JPS6140080B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cleaning device for water supply pipes of boiling water nuclear reactors and the like.

The water supply system of a conventional boiling water nuclear reactor was constructed as shown in FIG. That is, A is a reactor pressure vessel, B is a reactor containment vessel, C is a main steam pipe, D is a turbine, E is a condenser, and F is a recirculation pump. The water condensed in the condenser E is sent to the condensate desalination device I by a condensate pump G via a condensate pipe H. The water purified by the condensate desalination equipment I is sent to the low-pressure feed water heater K via the water supply pipe J and heated, then the pressure is increased by the water feed pump L and sent to the high-pressure feed water heater M. is heated and sent to header N. Water is supplied into the reactor pressure vessel A through a pair of water supply pipes O and P branched at this header N. Water supply flow rate regulating valves Q, Q are provided in the middle of these pair of water supply pipes O, P, respectively, and inlet valves R, R and R are provided on the upstream and downstream sides of these water supply flow rate regulating valves Q, Q, respectively. Outlet valves S, S are provided. In addition, these water supply pipes O and P are provided with water supply inner isolation valves T and T on the inside of the reactor containment vessel B, and water supply outer isolation valves U and U are provided on the outside of the reactor containment vessel B, respectively. T,T
Both of the water supply outer isolation valves U and U have a swing-type check valve structure that allows the reactor pressure to flow only toward the vessel A. In addition, a minimum flow pipe V branches from the header N and communicates with the condenser E.
An on-off valve W is provided in the middle of this minimum flow pipe V. By the way, most of the pipes mentioned above are carbon steel pipes, so they are prone to rust, and when the reactor is restarted after shutting down, such as during periodic inspections, it is necessary to clean the inside of these pipes to remove rust. . Conventionally, in order to perform such cleaning, water is poured into the condenser E, the condensate pump G is operated, and the inlet valves R and R of the water supply flow rate adjustment valves Q and Q are closed to minimize the water flow. It was circulated in a closed loop through pipe V to clean and deaerate the inside of the pipe, and to remove rust collected in condenser E. Also, on the furnace side, the condenser E was evacuated and the recirculation pump F was operated to perform deaeration. However, in the above system, the water supply flow rate adjustment valve Q,
The water supply pipes O and P on the downstream side of the inlet valves R and Q cannot be cleaned or degassed. The length of the water supply pipes O, P from these inlet valves R, R to the reactor pressure vessel A is nearly 100 m, and a considerable amount of rust occurs inside, and a considerable amount of air remains.
Therefore, if the reactor is operated without cleaning and degassing this part, rust will not only flow into the reactor pressure vessel A and cause a failure, but also cause this rust to become radioactive and circulate within the system. , there were problems such as an increase in the level of contamination of the entire system.

The present invention was made based on the above circumstances, and its purpose is to completely clean and deaerate the water supply pipe between the inlet valve of the water supply flow rate adjustment valve and the reactor pressure vessel. Moreover, the object is to obtain a water supply pipe cleaning device for a nuclear reactor that has a simple structure.

The present invention will be explained below with reference to an embodiment shown in FIGS. 2 to 5. This embodiment is an application of the present invention to a boiling water nuclear reactor.

