JP2953729B2 - Steam injector system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention is particularly suitable for a water injection device for an emergency core cooling system such as a light water reactor by connecting a multistage steam injector for jetting high pressure water used for boiler water supply or the like. Steam injector system.

(Prior Art) A steam injector is used for supplying water to a steam locomotive or other boilers, and a steam injector having a configuration shown in FIG. 8 is conventionally known.

That is, a steam ejection nozzle 4 with a needle valve 3 is provided in a casing 2 having a steam intake port 1, and a water suction port 5 is adjacent to the steam ejection nozzle 4. A steam / water mixing nozzle 6 and a pressurizing diffuser 7 are arranged downstream of the steam jet nozzle 4 and communicate with a discharge port 9 via a check valve 8. An overflow drain hole communicating with an overflow drain pipe 11 is provided in the throat portion 10 of the steam / water mixing nozzle 6.
12 are open. For example, when the needle valve 3 is pulled out from the steam ejection nozzle 4 by the handle 13 and the steam supplied from the steam inlet 1 is ejected from the steam ejection nozzle 4, the low-temperature water (70 ° C. or lower) sucked from the water suction port 5 causes The steam flows into the steam / water mixing nozzle 6 while being condensed, and forms a high-speed water flow in the throat section 10. That is, since the entapil ηg of the steam is higher than the entapil η1 of the saturated water by the latent heat of vaporization, the latent heat of vaporization is converted into kinetic energy to form a high-speed water flow. When this high-speed water stream flows through the inside of the pressure increasing diffuser 7, the pressure is increased by the pressure Δp represented by the following equation according to the law of fluid dynamics.

Δp = 1/2 · ρW · U t2 ...... (1) by (ρW:: density of water, U _t fast flow speed of the water flow passing through the throat) which, the higher discharge pressure than the supply pressure of the steam in the steam injector When the pressure on the outlet side of the pressure increasing diffuser 7 that can be obtained becomes sufficiently high, the check valve 8 is automatically opened, and pressurized water is ejected from the discharge port 9. However, according to the steam injector having the conventional configuration described above, only a discharge pressure of at most 7 kg / cm ² G can be obtained. This is low enough to be used in steam locomotive boilers. The reason why such a limit point occurs is considered to be that the cross-sectional shape of the steam ejection nozzle 4 only gradually decreases in diameter toward the tip. That is, as is apparent from the hydrodynamics, with such a nozzle shape, a sufficient steam ejection speed cannot be obtained because the condensation speed in the steam / water mixing nozzle is low. By the way, for example, the pressure in a boiling water reactor pressure vessel in an emergency is set at 70 kg / cm ² G. It is difficult to apply a conventional steam injector as a water injection device for an emergency core cooling system that jets cooling water under such high pressure. Therefore, various studies have been conducted on increasing the discharge pressure as a steam injector for a reactor emergency cooling system, and an example of the configuration is shown in FIG.

The steam injector has a configuration substantially the same as that described above, except that the steam jet nozzle 4 has a diffuser shape whose diameter gradually increases, so that a supersonic speed of the steam flow can be obtained.

A main nozzle 14 is provided next to the steam / water mixing nozzle 6, and an overflow drain 12 is formed on the upstream side of the throat portion 10.

(Problems to be Solved by the Invention) According to the injector configured as described above, the discharge pressure (about 40 kg / cm ²⁾ is about six times that of the steam injector shown in FIG.
G) can be obtained. However, in the steam injector of FIG. 9, the cross section of the flow path from the inlet of the steam / water mixing nozzle 6 to the throat section 10 is formed in a conical shape, and the overflow drain hole 12 is formed at the inlet of the main nozzle 14 Since it is formed over the entire circumferential direction of the throat portion 10, the pressure loss due to the separation of the flow is relatively large, the discharge pressure is relatively large, and the discharge pressure does not become sufficiently high. Therefore, it is difficult to obtain a discharge pressure of 70 kg / cm ² G with a conventional injector. In addition, the pressure in the reactor pressure vessel temporarily drops due to water injection from the core cooling system in an emergency, and eventually reaches the atmospheric pressure, but a steam injector that can adjust the discharge steam pressure in response to such changes Has a problem that cannot be realized by the conventional one-stage system.

