JPH10186079A - Steam separator and steam separator - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce carryover of a coolant-liquid two-phase flow in a steam-water separator and enhance separation performance. Further, the structure of the steam separator is simplified. A set of outlet diameter d ₃ of the gas-liquid two-phase flow of the standpipe 11 through the gas-liquid two-phase flow smaller than the inlet side diameter d _2. The gas-liquid two-phase flow is swirled by the reduced pipe structure. d ₃ = d _2/2 and particularly remarkable effect when the can be obtained. In addition, the stand pipe 11 and the swivel cylinder 4a immediately above the stand pipe 11 are integrally formed, a torsion plate is inscribed in the stand pipe as swivel means, and a riblet is provided on the inner wall surface of the swivel pipe 3a. There is a method in which a fin (small fin) is provided above the nozzle, and the outlet side diameter of the revolving cylinder 3a is set smaller than the diameter of the stand pipe 11. In addition, the number of steam-water separation stages is reduced and the steam-dryer is integrated with the steam dryer, resulting in a simpler structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam / water separator for separating a gas-liquid two-phase flow into a liquid and a gas, and to a steam / water separator having the steam / water separator as a component, and more particularly to a boiling water type. The present invention relates to a steam-water separator and a steam-water separator for separating a gas-liquid two-phase flow of a coolant from a reactor core into water and steam.

[0002]

2. Description of the Related Art A general boiling water reactor has a core loaded with a large number of fuel assemblies in a reactor pressure vessel, and a two-phase gas-liquid two-phase coolant from the core is provided above the core. A plurality of steam-water separators for separating a stream into water and steam, and a plurality of steam dryers above the steam-water separator for further drying the steam from which water has been removed and sending the steam to a turbine are provided.

FIG. 31 shows an improved boiling water reactor (ABWR).
It is a sectional system diagram showing an outline of. A reactor core 102 having a large number of fuel assemblies is disposed slightly below the center of the reactor pressure vessel 101. A number of control rod guide tubes 103 are provided below the core 102, and the upper end opening of a shroud 104 forming the core 102 is closed by a shroud head 105. The stand pipe 1 of the steam separator 91 is erected on the shroud head 105, and a rectangular flat steam dryer 100 is arranged on the steam separator 91.

A control rod driving mechanism 106 is provided below the reactor pressure vessel 101 to drive a cross-shaped control rod in the reactor core 102 using the inner surface of the control rod guide tube 103 as a guide. At the bottom between the inside of the reactor pressure vessel 101 and the outside of the shroud 104, a plurality of internal pumps 107 are installed.

[0005] The core 102 has a plurality of fuel assemblies, the lower part of which is supported by a core indicator plate 108 and the upper part thereof which is supported by an upper lattice plate 109, and the whole is surrounded by a shroud 104. At the bottom between the inside of the reactor pressure vessel 101 and the outside of the shroud 104, a main steam pipe 110 for sending steam dried by the steam dryer 100 to the turbine is connected. The coolant flowing into the reactor pressure vessel 1 through the water supply pipe 111 is forcibly circulated by the internal pump 107.

Next, the steam separator will be described with reference to FIGS. FIG. 32 is a longitudinal sectional view of a general steam separator, FIG. 33 is a diagram schematically showing a gas-liquid two-phase flow of a coolant in the steam separator shown in FIG. 32, and FIG. AA in
FIG. 35 is an enlarged cross-sectional view of the swirling blade of the steam separator, as viewed in the direction of the arrow.

As shown in FIG. 32, a steam-water separator 91 is located just above a reactor core and is a standpipe 1 (both a riser pipe and a riser pipe) through which a gas-liquid two-phase flow of coolant and voids from the reactor core flows upward. The swirl vanes 2 provided above the stand pipe 1 and serving as swirling means for applying a swirling action to the gas-liquid two-phase flow.
And a water / water separation stage 3a, 3b, 3c, which is provided above the swirl vane 2 and is provided as a water / water separation means for performing gas / water separation of a gas-liquid two-phase flow, and which is normally connected in three stages in the axial direction. Become. As shown in FIG. 35, the swirling blade 2 has a plurality of, for example, eight spiral inclined blades 2b around an inverted conical center hub 2a. In addition, steam-water separation stage 3
a, 3b, 3c are the turning cylinders 4a, 4b, 4c, respectively.
And outer cylinders 5a, 5b, 5c located outside of the turning cylinders 4a, 4b, 4c, and outer cylinders connected to the outer cylinders 5a, 5b, 5c so as to be positioned inside the turning cylinders 4a, 4b, 4c. Hook-shaped pickoff rings 6a, 6b, 6c formed
(Also referred to as a catch ring).
The key-shaped pick-off rings 6a, 6b, 6c capture the liquid film of the coolant formed on the inner wall surfaces of the swirling cylinders 4a, 4b, 4c, and the swirling cylinders 4a, 4b, 4c and the outer cylinders 5a, 5b,
5c can be reliably led to the gap. In general, the lower the water / water separation stage 3a, 3b, 3c is, the longer the turning cylinder and the outer cylinder are designed in the axial direction, but the pick-off rings 6a, 6b, 6c have substantially the same length. is there.

In FIG. 32, the length x of the pickoff ring 6a in the lowermost water / water separation stage 3a of the current water / water separator 91 is about 1/20 of the length L of the revolving cylinder 4a. Designed. Turning cylinder 4a in each steam separator stage, 4b, the inner diameter of the 4c is set substantially the same length d _1, and the turning cylinder inner diameter d ₁ is larger than the inner diameter d ₂ of the standpipe 1.

Next, the operation of the steam separator 91 will be described. In a boiling water reactor, the coolant is boiled by the heat of the fission reaction, and usually becomes a gas-liquid two-phase flow of a mixture of water and gas in an upper plenum (not shown) provided above the core. And mixed well. The mixed gas-liquid two-phase flow is distributed to a plurality of steam separators arranged in the reactor pressure vessel, and rises in the stand pipe 1. Figure 33
As shown in FIG. 34, the coolant in the stand pipe 1 is in a flow state called an annular flow. That is, the inner wall surface of the stand pipe 1 is covered with a liquid film, and the inside of the liquid film has a flow in which droplets and vapor bubbles 95 are mixed.

The gas-liquid two-phase flow of water and steam that has risen on the stand pipe 1 is forcibly given a centrifugal force by the rotation of the swirling blade 2 immediately above the stand pipe 1, and is schematically shown by an arrow in FIG. As shown, a swirling flow occurs. At this time, under the normal operating pressure of the boiling water reactor, the gas-liquid density ratio of the coolant is approximately 1:21. There is a significant difference in centrifugal force.

Therefore, as shown in FIGS. 33 and 34, the low-density vapor is located at the center of the lowermost steam-water separation stage 3a, and the high-density liquid is the swirl tube of the steam-water separation stage 3a. A liquid film 94 is formed along the inner wall surface of 4a, and rises while turning together. Water drops 92 and steam 93 are mixed in the vicinity of the axis of the turning cylinder 4a.

The liquid film 94 is captured by the pick-off ring 6a located above the water / water separation stage 3a, passes through the gap between the swirl cylinder 4a and the outer cylinder 5b, passes through the break-down ring 9 as an orifice, and moves to the upper part of the core. It is discharged to the located downcomer part (not shown). On the other hand, most of the liquid phase not captured in the lowermost water / water separation stage 3a is captured by the pickoff rings 6b, 6c in the upper water / water separation stages 3b, 3c.

It is to be noted that about 90% of the moisture removed from the steam passing through the steam separator 91 by the steam separator 91 is designed to be removed in the lower steam separator stage 3a. ing. At the outlet of the gas-water separator 91, the mass fraction of water in the gas-liquid two-phase flow is designed to be suppressed to 10% or less.

The steam that has passed through the uppermost water / water separation stage 3c of the water / water separator 91 has a low moisture content due to the above-described operation, but is installed above the water / water separator 91. The steam is then guided to the steam dryer 100 to further remove moisture. The steam separator 91 is usually configured as a group of 200 to 300 vertical tubes, which are welded to the shroud head and suspended integrally, whereas the steam generator integrally stores a large number of corrugated groups. doing.

Next, the steam dryer will be described with reference to FIG. FIG. 36 (a) is a partially cutaway view of a general steam dryer, and FIG. 36 (b) is an enlarged top view of the corrugated plate in FIG. 36 (a).

The conventional steam dryer 100 has a plurality of units in which a corrugated plate 96 having a vertical length of less than 2 meters is vertically suspended. The corrugated plate group 96 is covered on its side with a perforated plate 97. Also, as shown in FIG. 36 (b), one corrugated plate 96 usually has three ridges, and two corrugated plates 96a and 96b and two corrugated plates 96a and 96b And a plate 96c in contact therewith. Further, the plates 96a and 96b have a notch 96d, and the vicinity of the contact point between the plates 96a and 96b and the plate 96c.
e is shaped like a hook. A drain gutter 98 is provided below the corrugated sheet group, and the removed moisture is removed by a steam dryer 100.
A drain pipe 99 for discharging to the outside is provided.

