JPS594680B2 - Reactor isolation valve control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In the event of a nuclear reactor accident, the present invention automatically closes all isolation valves provided at the inlet of the pipe penetrating the reactor containment vessel and the outlet to the outside of the vessel. The present invention relates to an isolation valve control device that closes to prevent the spread of an accident, and particularly relates to an improvement in a reset means for setting an isolation relay to a reset state.

In the event of a nuclear reactor accident, there is a risk that radioactive gas or liquid generated and released from the reactor may leak out of the containment vessel through piping.

To prevent this, generally various piping 3 penetrating the containment vessel 2 housing the reactor 1 as shown in FIG.
A, 3e, 3c, 3D, and 4 isolation valves 5A, 5B at the inlet into the container and outlet out of the container.

5Cj5Dt6Aj6B, 6Ct6D, and 7Aj7B are provided.

Note that 8 and 9 in FIG. 1 are a dry well and a suppression chamber that constitute the containment vessel 2.

Each of the above isolation valves is shown in Figure 2a. Opening and closing are controlled by isolation valve control circuits shown in b and c.

In addition, in FIGS. 2a to 2c, valves 5A to 5D are one group,
This is an example of a circuit that controls valves γA and 7B as another group.

In FIGS. 2a to 2c, 10 is a push button type reset operation switch as shown in FIG.
By suppressing , the relay 11 operates and closes its normally open contacts 11 al and 11 a2.

By closing the contacts 11 al and 11 a2, the isolation relays 14 and 15 are energized via the isolation switches 12 and 13, which normally have their contacts closed, and close the self-holding contacts 14a1 and 15at, resulting in a self-holding state.

Thus, the normally open contacts 14a2t15a2 of each of the relays 14 and 15 shown in FIG.

In order to open the isolation valves 5A to 5D, 7A, and 7B from this state, the valve operation switch contacts 16A, 16Bt 16C
, 16D, 17A.

17B are individually closed.

By doing so, the drive coil of the isolation valve corresponding to the valve operation switch that has been closed is energized, thereby opening the valve.

When an isolation command signal arrives due to the occurrence of an accident, isolation switches 12 and 13 open their contacts.

Therefore, the self-holding of isolation relays 14, 15 is released and contacts 14a1, 14a2, 15a1, 15a2 are opened.

For this purpose, the valve operation switch contacts 16A to 16D.

Each isolation valve 5A regardless of whether 17A or 17B is open or closed.
The energization of the 1 drive coils 5D, 7A, and 7B is cut off.

Therefore, all isolation valves are fully closed at once, and the reactor 1 is isolated.

The conventional device described above has the following drawbacks.

That is, during reactor isolation when the isolation valves are fully closed, when the isolation relay reset operation switch 10 is pressed to open only some of the isolation valves, all isolation relays 14, 15% As mentioned above, all of them enter a self-holding state all at once.

At this time, valve operation switch contacts 16A to 16D, 17A.

If all 17B are in the open state, the desired purpose can be achieved by closing the valve operation switch corresponding to the required isolation valve, but if the valve operation switch contact point corresponding to the valve other than the target valve is closed. Isolation relays 14 and 15
The isolation valve will be fully opened at the time when it performs a self-holding operation and the contact 14a2t1sa2 closes.

As a result, gas and liquid containing radioactivity generated and released from the nuclear reactor 1 will leak to the outside of the containment vessel 2, and there is a risk of a secondary accident occurring.

The present invention has been made in consideration of these circumstances, and its purpose is not only to quickly and reliably perform isolation operations when an isolation command signal arrives at the time of a nuclear reactor accident, but also to Even if the reset operation switch is closed, there is no risk that the isolation valve will immediately open due to the above reset operation, and at the same time, the reactor isolation valve is extremely safe, allowing operators to accurately recognize whether or not the isolation relay reset operation is possible. The purpose is to provide a control device.

The details of the present invention will be clarified below with reference to embodiments shown in the drawings.

FIG. 4 is a schematic explanatory diagram of an embodiment of the present invention, and is a diagram corresponding to FIG. 1.

Furthermore, FIGS. 5a, b, and c are block diagrams of the isolation valve control circuit of the same embodiment, and are diagrams shown corresponding to FIGS. 2a, b, and c.

Therefore, the same parts in FIGS. 1 and 2 are given the same reference numerals and detailed explanations will be omitted.

