JPH0514995U - Spray nozzle of pressurizer for reactor - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to provide a spray nozzle for a reactor pressurizer that can prevent vapor from entering from the inside of the pressurizer even when the flow rate of the spray water becomes minute. Therefore, the spray nozzle according to the present invention is provided with a plurality of through holes () so as to block the spray water inlet (11) and the spray water injection port (12) of the nozzle body (13). 16)
In order to guide the spray water from the spray water inlet to the spray water injection port, a water guide pipe (17) is attached to each through hole of the partition plate, and the spray water flowing in each water pipe is attached. A variable ball (19) is provided in each conduit so that the outlet (18) of the conduit is substantially closed when the flow is less than a certain amount, and the outlet of the conduit is opened when the spray water is more than a certain amount. ) Is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a pressurizer used in a pressurized water nuclear reactor, and more particularly to a structure of a spray nozzle of the pressurizer.

[0002]

[Prior Art]

 The cooling system of a pressurized water reactor has the function of circulating the primary coolant heated in the core, exchanging heat with the steam generator, and generating high-temperature high-pressure steam that drives the turbine. In order to keep the pressure of the primary coolant flowing through such a cooling system constant, a pressurizer is connected to the coolant pipe connecting the reactor and the steam generator.

As shown in FIG. 4, a conventional general pressurizer 1 has a substantially cylindrical shape, and a lower portion thereof is connected to a cooling pipe (not shown) by a surge pipe 2. A spray nozzle 3 is attached to the upper part of the pressurizer 1, and the spray nozzle 3 is connected to a spray pipe 4 of a spray system. The spray pipe 4 is equipped with a spray valve 5. The spray valve 5 is closed when the pressure inside the pressurizer 1 is stable within a predetermined range, and when the pressure inside the pressurizer 1 rises. , Open to supply the spray water into the pressurizer 1.

By the way, for the purpose of preventing supercooling of the spray pipe 4 due to heat dissipation, a bypass line 6 is provided in the spray valve 5, and when the spray valve 5 is in a closed state, a small amount of spray water is passed through the bypass pipe. 4 is flowing. However, in the conventional spray nozzle 3, when the flow rate of the spray water is very small, such as from the bypass line 6 when the spray valve is closed, the steam flows back through the spray nozzle 3 and the horizontal portion 4 of the spray pipe 4 As shown in FIG. 5, the thermal stratification phenomenon may occur in which the upper part of the horizontal portion 4'is steam 7 and the lower part is water 8 as shown in FIG. As a result, when the spray valve 5 is repeatedly opened and closed, the above-described thermal stratification phenomenon frequently occurs and disappears, which may cause severe fatigue evaluation. The invasion of steam, which is a cause of such a thermal stratification phenomenon, has the structure of the conventional spray nozzle 3 as shown in FIG. It results from the vapor rising through the space in 3.

[0005]

[Problems to be solved by the device]

 Therefore, the problem to be solved by the present invention is to prevent steam from entering the horizontal portion of the spray pipe through the spray nozzle from the pressurizer even when the flow rate of the spray water becomes minute.

[0006]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention has a nozzle body attached to the upper part of a pressurizer, and is arranged in the nozzle body so as to block the spray water intake port and the spray water injection port of the nozzle body. A partition plate with multiple through holes, a water guide pipe attached to each through hole of the partition plate to guide the spray water from the spray water inlet to the spray water injection port, and the spray water flowing in each water pipe is constant. When the flow rate is less than or equal to that of the water pipe, the outlet of the water pipe is substantially closed with a predetermined gap, and when the flow rate of the spray water is more than a certain amount, the water outlet of the water pipe is opened. And a variable ball and a spray nozzle.

[0007]

[Action]

 In the above configuration, when the spray water has a small flow rate, the variable ball substantially closes the outlet of the conduit, so that the steam in the pressurizer passes through the conduit of the spray nozzle and enters the spray pipe. There is no.

[0008]

【Example】

 Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS.

As shown in FIG. 1, a spray nozzle 10 according to the present invention includes a nozzle body 13 having a spray water inlet 11 at an upper part and a spray water injection port 12 at a lower part. The spray water inlet 11 has a threaded portion 14, which is screwed onto the upper part of the pressurizer and is connected to the spray pipe of the spray system (see FIG. 4).

A partition plate 15 is installed inside the nozzle body 13 so as to block the spray water intake 11 and the spray water injection port 12. A plurality of through holes 16 are formed in this partition plate 15, and a substantially L-shaped water conduit 17 is fitted in each through hole 16.