Next, the operation of the steam dryer 100 will be described. The steam sent from the steam separator 91 is a low-moisture atomized steam containing fine droplets. The flow of the mist vapor is shown by a wavy arrow in FIG. First, the steam enters the corrugated plate group 96 from the holes of the perforated plate 97 and passes between the corrugated plates 96. However, at this time, the fine droplets in the mist vapor cannot follow the rapid change of the streamline of the corrugated plate 96 while passing through the corrugated plate 96, and the hook-shaped droplet provided on the corrugated plate 96 The water enters the capture portion 96e, flows down along the hook-shaped portion 96e, and flows into the downcomer portion (not shown) above the core through the drain gutter 98 and the drain pipe 99. Thus, steam dryer
The steam passing through 100 is further dehumidified and sent to the turbine through main steam pipe 110.

[0018]

In a boiling water reactor, steam from a reactor core is directly supplied to a turbine for power generation, but the mass fraction of water in the gas with respect to the steam is reduced to a certain value or less. That is, it is necessary to reduce carryover in the steam separator. However, actually, the swirl blade 2
32, the swirling force of the gas-liquid two-phase flow becomes weaker toward the upper part. Therefore, in the steam-water separation means of the steam-water separator 91 shown in FIG. The liquid film 94 is torn off by the flow, and a droplet 92 is generated. The droplets 92 generated here are mixed into the steam 93 flowing through the central portions of the swirling cylinders 4b and 4c, and are carried to the steam dryer 100 above the steam / water separator 91, so that carryover increases.

Further, as described above, most of the liquid phase of the coolant flowing into the steam separator 91 is removed in the lowermost steam separator stage 3a. That is, as schematically shown in FIG. 33, compared with the liquid film 94 of the lowermost water / water separation stage 3a, the upper water / water separation stages 3b, 3c
Since the liquid film 94 becomes very thin, the liquid removed in the water / water separation stages 3b and 3c is very small. However, since the steam-water separation stages 3b and 3c are required, the steam-water separator 91 has many components and accordingly, much time and labor are required for manufacture and inspection.
Also, since the structure of the revolving blade 2 is complicated because it has the central hub 2a, much time and labor are required for production and inspection.

The steam flowing through the center of the swirl cylinder of the steam separator 91 goes upward without being caught by the pickoff rings 6a, 6b, 6c. Forms a vortex at This vortex increases the pressure loss at the top of each steam separation stage.

Further, the frictional resistance due to the liquid film 94 generated on the inner wall surface of the swirl tube in each steam / water separation stage of the steam / water separator 91 is also a main factor of such an increase in pressure loss. Further, in the swirl vanes 2, since the flow area of the coolant decreases due to the presence of the center hub 2a, the pressure loss when the coolant passes through the swirl vanes 2 is large. In particular, at the upper portion of the center hub 2a, the flow of the gas-liquid two-phase flow flowing out of the swirl vanes 2 is disturbed, and a vortex is generated, thereby increasing the pressure loss. In fact, about 30% of the total pressure loss of the steam separator is caused by the swirl blade 2.

If such a pressure loss increases beyond an allowable range, it hinders the smooth delivery of steam from the reactor pressure vessel to the turbine. In particular, the load on the pump that circulates the coolant in the reactor becomes large, which is not suitable for the sound operation of the reactor. It is also conceivable that the circulation flow rate of the coolant due to natural convection fluctuates greatly.

In a conventional boiling water reactor,
It takes a lot of time to remove equipment during refueling.
In other words, when removing the equipment inside the reactor pressure vessel before replacing the fuel, it takes time and effort to go through the work process of first removing all steam dryers and then removing the shroud head and steam-water separator. It takes a lot.

Further, since the current lower part of the steam separator 91 to the upper part of the steam dryer 100 occupies a length of about 6 meters, the volume of the reactor pressure vessel 101 has to be increased accordingly. .

In order to solve the above problems, in the present invention, the liquid phase is efficiently removed from the gas-liquid two-phase flow passing through the gas / water separator, and the carryover generated due to the gas / water separation is reduced. The purpose is to do.

In the steam-water separator, by improving the structure of the swirl vane having a complicated structure and the structure of the three-stage steam-water separation stage, the steam-water separation performance can be maintained at a high level. An object of the present invention is to make the separator simpler.

In the steam-water separation stage of the steam-water separator, a new device is added to the inner wall surface of the swirl cylinder,
It is an object to reduce frictional resistance due to a liquid film generated on the inner wall surface and suppress pressure loss.

Further, by reviewing the structure of the conventional steam-water separator in which the steam-water separator and the steam dryer are independently configured, the steam-water separator can be maintained at a high performance while maintaining the high performance of the steam-water separation. Has a simpler structure.

[0029]

According to the present invention, there is provided a stand pipe for passing a gas-liquid two-phase flow from a reactor core, and a stand pipe positioned above the stand pipe for a gas-liquid two-phase flow. In a steam / water separator comprising a swirl tube for performing water / water separation and a steam / water separation stage comprising an outer tube located outside the swirl tube, the outlet diameter of the gas-liquid two-phase flow of the stand pipe is the inlet side Provided is a steam-water separator having a smaller diameter.

According to this configuration, the gas-liquid two-phase flow passes through the reduced pipe and receives a swirling action, whereby a high-density liquid forms a liquid film near the inner wall of the pipe, and gas-liquid is separated. Also, the diameter of the outlet side of this standpipe is about 1/2 of the diameter of the inlet side.
Set to. Thus, the gas-liquid two-phase flow has a steep velocity distribution in the pipe axis direction, thereby enhancing the gas-water separation effect.

Further, of the steam-water separation stage, the swiveling cylinder of the steam-water separation stage located at the lowest stage has an integral structure with the stand pipe, and the wall surface from the outlet side of the stand pipe to the inlet side of the swirling cylinder has a constricted structure. I do. As a result, the number of components is reduced, and the pressure loss is further reduced by making the side wall not a sharp angle but a streamline.

Further, according to the present invention, there is provided a stand pipe through which a gas-liquid two-phase flow from a reactor core is passed, and a swirl means positioned above the stand pipe for giving a swirling action to the gas-liquid two-phase flow,
In a steam-water separator comprising a swirl cylinder positioned above the swirl means and configured to perform gas-water two-phase flow gas-water separation, and a steam-water separation stage including an outer cylinder positioned outside the swirl cylinder,
The turning means is a twisted plate which is formed by twisting at least one of the upper and lower ends of a rectangular plate and is inscribed in a stand pipe. As a result, the pressure loss generated when the gas-liquid two-phase flow passes through the swirling means can be reduced as compared with the conventional swirling blade including the center hub and the inclined blade.

According to the present invention, there is provided a steam-water separator comprising a standpipe through which a gas-liquid two-phase flow from a reactor core passes and a swirl tube positioned above the standpipe. The outlet diameter of the two-phase flow is smaller than the inlet diameter, and a twisted plate formed by twisting at least one of the upper and lower ends of the rectangular plate as a turning means on the stand pipe and inscribed in the stand pipe is inscribed. A steam separator is provided. As a result, the gas-liquid two-phase flow passes through the swirl means when the gas-liquid two-phase flow passes through the swirling means as compared with the related art, while being swirled to separate gas and liquid. Pressure loss can be reduced.

Further, according to the present invention, there is provided a gas pipe comprising a stand pipe through which a gas-liquid two-phase flow from a reactor core is passed, and a swirling means positioned above the stand pipe to give a swirling action to the gas-liquid two-phase flow. In the water separator, the turning means is formed by twisting at least one of the left and right ends of the rectangular plate and joining both ends thereof, has a plurality of holes, and is a twisted plate inscribed in the stand pipe. A steam separator is provided.

According to this configuration, the pressure loss is reduced and the flow of the separated droplets in the gas-liquid two-phase flow is adjusted by the torsion-shaped plate as the turning means formed in the shape of a “Mobius loop”. Thereby, the gas-liquid separation performance can be further improved.

Further, by providing a guide path on the surface of the torsion plate to capture the gas-liquid two-phase liquid droplets, the liquid droplets are reliably guided to the gap between the stand pipe and the outer cylinder and discharged. To improve steam-water separation performance.

Further, according to the present invention, there is provided a stand pipe through which a gas-liquid two-phase flow from a reactor core is passed, and a swirl means positioned above the stand pipe for giving a swirling action to the gas-liquid two-phase flow,
In a steam-water separator comprising a swirl cylinder positioned above the swirl means and configured to perform gas-water two-phase flow gas-water separation, and a steam-water separation stage including an outer cylinder positioned outside the swirl cylinder,
A riblet formed by arranging a plurality of narrow grooves along the flow direction of the gas-liquid two-phase flow is formed on the inner wall surface of at least the lowermost steam-water separation stage of the stand pipe or the steam-water separation stage. A steam separator is provided. Thereby, the frictional resistance generated from the liquid film formed on the inner wall surface of the turning cylinder can be further reduced.

Further, the groove width and the groove depth of the riblet are determined using at least the flow velocity of the gas-liquid two-phase flow.
By employing the optimum riblet groove width determined in this way, it is possible to further reduce the frictional resistance due to the liquid film generated on the inner wall surface of the swirl cylinder.

Further, according to the present invention, there is provided a stand pipe through which a gas-liquid two-phase flow from a reactor core is passed, and a swirl means positioned above the stand pipe for giving a swirling action to the gas-liquid two-phase flow,
In a steam-water separator comprising a swirl cylinder positioned above the swirl means and configured to perform gas-water two-phase flow gas-water separation, and a steam-water separation stage including an outer cylinder positioned outside the swirl cylinder,
Provided is a steam separator which is provided with a fin above the turning means. This prevents the flow of the gas-liquid two-phase flow from being disturbed by the vortex that has conventionally occurred at the upper part of the swirling means, and reduces the pressure loss.