In the conventional steam injector, the discharge pressure is relatively low and the working steam pressure is also limited, so that there is a problem that is difficult to apply to an emergency core cooling system or the like of a nuclear reactor.

The present invention has been made to solve the above problems,
It is an object of the present invention to provide a steam injector system capable of jetting discharge water having a sufficiently high pressure applicable as a water injection device for an emergency core cooling system of a nuclear reactor and having a wide operating range.

[Configuration of the invention]

(Means for Solving the Problems) The present invention relates to a steam injector system in which a second-stage steam injector is connected to a first-stage steam injector, wherein the first-stage steam injector and the second-stage steam injector are provided. The steam injector comprises a water nozzle communicating with a water supply port, and a steam / water mixing nozzle communicating with a steam discharge port and mixing steam introduced from around the water nozzle with water. The water supply port of the second stage steam injector is connected to the discharge port of the steam injector,
A water supply port of the stage steam injector is connected to a water container, and a steam supply valve is connected to each of the first stage steam injector and the second stage steam injector, and the steam supply valve is connected to a steam source. It is characterized by being connected.

(Operation) The discharge side of the first-stage steam injector is connected to the water supply port of the second-stage steam injector, and a safety valve is attached to the overflow drain from the second stage.

In addition, a plurality of steam injectors are integrated and downsized, and the position of the internal nozzle is driven by external power.

In the present invention, based on the concept of a conventional injector,
Since it is difficult to simply operate water equivalent to atmospheric pressure with 7 Mpa steam, the pressure of water equivalent to atmospheric pressure is increased by the first-stage steam injector and supplied to the second-stage steam injector to reduce the pressure from atmospheric pressure to 7 MPa. A wide range of steam can be supplied and operated, and a high discharge pressure exceeding 7 MPa can be easily obtained.

Further, by driving the position of the internal nozzle with external power, it is possible to secure an optimum nozzle position when the steam injector is operated.

(Embodiment) An embodiment of the present invention will be described with reference to FIG. 1 and FIG.

As a configuration example of the multistage steam injector system, an example in which two steam injectors are connected in series will be described. That is, the water supply valve 101 is connected to the water supply port 103 of the first-stage steam injector 102 via the water supply valve 101, and the first-stage discharge port
A second-stage discharge port 107 is provided below the second-stage steam injector 106 that leads from the 104 to the second-stage water supply port 105. A pressure reducing valve 110 and a first-stage steam supply valve 111 are connected from a steam source, for example, a boiler 108 to a first-stage steam supply port 109, and a second-stage steam supply port 112 is connected to the second-stage steam supply port 112 from the boiler 108. The steam supply valve 113 is connected. Further, a check valve 115 is provided at the overflow drain port 114 of the first stage, and a safety valve 117 is provided at the overflow drain port 116 of the second stage.

Next, the operation of the present embodiment will be described. Water container 100
Supplies water to the first-stage steam injector 102 through the first-stage water supply port 103. Subsequently, steam is supplied from the boiler 108 to the first-stage steam injector 102 via the pressure reducing valve 110. When the first stage steam injector 102 operates,
From the first-stage discharge port 104 through the second-stage water supply port 105, the second
Water is supplied to the stage steam injectors 106. continue,
The steam is supplied from the boiler 108 and the second stage steam injector 1
When 06 operates, high-pressure water is discharged from the second-stage discharge port 107.

FIG. 2 shows the water supply pressure, the steam supply pressure, and the discharge pressure of each stage in the steam injector system having the above configuration in relation to time.

As time passes, the pressure of the second stage becomes higher than that of the first stage.