As shown in FIGS. 2 and 3, the water conduit 17 has an open upper end connected to the partition plate 15, and a spray water outlet 18 is formed on the lower surface side of the substantially horizontal portion. Therefore, the spray water that has flowed into the spray water inlet 11 of the nozzle body 13 is guided from the upper end of the water guide pipe 17 to the spray water jet port 12 through the outlet 18.

Further, the variable ball 19 is arranged inside the water conduit 17, and when the flow rate of the spray water flowing through the water conduit 17 is large, the variable ball 19 is used as the spray water as shown in FIG. By the pressing force, the water guide pipe 17 is pushed toward the tip of the substantially horizontal portion, and the outlet 18 is opened. On the other hand, when the flow rate of the spray water is very small, the front end of the water conduit 17 is bent slightly upward, so that the variable ball 19 is held at the position where it blocks the outlet 18 by its own weight ( (See FIG. 3). In this closed state, the outlet 18 of the water conduit 17 is not completely closed, and a gap is formed to the extent that only a small amount of spray water can flow. In the figure, reference numeral 20 is a stopper, which prevents the variable ball 19 from moving beyond the outlet 18 to the vertical portion side of the water conduit 17.

When the spray nozzle 10 having such a configuration is used in the pressurizer for the pressurized water reactor described above, the spray valve 5 of the spray pipe 4 will be described with reference to FIG. When the spray water is closed and a small amount of spray water is supplied to the spray nozzle 10 through the bypass line 6, the spray water is guided from the spray water inlet 11 of the nozzle body 13 to each water pipe 17. In this state, the outlet 18 of the water conduit 17 is substantially closed by the variable ball 19, so that the fine spray water passes through the gap between the outlet 18 and the variable ball 19 and sprays the spray water of the nozzle body 13. Although flowing through the mouth 12, the steam inside the pressurizer 1 does not enter the water conduit 17 through the gap. Therefore, the spray system is always kept in the vicinity of the liquid temperature of the spray water flowing through the bypass line 6, and the supercooling of the bypass pipe 4 is prevented.

On the other hand, when the internal pressure of the pressurizer 1 rises, the spray valve 5 is opened, and the spray water exceeds a certain flow rate, as described above, the variable ball 19 in the water conduit 17 is pushed, The outlet 18 is opened. Therefore, since the spray water flows at a large flow rate through the water conduit 17 with a small pressure loss, the descending force of the fluid suppresses the rise of the steam, and in this case also, the steam enters the spray pipe 4 from the water conduit 17. Prevent. Therefore, a spray effect equivalent to that of a conventional spray nozzle can be obtained.

[0015]

[Effect of the device]

 As described above, the spray nozzle according to the present invention can block the inflow path of steam by the variable ball when the flow rate of the spray water is very small. Therefore, steam does not enter the spray pipe, helps prevent the thermal stratification phenomenon of the spray pipe, and further improves the reliability of the equipment.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a spray nozzle according to the present invention.

FIG. 2 is a cross-sectional view showing in detail the structure of a water conduit in the spray nozzle of FIG. 1, showing a state when the spray water has a large flow rate.

FIG. 3 is a cross-sectional view showing in detail the configuration of a water conduit in the spray nozzle of FIG. 1, showing a state when the spray water has a minute flow rate.

FIG. 4 is a schematic diagram showing a conventional general pressurizer and spray system.

FIG. 5 is a schematic diagram showing a thermal stratification phenomenon occurring in a spray pipe.

FIG. 6 is a cross-sectional view showing a conventional general spray nozzle.

[Explanation of symbols]

 10 spray nozzle 11 spray water inlet 12 spray water injection nozzle 13 nozzle body 15 partition plate 16 through hole 17 water conduit 18 outlet 19 variable ball

Claims (1)

[Scope of utility model registration request] 1. A nozzle body attached to an upper part of a reactor pressurizer, and a plurality of penetrating holes arranged in the nozzle body so as to block a spray water intake port and a spray water injection port of the nozzle body. A partition plate having a hole, a water guide pipe attached to each of the through holes of the partition plate to guide spray water from the spray water inlet to the spray water injection port, and a spray flowing in each water pipe. When the water is below a certain flow rate, the outlet of the water guide pipe is substantially closed with a predetermined gap left, and when the spray water is above a certain flow rate, the outlet is opened. A spray nozzle of a pressurizer for a nuclear reactor, which is provided with a variable ball provided.