Further, according to the present invention, there is provided a stand pipe through which a gas-liquid two-phase flow from a reactor core is passed, and a swirl means positioned above the stand pipe for giving a swirling action to the gas-liquid two-phase flow,
In a steam-water separator comprising a swirl cylinder positioned above the swirl means and configured to perform gas-water two-phase flow gas-water separation, and a steam-water separation stage including an outer cylinder positioned outside the swirl cylinder,
Provided is a steam-water separator characterized in that the size of the inner diameter of the revolving cylinder of the steam-water separation stage located at the lowermost stage of the steam-water separation stage is substantially smaller than the size of the inside diameter of the stand pipe. When a gas-liquid two-phase flow flows through such a tapered reduction pipe, the gas-water separation performance is improved due to the swirling action.

Further, in the present invention, there is provided a stand pipe through which the gas-liquid two-phase flow from the reactor core passes, and a steam-water separation stage located above the stand pipe and performing the steam-water separation of the gas-liquid two-phase flow. In a steam / water separator comprising a steam / water separator and a steam dryer located above the steam / water separator and separating droplets contained in steam passing through the steam / water separator, the steam dryer is An inner cylinder provided integrally with the steam separator stage of the water separator and having a plurality of vertical slits on a side wall,
A steam-water separator is provided, which comprises an outer cylinder containing the inner cylinder. As a result, the number of components is reduced as compared with the conventional steam-water separation device, resulting in a simpler structure.

Further, in the steam dryer integrated with the steam-water separation stage, the space between the inner cylinder and the outer cylinder is partitioned into a plurality of sections, and each of these partitioned spaces has a plurality of corrugated plate members. Further, an upper lid having a hole for discharging steam is provided at the upper part of the outer cylinder. Thus, the structure of the water / water separator can be simplified while maintaining the performance of the water / water separation as high as before.

[0043]

Embodiments of the present invention will be described below with reference to the drawings. The same components as those in the above-described conventional technology are denoted by the same reference numerals, and detailed description thereof will be omitted. FIG. 1 is a longitudinal sectional view of the steam separator according to the first embodiment of the present invention. In the steam separator 21 according to the present embodiment, the swirl vanes 2 in the conventional steam separator 91 shown in FIG. 32 are deleted, and the diameter of the stand pipe 11 is set to be smaller as it goes upward. is there. In other words, the stand pipe 11 an outlet side diameter d ₃ of the gas-liquid two-phase flow is in the inlet side diameter d ₂ smaller destination tubules. Above the standpipe, a plurality of steam-water separation stages 3a, 3b, 3c are installed as in the conventional steam-water separator 91.

As described above, it is known that when a fluid is caused to flow through a reduced pipe having an outlet-side diameter smaller than an inlet-side diameter, the fluid is swirled by the tapered structure to form a swirling flow. . This is disclosed, for example, in Kiyoyuki Horii, "Spiral Flow and Its Applications", Turbomachinery, Vol. 22, No. 4, page 57. The swirling flow obtained in this way is called a spiral flow, which is a stable flow having a fast flow near the pipe axis in the axial direction and having a very small fluctuation of the flow with time. The technology using such reduced pipeline structure is
It is also used for transmitting optical cables to pipelines, and is of high value for industrial applications.

The operation of this embodiment will be described below.
The coolant rising from the reactor core becomes a gas-liquid two-phase flow under high temperature and high pressure, and flows into the steam separator 21 from the inlet of the stand pipe 11. Due to the reduced pipe structure of the stand pipe 11, this gas-liquid two-phase flow becomes a swirling flow having a fast flow near the pipe axis of the stand pipe 11. The gas-liquid two-phase flow is simultaneously centrifuged by the swirling action and sent from the stand pipe 11 to the swirling cylinder 4a of the steam-water separation stage 3a located immediately above the pipe. That is, a low-density vapor forms a liquid film near the axis of the swirl tube 4a where the high-speed flow is concentrated, and a high-density liquid forms a liquid film near the wall surface of the swirl tube.
The following operations relating to water / water separation are the same as those described in the above-mentioned conventional technology.

FIG. 2 is a graph schematically showing the axial velocity distribution of the gas-liquid two-phase flow in this embodiment. The vertical axis of the graph shows the velocity in the axial direction as a relative value with the velocity of the stand pipe 11 on the pipe axis being 1. The horizontal axis represents the distance of the stand pipe 11 from the pipe axis as a relative value with the pipe opening radius being 1. In this graph, as the case where the analysis is considered to be the most effective, d _{3 in} FIG.
= D _2/2, i.e. exhibited outlet diameter d ₃ of the standpipe 11 the velocity distribution in the case of 1/2 of the inlet side diameter d ₂ by the solid line indicated by symbol 12. For comparison,
When d ₃ = d ₂ , that is, when the stand pipe is a circular pipe having a constant diameter as in the related art, the velocity distribution is denoted by reference numeral 13.
Also indicated by a broken line with.

According to this graph, in the case of the tapered reduced-pipe structure, the flow has a fast flow in the axial direction, and the speed decreases a little at a distance from the pipe axis. It can be seen that the velocity distribution becomes steep.

Thus, it can be seen that the use of the tapered stand pipe 11 can provide a large gas-water separation effect with respect to the gas-liquid two-phase swirling flow. As a result, a sufficient air-water separation effect can be obtained without using the swirl blade used in the conventional steam-water separator, and at the same time, the pressure loss that has conventionally occurred mainly in the swirl blade is greatly reduced in the present embodiment. be able to.

A steam-water separator shown in FIG. 3 is a modification of the present embodiment. In each case, the tapered reduced pipe structure of the stand pipe 11 of the steam separator is changed, and the other portions are the same as those of the above-described embodiment, and are not shown. The stand pipe 14 shown in FIG.
Has a tapered reduced pipe structure like the stand pipe 11, but the outlet of the pipe protrudes inside the revolving cylinder 4a. FIG.
The stand pipe 15 shown in (b) is formed into a circular tube having the same diameter at the lower part of the pipe, and has a tapered reduced pipe structure at the upper part of the pipe. Also, the stand pipe 16 shown in FIG. 3 (c) has a circular tubular lower part and a tapered upper part like the stand pipe 15 of FIG. 3 (b), and the outlet of the pipe is located inside the revolving cylinder 4a. It protrudes. Even when these stand pipes 14, 15, 16 are used, substantially the same operation and effect as in the present embodiment can be obtained.

The stand pipes 11, 14, 15, and 16 described in the present embodiment and its modifications are not limited to the turning cylinder 4a.
Is welded to the swivel cylinder 4a by welding. In addition, the stand pipes 14 and 16 are provided with a thread groove structure on the outer wall surface of the stand pipe in the vicinity of the contact portion with the swivel cylinder 4a, and by applying a corresponding screw structure to the swivel cylinder 4a. It is conceivable that the connecting parts 14 and 16 are screwed and fixed to the swivel cylinder 4a, or the contact portions are welded and fixed after being screwed in this way. Such fixation by screwing further facilitates the processing of the steam separator.

Hereinafter, a second embodiment of the present invention will be described. FIG. 4 is a longitudinal sectional view of the steam separator according to the present embodiment. The steam separator 22 according to the present embodiment is different from the conventional steam separator 91 shown in FIG. 32 in that the swirl vanes 2 are omitted, and the conventional stand pipe 1 and the lowermost steam separator stage 3 are removed.
a and the revolving cylinder 4a are integrated. That is, in the present embodiment, the long turning cylinder 17 having a constriction is located inside the outer cylinder 5a of the lowermost water / water separation stage 3a, and the long turning cylinder 17 is formed in a part of the cylinder. 17c
A long swirl tube lower part 17b for passing the gas-liquid two-phase flow from the reactor core to the lowermost steam-water separation stage 3a through the reactor, and a long swirl tube for separating the gas-liquid two-phase flow rising through the constriction Upper 17a
Consists of Above the lowermost steam-water separation stage 3a, steam-water separation stages 3b and 3c are installed as in the conventional steam-water separator 91 of FIG.

With this configuration, it is possible to obtain substantially the same structure as the tapered reduction pipeline shown in the first embodiment. That is, since towards the diameter d ₃ of the portion 17c constricted than the inlet side diameter d ₂ of the long swivel cylinder bottom 17b is small, gas-liquid two-phase flow passing through the long swivel cylinder bottom 17b is similar to the first embodiment Is subjected to a turning action. Therefore, in the upper part 17a of the long swirling cylinder, the gas phase concentrates near the pipe axis and the liquid phase concentrates near the pipe wall surface, and rises while turning. The following steam-water separation action is the same as in the first embodiment.

In the present embodiment, in particular, when the minimum value d ₃ of the diameter of the constricted portion 17c of the long turning cylinder 17 is set to １ ／ of the inlet diameter d ₂ of the long turning cylinder lower part 17b, the first embodiment As described with reference to FIG. 2 in the embodiment, a steep velocity distribution can be obtained, and a large steam-water separation effect can be obtained.