FIGS. 3 and 4 show an example in which the multistage steam injector system according to the above-described embodiment is applied to an emergency cooling system of a next-generation nuclear reactor which places particular emphasis on safety. This will be described below.

The main steam pipe 119 connected to the reactor pressure vessel 118
A pressure reducing valve 110 and a first-stage steam supply valve 111 are connected to a steam supply port 109 of the first-stage injector 102 and connected to the first-stage steam injector 102. On the other hand, in the same manner, it branches off from the main steam pipe 119 and connects to the steam supply port 112 of the second stage steam injector 106. A second-stage steam supply valve 113 is connected to the steam supply port 112. Pool water 1
20 through a water supply valve 101, the first stage steam injector 1
02 is connected to the water supply port 103. One from the first stage discharge port 104 to the reactor pressure vessel 118 via the first stage water injection valve 121,
The other is connected to the water supply port 105 of the second stage steam injector 106 via the second stage water supply valve 122. 2nd stage outlet
107 is connected to a reactor pressure vessel 118 via a second-stage water injection valve 123.

A check valve 115 is provided at the first stage overflow drain 114,
A safety valve 117 is connected to the overflow drain 116 of the second stage.

In the above configuration, if a primary coolant loss accident occurs in the nuclear reactor, the first stage steam injector 102 and then the second stage steam injector 106 operate immediately, and the pressure becomes close to 7 Mpa. Water can be injected into the reactor pressure vessel 118 immediately after the reactor accident. Also, when the pressure in the reactor pressure vessel 118 decreases with time and the second-stage steam injector 106 stops, the valve is automatically switched by the signal of the reactor pressure gauge 124, and the first-stage steam Water is injected into the reactor pressure vessel 118 by the injector 102. As described above, the integrity of the reactor can be ensured by the steam injector system that can cope with the pressure change of the reactor pressure vessel 118 at the time of the accident that drops from 7 MPa to the vicinity of the atmospheric pressure.

FIG. 4 shows the relationship between steam supply pressure, discharge pressure, reactor pressure and time in the operating range of the first and second stage steam injectors shown in FIG.

Next, a second embodiment of the present invention will be described with reference to FIG. This embodiment is an example of a steam injector system in which a plurality of steam injectors are integrated and reduced in size.

In FIG. 5, reference numeral 125 denotes a water supply port,
Below the 26, the first steam / water mixing nozzle 127, the first throat 12
8, an intermediate nozzle 131 including the first overflow hole 129 and the first diffuser 130 is disposed, and a second water nozzle 132 is connected below the intermediate nozzle 131. The second water nozzle 132
Downstream of the second steam / water mixing nozzle 133 and the second throat 13
4, a lower nozzle 137 including the second overflow hole 135 and the second diffuser 136 is disposed, and is guided to the discharge port 138 via the lower nozzle 137. Subsequently, a first steam port 139 and a second steam port 140 for taking in steam into the inside, and a first overflow drain port 141 and a second overflow port 135 for guiding the fluid discharged from the first overflow hole 129 to the outside are discharged. Second overflow drain 14 that guides fluid to the outside
Two are provided. Further, a nozzle rotating gear 143 and a worm gear 144 are attached to the first nozzle 126 and the lower nozzle 137, and a shaft 145 is attached to the tip of the worm gear 144.
Is attached.

In the drawing, reference numeral 154 denotes a first casing, and 155 denotes a second casing.
FIG. In the first casing 154, a first water nozzle 126 is supported via a first support member 156.

The water supply port 125 and the first casing 154 are connected by a flange 157.

A second support member 158 is provided at the lowermost portion of the second casing 155, and a discharge port 138 is formed through the second support member 158.

The second casing 155 and the second support member 158 are flanged.
Connected at 159.

