JP2577352B2 - Reactor residual heat removal equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a residual heat removing apparatus for a nuclear reactor, and more particularly to a residual heat removing apparatus for a nuclear reactor for cooling a nuclear reactor when the reactor is stopped.

(Prior Art) Generally, in a boiling water nuclear power plant, when the reactor is shut down, the reactor steam is condensed by a turbine condenser to cool the reactor.
When the amount of generated reactor steam decreases, the reactor is cooled by the residual heat removing device.

FIG. 2 shows a conventional residual heat removing apparatus. A reactor water suction pipe 2 and a return pipe 4 are connected between a reactor pressure vessel 1 and a circulation pump 2, respectively. After being drawn out by the suction pipe 3 and pressurized by the circulation pump 2, the pressure is returned to the reactor pressure vessel 1 through the return pipe 4.

Further, the suction pipe 3 is branched at an intermediate portion thereof, and the branch side pipe is supplied with cooling water by way of an isolated part 5, 5, a cooling pump 6, a heat exchanger inlet valve 7, and a cooling water system 8 on the way. The heat exchanger 9, the heat exchanger outlet valve 10, the injection valve 11, and the injection check valve 12 are connected to an intermediate portion of the return pipe 4 via each of them. On the downstream side of the cooling pump 6,
A pipe bypassing the heat exchanger 9 is connected via a heat exchanger bypass valve 13 on the way, and a pipe bypassing the injection check valve 12 is provided on the way via a check valve bypass valve 14.

Further, the downstream side of the heat exchanger 9 is branched and a discharge valve is provided.
It is connected to a pressure suppression chamber 16 via 15, and the upstream side of the injection valve 11 is branched and connected to a radioactive waste treatment facility 18 via communication valves 17, 17. Further, the condensate tank 19 is connected to the upstream side and the downstream side of the heat exchanger 9 via an upstream side cleaning valve 21 and a downstream side cleaning valve 22 after passing through a condensate pump 20, respectively. The reactor pressure vessel 1 is housed in a reactor containment vessel 23.

In the above device, the reactor water in the reactor pressure vessel 1 is constantly circulated by the circulation pump 2. When the reactor is stopped, the reactor water is sent to the isolation valve 5 side, and after the reactor pump is pressurized by the cooling pump 6, Cool in heat exchanger 9. Thereafter, the cooled reactor water is returned to the reactor pressure vessel 1 through the injection valve 11, the injection check valve 12, and the return pipe 4, so as to cool the reactor.

Since such a residual heat removal device is not used during normal operation of the plant, the water in the pipes has a low temperature (about 30
° C) and the product of corrosion is mixed. Therefore, if the operation is started immediately, the reactor water temperature of the reactor is as high as about 150 ° C, causing thermal shock, which is not desirable in terms of the soundness of the material. The amount of substance increases.

Therefore, prior to the operation of the system, cleaning and warming of the pipes have been conventionally performed.

First, when cleaning the system, the isolation valve 5 and the injection valve 11 are closed, and the communication valve 17 and the downstream side cleaning valve 22 are opened. Then, the condensed water pressurized from the condensate tank 19 via the condensate pump 20 is washed on the upstream side of the injection valve 11 and sent to the radioactive waste treatment equipment 18. Next, the cooling pump 6 and the heat exchanger 9 are cleaned by closing the downstream side cleaning valve 22 and the heat exchanger bypass valve 13 and opening the upstream side cleaning valve 21, the heat exchanger inlet valve 7 and the outlet valve 10. Thereafter, the condensate is sent to the radioactive waste treatment facility 18. Finally, the heat exchanger inlet valve 7
The outlet valve 10 is closed, the bypass valve 13 is opened, and the piping before and after the bypass valve 13 is washed.

Subsequently, when performing warm-up, the cleaning valves 21 and 22 and the communication valve 17 are closed, and the check valve bypass valve 14 can be opened if the pressure before and after the injection check valve 12 is equalized. So
The injection valve 11, the check valve bypass valve 14, and the injection check valve 12 are opened in this order. Further, the heat exchanger outlet valve 10 is closed, and the heat exchanger inlet valve 7 and the bypass valve 13 are opened. If the discharge valve 15 is gradually opened and its opening is adjusted in this state, the high-temperature reactor water flows into the pressure suppression chamber 16 after warming the pipe and the heat exchanger 9 through the injection check valve 12. Next, the injection valve 11, the injection check valve 12, the check valve bypass valve 14, and the heat exchanger inlet valve 7 are closed, and the isolation valve 5, the heat exchanger bypass valve 13, and the outlet valve 10 are opened. By gradually opening the discharge valve 15, the cooling pump 6
For example, the upstream side of the heat exchanger 9 is warmed up.

