JPS6140078B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a residual heat removal device for a light water reactor such as a boiling water reactor.

Generally, this type of residual heat removal device has a cooling pipe branched from the furnace cooling water recirculation pipe, etc. to provide a cooling pipe during shutdown.
A cooling pipe opening/closing valve, a pump, and a heat exchanger are installed in the middle of this cooling pipe, and when the furnace is stopped, the cooling water is circulated through the heat exchanger by the pump.
Configured to remove residual heat from the furnace. In addition, an emergency water supply pipe is provided that branches from between the cooling pipe opening/closing valve and the pump and communicates with the suppression chamber, and an emergency water supply valve is provided in the middle of this emergency water supply pipe, so that the The emergency water supply valve is kept closed, and in the event of an emergency such as a loss of coolant accident, the emergency water supply valve is opened to supply water in the suppression chamber to the cooling pipe during shutdown. It is configured to be supplied into the reactor via a cooling pipe line, and is configured to also operate as an emergency core cooling system. By the way, it is necessary for the above-mentioned emergency water supply valve to open reliably in an emergency, and for this reason, conventionally, this emergency water supply valve can be opened by manual operation using a key lock switch without an interlock to prevent the valve from opening. It is configured as follows. However, with such a system, there is a possibility that the above-mentioned emergency water supply valve may be opened due to an erroneous operation during the shutdown cooling mode of the reactor. and was released into the suppression pool through the emergency water supply valve, potentially leading to a reactor water loss accident.

The present invention has been made based on the above circumstances, and its purpose is to provide a residual heat removal device for a nuclear reactor that does not have the possibility of a loss of reactor water accident due to incorrect operation and does not impair the reliability of the entire device. It's about getting.

The present invention will be described below with reference to an embodiment shown in the drawings. In this embodiment, the present invention is applied to a residual heat removal device for a boiling water nuclear reactor, and the overall configuration will first be explained with reference to FIG. In the figure, 1 is a furnace vessel, 2... is a recirculation pipe, 3... is a recirculation pump, and 4... is a jet pump. and,
A pair of stop cooling pipes 5 branched from the suction side of the recirculation pump 3 of the recirculation pipe 2 and connected to the discharge side of the recirculation pump 3 of the recirculation pipe 2, 5 is provided. Heat exchangers 6, 6 are provided in the intermediate portions of these cooling pipe lines 5, 5 when stopped, respectively, and these cooling pipe lines 5, 5 when stopped,
It is configured to cool the cooling water flowing through 5. The upstream portion of these cooling pipes 5, 5 at the time of shutdown is configured as one common pipe 7 shared by both the cooling pipes 5, 5 at the time of shutdown, and this common pipe 7
penetrates the containment vessel 8 and is led out of the containment vessel 8. Further, this common pipe line 7 is branched into a pair of parallel pipe lines 9a, 9b, 9c, and 9d, which are arranged in parallel for each of the stop cooling pipe lines 5, 5, and these parallel pipe lines 9a, 9b, 9c and 9d are connected to heat exchangers 6 and 6, respectively. Cooling pipe opening/closing valves 10 and 11 are provided in the middle of the common pipe line 7, located on the inside and outside of the containment vessel 8, respectively. In addition, the parallel pipe lines 9a, 9
Cooling pipe opening/closing valves 12a, 12b, 12c, 12d and pumps 13a, 13b, 13c, 113d are provided in cooling pipes b, 9c, and 9d, respectively, from the upstream side. In addition, on-off valves 14, 14 are provided in the middle of the stop cooling pipes 5, 5 on the downstream side of the heat exchangers 6, 6, respectively, and both the stop cooling pipes 5, 5 have a tie valve 15. communicate with each other through. Then, the cooling pipe opening/closing valves 12a, 12b, 12c, 12d of the parallel pipes 9a, 9b, 9c, 9d of the cooling pipes 5, 5 at the time of stop and the pump 13
Emergency water supply pipes 16, 16 are provided branching off from between a, 13b, 13c, and 13d, respectively.
These emergency water supply pipes 16, 16 are inserted into the suppression chamber 17. Moreover, in the middle of these water supply pipes 16, 16, the above-mentioned parallel pipe 9 is provided.
Emergency water supply valves 18a, 18b, 18c, and 18d are provided corresponding to a, 9b, 9c, and 9d, respectively. And the parallel pipe lines 9a, 9b, 9
c, 9d cooling pipe opening/closing valves 12a, 12b, 12
c, 12d and the corresponding emergency water supply valves 18a, 18b, 18c, 18d are configured to be opened and closed in a predetermined relationship by control mechanisms 19a, 19b, 19c, 19d, respectively. These control mechanisms 19a, 19b, 19
Both c and 19d have the same configuration, and the following 1
Set of cooling pipe opening/closing valve 12a and emergency water supply valve 18a
The control mechanism 19a will be explained with reference to FIG. The cooling pipe opening/closing valve 12a and the emergency water supply valve 18a are, for example, motor-driven opening/closing valves, and are configured to be opened and closed by electric signals. The cooling pipe opening/closing valve 12a
are configured to be opened and closed by signals from the cooling pipe opening/closing valve control circuit 20a, and the emergency water supply valve 18a is configured to be opened and closed by signals from the emergency water supply valve control circuit 21a. The cooling pipe opening/closing valve control circuit 20a receives a valve opening signal 22 from a valve operation switch (not shown) of the cooling pipe opening/closing valve 12a and a reactor accident signal 23 through a signal inversion circuit 24. The cooling pipe opening/closing valve 12a is opened by the output signal from the AND circuit 25, and the valve closing signal 26 of the valve operation switch is activated.
OR circuit 2 into which the and reactor accident signal 23 are input.
The cooling pipe opening/closing valve 12a is activated by the output signal from 7.
The valve is configured to close the valve. In addition,
The above reactor accident signal 23 is a signal that is output in response to the loss of reactor cooling water and the rise in pressure within the containment vessel 8. Further, the cooling pipe opening/closing valve 12a has a limit switch 28 which is linked to its opening/closing operation.
is provided, and when the cooling pipe opening/closing valve 12a is completely closed, a signal to that effect is output and sent to the emergency water supply valve control circuit 21a. And the above emergency water supply valve control circuit 2
1 is a valve opening signal 29 of a valve operation switch (not shown) of the emergency water supply valve 18a and the limit switch 2
The output signal of this AND circuit 30 is input to an OR circuit 31.
The reactor accident signal 23 is also input to this OR circuit 31, and the emergency water supply valve 18a is opened by the output signal of this OR circuit 31. Further, an AND circuit 34 is provided with the valve closing signal 32 of the valve operation switch described above and the reactor accident signal 23 being inputted via a signal inverting circuit 33.
The emergency water supply valve 18a is activated by the output signal from the
is configured so that the valve is closed.

