JP2013003083A - Steam separator and boiling-water reactor with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce pressure loss and a liquid film quantity increasing a carryover without increasing a carryunder.SOLUTION: A steam separator 54 has a swirler including a hub 2 which is provided in the axis center of a cylindrical body forming a flow passage of a gas-liquid two-phase flow W from below to above, and a plurality of swivel blades 3 fitted around the hub 2 radially so as to face the cylindrical body, and also having an inner edge fixed to the hub 2 in radial directions of the swivel blades 3 and an outer edge fixed to an inner wall of the cylindrical body in the radial directions of the swivel blades 3. The steam separator 54 is provided with a hole or a slit 11 including in its opening a nodal line of a swivel blade surface 13 and an inner wall surface of a diffuser 9 or a nodal line of the swivel blade surface and an inner wall surface of a first-stage inner cylinder.

Description

  The present invention relates to a steam / water separator and a boiling water reactor equipped with the steam / water separator, and more particularly to a steam / water separator suitable for an upper part of a core for separating water and steam generated in the core. And a boiling water reactor including the same.

  In general boiling water reactors, a steam separator is installed in the upper part of the core in order to separate water and steam generated in the core. In this steam separator, swirling speed is given to the two-phase flow of water and steam by a swirler composed of swirling blades and a hub, and water and steam are separated by utilizing the gas-liquid density difference by centrifugal force. Is done.

  The separated water is drained from below the steam separator, returns to the downcomer, and is sent to the core again by the recirculation pump. On the other hand, the separated steam is sent to a turbine after moisture is further removed through a steam dryer. That is, power generation efficiency is improved by removing moisture from the steam generated in the core as much as possible.

  By the way, the performance of the steam separator is expressed by the pressure loss of the gas-liquid two-phase flow passing through the inside and the steam-water separation efficiency that removes moisture contained in the steam. This steam-water separation efficiency is expressed as a carry-over expressed by the weight ratio of the moisture contained in the steam after passing through the steam-water separator, and as a weight ratio of the steam contained in the moisture separated from the steam. It is evaluated by carry under.

  FIG.1 and FIG.2 expands and shows the swirler part which comprises a steam-water separator, and its periphery.

  1 and 2, a plurality of swirl blades 3 are installed around the hub 2 to form a swirler 80. The swirler 80 is fixed to the inner wall surface of the diffuser 9 which is a tapered expansion pipe, that is, an expansion pipe whose flow path cross-sectional area expands upward from the flow path cross-sectional area of the upper end surface of the stand pipe 1. . Then, when the gas-liquid two-phase flow W of water and steam from the core located below enters the swirler 80 after entering from the stand pipe 1, the swirl blade 3 gives a swirl speed in the circumferential direction, The gas-liquid two-phase flow W thus formed is centrifuged by the density difference between water and steam. The water having a higher density than the steam moves in the radial direction in the first stage inner cylinder 4 and forms a liquid film 30 on the inner wall surface of the first stage inner cylinder 4.

  The liquid film 30 rises while turning on the inner wall surface of the first stage inner cylinder 4, and most of the liquid film 30 is guided to the first stage drainage flow path 12 by the first stage pickoff ring 6 and the first stage annular plate 7. Then, the separated water is drained from below the steam separator 54 and returned to the downcomer (not shown).

  In this phenomenon, when the amount of the liquid film 30 is large, the liquid film 30 passes from the inner wall surface of the first-stage inner cylinder 4 through the first pick-off ring 6 and the first-stage annular plate 7 to the first-stage drain passage 12. The pressure loss caused by moving over a long distance is large. Furthermore, the amount of the liquid droplets 31 separating from the liquid film 30 on the inner wall of the first stage inner cylinder 4 also increases, so that carry-over increases and the steam-water separation performance is deteriorated.

  Therefore, if the amount of the liquid film 30 on the inner wall of the first stage inner cylinder 4 is reduced, both the pressure loss and carryover of the steam separator 54 can be improved.

  Patent Document 1 describes that as a means for reducing the liquid film amount on the inner wall surface of the first stage inner cylinder, a slit is provided in the first stage inner cylinder and the liquid film is guided to the slit by a flow divider. ing.

  FIG. 3 shows a steam / water separator 54 provided with a slit in the first stage inner cylinder described in Patent Document 1. As shown in the figure, the steam separator 54 described in Patent Document 1 is provided with a plurality of slits 10 extending in the axial direction in the middle of the first stage inner cylinder 4 at predetermined intervals in the circumferential direction. .

JP-A-4-315993

  However, in the steam / water separator 54 described in Patent Document 1, the liquid film 30 formed on the inner wall surface of the first stage inner cylinder 4 is discharged out of the first stage inner cylinder 4 by the slit 10. Since the thickness of the liquid film 30 is generally thin, there is a high possibility that the vapor is discharged to the first-stage drainage flow path 12 outside the first-stage inner cylinder 4 as in the path 34 at the same time as the liquid film 30. Therefore, if the amount of liquid film that increases the pressure loss and carryover of the steam separator is reduced, there is a problem that the carry under possibility is likely to increase.