In the figure, 1 is a reactor pressure vessel, 2 is a reactor containment vessel, 3 is a recirculation pump, 4 is a main steam pipe, 5 is a turbine, and 6 is a condenser. The steam generated within the reactor pressure vessel 1 is sent to a turbine 5 via a main steam pipe 4, drives the turbine 5, and is then condensed into water in a condenser 6. The water in the condenser 6 is configured to be supplied into the reactor pressure vessel 1 via a series of water supply systems. Reference numeral 7 denotes a condensate pump, which is configured to send water in the condenser 6 to a condensate desalination device 9 via a condensate pipe 8. Water purified by this condensate desalination device 9 is configured to be sent to a header 11 via a water supply pipe 10. The water supply pipe 10 is sequentially provided with a low pressure water heater 12, a water supply pump 13, and a high pressure water heater 14 from the upstream side, and the water to be sent is heated by the low pressure water heater 12 and the high pressure water heater 14. , and is configured to be pressurized by the water supply pump 13. And header 1 above
2, the water supply system is branched into a pair of water supply pipes 15 and 16, and these water supply pipes 15 and 16 penetrate the reactor containment vessel 2 and communicate with the inside of the reactor pressure vessel 1. Water is supplied into the reactor pressure vessel 1 through pipes 15 and 16. Further, a minimum flow pipe 17 is provided branching off from the header 11, and this minimum flow pipe 17 is communicated with the condenser 6, and an on-off valve 18 is provided in the middle thereof. When adjusting the water supply flow rate, a portion of the water supply flows through this minimum flow pipe 17.
The water is returned to the condenser 6 via the water supply pump 13.
The structure is such that water is circulated through this minimum flow pipe 17 during test runs. Water supply flow rate adjustment valves 19 and 20 are provided in the portions of the pair of water supply pipes 15 and 16 outside the reactor containment vessel 2, respectively, and these water supply flow rate adjustment valves 1
Inlet valves 21, 21 and outlet valves 22, 22 are provided on the upstream and downstream sides of 9, 20, respectively, and these water supply flow rate adjustment valves 19, 20 are configured to adjust the water supply flow rate. There is. In addition, on the downstream side of these water supply flow rate adjustment valves 19 and 20, water supply outer isolation valves 23 and 24 are provided, respectively, located near the outside of the reactor containment vessel 2. Both of these water supply outer isolation valves 23 and 24 have a check valve structure that allows only flow toward the reactor pressure vessel 1. In addition, water supply inner isolation valves 25 and 26 are provided in the portions of the pair of water supply pipes 15 and 16 inside the reactor containment vessel 2, respectively. Both of these water supply inner isolation valves 25 and 26 are valves that can be opened and closed, for example, gate-type valves driven by a motor. Further, cleaning on-off valves 27 and 28 are provided downstream of the water supply inner isolation valves 25 and 26 and near the reactor pressure vessel 1, respectively. These cleaning on-off valves 27 and 28 are motor-driven gate-type valves similar to the water supply inner isolation valves 25 and 26. Further, a cleaning communication pipe 29 is provided which branches from the water supply pipes 15, 16 between these cleaning on-off valves 27, 28 and the water supply inner isolation valves 25, 26 and communicates these water supply pipes 15, 16 with each other. It is being A cleaning communication pipe on-off valve 30 is provided in the middle of this cleaning communication pipe 29, and this washing communication pipe on-off valve 30 is a motor-driven gate type valve similar to the water supply inner isolation valves 25 and 26. be. In addition, cleaning return pipes 31 and 3 are branched from between the water supply outer isolation valves 23 and 24 of these pair of water supply pipes 15 and 16 and the penetration part of the reactor containment vessel 2, respectively.
2 are provided respectively, and these cleaning return pipes 3
1 and 32 are in communication with the condenser 6, respectively. Cleaning return pipe opening/closing valves 33 and 34 are provided in the middle of these cleaning return pipes 31 and 32, respectively.

One embodiment of the present invention configured as described above has a cleaning communication pipe opening/closing valve 29 and both cleaning return pipe opening/closing valves 33, as shown in FIG. 3, during reactor operation.
34 is closed, and the water supply inner isolation valves 25, 26 and the cleaning on/off valves 27, 28 are opened. Therefore, the water sent by the water supply pump 13 is branched at the header 11 and is supplied into the reactor pressure vessel 1 through both water supply pipes 15 and 16. When cleaning the water supply system before starting operation after stopping the reactor operation for a long time, such as during periodic inspections, first, as shown in Figure 4, both cleaning on-off valves 2
7 and 28, and the inlet valve 21 and outlet valve 2 of the water supply flow rate adjustment valve 19 of one water supply pipe 15.
2 is closed, and the cleaning return pipe opening/closing valve 3 of the other cleaning return pipe 32 branched from the other water supply pipe 16
4 is closed, the cleaning communication pipe on-off valve 30 and one of the cleaning return pipe on-off valves 33 are opened, and the condensate pump 7 is operated. Water is therefore sent to the header 11 through the feed water desalination device 9, the low pressure feed water heater 12, the feed water pump 13 and the high pressure feed water heater 14.
And the water supply flow rate adjustment valve 19 of one water supply pipe 15
Since the inlet valve 21 and outlet valve 22 of the header 11 are closed, the water supplied to the header 11 is transferred to the other water supply pipe 16, the cleaning communication pipe 29, and the one water supply pipe 15.
The water is returned to the condenser 6 and circulated through the inner part of the reactor containment vessel 2 and one of the cleaning return pipes 31, and the inside of the piping in these parts is cleaned and degassed. Next, as shown in FIG. 5, contrary to the above, the inlet valve 21 and outlet valve 22 of the water supply flow rate adjustment valve 20 of the other water supply pipe 16 and the cleaning return pipe opening/closing valve 33 of one of the water supply pipes 16 are closed, and the one of the water supply pipes 16 is closed. water supply flow rate adjustment valve 19 of the water supply pipe 15
The inlet valve 21, the outlet valve 22, and the other cleaning return pipe opening/closing valve 34 are opened. Therefore, water circulates through the water supply pipe 15 on one side, the communication pipe 29 for cleaning, the internal portion of the reactor containment vessel 2 of the water supply pipe 16 on the other side, and the return pipe 32 for cleaning on the other side, and cleans these parts. Perform deaeration. Therefore, all parts of these water supply pipes 15 and 16 can be cleaned and deaerated. In addition, the cleaning on-off valves 27, 28
Since the water supply pipes 15 and 16 between the reactor pressure vessel 1 and the reactor pressure vessel 1 cannot be cleaned, these cleaning on-off valves 27 and 2
8 is preferably provided as close to the reactor pressure vessel 1 as possible. Since this thing is provided with a cleaning communication pipe 29 that communicates the water supply pipes 15 and 16 with each other in the reactor containment vessel 1, the cleaning water inside the reactor containment vessel 2 is supplied to the cleaning communication pipe 29. and both water supply pipes 1
5, 16, so the cleaning return pipe 3
1 and 32 are water supply pipes 15 and 1 outside the reactor containment vessel 2.
These cleaning return pipes 31 and 32 do not need to penetrate the reactor containment vessel 2, so the structure is simple, and they can be easily modified when existing equipment is modified. . In addition, with such a type, when cleaning, either water supply pipe 1
5 and 16, water will flow in the opposite direction, so for example, the water supply inner isolation valves 25 and 26 need to be gate-type valves that can be opened and closed without using conventional check valves. In one embodiment, the cleaning return pipes 31 and 32 are connected to the water supply outer isolation valves 23 and 24.
Since the water supply outer isolation valves 23 and 24 can be of the same type as conventional check valves, the structure is simple and the existing equipment can be used. It is easy to remodel.