(Problems to be Solved by the Invention) As described above, when the residual heat removing device is warmed up, the reactor water flows into the pressure suppression chamber 16. Is discharged outside the room when the water level exceeds a specified level, so that radioactive substances brought in by the reactor water are unplannedly managed, which is not preferable for preventing radioactive contamination in the power plant.

For this purpose, it is conceivable that the reactor water discharged during warm-up is sent to the radioactive waste treatment facility 18 for treatment.However, since the maximum operating temperature of the radioactive waste treatment facility 18 is about 70 ° C., There is a problem that the reactor water cannot be sent directly to the radioactive waste treatment facility 18.

The present invention has been made in view of the above points, it is possible to transfer the reactor water to the radioactive waste treatment equipment during warm-up,
It is an object of the present invention to provide an apparatus for removing residual heat of a nuclear reactor capable of performing a planned treatment of radioactive materials.

(Means for Solving the Problems) In order to achieve the above object, the present invention derives a coolant from a suction pipe connecting a reactor pressure vessel and a suction port of a circulation pump, and transfers the coolant to a heat exchanger. In a residual heat removing device for a nuclear reactor having a circulation piping system configured to return to a return piping connecting the reactor pressure vessel and the discharge port of the circulation pump after cooling in the reactor, the circulation piping system includes the suction piping. And an isolation valve, an injection valve, an injection check valve, and a check valve provided in a bypass pipe connected upstream and downstream of the injection check valve, respectively, near the connection portion of the return pipe and the isolation valve. At the downstream vicinity position and at the upstream vicinity position of the injection valve, respectively, are communicated with the condensate tank via the upstream cleaning valve and the downstream cleaning valve, respectively, and the heat exchanger is provided with a heat exchanger inlet at its upstream side and downstream side, respectively. Warm-up of valves and residual heat removal equipment It has a heat exchanger outlet valve that is closed at the time of rotation, and a pipe upstream of the heat exchanger inlet valve and a pipe downstream of the heat exchanger outlet valve is a heat exchanger bypass pipe having a heat exchanger bypass valve. Connected, piping between the heat exchanger and the heat exchanger outlet valve,
A residual heat removal device for a nuclear reactor, characterized in that the residual heat removal device is connected to a radioactive waste treatment facility via a communication valve that is opened during a warm-up operation of the residual heat removal device.

(Operation) According to the present invention configured as described above, when warming up the downstream side of the heat exchanger, the injection valve, the injection check valve, the check valve bypass valve, the heat exchanger bypass valve, and the heat exchange Open the unit inlet valve, close the heat exchanger outlet valve, gradually open the communication valve, and warm the piping and heat exchanger with reactor water. At this time, since the reactor water is sent directly to the radioactive waste treatment facility, the radioactive material can be systematically treated, and the heat is exchanged with the constantly flowing cooling water in the heat exchanger. After that, it will flow into the radioactive waste treatment facility.

When warming up the upstream side, the injection valve, the injection check valve, and the check valve bypass valve are closed and the isolation valve is opened with the heat exchanger bypass valve and the heat exchanger outlet valve closed. Then, the communication valve is gradually opened to supply the reactor water. In this case, the reactor water is cooled by the heat exchanger, so that the radioactive material can be reliably treated.

Example An example of the present invention will be described below with reference to FIG.
The same parts as those in FIG. 2 are denoted by the same reference numerals, and the description of the configuration will be omitted.

In FIG. 1, the present embodiment is different from the conventional example in that the reactor water used for warming-up is not guided to the pressure suppression chamber through the discharge valve.
The communication valves 17, 17 and the radioactive waste treatment equipment 18 are connected to the downstream side of the heat exchanger 9, and the other parts are connected to the second
It is similar to that shown in the figure.

In the present embodiment, first, when cleaning is performed, the downstream side cleaning valve 22, the heat exchanger outlet valve 10 is opened, the heat exchanger bypass valve 13 is closed, and the communication valves 17, 17 are opened, so that the condensate tank is opened. The condensate 19 cleans the piping downstream of the heat exchanger 9 and flows into the radioactive waste treatment facility 18. Next, the heat exchanger outlet valve
By closing 10 and opening the heat exchanger bypass valve 13 and the inlet valve 7, the pipes before and after the heat exchanger 9 and the bypass valve 13 are cleaned. And finally, the heat exchanger bypass valve 13,
By closing the downstream cleaning valve 22 and opening the upstream cleaning valve 21, the cooling pump 6 and the heat exchanger 9 are cleaned.