  The present invention has been made in view of the above-described points, and an object of the present invention is to provide a steam / water separator that can reduce the amount of liquid film that increases pressure loss and carryover without increasing carry under, and the same. It is to provide a boiling water reactor.

In order to achieve the above object, the steam-water separator of the present invention forms a flow path in communication with a stand pipe that guides a gas-liquid two-phase flow from below to above, and an upper end face of the stand pipe, A diffuser that expands the cross-sectional area of the channel upward from the cross-sectional area of the channel on the upper end surface, a first-stage inner cylinder that communicates with the upper end surface of the diffuser to form a channel, A first-stage outer cylinder that concentrically surrounds the cylinder to form an annular flow path, closes the inner peripheral edge of the upper end surface of the first-stage outer cylinder, and has a smaller diameter than the first-stage inner cylinder A first-stage annular plate in which a circular hole is formed, and the circular hole in the second-stage inner cylinder by standing downward in a cylindrical shape from an inner peripheral edge forming the circular hole of the first-stage annular plate At least a first-stage pick-off ring formed as a flow path to the gas-liquid two-phase flow path. A hub, and a plurality of swirl vanes attached radially about the hub, the inner edge of the swirl vane being fixed in the radial direction to the hub, the inner wall of the diffuser or the inner wall of the first stage inner cylinder In the steam-water separator provided with a swirler whose outer edge is fixed in the radial direction of the swirl vane, on the inner wall surface of the diffuser including an intersection line between the surface of the swirl vane and the inner wall surface of the diffuser, Providing a hole or slit,
Or, a hole or a slit is provided on the inner wall surface of the first stage inner cylinder including the intersection line between the surface of the swirl blade and the inner wall surface of the first stage inner cylinder in the opening,
Alternatively, a hole or a slit is provided on the inner wall surface of the diffuser including the side on the side where the gas-liquid two-layer flow abuts the end surface of the swirl blade facing the inner wall surface of the diffuser. .

  In order to achieve the above object, the boiling water reactor of the present invention includes a reactor pressure vessel, a core provided in the reactor pressure vessel and loaded with a plurality of fuel assemblies, and the core. A plurality of shrouds disposed in parallel above the core in the reactor pressure vessel, and a steam / water separator that separates a steam / water mixture flow generated in the core into steam and water. A steam dryer located above the steam separator for drying the wet steam separated by the steam separator, and a main steam pipe for supplying steam dried by the steam dryer to the turbine; A downcomer formed between the reactor pressure vessel and the shroud, in which water separated by the steam separator is circulated, and an internal pump disposed below the downcoma and supplying water in the downcoma to the core In a boiling water reactor equipped with The steam separator is characterized by a steam separator having the above configuration.

  By doing the above, on the inner wall surface of the first-stage inner cylinder that causes pressure loss and carry-over increase, while preventing steam from entering the first-stage drainage flow path that causes an increase in carry-under. The amount of liquid film can be reduced.

  According to the present invention, it is possible to reduce the amount of liquid film that increases pressure loss and carryover without increasing carry under.

It is sectional drawing which shows the conventional steam separator and expands and shows a swirler part and its periphery. It is sectional drawing which follows the AA 'line of FIG. It is sectional drawing which shows the steam-water separator described in patent document 1, and expands and shows a swirler part and its periphery. It is a longitudinal cross-sectional view which shows schematic structure of the boiling water reactor to which the steam-water separator of this invention is applied. It is a longitudinal cross-sectional view which shows the conventional steam separator. It is sectional drawing which shows one Example of the steam-water separator of this invention, and expands and shows a swirler part and its periphery. It is sectional drawing which follows the BB 'line of FIG. It is a characteristic view which shows the relationship between the thickness of a liquid film and the diffuser inner wall surface in one Example of the steam-water separator of this invention. It is sectional drawing which follows the CC 'line of FIG. It is a cross-sectional perspective view which expands and shows the swirler part for demonstrating the principal point in one Example of the steam-water separator of this invention, and its periphery. It is an expanded sectional view of the swirler part and its periphery for demonstrating one Example of the steam-water separator of this invention compared with the case where it does not correspond to this invention.

  Hereinafter, based on the illustrated embodiment, the steam separator of the present invention will be described. Note that the same reference numerals are used for the same reference numerals.

  First, before explaining the steam separator of the present embodiment, the schematic structure of a boiling water reactor to which the steam separator is applied will be described with reference to FIG.

  FIG. 4 shows an improved boiling water reactor (hereinafter referred to as ABWR).

  As shown in the figure, ABWR has a reactor pressure vessel 51, a reactor core 53 in which a core shroud 50 is installed, and a plurality of fuel assemblies (not shown) are loaded. Is disposed in the core shroud 50. Further, above the core 53 in the reactor pressure vessel 51, a plurality of steam-water separators 54 for separating the steam-water mixed flow generated in the core 53 into steam and water are arranged in parallel. Above the water separator 54, a steam dryer 55 for drying the wet steam separated by the steam separator 54 is disposed.

