JPS5855798A - Method of protecting overflow in semi-underground type power plant - 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 The present invention provides a method for preventing overflow of condenser cooling water in, for example, steam power generation equipment, particularly in a semi-underground power plant where the condenser is installed at a location lower than the cooling water intake surface or water discharge surface. Regarding.

With the recent increase in the capacity of steam power plants, the flow rate of condenser cooling water has increased, and in the case of nuclear power plants, for example, buildings have to be built on bedrock for seismic design reasons. In some cases, the condenser is located below the water level of the cooling water intake or water discharge surface.

In other words, it is an underground type power plant, an example of which is shown in Figure 1.
In FIG. 1, a piping stop is connected to a cooling water pump disposed at a water intake source via a pump outlet valve J. On the other hand, the ground surface! Equipment such as a turbine 1 and a condenser are installed in [117] on the artificial bedrock 4 at a lower position. As shown in Fig. 1, the condenser device is equipped with a plurality of heat exchange sections 9* and 9b arranged in parallel, a branch conduit of 1 m branched from the piping bow, and a condenser valve for each condenser. io, connected via //. Also, the internal heat exchange section? a, Wb are connected to the piping system via the condenser outlet valve lko, 13, and the piping t4Ild is the tailrace l! It is open at the top. Furthermore, the ice chambers of the heat exchange section are connected to each other by connecting pipes having connecting valves /4°/.

Therefore, the cooling water is pumped up from the condenser cooling water drain and the cooling water intake source L by the pump valve J,
Piping, condenser valve 10. It passes sequentially through // and enters the condenser 9, where the exhaust steam of the turbine t is indirectly cooled and condensed to the condenser outlet valve /Lm, /, ? It is discharged to the water discharge channel /j via the pipe /41. In the cooling water system configured as described above, if a pipe or pipe ruptures in the middle of the system, the cooling water will flow into the equipment room. Particularly in large-capacity nuclear power plants, etc., where the condenser is installed at a lower position than the water spray source, cooling water accumulates in the equipment room, and the pump must be stopped or the straddle pump outlet valve 3 If the piping or pipe is large in diameter and very long, a large amount of cooling water will flow in until the pipe is closed. Due to such an event, a condenser was installed in the equipment room! In extreme cases, there is a risk that various equipment, electrical items, etc., including water may be submerged in water to the same level as the water level of the water intake source.

This is thought to cause failures and malfunctions of various devices, electrical products, etc., and there is concern that reliability will deteriorate significantly. Conventionally, there are methods of stopping the flow of cooling water, such as stopping the pump pump or closing the pump outlet valve 3, to prevent water from overflowing when a pipe ruptures.

However, with these methods, in cases where the piping is large in diameter and very long, or where the height difference between the piping is very large, even if a method of stopping the flow of cooling water is used, the inertia is large and it may take a long time to stop the flow. This method has drawbacks such as it takes time, and the cooling water separates into steam and water, making it difficult for it to flow into low areas, and it is not very effective in reducing the amount of water overflowing into the equipment room.

The present invention has been developed in consideration of these points, and is a semi-underground power generation system that minimizes the amount of overflow of cooling water even if it overflows, thereby preventing submergence of installed equipment and electrical items. In order to provide a method to prevent overflows, the inlet valves and outlet valves installed before and after the condenser, as well as the connecting valve on the connecting pipe connecting the ice chamber of the condenser, are cooled from the piping. The system is characterized in that water leakage is detected and valves at the inlet and outlet of the leakage point are closed to stop only the outflow of cooling water at the leakage point.

An embodiment of the present invention will be described below with reference to FIG. 7 and FIG.

In FIGS. 7 and 2, the pipe rupture generally occurs at condenser inlet valve 10. Downstream side of //, condenser outlet valve /ko, /
Line parts /I, /l of the upstream side of J and the connecting pipe section.

It is thought to occur in 〃, ko/, u, 2J, 2'l, #.

As shown in the diagram, close the condenser communication valves /A, /7, and close the condenser population valves lθ, it and condenser outlet valves lθ,
i3 is opened, the flow is in the direction of the arrow in the figure, that is, the cooling water is pumped up from the water intake source 1 at the Bonpco, passes through the piping d, and then flows through each inlet valve 10 of the condenser d. // and the condenser outlet valve l, i3, and flowing to the discharge channel /1, for example, if there is a piping rupture at the shaded area /l or /1, and cooling water leaks, Conventionally, the Bonpco is stopped or the pump outlet valve 3 is closed, but due to the inertia of the cooling water and the time it takes to fully close the pump outlet valve 3, a large amount of water passes through the large diameter piping. Cooling water flows out from the rupture.

In addition, cooling water flows back from the waterway /j to the rupture part through the pipe /41, causing a large amount of water to flow out as well. In contrast, in the present invention, leakage of cooling water is detected and the condenser artificial valve IO and the outlet valve IO are rapidly closed.

This prevents water from flowing into the rupture part from the pump side, and also prevents water from flowing back from the spillway tj side, making it possible to minimize the flow of cooling water into the equipment room. Mud. Such treatment may be applied to other rupture locations, such as the shaded area 1. ! /, u.

Jj, 24I, # can be similarly implemented.

As explained above, according to the present invention, without stopping the pump, the large mouth valve, outlet valve, and communication valve that send cooling water to the condenser can detect leakage of cooling water from piping, and detect leakage points. It is possible to minimize the outflow of cooling water by closing the valves at the inlet and outlet of the leakage point so as to stop only the outflow of cooling water. This point 1: For example, in the case of leakage from the piping between the large outlet valve and the condenser, without stopping the pump, the condenser side of the other 1 series, that is, the piping, the large outlet valve, the condenser, The condenser can be operated by maintaining a healthy flow path through the outlet valve to the discharge waterway and by passing water through one heat exchange section of the condenser. Therefore, it is possible to recover from a cooling water leakage accident without shutting down the plant.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a condenser cooling water system, and FIG. 2 is a flowchart of cooling water in the same system. /...Water intake source, K...Cooling water pump, q
. lda...piping, 9...condenser, 10. /C... Condenser population valve, /J /J... Condenser output valve, /j...
・Discharge channel, /A, /7...Connection valve. Applicant's agent Kiyoshi Inomata

Claims (1)

[Claims] In an underground power plant with a condenser installed below the cooling water intake or discharge surface, connect the large outlet valve, outlet valve, and ice chamber of the condenser installed before and after the condenser. 4. Detect the leakage of cooling water from the piping with the connecting valve on the connecting pipe, and close the valves in front and behind the leakage point so as to stop the flow of cooling water only at the leakage point! A method for preventing flooding in semi-underground power plants.