Next, the operation of the present embodiment will be described. First, water is supplied from the water supply port 125 into the first steam / water mixing nozzle 127 via the first water nozzle 126, and subsequently, when steam is supplied from the first steam port 139, the water accelerated by the steam is supplied to the first steam / water mixing nozzle 127. The pressure is increased by one diffuser 130 and supplied to a second steam / water mixing nozzle 133 via a second water nozzle 132. Subsequently, when steam is supplied from the second steam port 140, the water is accelerated again by the steam,
The pressure is increased by the diffuser 136 and released through the discharge port 138. Here, the steam pressure supplied at the first steam port 139 and the second steam 140 are different steam pressures, and the steam pressure supplied at the second steam port 140 is higher than the steam pressure supplied at the first steam port 139. There must be. The nozzle drive mechanism shown in FIG. 6 (a) transmits the rotational force of the external power device 146 of the steam injector (a motor is used in the figure) to the worm gear 144 via the shaft 145 to rotate the nozzle rotary gear 143. As a result, the screw above the first water nozzle 126 turns, and the vertical movement of the first water nozzle 126 is obtained. In this manner, the flow rate of the steam 147 flowing from the first steam port 139 to the first steam / water mixing nozzle 127 is adjusted, so that an optimum nozzle position required when the steam injector is operated is obtained. . In FIG. 6 (b), similarly to FIG. 6 (a), the lower nozzle 137 moves up and down to cover the second water nozzle 132, and the second steam / water is mixed from the second steam port 140. Nozzle 1
The mechanism is such that the amount of steam 147 flowing into 33 is adjusted to obtain an optimal nozzle position required when the second stage steam injector is operated.

FIG. 7 shows an example in which a multistage integrated steam injector system according to the second embodiment is applied to reactor water supply, which will be described below.

Turbine from reactor pressure vessel 118 via main steam line 119
Directs steam to 148, downstream in turbine 148 (low pressure section)
1st stage steam supply valve 1 from low pressure steam pipe 149 taken out
11 and is connected to the first steam port 139 of the multistage integrated steam injector 150. A high-pressure steam pipe 151 taken out from the upstream side (high-pressure section) in the turbine 148 is connected to a second steam port 140 via a second-stage steam supply valve 113. Turbine 148
From the condensate pool 152 through the water supply valve 101 to the water supply port 125
Connect to A discharge port 138 of the multistage integrated steam injector 150 is connected to the reactor pressure vessel 118 via a water injection valve 153.

In the above configuration, the steam that has completed the work in the turbine 148 condenses and accumulates in the condensate pool 152. Water supply valve 1
The fuel is supplied to the multi-stage integrated steam injector 150 via 01. Subsequently, the low-pressure steam in the turbine 148 is supplied to the multi-stage integrated steam injector 150 via the first-stage steam supply valve 111, and the high-pressure steam is supplied to the multi-stage integrated steam injector 150 via the second-stage steam supply valve 113. Supply to the steam injector 150. By supplying water and steam to the multi-stage integrated steam injector 150, the steam injector operates and water can be supplied to the reactor pressure vessel 118.

 The embodiments of the present invention are as follows.

(1) In a steam injector that can obtain discharge water at a pressure higher than the supplied steam pressure by utilizing the condensation and development of steam, a plurality of steam injectors are connected in series to have a wide operating range and high discharge. Pressure is obtained.

(2) A check valve is provided in the first stage overflow drain section, and a safety valve is provided in the second and subsequent overflow drain sections.

(3) The feature is that the functions of a plurality of steam injector systems are integrated into a single unit and downsized.

(4) The activation of the steam injector system is characterized in that it is operated sequentially from the first stage.

(5) In the case of a multi-stage steam injector system, a relief pipe is provided in the discharge pipe, the pump is operated until the required number of pressures is obtained, and the operation of the remaining steam injectors is stopped.

(6) In the case of the multistage steam injector system, the same number of overflow drains as the supply steam ports is provided.

(7) In the case of a multi-stage steam injector system, the internal nozzle position is driven by external power.