In Figures 4 and 5 a"c, 26A.

26B, 26C, 26D and 27A, 27B are contacts of valve operation switches.

The valve operation switch contact 26A is paired with the valve operation switch contact 16A, and when 16A is closed, the valve operation switch contact 26A is connected to the valve operation switch contact 16A.
When 26A opens and 26A closes, 16A opens.

26B and 16B at the same time. 26C and 16C, 26D and 16
D, 27A and 17A.

27B and 17B each form a pair and are interlocked.

The valve operation switch contacts 26A to 26D are connected in series to the normally open contact 11a1 of the reset relay 11.

Also, valve operation switch contact 27A. 27B is connected in series with another normally open contact 11a2 of the reset relay 11.

On the other hand, 21 and 22 are indicator lamps, which are installed near the reset operation switch 10 as shown in FIG.

The indicator lamp 21 is connected to the power supply line L1. L2, and the indicator lamp 22 is connected to the power supply line L1. It is connected between L2.

Next, the operation of the apparatus configured as described above will be explained.

When setting all or part of the isolation valves 58 to 5D, 7A, and 7B to open, and to automatically close the valves in response to an isolation command signal during reactor isolation, first open the valves. Operation switch contacts 16A to 16D, 17A,
Open all 17B.

By doing so, the valve operation switch contacts 26A to 26Dt27A are linked to each of the above contacts.

27B are all closed.

In this state, when the reset operation switch 10 is closed, the reset relay 11 operates and the contacts 11a1, 11
Close a2.

Therefore, the isolation relay 14 is energized via the valve operation switch contacts 26A to 26D and the relay contact 11a1, and further via the isolation switch 12 whose contacts are normally closed, and is self-held at its own contact 14a1.

At this time, the other contacts 14a2 of the relay 14 are also closed, but since the contacts of the valve operation switches 16A-16D are open, the drive coils of the isolation valves 58-5D are not energized.

Similarly, the isolation relay 15 has valve operation switch contacts 27A, 2
7B, the relay contact 11a2, and the isolation switch 13, the isolation valve 7 is energized and self-maintained.
The drive coils A and 7B are not energized.

In such a state, that is, when the isolation relays 14 and 15 are in the reset state, the valve operation switch contacts 16A to 1
6D, 17A, and 17B are closed one by one while confirming safety, the isolation valves 5A to 5D corresponding to each switch,
7A and 7B are in an open state.

So now, when the isolation command signal arrives, isolation switch 1
2,13 opens the contact.

Therefore, the self-holding of isolation relays 14 and 15 is released and contacts 14a2 and 15a2 are opened.

Therefore, the energization of the drive coils of each valve is cut off, and all the valves are completely closed at the same time.

By the way, even if the reset operation switch 10 is closed by mistake or intentionally after the isolation state as described above is established, the isolation relays 14 and 15 will not be reset immediately.

That is, if any one of the valve operation switch contacts 26A to 26D is open, the valve operation switch contacts 27A,
If any one of 27B is open, relays 14, 15 will not be energized even if isolation switches 12, 13 are closed again due to the absence of the isolation command signal.

As mentioned above, if the isolation valve is once opened and then fully closed by the isolation command signal, if the valve operation switch is not operated after that, the valve operation switch contacts 16A to 16D, 17A, 17B
At least one of each group must be in a closed state.

This means that at least one of the valve operation switch contacts 26A to 26D and at least one of the valve operation switches 27A and 27B are open.

On the other hand, valve operation switch contacts 26A to 26D.

In the case where all groups 27A and 27B are closed, the valve operation switch contacts 16A to 16D.

This is a case where each of the loops 17A and 17B are all connected, so in this case, the contacts 16A to 17B are connected.
16D, 17A, and 17B prevent the valve drive coil from being energized.

The above case is nothing but the operation at the time of the reset operation described above.

Note that when all the valve operation switch contacts 26A to 26D are closed, and the valve operation switch contact 27A.

When both 27B are closed, each indicator lamp 2L22 lights up, so the operator should check the above lamp 2L2.
2, it can be recognized that a reset operation can be performed.

Conversely, when the indicator lamps 21 and 22 are not lit, it is understood that the reset operation cannot be performed.