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

For example, the location at which the cleaning return pipe is branched and connected to the water supply pipe is not necessarily limited to the location in the above embodiment, but may be at any location outside the reactor containment vessel.

Further, the cleaning return pipes may be combined into one on the downstream side of the cleaning return pipe opening/closing valve.

As described above, the present invention connects water supply pipes within the reactor containment vessel with a cleaning communication pipe, circulates cleaning water through the cleaning communication pipe and both water supply pipes, and circulates water outside the reactor containment vessel. The water is returned to the condenser via a cleaning return pipe branched from the water supply pipe. Therefore, the entire water supply pipe can be cleaned,
Since the water in the system can be kept clean, there will be no malfunction or contamination of the system, and the health of the reactor can be maintained at all times. In addition, the cleaning return pipe does not need to penetrate the reactor containment vessel, so the structure is simple, and when existing equipment is to be modified, it can be easily modified, which has great effects.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a conventional example. In addition, Figures 2 to 5 show an embodiment of the present invention, Figure 2 is an overall system diagram, Figure 3 is a system diagram of main parts during operation, and Figures 4 and 5 are during cleaning. It is a system diagram of the main part in. 1... Reactor pressure vessel, 2... Reactor containment vessel, 5... Turbine, 6... Condenser, 11... Header, 13... Water supply pump, 15... One water supply pipe, 16... Other water supply pipe, 19, 20... Water supply flow rate adjustment valve, 23, 24... Water supply outer isolation valve, 2
5, 26...Water supply inner isolation valve, 27, 28...Cleaning on/off valve, 29...Cleaning communication pipe, 30...Cleaning communication pipe on/off valve, 31,32...Cleaning return pipe, 33, 34...Cleaning return pipe opening/closing valve.

Claims (1)

[Claims] 1. A reactor pressure vessel, a main steam pipe that supplies steam generated within the reactor pressure vessel to the turbine,
a condenser that condenses the steam sent to the turbine through the main steam pipe; a condensate pump that supplies the condensate condensed in the condenser to the condensate desalination device through the condensate pipe; A feed water heater that heats the water purified by the desalination equipment; a water pump that supplies the water heated by the feed water heater to the water supply header; first and second water supply pipes that supply into the reactor pressure vessel;
and a water supply flow rate adjustment valve provided in each of the second water supply pipes to adjust the water supply flow rate to the reactor pressure vessel; an inlet valve provided on the upstream side of the water supply flow rate adjustment valve; A cleaning on-off valve installed downstream and near the reactor pressure vessel;
A cleaning communication pipe provided between the cleaning on-off valve and the water supply flow rate adjustment valve and communicating the first and second water supply pipes with each other, and a cleaning communication pipe provided in the cleaning communication pipe to open/close the cleaning communication pipe. a first cleaning return pipe located on the downstream side of the water supply flow rate adjustment valve, branched from the first water supply pipe and connected to the condenser, and also on the downstream side of the water supply flow rate adjustment valve. a second water supply pipe located at the second water supply pipe branched from the second water supply pipe and connected to the condenser;
a cleaning return pipe, a cleaning return pipe opening/closing valve provided on the first and second cleaning return pipes, and a minimum flow pipe connected between the condenser and the water supply header. A water supply pipe cleaning device for a nuclear reactor, characterized by comprising: