JPS5915891A - Cooling circuit for reactor equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Technical field of invention J The present invention relates to a nuclear reactor equipment cooling system.

1. Technical burden of the invention] In general, a light water nuclear reactor C such as a boiling water reactor is provided with a reactor equipment cooling system to remove heat generated in the reactor core.

This reactor equipment cooling system I system is used for various operation modes such as during a reactor cold Ml loss accident or during normal operation.Specifically, it has the following functions. There is.

(1) In the event of a loss of coolant accident, it works together with other emergency core cooling systems to restore and maintain the reactor water level and prevent damage to the fuel cladding.

(2) Remove decay heat and residue to facilitate fuel replacement and other operations.

(3) Direct condensation of furnace steam during scram.

(4) Cool the pressure suppression chamber so that steam can be completely condensed in the pressure suppression chamber in the event of a loss of coolant accident.

(5) Assist the fuel pool and containment pool cooling fj'I equipment when a large load is placed on them.

FIG. 1 shows such a conventional nuclear reactor equipment cooling system, and in the figure, the symbol @1 indicates a residual heat removal heat exchanger. The high temperature side of this residual heat removal heat exchanger 1 is equipped with a nuclear reactor.
A secondary cooling water loop 2 is connected.

The low temperature side of the residual heat removal heat exchanger 1 is connected to the 2
The two intermediate loop heat exchangers 4a and 4b are connected to a fresh water intake port 5a through a seawater loop 5.

6b and the seawater discharge lower.

That is, from the seawater intake ports 5a and 5b, the seawater pump 8a1
The seawater sucked into 8b passes through on-off valves 9a, 9b and on-off valves 10a, 10b, and then enters intermediate loop heat exchangers 4a, 4.
After exchanging heat at step b, it passes through the on-off valves 11a and 11b and is discharged into the sea from the seawater discharge lower.

On the other hand, the cooling water of the intermediate loop 3, which has been heat exchanged with seawater on the high temperature side of the intermediate loop heat exchangers 4a and 4b, is transferred to the on-off valve 12a.
, 12b1 on-off valves 13a, 13b.

Intermediate loop circulation pumps 14a, 14b and on-off valve 15
After passing through a and 15b, it flows into the low temperature side of the residual heat removal heat exchanger 1, where it is heat exchanged with the cooling water in the sub-reactor cooling water loop 2, passes through the on-off valve 16, on-off valves 17a and 17b, and then flows into the intermediate Recirculated into loop heat exchanger 4a14b.

Generally, two such reactor equipment cooling systems are installed in a power plant, and for example, two intermediate loop circulation pumps 1.4a and 14b or a seawater pump 8a, which are installed in one system, 8b trip at the same time for some reason, only the remaining residual heat removal heat exchanger 1 can be operated.

In this state, for example, if the reactor equipment cooling system is activated, only one residual heat removal heat exchanger 1 can be operated in high-temperature standby operation, and for example, it is difficult to sufficiently condense the reactor steam. become unable to do so. In this case, even if the temperature rise in the pressure suppression chamber approaches its limit, the residual heat removal heat exchanger 1 is used in the furnace steam condensation mode, so there is a risk that it will not be able to operate in the pressure suppression chamber cooling mode. be.

[Object of the invention] The present invention has been made in response to such conventional circumstancesCX
It is an object of the present invention to provide a reactor equipment cooling system that can fully demonstrate the functions of the reactor equipment cooling system even when the intermediate loop circulation pumps 14a, 14b or seawater pumps 8a, 8b installed in the reactor equipment cooling system trip. That is.

[Summary of the Invention] That is, the present invention provides a seawater loop that circulates seawater sucked by a seawater pump to the low-temperature side of an intermediate loop heat exchanger, and a high-temperature side of the intermediate loop heat exchanger and a residual heat removal heat exchanger. An intermediate loop that circulates cooling water between the low temperature side and the intermediate loop circulation pump, and the residual heat removal heat exchange through which the seawater sucked by the seawater pump is passed through either the seawater pump or the intermediate loop circulation pump. consisting of a suction bypass line into which an on-off valve is inserted that allows the flow to flow into the low temperature side of the heat exchanger, and a discharge bypass line that discharges the seawater that has flowed into the low temperature side of the residual heat removal heat exchanger into the seawater from the seawater outlet. This is a nuclear reactor equipment cooling system characterized by:

[Embodiment of the Invention] The details of the present invention will be described below with reference to an embodiment shown in FIG. In FIG. 2, parts common to those in FIG. 1 are given the same reference numerals.