In this way, in this device, when the valve operation switch contacts 16A to 16D, 17A, and 17B of each group are all in a state where they cannot energize the drive coils of the isolation valves 58 to 5D, 7A, and 7B, As long as the reset operation switch 10 is closed, the isolation relays 14, 15, etc. can be reset, that is, perform self-holding operation, and conversely, if even one of the contacts in each group is closed, the isolation relay 14
A reset of °15 cannot be performed.

Therefore, like the conventional device, the reset operation switch 1
By closing 0, there is no risk that the isolation valve will open.

After the reset operation is completed, the required isolation valves can be sequentially and individually opened only by individually operating the required valve operation switches.

Therefore, since the operator's attention is called to attention through the special task of individually opening the valves, leakage of radioactivity due to malfunction can be prevented.

On the other hand, in this device, a specific group of isolation relays 14 or 15 can be selected by opening/closing the valve operation switch.
can be selectively reset.

In this respect, it has the advantage of being able to perform a variety of controls that are different from the simultaneous reset operation of conventional devices.

Note that the present invention is not limited to the above-mentioned embodiment.

For example, in the above embodiment, a contact of a valve operation switch is used as a means for prohibiting a reset operation by the reset operation switch, but a relay contact or the like linked to the valve operation switch may also be used, and further, a reset operation switch may be used. It is also possible to mechanically lock the movement of the

In addition, in the above embodiment, a valve that is in an open state when the drive coil is energized and is in a closed state when the energization is cut off is used as an isolation valve. A structure whose state is opposite to the above may also be used.

However, in this case, it is necessary to change the isolation logic so that the valve drive coil is energized when the isolation command signal arrives.

Further, in the above embodiment, a self-holding type relay is used as the isolation relay, but a magnetic holding type latch relay or the like may be used.

Of course, various other modifications can be made without departing from the gist of the present invention.

As explained above, according to the present invention, when an isolation command signal arrives in the event of an accident in a nuclear reactor, the isolation valves are fully closed all at once by the isolation relay that operates in reverse from the first state to the second state. Therefore, not only is the isolation operation performed quickly and reliably, but the isolation switch cannot be reset from the second state to the first state unless all the valve operation switches are operated to the side where the valves are fully closed. Therefore, even if the reset operation switch is closed during isolation, there is no risk that the isolation valve will immediately open due to the reset operation described above.Furthermore, since the reset operation prohibited status is displayed by display means such as an indicator lamp, the isolation valve can be closed. It is possible to provide an extremely safe nuclear reactor isolation valve control device that allows operators to accurately recognize whether a reset operation is possible or not.

[Brief explanation of drawings]

1 to 3 are diagrams showing a conventional reactor isolation valve control device, and FIGS. 4 to 6 are diagrams showing an embodiment of the reactor isolation valve control device of the present invention. 1, FIG. 5 a"-c is a circuit diagram showing the isolation valve control circuit corresponding to FIG. 2 a"-c, and FIG. It is a front view which shows the reset operation switch and indicator lamp shown corresponding to the figure. 1... Nuclear reactor, 2... Containment vessel, 3A
~3D. 4...Piping, 5A-5Dt6A-6D, 7A. 7B...Isolation valve, 10...Reset operation switch, 11...Reset relay, 12
, 13... Isolation switch, 14, 15...
...isolation relays, 16A-16D, 17A, 17B and 26A-26D. 27A, 27B...Valve operation switch contact, 21
゜22...Indication lamp.

Claims (1)

[Claims] 1. A reset operation switch, an isolation relay that is reset to a first state in response to a reset operation of the reset operation switch, and a contact that opens and closes when the isolation relay is in the first state. a valve operating switch that individually opens the reactor isolation valves; and a valve operating switch that opens the reactor isolation valves individually by operating the relay from a first state to a second state when an isolation command signal arrives. An isolation switch that closes the reactor isolation valves all at once, a means for prohibiting a reset operation by the reset operation switch unless all the valve operation switches are reset, and a means for displaying a state in which the reset operation is prohibited by this means. A nuclear reactor isolation valve control device characterized by: 2. The means for prohibiting the reset operation by the reset operation switch is a contact provided to close when the valve opening contact in the valve operation switch opens and to open when the above contact is closed, so that the operation signal from the reset operation switch is generated. A nuclear reactor isolation valve control device according to claim 1, characterized in that the control device is not applied to an isolation relay.