〔The invention's effect〕

According to the present invention, a steam injector system having a high discharge pressure and a wide operating range can be provided by using a plurality of steam injectors having different pressure specifications.

In addition, by integrating them into an integral type, the size can be reduced, and a nozzle drive mechanism can be incorporated to easily secure an optimum nozzle position required when the steam injector is operated, and a high discharge pressure can be obtained.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a first embodiment of a multi-stage steam injector according to the present invention, FIG. 2 is a characteristic diagram showing pressure during operation of the multi-stage steam injector in FIG. 1, and FIG. FIG. 4 is a system diagram showing an example in which the multistage steam injector according to the first embodiment is applied to an emergency core cooling system of a next-generation reactor, FIG. 4 is a characteristic diagram showing pressure during operation in FIG. 3, and FIG. 6 is a cross-sectional view showing a multistage integrated steam injector according to a second embodiment of the present invention, and FIG. 6 (a) is a cross-sectional view showing a driving mechanism of a first water nozzle of the multistage integrated injector in FIG. FIG. 6 (b) is a cross-sectional view showing a driving mechanism of a lower nozzle of the multi-stage integrated steam injector in FIG. 5, and FIG. 7 is an atomized multi-stage integrated injector showing a second embodiment of the present invention. System diagram showing an example of using as a furnace water supply system, Figure 8 and Figure 9 is a sectional view showing a conventional injector, respectively. 100: water container, 101: water supply valve, 102: first-stage steam injector, 103: water supply port, 104: first-stage discharge port, 105: second-stage water supply port , 106 steam supply port, 107 second stage discharge port, 108 boiler, 109 first stage steam supply port, 110 pressure reducing valve, 111 first stage steam supply valve 112 second stage steam supply port 113 second stage steam supply valve 114 first stage overflow drain 115 115 check valve 116 second stage overflow drain Mouth, 117… Safety valve, 118… Reactor pressure vessel, 119 …… Main steam piping, 120… Pool, 121 …… First stage water injection valve, 122 …… Second stage water supply valve, 123 …… Second-stage injection valve, 124 Pressure gauge, 125 Water supply port, 126 First water nozzle, 127 First steam / water mixing nozzle, 128 First throat, 129 Second 1 overflow hole, 130 ... 1st diffuser, 131 … Intermediate nozzle, 132… Second water nozzle, 133… Second steam / water mixing nozzle, 134… Second throat, 135… Second overflow hole, 136… Second diffuser, 137… Lower part Nozzle, 138 discharge outlet, 139 first steam port, 140 second steam port, 141 first overflow drain port, 142 second overflow drain port, 143 nozzle rotating gear, 144 …… worm gear, 145… shaft, 146 …… external power mechanism, 147 …… steam, 148 …… turbine, 149 …… low-pressure steam pipe, 150 …… multi-stage integrated injector, 151 …… high-pressure steam pipe, 152 condensing pool, 153 injection valve, 154 first casing, 155 second casing, 156 first support member, 157, 159 flange, 158 second Support members

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tonegawa ▲ Rei ▼ 1-1-1, Shibaura, Minato-ku, Tokyo Inside Toshiba head office (56) References JP-A-53-1311 (JP, A) Patent 69553 (JP, C2) (58) Fields investigated (Int. Cl. ⁶ , DB name) F04F 5/26 F04F 5/54

Claims (1)

(57) [Claims] 1. A steam injector system comprising a first-stage steam injector and a second-stage steam injector connected to each other, wherein the first-stage steam injector and the second-stage steam injector are provided with a water supply port. And a steam / water mixing nozzle which communicates with a steam outlet and mixes steam introduced from around the water nozzle with water, and the first stage steam injector has Connecting the water supply port of the second stage steam injector, connecting the water supply port of the first stage steam injector to a water container,
Connecting a steam supply valve to each of the steam supply ports of the first-stage steam injector and the second-stage steam injector;
A steam injector system comprising the steam supply valve connected to a steam source.