Next, the operation of the above embodiment will be explained. First, during normal operation of the furnace, the cooling pipe opening/closing valves 10, 11, 12a, 12b, 12 of the cooling pipes 5, 5 during shutdown.
Both valves c and 12d are closed, and reactor water is circulated through the recirculation pipes 2. Next, when the furnace is stopped and the residual heat is removed, that is, in the cooling mode during shutdown, the cooling pipe opening/closing valves 10, 11, 1
2a, 12b, 12c, 12d and on-off valve 1
4, 14 open, pumps 13a, 13b, 13
c, drive 13d. Therefore, the reactor water is circulated through the heat exchangers 6, 6 via the cooling pipes 5, 5 during shutdown to cool the reactor core. In this case, when the cooling pipe opening/closing valve 12a is open, no signal is output from the limit switch 28, so even if the valve operation switch of the emergency water supply valve 18a is opened, the AND of the emergency water supply valve control circuit 21a is No signal is output from the circuit 30, and therefore the emergency water supply valve 18a does not open. Therefore, even if the valve operation switch of the emergency water supply valve 18a is opened by mistake while the cooling pipe opening/closing valve 12a is open, the emergency water supply valve 18a will not be opened, and the reactor water will not be opened. There is no possibility that the liquid will be released into the suppression chamber 17. Next, when the water in the suppression chamber 17 is manually injected into the reactor without the reactor accident signal 23 being output, that is, when the low-pressure water injection mode is manually set, first the cooling pipe opening/closing valve is 12a is closed. Therefore, a signal is output from the limit switch 28 of the cooling pipe opening/closing valve 12a, and the emergency water supply valve control circuit 21a is activated.
It is sent to the AND circuit 30. Therefore, by operating the valve operation switch of the emergency water supply valve 18a in this state, the emergency water supply valve 18a can be opened and set to the low pressure water injection mode. In addition, in the event of a reactor accident such as loss of cooling water, the reactor accident signal 2
3 is sent to the cooling pipe opening/closing valve control circuit 20a and the emergency water supply valve control circuit 21a. Therefore, no signal is always output from the AND circuit 25 of the cooling pipe opening/closing valve control circuit 20a, regardless of the operating state of the valve operation switch of the cooling pipe opening/closing valve 12a.
A signal is output from the OR circuit 27 regardless of the operating state of the valve operating switch, and thus the cooling pipe opening/closing valve 12a is automatically closed. In addition, the reactor accident signal 23 is output from the emergency water supply valve control circuit 21a.
Since it is input to the OR circuit 31, this OR circuit 31
A signal is always output from the valve control switch of the emergency water supply valve 18a to automatically open the emergency water supply valve 18a, and the water in the suppression chamber 17 is supplied to the pump 13a. Therefore, it is injected into the reactor and automatically enters low pressure injection mode. In this embodiment, the closing signal for the cooling pipe opening/closing valve 12a input to the emergency water supply valve control circuit 21a is outputted by a limit switch 28 that is linked to the opening/closing operation of the cooling pipe opening/closing valve 12a. Because it is a product, its reliability is high.
In addition, although the above-mentioned operation was explained only for the cooling pipe opening/closing valve 12a and the emergency water supply valve 18a, it also applies to the other cooling pipeline opening/closing valves 12b, 12c, 12d and the emergency water supply valves 18b, 18c, 18d. It's very similar.

