JPS597885A - Cooling water system - Google Patents

Abstract

PURPOSE:To contrive to reduce the size of a device, by moving an air extractor and a gland vapor condenser into a cooling water system for an auxiliary equipment. CONSTITUTION:Cooling water for auxiliary equipment discharged from a cooling water pump 15 is passed through a cooling water pipe 16, is cooled by sea water (a) in a fresh water coolor 17 as an auxiliary equipment, and the temperataure thereof is adjusted to be constant by regulating the flow rate thereof when flowing through a cooling water temperature regulating valve 18 and a bypass pipe 19. The temerature-adjusted cooling water is supplied to each auxiliary equipment 20 to be cooled, where it is heated, thereafter it is returned to the pump 15 through a circuit, and the air extractor 6 and the gland vapor condenser 7 are incoroporated into the cooling water system for auxiliary equipment. Accordingly, since it is sufficient to feed only a required quantity of water to the air extractor 6 and the condenser 7, a water chamber is largely reduced in size, and surface area of contact with condensate can also be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling water system for a power plant, and more particularly to a cooling water system suitable as a cooling water source for a steam air extractor of an atomic couplant and a ground steam condenser of a turbine.

The prior art will be explained with reference to FIG. 1, FIG. 2, and FIG. 3.

In Figure 1, the steam generated in the reactor 1 is transferred to the turbine 2.
After doing work through expansion in the condenser 3, it is cooled and becomes condensate. Condensate is sucked out by a condensate pump 4, passed through a condensate pipe 5, heated by an air extractor 6 and a gland steam condenser 7, and then impurities are removed by a condensate purifier &, and then the condensate is A closed circuit is formed in which the pressure is increased by the pressure boost pump 9 and the reactor feed water pump 10, the temperature is raised by the feed water heater 11, and then returned to the reactor 1.

On the other hand, in order to ensure the minimum amount of cooling water for the air extractor 6 and the grand steam condenser 7, when the plant is started or stopped,
The condensate recirculation valve 12 is opened and operated.

In addition, the air extractor 6 must be installed on a high level floor (generally on the second floor) in order to ensure the U-seal dimension (approximately 10 m) of the fuselage drain pipe 13 to the condenser 3. In order to make the ground steam pipe 14 as short as possible and to ensure a drain slope, it is generally installed on the second floor.

On the other hand, the condensate pump 4 is installed in the basement in order to suck out the condensate accumulated at the bottom of the condenser while ensuring sufficient inlet pressure.

Further, the condensate purification device 8 is generally located in the basement due to the equipment layout of the building.

Among the conventional techniques described above, when condensate is used as the cooling water source for the air extractor 6 and the grand steam condenser 7, there are the following problems. The first problem is shown in FIG. As shown, air extractor 6,
In both the grand steam condenser 7, the entire amount of condensed water is passed through the ice chamber, so the ice chamber becomes large and the amount of water fluctuates depending on the plant output. The condensate recirculation flow rate (included in the recirculation valve) also increases.

The second problem is as shown in Figure 2.
0φ) goes back and forth between the basement and the second floor, meandering over the second floor, and the radiation concentration is high up to the condensate purification device 8, so it is necessary to shield the piping from moisture. I have no choice but to take up space.

The third problem is that since the upstream equipment and piping of the condensate purification device 8 have a large surface area, there are many eluted impurities, which leads to an increase in the load on the purification device.

The fourth problem is that the internal power for the condensate pump 4 increases due to the increase in the head loss of piping and equipment in the condensate system, and the maximum working pressure of the condensate system increases. This leads to an increase in the cost of the purification device 18).

The fifth problem is the potential of the condensate water hammer when external power is lost.

An object of the present invention is to provide a cooling system that makes it possible to solve the problems of the prior art described above by changing the cooling water source of the air extractor and the gland steam condenser from condensate to auxiliary cooling water (fresh water). Located in providing water system.

A cooling water system according to an embodiment of the present invention will be described below with reference to FIGS. 5 and 7.

In FIG. 7, the auxiliary equipment cooling water (fresh water) discharged by the cooling water pump 15 is cooled by seawater in the auxiliary equipment freshwater cooler 17 via the cooling water pipe 16, and then cooled by the cooling water temperature adjustment valve 18.
The cooling water temperature is adjusted to a constant temperature (generally 35C) by adjusting the flow rate through the bypass pipe 19.

The temperature-adjusted cooling water is supplied to each of the cooled auxiliary machines 20, forming a closed circuit in which it returns to the cooling water pump 15 again after being heated.

The present invention consists in transferring the air extractor 6 and the gland steam condenser 7 to the aforementioned auxiliary cooling water system.

However, in the unlikely event that the cooling water source for this equipment is lost (cooling water pump trips, etc.), continued operation will be hindered, so
As shown in the diagram, at least one of the 15.3 cooling water pumps should be turned on to emergency power, or a communication valve 21 from another system (for example, the reactor auxiliary cooling water system) should be installed to enable the supply of cooling water. .

The effects of the present invention include the following points.

The first point is that, as shown in Fig. 5, only the required amount of water needs to flow into the air extractor 6 and the grand steam condenser 7, so the ice chamber has become much smaller in width, and the inlet and outlet piping has been changed from the conventional 1100 MWe.
The diameter can be reduced from 800φ for the class to about 200φ.

The second point is that the contact surface area with condensate is reduced, and the amount of impurities treated by the condensate purification device 8 is reduced.

The third point is that the internal power of the condensate pump 4 is reduced.

Although the capacity of the cooling water pump 15 increases somewhat, the reduction in operating cost of the power for the condensate pump is greater.

The fourth point is that the condensate recirculation flow rate only needs to be equal to the minimum flow rate of the condensate pump 4, so it is significantly reduced.

Fifth, by reducing the maximum operating pressure of the condensate system, equipment costs for the condensate purification device, piping, and valves are reduced.

The sixth point is that the maximum working pressure of the air extractor 6 and the gland steam condenser 7 is approximately 20Kf 7cm”g to 10Kp.
The width has been reduced to 7cm''g, reducing the cost of the ice chamber and cooling pipe.

The seventh point is the removal of the aforementioned water hammer Poran 7-yal.

The above-mentioned operating costs and facility costs) will result in a total cost reduction of 200 to 300 million yen.

[Brief explanation of drawings]

Figure 1 is a schematic system diagram of the steam, condensate, and water supply systems in a nuclear power plant, Figure 2 is a diagram showing the relative installation levels of equipment in the condensate system, and Figure 3 is a diagram of the conventional air extractor and grand steam condenser. 4 is a conceptual characteristic diagram of FIG. 3, FIG. 5 is a structural diagram of a gland steam condenser to which the present invention is applied, FIG. 6 is a conceptual characteristic diagram of FIG. 5, and FIG. 7 is a conceptual diagram of characteristics of FIG. FIG. 2 is an auxiliary cooling water system diagram according to an embodiment of the present invention. 4... Condensate pump, 5... Condensate pipe, 6... Air extractor, 7... Grand steam condenser, 8... Condensate purification device, 12... Condensate recirculation Valve, 15... Cooling water pump, 17 4P Station zffl Furanile Fb■llt%ノ

Claims (1)

[Claims] 1. In a power generation plant, a cooling section of the air extractor that cools and condenses the driving steam of the steam air extractor, and a gland steam condensate that cools and condenses the gland steam discharged from the gland of the steam turbine. A cooling water system characterized in that auxiliary cooling water of a power generation plant is used as a cooling water source for a cooling part of a power generation plant.