FIG. 2 shows a reactor equipment cooling system according to an embodiment of the present invention, and shows the on-off valves 15a and 15b between the seawater intake port 6a and the seawater pump 8a, the intermediate loop 3, and the residual heat removal heat exchanger. 1. A suction bypass line 18 is provided to connect the low temperature side inlet, and a seawater suction bypass valve 19 and a suction bypass valve 20 are interposed in this suction bypass line 18 in order from the seawater intake lobe 6a side. It is inserted. On-off valves 9a, 9b and on-off valves 10a, 1ob of the seawater loop 5
A seawater auxiliary line 22 into which a seawater auxiliary line valve 21 is inserted is connected between the seawater suction bypass valve 19 and the suction bypass valve 20 of the suction bypass line 18, and a seawater auxiliary line 22 in which a seawater auxiliary line valve 21 is inserted is connected. On-off valves 12a, 12b,
! : Between the on-off valves 13a and 13b, and between the seawater suction bypass valve 19 and the suction bypass valve 2o of the suction bypass line 18.
An intermediate auxiliary line 24, into which an intermediate auxiliary line valve 23 is inserted, is arranged to connect between the two.

Furthermore, the on-off valve 16 of the intermediate loop 3, the low-drainage outlet side of the residual heat removal heat exchanger 1, and the on-off valve 11 of the seawater loop 5
A discharge bypass line 26, in which a discharge bypass valve 25 is disposed, is connected between the seawater discharge lower portions a and 11b and the seawater discharge lower.

It should be noted that since the structure is the same as that shown in FIG. 1 except as described above, the same parts are given the same reference numerals and the explanation will be omitted.

In the reactor equipment cooling system configured as described above, for example, if both seawater pumps 8a and 8b fail to start, the seawater suction bypass valve 19 and the intermediate auxiliary line valve 23
Then, the discharge bypass valve 25 is opened, and after the seawater is sucked from the seawater intake port 6a, it passes through the suction bypass line 18 where the seawater suction bypass valve 19 is installed, and the intermediate auxiliary line valve 23 is installed. After passing through the auxiliary line 24, on-off valves 13a, 13b, intermediate loop circulation pumps 14a, 1
4b and on-off valves 15a and 15b, and flows into the residual heat removal heat exchanger 1 from the low-temperature inlet side of the residual heat removal heat exchanger 1, and after exchanging heat with the cooling water in the reactor-subcooling water loop 2. , and is discharged into the sea from the seawater discharge lower through a discharge bypass line 26 in which a discharge bypass valve 25 is disposed. Therefore, even if the two seawater pumps 8a and 8b fail to start at the same time, the function of the residual heat removal heat exchanger 1 will not be impaired.

In addition, in the reactor equipment cooling system configured as above,
Intermediate loop circulation pump 14. a and 14b fail to start at the same time, the seawater auxiliary line valve 21, suction bypass valve 20, and discharge bypass valve 25 are opened, and the seawater pumps 8a and 8b suck seawater from the seawater intake ports 6a and 6b. After passing through the seawater auxiliary line 22 and the suction bypass line 18, it flows into the residual heat removal heat exchanger 1 from the low temperature side inlet of the residual heat removal heat exchanger 1, and flows into the reactor-subcooling water loop 2. Cooling water of the discharge bypass valve 2
The seawater is discharged into the sea from the seawater discharge lower through the discharge bypass line 26 provided in No. 5. Therefore, even if two intermediate loop circulation pumps 14a and 14b fail at the same time, the cooling function of the residual heat removal heat exchanger 1 will not be impaired.

FIG. 3 shows the automatic opening and closing of various valves in the reactor equipment cooling system configured as described above, and the intermediate loop circulation pumps 14a, 14.
This shows a control device that allows the reactor equipment cooling system to function normally even in the event of a failure of the reactor pumps 8a and 8b and the seawater pumps 8a and 8b. There is.