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

For example, the specific configurations of the cooling pipe opening/closing valve control circuit and the emergency water supply valve control circuit are not necessarily limited to those described above, and may be of any type as long as they operate in the same way.

Furthermore, the cooling pipe opening/closing valve that is controlled in conjunction with the emergency water supply valve is not necessarily limited to the cooling pipe opening/closing valve of the above-mentioned embodiment; It is sufficient to control a certain cooling pipe opening/closing valve and an emergency water supply valve in the relationship as described above.

As described above, the present invention enables manual opening and closing of the cooling pipe opening/closing valve only when a reactor accident signal is not input, and closes the cooling pipe opening/closing valve when a reactor accident signal is input. A cooling pipe opening/closing valve control circuit that enables manual opening/closing of the emergency water supply valve only when a closing signal for the cooling pipe opening/closing valve is input and a reactor accident signal is not input, and a reactor accident An emergency water supply valve control circuit is provided which opens the emergency water supply valve when a signal is input. Therefore, it is possible to manually switch between shutdown cooling mode and low-pressure water injection mode, and in the event of a reactor accident, it is possible to automatically switch to low-pressure water injection mode, and the emergency water supply valve is closed unless the cooling pipe opening/closing valve is closed. Since the valve cannot be opened, there is no possibility that the emergency water supply valve may be opened by mistake while the cooling pipe opening/closing valve is open. The effects are great, such as being able to reliably prevent water loss.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, with FIG. 1 being an overall system diagram and FIG. 2 being a block diagram of a control circuit. DESCRIPTION OF SYMBOLS 1... Furnace vessel, 2... Recirculation pipe line, 5... Cooling pipe line during shutdown, 6... Heat exchanger, 12a, 12b,
12c, 12d... Cooling pipe opening/closing valve, 13a, 1
3b, 13c, 13d...pump, 18a, 18
b, 18c, 18d...Emergency water supply valve, 20a...
...Cooling pipe opening/closing valve control circuit, 21a...Emergency water supply valve control circuit, 28...Limit switch.

Claims (1)

[Scope of Claims] 1. A shutdown cooling pipe that circulates cooling water in the reactor when the reactor is shut down, and a cooling pipe opening/closing valve, pump, and heat exchanger provided in the middle of this shutdown cooling pipe. and an emergency supply branched from between the cooling pipe opening/closing valve and the pump and communicating with the suppression chamber to supply water in the suppression chamber to the cooling pipe during shutdown in an emergency. In a system equipped with a water pipe and an emergency water supply valve installed in the middle of the emergency water supply pipe, the cooling pipe opening/closing valve can be manually opened and closed only when a reactor accident signal is not input. and a cooling pipe opening/closing valve control circuit that closes the cooling pipe opening/closing valve when a reactor accident signal is input, and a cooling pipe opening/closing valve control circuit that closes the cooling pipeline opening/closing valve when a reactor accident signal is input, and a reactor accident signal is input. The emergency water supply valve is equipped with an emergency water supply valve control circuit that enables the emergency water supply valve to be manually opened and closed only when the reactor accident signal is input. Characteristic residual heat removal equipment for nuclear reactors. 2. The valve closing signal of the cooling pipe opening/closing valve is output by a switch mechanism that operates in conjunction with the opening/closing operation of the cooling pipe opening/closing valve. residual heat removal equipment for nuclear reactors.