rod latch mechanism. A control rod drive mechanism control device for a nuclear reactor can be provided.

Further, according to the invention corresponding to claim 7, in the control device for a reactor control rod drive mechanism of the invention corresponding to claim 4, detection by the control rod falling event detecting means from the separation detecting means. If it is confirmed based on the signal that there is a control rod that has not been separated from the electric drive unit during the hydraulic scram, it is determined that there is some abnormality in the connection between the control rod and the electric drive unit, and `` control rod separation Abnormal "
The control rod separation abnormality detection function that notifies the operator of the fact that this is the case has been added to the control rod drop event detection means, so that the plant operator can confirm that there is some abnormality in the connection between the electric drive unit and the control rod. Can be provided.

On the other hand, according to the invention corresponding to claim 8,
In the reactor control rod drive mechanism control device according to any one of claims 1 to 7, when an event occurs in which the control rods cannot be completely inserted after a scrum signal is generated from a scram circuit. In addition, a function to notify the operator that a control rod drop event has occurred and to notify the operator that the control rod has been fully inserted by the control rod fall prevention means to prevent the control rod from falling has been implemented. Since the control rod is added to the event detection means, if an event occurs in which the control rod cannot be fully inserted after the scrum occurs, it notifies the operator that the control rod is in a falling state and prevents the control rod from falling. Thus, it is possible to provide a reactor control rod drive mechanism control device capable of notifying the operator of the fact.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a first embodiment of a control device for a reactor control rod drive mechanism according to the present invention.

FIG. 2 is a schematic diagram showing a second embodiment of the control device for a reactor control rod drive mechanism according to the present invention.

FIG. 3 is a schematic diagram showing a third embodiment of the control device for a reactor control rod drive mechanism according to the present invention.

FIG. 4 is a schematic diagram showing a configuration example of a control device for a reactor control rod drive mechanism according to a conventional technique.

FIG. 5 is a schematic diagram showing a configuration example of a latch mechanism of a control rod driving mechanism for a nuclear reactor according to a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Reactor pressure vessel, 2 ... Control rod, 3 ... PIP, 4 ... Electric drive part, 5 ... HCU, 6 ... Scrum valve, 7 ... ARI valve, 8 ... Separation detection switch, 9 ... Scrum circuit, 10 ... Scrum Signal: 11 Latch mechanism, 12: PIP signal, 13: Separation detection signal, 14: Control rod fall prevention device, 15: Control rod fall event detection circuit, 16: Control rod fall prevention circuit, 17: Control rod fall prevention signal 18 alarm signal 19 display device 19A display lamp 19B CRT 20 control rod drive mechanism

Claims (8)

[Claims] In a control rod drive mechanism having an electric drive unit and a hydraulic drive unit, during normal operation of a nuclear reactor, a control rod is inserted or withdrawn from the reactor by the electric drive unit to reduce the reactivity of the reactor. In the event of an accident such as a pipe break in the reactor, the scram valve is opened by a scram signal from a scram circuit, high-pressure water flows into the control rod drive mechanism, and the water pressure drive unit drives the reactor into the reactor. A control rod drive mechanism control device for urgently inserting a control rod to stabilize the output of the nuclear reactor, provided at a supply source of pneumatic pressure that is a driving source of the scram valve, and a scram from the scram circuit. An alternative control rod insertion function valve that opens in response to a signal to open the entire scrum valve, and a latch mechanism that holds the control rod separated after the hydraulic scram in a fully inserted state. In a control rod position detection means for detecting the insertion position into the reactor of the control rod, the scram signal from the scrum circuit is inputted,
Based on the detection signal from the control rod position detecting means, it is determined whether or not all the control rods are fully inserted, and if all the control rods are not fully inserted, it is detected that a control rod drop event has occurred. A control rod drive mechanism control device, comprising: a control rod drop event detecting means. 2. The control rod according to claim 1, wherein when the control rod drop event detection unit detects a control rod drop event, the electric drive unit is separated. A control rod drop prevention means for outputting a control rod drop prevention signal to the scram circuit so that the scram circuit continues to output a scram signal until the control reaches Bar drive mechanism controller. 3. The reactor control rod drive mechanism control device according to claim 1, wherein when the control rod drop event detection unit detects a control rod drop event, the electric drive unit reaches the control rod. A control rod drop prevention means for outputting a command signal for opening the alternative control rod insertion function valve to the alternative control rod insertion function valve as a control rod fall prevention signal. Furnace control rod drive mechanism controller. 4. The reactor control rod drive mechanism control device according to claim 1, further comprising: a separation detection unit that detects that the electric drive unit and the control rod are separated during the hydraulic scram, and By detecting control rods that have not been completely inserted based on the detection signal from the control rod position detection means, and detecting control rods that have not been separated from the electric drive unit based on the detection signal from the separation detection means The control rod drop event detection has a function of specifying only control rods that have not been held at all insertion positions by the latch mechanism after being separated from the electric drive unit during the hydraulic scram, as control rods in a drop event. A control device for a control rod drive mechanism of a nuclear reactor, characterized by being added to the means. 5. The control rod drive mechanism control device according to claim 4, wherein when the control rod drop event detecting means detects a control rod drop event, the control rod is identified as a control rod in the drop event. A control rod fall prevention means for directly outputting a control rod fall prevention signal only to the target scram valve. 6. The reactor control rod drive mechanism control device according to claim 4, wherein, among the control rods identified as being in a fall event by the control rod fall event detection means, the control rod position detection means detects When it is confirmed based on the detection signal that the control rod has once reached all the insertion positions, it is determined that there is some abnormality in the latch mechanism of the control rod, and the “latch mechanism abnormality” is determined.
A reactor control rod drive mechanism control device characterized by adding a latch mechanism abnormality detection function for notifying an operator of the fact to the control rod drop event detection means. 7. The reactor control rod drive mechanism control device according to claim 4, wherein the control rod drop event detecting means outputs a signal from the electric drive unit during the hydraulic scram based on a detection signal from the separation detecting means. When it is confirmed that there is a control rod that has not been separated, a control that determines that there is some abnormality in the coupling portion between the control rod and the electric drive unit and notifies the operator of "control rod separation abnormality". A control rod drive mechanism control device for a nuclear reactor, wherein a rod separation abnormality detection function is added to the control rod drop event detection means. 8. The method according to claim 1, wherein
The control rod drive mechanism control device according to the item, after the scram signal is generated from the scram circuit, if an event occurs in which the control rods could not be fully inserted, an operator is notified that a control rod drop event has occurred. The control rod drop event detecting means has a function of notifying the operator that the control rod has been completely inserted by the control rod drop prevention means and that the control rod has been prevented from falling. Reactor control rod drive mechanism controller.