Subsequently, when warming up, the communication valve 17 may be gradually opened instead of the discharge valve basically in the same manner as the conventional one. That is, when warming up the downstream side of the heat exchanger 9, the injection valve 11, the check valve bypass valve 14, the injection check valve
15. The heat exchanger bypass valve 13 and the heat exchanger inlet valve 7 are opened, the heat exchanger outlet valve 10 is closed, the communication valve 17 is gradually opened, and the piping and the heat exchanger 9 are heated by the reactor water. At this time,
Since the reactor water is directly sent to the radiant waste treatment facility 18, the radioactive material can be systematically treated, and the heat is exchanged with the constantly flowing cooling water in the heat exchanger 9, so that the reactor water is sufficiently cooled. After that, it will flow into the radioactive waste treatment facility.

When warming up the upstream side, the injection valve 1 is kept closed with the heat exchanger bypass valve 13 and the heat exchanger outlet valve 10 closed.
1. Close the injection check valve 12, the check valve bypass valve 14, and open the isolation valve 5. Then, the communication valve 17 is gradually opened to feed the reactor water. In this case as well, the reactor water is cooled by the heat exchanger 9, so that the radioactive substance can be reliably treated.

In this embodiment, since the reactor water used at the time of warm-up can be sufficiently cooled by the conventionally used heat exchanger 9, the capacity of the heat exchanger 9 is increased with the implementation of the present invention. Therefore, the present invention can be implemented without expanding the equipment within the range conventionally used.
Therefore, it is possible to obtain an apparatus for removing residual heat of a nuclear reactor with improved performance within a limited space in a nuclear power plant.

(Effect of the Invention) As described above, the reactor residual heat removal apparatus according to the present invention cools all the reactor water used when the apparatus is warmed up by the heat exchanger, and then sends it to the radioactive waste treatment facility. That allows for the planned treatment of radioactive material,
It is possible to reduce the number of contamination sources in the pressure suppression chamber. Further, piping to the pressure control chamber is not required, and the reactor water used during warm-up can be sufficiently cooled by the heat exchanger of the residual heat removing device, and the capacity of the heat exchanger is reduced in the practice of the present invention. Therefore, the present invention can be implemented without increasing the equipment.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a residual heat removing device for a nuclear reactor according to one embodiment of the present invention, and FIG. 2 is a system diagram showing a conventional example of a residual heat removing device for a nuclear reactor. 1 ... Reactor pressure vessel, 2 ... Circulation pump, 3 ... Suction pipe, 4 ... Return pipe, 5 ... Isolation valve, 7 ... Heat exchanger inlet valve, 9 ... Heat exchanger, 10 ... … Heat exchanger outlet valve, 11…
... injection valve, 12 ... injection check valve, 13 ... heat exchanger bypass valve, 14 ... check valve bypass valve, 17 ... communication valve, 18 ... radioactive waste treatment equipment, 19 ... condensate Tank, 21 ... upstream cleaning valve, 22 ... downstream cleaning valve.

Claims (1)

(57) [Claims] 1. A coolant is drawn out from a suction pipe connecting a reactor pressure vessel and a suction port of a circulation pump, and the coolant is cooled by a heat exchanger, and then discharged from the reactor pressure vessel and the circulation pump. In a residual heat removing device for a nuclear reactor having a circulation piping system configured to return to a return piping connecting an outlet, the circulation piping system includes an isolation valve, an injection valve, and a valve near a connection between the suction piping and the return piping, respectively. An injection check valve and a check valve provided on a bypass pipe connected to the upstream and downstream of the injection check valve, wherein the check valve is located upstream and downstream of the isolation valve and upstream of the injection valve, respectively. The heat exchanger is communicated with a condensate tank via a washing valve and a downstream washing valve, and the heat exchanger is closed on the upstream side and the downstream side during a warm-up operation of the heat exchanger inlet valve and the residual heat removing device, respectively. A heat exchanger outlet valve, wherein the heat The pipes upstream of the exchanger inlet valve and downstream of the heat exchanger outlet valve are connected by a heat exchanger bypass pipe having a heat exchanger bypass valve, between the heat exchanger and the heat exchanger outlet valve. The residual heat removal device for a nuclear reactor, wherein the pipe is connected to the radioactive waste treatment facility via a communication valve that is opened when the residual heat removal device is warmed up.