Therefore, in the present embodiment, substantially the same effects as in the first embodiment can be obtained. Further, since the long swivel cylinder 17 having the constricted structure can be manufactured by a method such as forming the constricted part 17c with a die with respect to a right circular pipe, the connection between the stand pipe and the revolving cylinder by welding or the like is unnecessary, and the reliability is improved. And the cost required for manufacturing can be reduced. In addition, since the long swivel cylinder 17 of the present embodiment has a streamlined shape without a sharp side wall except for the upper and lower ends, the pressure loss can be further reduced as compared with the first embodiment. .

Hereinafter, a third embodiment of the present invention will be described. FIG. 5 is a longitudinal sectional view of the steam separator according to the present embodiment. The steam separator 23 according to the present embodiment is different from the conventional steam separator 91 shown in FIG. 32 in that the swirl vanes 2 are eliminated, and the conventional stand pipe 1 and the lowermost steam separator stage 3 are removed.
a and the revolving cylinder 4a are integrated. That is, in the present embodiment, the stand pipe 18 integrally connected to the swivel cylinder 4a of the lowermost steam-water separation stage 3a is
A stand pipe lower part 18b including a gas-liquid two-phase inlet opening and a stand pipe upper part 18a including an outlet opening,
The upper 18a and lower 18b of the stand pipe a circular tube of different diameters, the diameter d ₃ of the upper circular tube 18a smaller than the diameter d ₂ of the lower circular pipe 18b, and the two circular tube 18a, junction 18b 18c is formed not in an acute angle but in a streamlined shape. As shown in the figure, the cross section of the joint 18c is a circular arc or an elliptical arc. Also, the junction 18d between the inlet opening of the lower portion of the stand pipe 18b and the core shroud head 105 is formed not in an acute angle but in a streamlined shape.

Thus, since the stand pipe 18 is also a tapered reduced pipe whose outlet-side diameter is smaller than the inlet-side diameter, it has the same operation and effect as the second embodiment. Furthermore, by making the joints 18c and 18d streamlined, it is possible to reduce the pressure loss when the gas-liquid two-phase flow flows into the stand pipe 18 and when the two-phase flow shifts from the lower part 18b of the stand pipe to the upper part 18c.

Further, the suction of the gas-liquid two-phase flow at the inlet on the circular or elliptical arc of the cross section enhances the swirling action like the drain of the sink, so that the gas-liquid two-phase flow is swirled. The action, that is, the steam-water separation effect is further improved.

Hereinafter, a fourth embodiment of the present invention will be described. FIG. 6 is a longitudinal sectional view of the steam separator according to the present embodiment. The steam separator 24 according to the present embodiment has a twist blade 31 installed as a turning means instead of the swirl blade 2 in the steam separator 91 shown in FIG.

The torsion blade 31 is formed by twisting at least one of the upper and lower ends of the rectangular plate, and is a turning means that looks like an hourglass from the side, and has a turbulence promoting action. The outer peripheral portion of the side surface of the torsion blade 31 is inscribed in an upper portion of the stand pipe 1. Therefore, during normal operation, as in the case of the swirl vanes 2, by applying a swirling action to the gas-liquid two-phase flow that rises while rotating, the steam in the gas-liquid two-phase flow is mainly at the center of the swirl cylinder 4a. On the side, the droplet is swirled 4
The liquid phase moves to the inner wall of a, and the liquid phase is efficiently taken out at the steam-water separation stages 3a, 3b, 3c located above the torsion blades 31.

In the conventional swirl vane 2, the presence of the center hub 2a reduces the flow area of the gas-liquid two-phase flow passing through the swirl vane 2, resulting in a large pressure loss. Since the decrease in the flow path area at 31 is only the thickness of the torsion blade 31, the increase in pressure loss due to the decrease in the flow path area can be suppressed to a considerably low level. Further, since the structure is very simple as compared with the conventional swirling blade 2, repair and inspection are easy, and the time and cost required for manufacturing can be reduced.

As a modified example of this embodiment, a steam separator shown in FIG. 7 can be mentioned. In these modified examples, the structure inside the stand pipe is partially changed, and the other portions have the same structure as that of the above-described embodiment, and are not shown.

FIGS. 7 (a), (b), (c) and (d)
In any case, the torsion blade according to the present embodiment is added to the stand pipe of the steam separator according to the first to third embodiments.
31 is provided. In particular, FIG. 7D shows the steam-water separator 23 according to the third embodiment in which two stand blades 31 are provided on the stand pipe 18. In the steam separator shown in FIG. 7E, the position of the torsion blade 31 is changed to the stand pipe 1.
Above. That is, the stand pipe 1
The upper end of the torsion blade 31 is connected to the lower end of the torsion blade 31 by welding or the like,
The torsion blade 31 is turned to the rotating cylinder 3 of the lowermost water / water separation stage 3.
a. With these configurations, the same operation and effect as those of the above-described embodiment can be obtained.

Hereinafter, a fifth embodiment of the present invention will be described. FIG. 8 is a cross-sectional view of the steam separator according to the present embodiment, and FIG. 9 is a partial perspective view of the turning means of the steam separator. The steam-water separator 25 according to the present embodiment has a twisting blade 32 inscribed above the stand pipe 1 as a turning means instead of the turning blade 2 in the steam-water separator 91 shown in FIG. The torsion blade 32 is formed by twisting at least one of the left and right ends of the rectangular plate and joining both ends thereof to form a Mobius loop, and has a turbulent flow promoting action, and also has a torsion blade as described later. 32 itself has a steam-water separating action. The shape of the original plate of the torsion blade 32 is not limited to a rectangular shape, and it is sufficient that the left and right ends of the plate can be joined.

As shown in FIG. 9, a plurality of drain holes 33 are provided in the contact surface between the curved surface of the torsion blade 32 and the stand pipe 1. It is led to the gap between the outer cylinder 5a of the separation stage 3a and the stand pipe 1. In FIG. 9, the stand pipe 1 and the outer cylinder 5a are shown as transparent for explanation.

FIG. 10 is a sectional view of the torsion blade 32 shown in FIG.
It is arrow sectional drawing. As an example of a method of fixing the torsion blade 32 and forming the drain hole 34, as shown in the drawing, the torsion blade 32 having a fixing bolt hole or a rivet hole is provided.
Is fixed by bolts or rivets 34, the contact surfaces of both are welded at several places, and then the drain holes 33 are squeezed with a drill.

The operation of this configuration will be described. The gas-liquid two-phase flow flowing from the reactor core into the standpipe 1 hits the surface of the torsion blade 32 and is prevented from rising. The droplets of the gas-liquid two-phase flow rise along the curved surface of the torsion blade 32 under the action of the centrifugal force generated by the torsion blade 32, and pass through the drain hole 33 of the torsion blade 32 and stand pipe 1 and the outer cylinder 5 a. And is discharged to a core shroud head (not shown) below the stand pipe 1.

According to this structure, in the conventional swirl vane 2, the flow path area of the gas-liquid two-phase flow passing through the swirl vane 2 is reduced due to the presence of the center hub 2a, causing a large pressure loss.
In the present embodiment, the decrease in the flow path area in the torsion blade 32 is only by the plate thickness of the torsion blade 32, so that an increase in pressure loss due to the decrease in the flow path area can be suppressed. Further, since the structure is simpler than the conventional steam-water separator having the swirling blade 2 and a plurality of steam-water separation stages, repair and inspection are easy, and the time and cost required for manufacturing can be reduced.

In this embodiment, a steam-water separator provided with a plurality of torsion blades 32 installed in the stand pipe 1 is also conceivable. FIG. 11 shows a partial perspective view of a steam separator provided with two torsion blades 32a and 32b. As shown in the figure, the torsion blade 22a in a state where the lower torsion blade 32b is rotated by 180 degrees with respect to the tube axis of the stand pipe 1 is installed above the torsion blade. When a plurality of torsion blades are installed, by disposing the torsion blades in a state where each torsion blade is rotated with respect to the tube axis, the gas-liquid two-phase flow in the stand pipe 1 is dispersed. In addition to preventing water-water separation, the steam of the gas-liquid two-phase flow, whose moisture has been reduced by the lower torsion blades and which has become low in moisture, is further subjected to the water-water separation action by the upper torsion blades, thereby achieving the gas-water separation. The effect can be further enhanced.

In this case, if the steam-water separation action by the twisted blade is large, the number of the steam-water separation stages conventionally provided in three stages may be reduced, or a steam dryer may be provided directly above the twisted blade without providing the steam-water separation stage. It is also possible to provide. Alternatively, as shown in a perspective view in FIG. 12, a steam / water separator comprising a plurality of steam / water separators having the twisted blades may be installed above a shroud head (not shown).

Further, as shown in a perspective view in FIG. 13, a groove or a protrusion is formed on the surface of the torsion blade 32 of the steam separator according to the present embodiment along the flow direction of the gas-liquid two-phase flow. It is also conceivable to provide a guide path 35 and to provide an eave 36 at a part of the upper end of the torsion blade 32. Figure shows an example of taxiway 35
FIG. 14 shows an enlarged sectional view. In addition to the V-shaped guideway shown in FIG. 14A, the U-shaped guideway shown in FIG. 14B and the projection shown in FIG. 14C are formed. Taxiways are conceivable. In addition, the eaves 36 are formed in the shape of a flange of a hat, and reliably capture the liquid phase rising along the surface of the torsion blade 32, and prevent the liquid droplets from escaping outside the surface of the torsion blade 32. With this configuration, the liquid-water separation effect is further enhanced by reliably guiding the liquid droplets to the drain holes 33 of the torsion blades 32.