That is, the input device 27 inputs signals indicating the open/closed states of all the on-off valves disposed in the reactor equipment cooling system, and also inputs signals indicating the open/closed states of the on-off valves disposed in the reactor equipment cooling system, and also inputs signals indicating the open/closed states of the on-off valves disposed in the reactor equipment cooling system.
and signals indicating these operating states are input from the seawater pump 8a18b.

The monitoring bag ff128 inputs the signals input to the input device 27, constantly monitors the state of these signals, and determines which on-off valve should be opened or closed when an abnormal situation occurs. The monitoring device 28 outputs to the display device 29, together with the abnormality signal, signals of the on-off valves to be opened and closed and signals of the on-off valves that have been opened and closed. The display device 29 receives these signals and displays them.

FIG. 4 shows the seawater loop monitoring logic of the monitoring device 28. In this monitoring 1", for example, starting the seawater pumps Ba, Bb, opening/closing valves 9a, 9b, 10a,
10b, lla, and 11b are respectively determined, and for example, when the seawater pump 8a is not activated, the opening/closing valve 9b
is closed, the OR circuit as shown in the figure,
Finally, the on-off valve 19. passes through an AND circuit and an OR circuit.
20.25 is opened, and the residual heat removal heat exchanger 1 is cooled by seawater.

FIG. 5 shows the intermediate loop monitoring logic of the monitoring device 28. In this monitoring logic, for example, the activation state of the intermediate loop circulation pumps 14a, 14b and the opening/closing valve 12a are determined.
, 12b113a, 13b.

The open/close states of 15a, 15b, 16.17a, and 17b are determined. For example, if the intermediate loop circulation pump 14b does not start and the on-off valve 13a is closed, a signal is output, and the O
It passes through the R circuit, the AND circuit, and the OR circuit, and finally the on-off valves 2'0, 21.25 are opened. That is, in this case, seawater is directly guided to the residual heat removal heat exchanger 1 by the seawater pumps 8a and 8b, and the function of the residual heat removal heat exchanger 1 is maintained.

[Effects of the Invention] As described above, according to the reactor equipment cooling system of the present invention,
Even if an abnormality occurs in the intermediate loop circulation pump or seawater pump, the functionality of the reactor equipment cooling system can be maintained by directly guiding seawater into the residual heat removal heat exchanger.
The reliability of the reactor equipment cooling system can be significantly improved.

[Brief explanation of drawings]

Fig. 1 is a piping system diagram showing a conventional reactor equipment cooling system, Fig. 2 is a piping system diagram showing a reactor equipment cooling system according to an embodiment of the present invention, and Fig. 3 is a piping system diagram showing a reactor equipment cooling system according to an embodiment of the present invention. FIG. 4 is a logic diagram showing the seawater loop monitoring logic of the monitoring device, and FIG. 5 is a logic diagram showing the intermediate loop monitoring logic of the monitoring device. 1... Residual heat removal heat exchanger 2...
・・・・・・・・・Reactor-subcooling 11 water loop 3・・
...... Intermediate loop 4a, 4b... Intermediate loop heat exchanger 5...... Water loop 6a, 6b... Seawater intake a・・・・・・・・・Inland water outlet 8a, 8b・
・・Seawater pump

Claims (1)

[Claims] A seawater loop 1 circulates the seawater sucked by the spring water pump to the low temperature side of the intermediate loop heat exchanger, and an intermediate loop is provided between the high temperature side of the intermediate loop heat exchanger and the low temperature side of the residual heat removal heat exchanger. an intermediate loop in which cold filtration water is circulated by a circulation pump, and seawater sucked in by the seawater pump is caused to flow into the low temperature side of the residual heat removal heat exchanger through either the seawater bonno or the intermediate loop circulation pump. Nuclear reactor equipment comprising a suction bypass line into which an on-off valve is inserted, and a discharge bypass line that discharges the seawater that has flowed into the low temperature side of the residual heat removal heat exchanger into high water from a seawater discharge port. cooling system.