By incorporating the structure of the present embodiment into the steam separator according to the first to third embodiments, the above-described operation and effect can be obtained, and at the same time, the effect of the second or third embodiment can be obtained. It can be obtained together. That is, in the steam separator shown in FIG. 1, FIG. 3, or FIG. 4 described in the second or third embodiment, the stand pipe 1
The above-mentioned torsion blade 32 is provided as a turning means. As a result, the gas-liquid two-phase flow that has passed through the torsion blades 32 and has a low moisture content due to the discharge of liquid droplets is guided to the lower-stage steam-water separation stage 3a. In the gas-liquid two-phase flow, the vapor mainly moves to the center side of the swirling cylinder 4a, and the droplet moves to the inner wall of the swirling cylinder 4a. Thus, the steam-water separation stage 3 located above the torsion blade 32
In a,..., the liquid phase is more efficiently taken out, so that the gas-liquid separation performance is further improved.

Hereinafter, a sixth embodiment of the present invention will be described with reference to FIGS. FIG. 15 is a cross-sectional view of the stand pipe of the steam separator according to the present embodiment or the turning cylinder of the lowermost steam separation stage. FIG. 15 corresponds to a cross-sectional view taken along the line AA of the vertical cross-sectional view of the steam separator shown in FIG. The steam separator according to the present embodiment has a riblet 37 formed on the inner wall surface of the standpipe 1 and the swirl cylinder 4a of the lowermost steam separator stage 3a in FIG.

The riblet 37 is a device composed of vertical grooves along the flow of the fluid, and serves to reduce frictional resistance by changing the structure of the turbulent boundary layer near the viscous bottom layer. And so on. Therefore, by providing the riblets 37 on the inner wall side surfaces of the stand pipe 1 of the steam separator and the swivel cylinder 4a of the lowermost steam separator stage 3a, the frictional resistance is reduced as compared with the conventional case without riblets. Can be achieved.

FIG. 16 is an enlarged sectional view showing an example of the shape of the rib pipe 37 provided on the inner wall surface of the revolving cylinder 3a of the stand pipe 1 and the lowermost water / water separation stage 3.
The riblets 37 provided in the present embodiment are shown in FIG.
It has a V-shape as shown in FIG. In this figure, h indicates the height of the riblets, and d indicates the interval between the riblets.

The gas-liquid two-phase flow rising on the stand pipe 1 is swirled by the swirling blades 2, and most of the liquid phase of the gas-liquid two-phase flow flows to the pick-off ring 6 a in the lowermost water-water separation stage 3 a. Be captured. Therefore, particularly in the stand pipe 1 and the swirl cylinder 6a of the lowermost gas-liquid separation stage 3a, pressure loss due to friction of the liquid film flow on the inner wall surface of the cylinder is large. Therefore, by providing the riblets 51a in this portion, the total pressure loss of the steam separator can be greatly reduced.

Here, the height h and the interval d of the riblets 37
Is optimal for reducing the friction of the liquid film flow on the wall surface when a material having a thickness equal to the thickness δ ₁ of the viscous bottom layer of the turbulent flow is adopted. The thickness δ ₁ of the viscous bottom layer at this time is called an optimum riblet groove width, that is, δ ₁ = h (riblet height) = d (interval).
It is. The optimum riblet groove width δ ₁ is determined by the flow velocity and the viscosity coefficient of the swirling flow of the gas-liquid two-phase flow, and is given by the following equation.

Δ ₁ = 123 · δ / (uD / ν) ＾ (7/8) u: Velocity of turbulent flow D: Diameter of stand pipe 1 or swirl tube 3a ν: Viscosity coefficient δ: Stand pipe 1 or swivel tube Radius of 3a uD / ν in this equation is called Reynolds number. The Reynolds number is important as a physical quantity that characterizes a flow, such as when distinguishing a turbulent flow from a laminar flow.
From this Reynolds number, that is, the flow velocity of the gas-liquid two-phase flow,
Optimal riblet groove width δ that maximizes the effect of reducing frictional resistance
Determine ₁

The riblets 37 used here are shown in FIG.
The shape is not limited to the V-shaped shape shown in FIG.
U-shaped shape shown in (b), or FIG. 16 (c)
It is conceivable to use the semicircular shape shown in FIG.
In any case, the riblet height h and the interval d shown in the figure are optimally those employing the above-described optimum riblet groove width δ1.

According to the configuration of the riblets shown in FIGS. 16B and 16C, the same operation and effects as those of the V-shaped riblet can be obtained, and the V-shaped riblet can be used for a long time. While it is conceivable that the sharp-angled tip of the riblet is worn by the high-speed coolant flow, the U-shaped or semicircular riblet has no sharp-angled portion, so that the degree of wear can be reduced.

Further, in the present embodiment, the swirl tube 4a of the lowermost steam-water separation stage 3a is formed by a spiral vertical groove along the direction of the swirl flow of the gas-liquid two-phase flow during the normal operation of the reactor. A riblet 37 is preferably provided. FIG. 17 is a perspective view of the swivel cylinder 4a in this case. In this figure, for the sake of explanation, the direction of the flow of the gas-liquid two-phase flow swirled by the swirling blade located at the lower part of the swirling cylinder 4a is indicated by an arrow. As the riblets 37, any of the V-shaped, U-shaped or semicircular type shown in FIG. 17 is employed.

If the riblets 37 of the turning cylinder 4a are formed parallel to the axial direction of the turning cylinder 4a, the swirling flow collides with the riblets at an angle, and the riblets act like a kind of surface roughness. It is conceivable that the effect of reducing the loss is reduced. However, since the riblets 37 are formed along the turning angle generated by the turning blade, the above-described friction loss can be suppressed, and the pressure loss can be further reduced.

Hereinafter, a seventh embodiment of the present invention will be described with reference to FIG. FIG. 18 is an enlarged sectional view of the swirl blade in the steam separator according to the present embodiment. The steam separator according to the present embodiment is provided with a fin (small fin) 38 above the center hub 2a of the swirl blade 2 of the conventional steam separator 91 shown in FIG. The configuration of other parts is the same as that of the conventional steam separator 91.

The fin 38 is a small blade used for a ship screw or the like. When turning the ship's screw, a vortex is generated at the rear end of the shaft of the screw, but by attaching fins (small fins) to the rear end of the shaft, the vortex is canceled and no longer generated. This saves ship fuel.

The operation of the present embodiment will be described. The gas-liquid two-phase flow flowing from the stand pipe 1 is swirled by the swirling blade 2 and rises into the swirling cylinder 4a. At this time, the gas-liquid two-phase flow flowing out between the inclined blades 2b of the swirling blade 2 rises. The swirling flow of the flow rises without vortices by the fins 38 installed above the central hub 2a. This reduces the pressure loss.

Further, by making the angle of the fin 38 equal to the angle of the inclined blade 2b of the swirling blade 2, the above-described effect of reducing the pressure loss is further enhanced. This embodiment can also be applied to the fourth or fifth embodiment. That is, by disposing the fins 38 above the torsion blades 31 or 32, the pressure loss can be further reduced.

Hereinafter, an eighth embodiment of the present invention will be described. FIG. 19 is a vertical cross-sectional view of the steam separator according to the present embodiment,
FIG. 20 is a diagram schematically showing the flow of the coolant in FIG.

In the steam / water separator 26 shown in FIG. 19, the length x of the pickoff ring 6a of the lowermost steam / water separation stage 3a is larger than the length of the pickoff rings 6b and 6c of the middle and uppermost steam / water separation stages. Is also getting longer.

That is, the steam-water separation stage 3a is configured to remove most of the moisture. However, in order to enhance the efficiency of the moisture removal, the moisture is generated in the lowermost steam-water separation stage 3a. It is important to increase the amount of liquid film captured. Therefore, the length of the pickoff ring 6a in the lowermost water / water separation stage 3a for capturing the liquid film is made longer than the length of the pickoff rings 6b, 6c in the middle and upper water / water separation stages 3b, 3c. The liquid film capture in the water separation stage 3a can be ensured, and the efficiency of moisture removal can be increased.

The operation of the steam separator 26 will now be described with reference to FIG.
It will be described in detail with reference to FIG. The gas-liquid two-phase flow of the coolant passes through the stand pipe 1, is swirled by the rotation of the swirling blade 2, and is passed to the lowermost steam-water separation stage 3 a. At this time, the stand pipe 1 and the lowermost steam-water separation stage 3
In the lower part of a, there are many bubbles 95 in the flow in the liquid phase.
Is recognized. On the other hand, droplets 92 are present in the steam 93 above the lowermost steam-water separation stage 3a.

Of the gas-liquid two-phase flow swirled by the swirling blade 2, the liquid film 9 of the lowermost water-water separation stage 3a
The long pick-off ring 6a surely captures the liquid 4 even at the upper part of the steam-water separation stage 3a where the swirling force is weakened, without becoming a droplet and entering the gas phase again. A part of the captured liquid film 94 is torn off by the flow of the steam 93 in the upper part of the water / water separation stage 3a because the swirling force received from the swirling blade 2 is attenuated.
By lengthening the pickoff ring 6a, the pickoff ring 6a is prevented from being mixed with the steam flowing through the center of the swirl cylinder 3a.

Liquid film 94 captured by pick-off ring 6a
Is discharged through a gap between the swirl cylinder 4a and the outer cylinder 5a, through a breakdown ring 9 as an orifice, to a downcomer part (not shown) located at an upper part of the core.

As described above, the lowermost steam-water separation stage 3
a of the middle and upper steam-water separation stages 3b. By making the length longer than the pick-off rings 6b and 6c of 3c, the liquid film 94 can be reliably captured in the lowermost water-water separation stage 3a, and therefore, the moisture of the gas-liquid two-phase flow is removed more than before. However, the carry-over amount of the steam separator can be reduced.

Next, optimization of the length of the pickoff ring 6a will be considered. It is considered that a longer carry-off ring 6a can reduce the carry-over amount. However, if the pick-off ring is too long, the carry-over amount increases. This is because if the length of the pickoff ring is too long, the pickoff ring may catch the coolant in the gas-liquid mixed state before the liquid film is completely formed, or the swirl cylinder without sufficient separation of the gas and liquid This is because a large amount of droplets are mixed in the steam flowing in the central portion, and the carry-over amount increases.

From the above consideration, it has been verified that it is preferable that the length of the pick-off ring 6a be approximately 3/8 to 1/2 of the length of the swivel cylinder in order to sufficiently reduce the carry-over amount. I can say.

FIG. 21 shows an example of a test result graph showing the correlation between the length of the pick-off ring 6a and the carry-over amount. In this test, a test machine of 1/3 scale of the actual machine was used. The vertical axis of the graph indicates the carry-over amount in this tester, and the horizontal axis indicates the length of the pick-off ring of the tester as a relative value with the swivel cylinder length as 1.

As shown in FIG. 21, the test results when the length of the pick-off ring in the test machine was changed from about 3/8 (= 0.375) to about 1/2 (= 0.5) of the length of the swivel cylinder were as follows. About 1/15 (= 0.067) to about 1/8 (= 0.125) of the length
It can be seen that the carry-over amount is reduced to about 40% or less as compared with the test result in the case of the above.

Therefore, taking into account the above test results, experimental accuracy, differences from the actual machine, etc., if the pickoff ring length is about 3/8 to about 1/2 of the swivel cylinder length, the effect of reducing carryover is obtained. Is large enough.

Hereinafter, a ninth embodiment of the present invention will be described with reference to FIG. Here, the flow of the coolant is schematically shown. The steam-water separator 27 according to the present embodiment has only one steam-water separation stage, and the length of the pick-off ring of this steam-water separation stage is about 3/3 of the length of the swirl cylinder.
It is reduced from 8 to 1/2.

According to this configuration, the steam-water separator 27 has the pick-off ring 6a of a suitable length, so that the steam-water separation efficiency is high, and even if the steam-water separation stage is a single unit, sufficient steam-water separation is performed. And the water / water separation stage can be reduced from three stages to one stage.
It can be reduced step by step. Thus, the pressure loss in the steam-water separation stage can be reduced by reducing the steam-water separation stage. That is, in the steam-water separator 26 having a plurality of steam-water separation stages, for example, the steam-water separator 26 shown in FIG. 6a
On the other hand, the steam 93 rising in the central portion of the swirl tube 4a generates a vortex at the upper portion of the swirl tube 4a, which is a factor of increasing the pressure loss.

Accordingly, when the number of steam-water separation stages is reduced from the conventional three-stage to one as in the steam-water separator 27 according to the present embodiment, the first of the pressure losses caused by the vortex of the steam 93 is reduced. In the embodiment, the middle and upper steam-water separation stages 3b,
The pressure loss can be reduced by the amount of the pressure loss occurring in 3c. Further, since the number of the steam-water separation stages is reduced by two, the number of parts is reduced by the number of the removed steam-water separation stages and the configuration becomes simpler, so that the cost and time required for manufacturing and inspection are reduced. be able to.

As a modification of the present embodiment, the upper steam-water separation stage 5 in the steam-water separator 26 shown in FIG. 19 is deleted, and the number of steam-water separation stages is reduced from the conventional three to two.
And the length of the pick-off ring of the lowermost steam-water separation stage is reduced from about 3/8 to about 1 /
There are two. According to this, the pressure loss caused by the vortex of the vapor of the gas-liquid two-phase flow can be reduced, and at the same time, the number of parts is reduced, and compared with the present embodiment, there are two stages of gas-water separation stages. It can be expected that the water-water separation efficiency is kept high.

Hereinafter, a tenth embodiment of the present invention will be described with reference to FIG. FIG. 23 is a steam-water separator 28 according to the present embodiment.
FIG. In the conventional steam separator 91 shown in FIG. 32, since the center hub 2a of the swirl vane 2 is an inverted conical type, the radial direction of the swirl vane becomes wider toward the upper part. turning cylinder 4a than the inner diameter d _2, 4b, the direction of the inner diameter d ₁ of 4c was great. On the other hand, the steam separator 28 according to the present embodiment
The central hub and cylindrical shape, by eliminating the radial extent of the swirl vane portion, the turning cylinder 4a, 4b, in which the inner diameter d ₁ of 4c was substantially equal to the inner diameter d ₂ of the conventional standpipe. The configuration of other parts is the same as that of the conventional steam separator 91.

As a result, since the steam separator 28 is a straight pipe having the same diameter d ₁ from the stand pipe 1 to the steam separator outlet, the steam separator itself is thinner than before. The gas-liquid two-phase flow flowing from the stand pipe 1 is swirled by the swirling vanes 39, and is centrifuged in the swirl cylinder 4a having an inner diameter substantially equal to that of the stand pipe 1.

In this way, the diameter of the single steam-water separator can be reduced without reducing the flow path area as compared with the conventional steam-water separator, so that the number of steam-water separators installed per unit area can be increased. can do. Accordingly, the flow rate of the gas-liquid two-phase flow processed by one gas-water separator decreases accordingly, and the flow rate of the gas-liquid two-phase flow flowing inside the gas-water separator 28 decreases accordingly. Since the pressure loss is proportional to the square of the flow velocity, this configuration can reduce the pressure loss by the steam separator.

Hereinafter, an eleventh embodiment of the present invention will be described with reference to FIG. FIG. 24 is a steam-water separator 29 according to the present embodiment.
FIG. Regarding the conventional steam separator 91 shown in FIG. 32, the inner diameters of the swirl cylinders 4a, 4b, 4c in the three steam separator stages 3a, 3b, 3c have substantially the same value d ₁ irrespective of the axial position. I was taking. On the other hand, as shown in FIG. 24, the steam-water separator 29 according to the present embodiment is characterized in that the inner diameters of the upper ends of the swirling cylinders 4a, 4b, 4c are smaller than the inner diameter of the lower ends. That is, the inner diameter of the upper end of the revolving cylinder 4c of the uppermost steam-water separation stage 3c is d ₄ ,
When the inner diameter of the lower end of the pivot tube 4a of the lowermost steam separator stage 3a and d _5, a d _5> d _4. The configuration of other parts is the same as that of the conventional steam separator 91.

In general, it is known that swirling flow is generated when a fluid flows through a tapered reducing pipe whose outlet-side diameter is smaller than the inlet-side diameter. In consideration of this, the operation of the present embodiment will be described below.

The gas-liquid two-phase flow flowing from the stand pipe 1 is swirled by the swirling blade 2 and rises into the swirling cylinder 4a. The low-density vapor of the gas-liquid two-phase flow subjected to the swirling action is located at the center side of the steam-water separation stage 3a, and the high-density liquid forms a liquid film on the inner wall surface of the swirling cylinder 4a and swirls together. While rising. At this time, since the turning cylinder 4a has a structure in which the inner diameter decreases toward the downstream, the turning force increases,
A radial outward force indicated by an arrow in the figure acts. As a result, the liquid film on the inner wall surface of the swirl cylinder 4a can be prevented from being torn by the vapor flowing through the center of the swirl cylinder 4a, so that carry-over is reduced. It should be noted that the same effect is obtained also in the steam-water separation stages 3b and 3c located above this.

In the present embodiment, since the gas-liquid separation effect in the swirl cylinder 4a of the lowermost water / water separation stage 3a is the largest, only the swirl cylinder 4a is a pipe having a smaller inside diameter as it goes downstream, and the other swirl cylinders 4b, It is also conceivable that 4c is a tube having a constant inner diameter similar to the conventional one. In the present embodiment,
It is also conceivable to replace the swirl blade 2 with the swirl blade 39 of the steam separator 28 according to the tenth embodiment.

Hereinafter, a twelfth embodiment of the present invention will be described with reference to FIG. FIG. 25 is a steam-water separator 30 according to the present embodiment.
FIG. The steam separator 30 according to the present embodiment
In this embodiment, the pickoff rings 6a, 6b, 6c in the steam separator 29 according to the eleventh embodiment are omitted. That is, the outer cylinders 5a and 5b of the lowermost and middle steam-water separation stages 3a and 3b have upper portions bent toward the revolving cylinders 4a and 4b, and the ends of the bent portions 10a and 10b are respectively positioned above them. It is in contact with the lower ends of the revolving cylinders 4b and 4c located. Further, similarly to the eleventh embodiment, the turning cylinders 4a, 4b, 4c
The inner diameter of the upper end is set to be smaller than the inner diameter of the lower end, so as to have a tapered reduced pipe structure.

With this configuration, the same function and effect as those of the eleventh embodiment can be obtained. Further, since the swirling cylinder 4a has a structure in which the inner diameter becomes smaller toward the downstream, the swirling force increases and a radially outward force acts, so that the liquid film on the inner wall surface of the swirling cylinder 4a flows through the center of the swirling cylinder 4a. It can be prevented from being torn by steam. The pick-off ring is for capturing the liquid film on the inner wall surface of the swirl cylinder, but in the present embodiment, the radially outward force acts. Is efficiently discharged to the outside of the steam separator 30 through a gap formed between the bent portion 10a of the outer cylinder 5a and the revolving cylinder 4a. The same effect can be expected also in the steam-water separation stage 3b located above this. Therefore, the number of parts of the steam separator can be reduced without lowering the steam separation performance and the pressure loss reduction effect.

Hereinafter, a thirteenth embodiment of the present invention will be described with reference to the drawings. 26 is a cross-sectional view of the steam / water separator 41 according to the present embodiment, FIG. 27 is a top view of FIG. 26, and FIG.
28 is a sectional view taken along the line CC in FIG. 26, and FIG.
It is the elements on larger scale of (a).

In the steam / water separator 31 according to the present embodiment shown in FIG. 26, the stand pipe 1 and the swirl vane 2 and the two layers of steam above it are provided as parts corresponding to the conventional steam / water separator. Water separation stages 3a and 3b are provided.
Although the steam-water separation stage has two stages here, a stage having three stages as before can be considered. Further, a double cylindrical steam dryer 7 is provided above the upper steam-water separation stage 3b. The steam dryer 7 and the steam-water separation stage 3b are integrated, and the steam-water separator 41 is
And a function corresponding to that of a conventional steam separator. The steam dryer 7 of the steam-water separator 41
The outer cylinder 7a has substantially the same outer diameter as the water / water separation stages 3a, 3b.

As shown in FIG. 28A, the steam dryer 7 includes an outer cylinder 7a and an inner cylinder 7c, and a partition plate 7b for dividing a space interposed between the outer cylinder 7a and the inner cylinder 7c. Here, a case where the space is partitioned into six spaces is shown, but the number of partition plates is not limited to this. The inner cylinder 7c is provided with a slit 7d in the axial direction over a plurality of locations. The slit 7d is provided at one position with respect to one partitioned space, at a portion where the inner cylinder 7c and the partition plate 7b are in contact with each other, on the same side as viewed from each partitioned space. Further, as shown in FIG. 27, the upper end of the inner cylinder 7c is closed by an upper lid 7e, and the upper lid 7e is provided with a partition 7b.
In accordance with the number, a fan-shaped hole 7f for discharging steam is provided above the partitioned space.

Further, as shown in FIG. 28 (b), several corrugated plates 8 are provided in each partitioned space in a substantially concentric manner. This corrugated plate is inscribed in the partition 7c on the side not having the slit 7d. In this figure, the case where the corrugated plate 8 is formed in three concentric circles is shown, but the number of corrugated plates 8 is not limited to this. The corrugated plate 8 here has the same shape as the corrugated plate 96 in the conventional steam dryer 100 shown in FIG. 36 (b), and has a hook-shaped droplet catching portion 8e.

The operation of the steam / water separator 41 having the above configuration will be described. The process is the same as before until the gas-liquid two-phase flow of the coolant is swirled from the stand pipe 1 by the swirling blades 2 and sent to the upper steam-water separation stage 4. The steam rising in the upper steam-water separation stage 4 still contains a trace amount of water. This steam enters the steam dryer 7 from the inner cylinder 7c and rises. However, since the upper lid 7e is provided above the inner cylinder 7c, the steam enters the space partitioned through the slit 7c and is provided concentrically. Along the corrugated sheet 8, it flows in the circumferential direction by sewing the gap of the corrugated sheet 8 by itself.
During the passage through the corrugated sheet 8, the droplets in the vapor cannot adhere to the rapid change of the streamline of the corrugated sheet 8 and adhere to the corrugated sheet 8 and are captured by the hook-shaped droplet capturing section 8e. It flows down and is discharged out of the steam separator from the space below the outer cylinder 7a. On the other hand, the steam that has passed through the corrugated plate becomes dry steam with lower moisture,
The gas is guided to the upper space of the reactor pressure vessel (not shown) through the fan-shaped hole 7f of e, and is sent from the main steam pipe to the turbine building outside the pressure vessel.

Therefore, by drying the steam using a corrugated plate as in the conventional case, it is possible to obtain steam having a low moisture equivalent to that obtained by a conventional structure in which the steam separator and the steam dryer are independent. it can. In addition, since the present embodiment has a compact configuration in which the steam-water separator and the steam dryer are integrated, the reactor pressure vessel of the reactor can be reduced by the amount that the steam dryer as shown in FIG. The volume and weight can be reduced, and at the same time, the total number of parts can be reduced, so that the time and cost required for manufacturing can be reduced.

Further, for example, in the past, it was necessary to remove the steam dryer at the time of refueling, but in the present embodiment, it is not necessary, so that the time and cost required for the periodic inspection can be reduced.

Further, if the present embodiment is employed while maintaining the volume of the conventional reactor pressure vessel, the volume occupied by the gas phase in the pressure vessel becomes larger than in the past, so that there is no thermal change in the pressure vessel. Even if it occurs, the change in pressure in the pressure vessel can be reduced by the large volume, and the pressure can be prevented from rising rapidly.

By combining this embodiment with the first to twelfth embodiments, the above-described effects can be obtained under the above-described operation, and at the same time, the effects of the first to twelfth embodiments can be obtained. be able to. In particular, the combined use of the present embodiment and the steam / water separator having the longer bottom pickoff ring according to the eleventh embodiment is extremely effective in improving steam / water separation performance.

As a modification of this embodiment, a modification of the structure of the inner cylinder of the steam dryer 7 and the arrangement of the corrugated plate 8 and the slits of the steam separator 41 shown in FIG. 26 will be described below. FIG. 29A is a cross-sectional view of the steam-water separator according to the present modification in which the inner cylinder 7c in the steam dryer 7 of the steam-water separator 41 shown in FIG. , FIG. 29
FIG. 29B is a partially enlarged view of FIG.

As shown here, the outer cylinder 7 of the steam dryer 7
The space sandwiched between a and the inner cylinder 7g is partitioned into a plurality of spaces by partitions 7b, and in each of these spaces, several corrugated plates 8 are radially installed in contact with the outer cylinder 7a. In addition, a slit 7h is provided in the inner cylinder 7g in the axial direction in the middle of a portion where each partition 7b contacts the inner cylinder 7g. In this figure, the case where the corrugated plate 8 has four radial stages is shown, but the number of corrugated plates 8 is not limited to this. According to this configuration, the steam flowing from the upper steam-water separation stage 3b into the inner cylinder 7g of the steam dryer 7 is radially sewn along the radially provided corrugated sheet 8 through the gap of the corrugated sheet 8 itself. Flow outward. During the passage through the corrugated sheet 8, the droplets in the vapor cannot adhere to the rapid change of the streamline of the corrugated sheet 8 and adhere to the corrugated sheet 8 and are captured by the hook-shaped droplet capturing section 8e. Down, outer cylinder 7
It is released to the outside from the space below a. Therefore, with this configuration, the same effect as that of the present embodiment can be obtained.

As another modification of the present embodiment, FIG.
The two-stage water-water separation stage of the steam-water separation device 41 is made into one stage like the steam-water separation device 42 shown in FIG. The steam-water separation performance is slightly reduced by the amount of one stage. Although the load on the steam dryer 8 is slightly increased, the steam-water separation device 41
A more compact configuration can be achieved as compared with. That is, when the present modified example is adopted and the size of the reactor pressure vessel is the same as the conventional one, the volume occupied by steam in the reactor pressure vessel increases because the configuration of the steam-water separation device becomes compact. Therefore, even if a thermal change occurs in the reactor pressure vessel, the width of pressure increase in the pressure vessel can be reduced, thereby contributing to stable operation of the reactor.

[0123]

As described above, according to the present invention, the number of components can be reduced while maintaining the steam-water separation function of the steam-water separator or the steam-water separator at the same or higher level as the conventional one. Since the structure is simpler than that of the above, it is possible to reduce the time and labor required for production and inspection.
Furthermore, in the gas-water separation stage, the liquid phase of the gas-liquid two-phase flow is efficiently removed to reduce the carryover amount, and the pressure loss increase width caused by the gas-liquid two-phase flow of the coolant is reduced, and the turbine and the Since the load on the pump can be reduced, the soundness of the reactor can be maintained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a steam separator according to a first embodiment of the present invention.

FIG. 2 is a graph schematically showing a velocity distribution of a gas-liquid two-phase flow in an axial direction of the steam separator shown in FIG.

FIGS. 3 (a), (b), (c), (d), and (e) are partial vertical cross-sectional views of a steam separator according to a modification of the first embodiment of the present invention.

FIG. 4 is a vertical sectional view of a steam separator according to a second embodiment of the present invention.

FIG. 5 is a vertical sectional view of a steam separator according to a third embodiment of the present invention.

FIG. 6 is a longitudinal sectional view of a steam separator according to a fourth embodiment of the present invention.

7 (a), (b), (c), (d) and (e) are partial longitudinal sectional views of a steam separator according to a modification of the fourth embodiment of the present invention.

FIG. 8 is a vertical sectional view of a steam separator according to a fifth embodiment of the present invention.

FIG. 9 is a partial perspective view of a steam separator according to a fifth embodiment of the present invention.

FIG. 10 is a cross-sectional view of the steam separator shown in FIG.

FIG. 11 is a partial perspective view of a steam separator provided with a plurality of twisted plates as a modification of the fifth embodiment of the present invention.

FIG. 12 is a partial perspective view of a steam / water separator including a plurality of steam / water separators according to a fifth embodiment of the present invention.

FIG. 13 is a partial perspective view of a twisted plate of a steam separator provided with a guideway and an eave as a modification of the fifth embodiment of the present invention.

14 (a), (b) and (c) are enlarged sectional views showing an example of a guide path of the steam separator shown in FIG.

FIG. 15 is a partial perspective view of a stand pipe of a steam separator according to a sixth embodiment of the present invention or a swirl cylinder of a lowermost steam separator stage.

16 (a), (b) and (c) are enlarged sectional views showing an example of the riblet of the steam separator shown in FIG.

FIG. 17 is a partial perspective view of a revolving cylinder of a lowermost steam-water separation stage of a steam-water separator according to a sixth embodiment of the present invention.

FIG. 18 is a partial sectional view of a steam separator according to a seventh embodiment of the present invention.

FIG. 19 is a longitudinal sectional view of a steam separator according to an eighth embodiment of the present invention.

20 is a cross-sectional view schematically showing a flow of a coolant in the steam separator shown in FIG.

FIG. 21 is a graph showing a correlation between a pick-off ring length and a carryover amount in a steam separator according to a seventh embodiment of the present invention.

FIG. 22 is a longitudinal sectional view of a steam separator according to a ninth embodiment of the present invention.

FIG. 23 is a longitudinal sectional view of a steam separator according to a tenth embodiment of the present invention.

FIG. 24 is a longitudinal sectional view of a steam separator according to an eleventh embodiment of the present invention.

FIG. 25 is a vertical sectional view of a steam separator according to a twelfth embodiment of the present invention.

FIG. 26 is a longitudinal sectional view of a steam separator according to a thirteenth embodiment of the present invention.

FIG. 27 is a top view of the steam separator shown in FIG. 26.

28 (a) is a cross-sectional view of the steam / water separator shown in FIG. 26 in the direction of arrows AA, and FIG. 28 (b) is a partially enlarged view of FIG.

FIG. 29A is a cross-sectional view of a steam-water separator according to a modification of the thirteenth embodiment of the present invention, taken along line AA in FIG. 26, and FIG. FIG.

FIG. 30 is a vertical cross-sectional view of a steam / water separation device in which one stage of a steam / water separation stage is deleted as a modification of the thirteenth embodiment of the present invention.

FIG. 31 shows a conventional general improved boiling water reactor (AB).
It is a sectional system diagram showing the outline of (WR).

FIG. 32 is a longitudinal sectional view of a general conventional steam separator.

FIG. 33 is a cross-sectional view schematically showing a flow of a coolant in the steam separator shown in FIG. 32.

FIG. 34 is a cross-sectional view of the steam separator shown in FIG.

FIG. 35 is a perspective view of a rotating blade of a general conventional steam separator.

FIG. 36A is a perspective view of a general conventional steam dryer, and FIG. 36B is a top view of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Stand pipe 2 Swirl vane 3a, 3b, 3c Steam-water separation stage 4a, 4b, 4c Swirl cylinder 6, 6a, 6b, 6c Pick-off ring 7, 100 Steam dryer 7d, 7h Slit 8, 96 Corrugated plate 8e Hook-shaped liquid Drop catching part 9 Breakdown ring 11, 14, 15, 16, 18 Stand pipe 17 Long swivel cylinder 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 30 91 Water / water separator 31, 32 Torsion blade 37 Riblet 38 Fin 41, 42 Steam separator 101 Reactor pressure vessel

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Seiichi Yokobori 1st Toshiba Research and Development Center, Komukai Toshiba, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture No. 1 Town, Toshiba R & D Center (72) Inventor Noriyuki Shirakawa No. 1, Komukai Toshiba-cho, Kawasaki City, Kanagawa Prefecture, Japan Toshiba R & D Center

Claims (13)

[Claims] 1. A standpipe through which a gas-liquid two-phase flow from a nuclear reactor core passes, a swivel cylinder located above the standpipe for performing gas-water separation of the gas-liquid two-phase flow, and a swirl tube outside the swirl tube. A steam-water separator having a steam-water separation stage comprising an outer cylinder, wherein an outlet-side diameter of the gas-liquid two-phase flow of the standpipe is smaller than an inlet-side diameter. 2. The steam / water separator according to claim 1, wherein the outlet-side diameter of the stand pipe is set to about 1/2 of the inlet-side diameter. 3. The swirl tube of the lowermost steam-water separation stage of the steam-water separation stage has an integral structure with the stand pipe, and an outlet side of the stand pipe to an inlet side of the swirl tube. The steam / water separator according to claim 1 or 2, wherein a wall of the steam-water separator has a constricted structure. 4. A standpipe through which a gas-liquid two-phase flow from the reactor core passes, a swirl means positioned above the standpipe to give a swirling action to the gas-liquid two-phase flow, and a swirl means above the swirl means. A steam-water separator comprising: a swirl tube positioned to perform gas-water separation of the gas-liquid two-phase flow; and a steam-water separation stage comprising an outer tube positioned outside the swirl tube. A steam-water separator formed by twisting at least one of the upper and lower ends of the base pipe and being inscribed in the stand pipe. 5. A standpipe for passing a gas-liquid two-phase flow from a reactor core, a revolving cylinder positioned above the standpipe for performing gas-water separation of the gas-liquid two-phase flow, and a revolving pipe outside the revolving pipe. A steam-water separation stage comprising an outer cylinder positioned at the outlet pipe of the gas-liquid two-phase flow of the stand pipe is smaller than the inlet diameter, and the stand pipe has a rectangular shape as a turning means. A steam-water separator characterized in that at least one of the upper and lower ends of the plate is formed by twisting, and a torsional plate inscribed in the stand pipe is inscribed. 6. A gas / water separator comprising a standpipe through which a gas-liquid two-phase flow from a nuclear reactor core passes, and a swirl means positioned above the standpipe to give a swirl action to the gas-liquid two-phase flow. In the container, the turning means is formed by twisting at least one of the left and right ends of a rectangular plate and joining both ends thereof, has a plurality of holes, and is a torsion plate inscribed in the stand pipe. Steam-water separator characterized by the following. 7. The steam-water separator according to claim 6, wherein a guide path for catching a droplet of the gas-liquid two-phase flow is provided on a surface of the twisted plate. 8. A standpipe through which a gas-liquid two-phase flow from the reactor core passes, a swirl means positioned above the standpipe to give a swirling action to the gas-liquid two-phase flow, and a swirl means above the swirl means. A water-water separator comprising a swirl tube positioned to perform gas-water separation of the gas-liquid two-phase flow and a steam-water separation stage comprising an outer tube positioned outside the swirl tube; At least a riblet formed by arranging a plurality of narrow grooves along the flow direction of the gas-liquid two-phase flow is formed on the inner wall surface of the swirl tube of at least the lowermost water-water separation stage of the water separation stage. Features a steam-water separator. 9. A groove width and a groove depth of a riblet formed on the inner wall surface of the turning pipe of the stand pipe and the lowermost water / water separation stage are determined using at least the flow rate of the gas-liquid two-phase flow. The steam / water separator according to claim 8, wherein 10. A standpipe through which a gas-liquid two-phase flow from a nuclear reactor core passes, swirling means positioned above the standpipe to give a swirling action to the gas-liquid two-phase flow, and A steam-water separator comprising a swirl cylinder positioned to perform gas-water separation of the gas-liquid two-phase flow and an air-water separation stage comprising an outer cylinder positioned outside the swirl cylinder; A steam separator comprising fins. 11. A standpipe through which a gas-liquid two-phase flow from a nuclear reactor core passes, swirling means positioned above the standpipe to give a swirling action to the gas-liquid two-phase flow, and a swirl means above the swirl means. A steam-water separator comprising a swirling cylinder positioned to perform gas-water separation of the gas-liquid two-phase flow and an air-water separation stage comprising an outer cylinder positioned outside the swirling cylinder; The steam-water separator, wherein the size of the inner diameter of the swirl cylinder of the steam-water separation stage located at the lowest stage is substantially equal to or smaller than the size of the inside diameter of the stand pipe. 12. A gas / water separator comprising a stand pipe through which a gas-liquid two-phase flow from a reactor core passes, and a steam-water separation stage located above the stand pipe and performing gas-water separation of the gas-liquid two-phase flow. A steam dryer that is located above the steam separator and separates droplets contained in the steam that has passed through the steam separator, wherein the steam dryer includes the steam dryer. An inner cylinder provided integrally with the steam separator stage of the water separator and having a plurality of vertical slits on a side wall,
An air / water separation device comprising an outer cylinder containing the inner cylinder. 13. The steam dryer, wherein a space between the inner cylinder and the outer cylinder is partitioned into a plurality of spaces, and each of the partitioned spaces has a plurality of corrugated plate members. The steam / water separator according to claim 12, further comprising an upper lid having a hole for discharging steam at an upper part of the cylinder.