  Further, an internal pump 57 (recirculation pump) for supplying water to the core 53 is disposed below the annular downcomer 52 formed between the reactor pressure vessel 51 and the core shroud 50. By operating this internal pump 57, the cooling water in the downcomer 52 is supplied to the core.

  On the other hand, in the core 53, the cooling water boils with the heat generated by the nuclear fission, resulting in a two-phase flow state of steam and water. The gas-liquid two-phase flow generated in the core 53 flows into the steam-water separator 54, and a swirl speed is given by the swirler in the steam-water separator 54, and centrifugal force acts on the two-phase flow by this swirl speed, Water and steam are separated due to the density difference between water and steam. The two-phase flow that has passed through the steam separator 54 flows into the steam dryer 55, and moisture is further removed.

  In this way, steam with a moisture content reduced to 0.1 weight percent or less is sent to a turbine (not shown) through the main steam pipe 56 to generate electricity.

  The configuration of the steam separator 54 will be described in detail with reference to FIG.

  As shown in FIG. 5, the steam separator 54 forms a flow path in communication with the stand pipe 1 that guides the gas-liquid two-phase flow from below to above and the upper end face of the stand pipe 1. A diffuser 9 that expands the flow path cross-sectional area upward from the flow path cross-sectional area of the end surface, a first stage inner cylinder 4 that communicates with the upper end face of the diffuser 9 to form a flow path, and the first stage A first stage outer cylinder 5 that forms an annular first stage discharge passage 12 by concentrically surrounding the inner cylinder 4 with a space therebetween, and the inner peripheral edge of the upper end surface of the first stage outer cylinder 5 are closed, A first-stage annular plate 7 in which a circular hole having a smaller diameter than the first-stage inner cylinder 4 is formed, and the first-stage annular plate 7 is erected in a cylindrical shape downward from the inner peripheral edge forming the circular hole. The first stage pick-off ring 6 that forms the circular hole as a flow path to the second stage inner cylinder 8, and the first stage annular plate 7 A second-stage inner cylinder 8 that is installed to form a flow path, and a second-stage outer cylinder 70 that concentrically surrounds the second-stage inner cylinder 8 to form an annular second-stage discharge flow path 76. The second stage annular plate 71 which closes the inner peripheral edge of the upper end surface of the second stage outer cylinder 70 and has a circular hole having a smaller diameter than the second stage inner cylinder 8, and the circular shape of the second stage annular plate 71. A second-stage pick-off ring 79 which forms a circular hole as a flow path to the third-stage inner cylinder 72 by standing upright from the inner peripheral edge forming the hole downward and a second-stage annular plate 71 The third-stage inner cylinder 72 that is installed above and forms a flow path, and the third-stage outer cylinder 72 that concentrically surrounds the third-stage inner cylinder 72 to form an annular third-stage discharge flow path 77. A third stage annular ring that closes the inner periphery of the upper end surface of the cylinder 74 and the third stage outer cylinder 74 and that has a circular hole with a smaller diameter than the third stage inner cylinder 72 75, and a third stage pick-off ring that forms a circular hole as a steam-water separator outlet channel by standing upward in a cylindrical shape from the inner peripheral edge forming the circular hole of the third stage annular plate 75 73, a hub 2 passing through the axial center of the gas-liquid two-phase flow channel, and a plurality of swirl vanes 3 that are attached radially about the hub 2, and the inner edges of the swirl vanes 3 are formed in the hub 2 in the radial direction. The swirler 80 is fixed to the inner wall of the diffuser 9 or the inner wall of the first stage inner cylinder 4 and has an outer edge fixed in the radial direction of the swirl vane 3.

  In the swirler 80 described above, a plurality of swirling blades 3 for giving a swirling speed to the two-phase flow are attached to a cylindrical structure called the hub 2, and the outer edge of the swirling blade 3 is fixed to the diffuser 9. Yes. For this reason, the swirler 80 itself does not rotate, but the fluid that has passed through the swirler 80 rotates.

  In addition, the swirl blade 3 is parallel to the vertical direction at the entrance of the swirler 80, and increases in angle with respect to the vertical direction toward the exit of the swirler 80. That is, although it is parallel to the vertical direction at the entrance of the swirler 80, it can be turned while increasing the angle with respect to the vertical direction toward the exit of the swirler 80. In the swirl vane 3, the angle of the swirler outlet with respect to the vertical direction of the swirl vane 3 is referred to as a swirler exit angle, and the larger the swirler exit angle, the greater the swirl speed of the fluid.

  In the gas / water separator 54 configured as described above, the gas-liquid two-phase flow W generated in the core 53 enters from the stand pipe 1 and reaches the swirler 80 installed in the diffuser 9 portion. The liquid two-phase flow W becomes a swirl flow and is centrifuged into water and steam.

  In the steam / water separator 54, the water separated by the swirler 80 is returned to the downcomer 52, and a path for guiding steam to the turbine is formed by the third-stage inner cylinder 72 and the third-stage outer cylinder 74. Has been.

  Further, a gap is formed between the top of the first stage inner cylinder 4 and the first stage annular plate 7, and the space between the first stage inner cylinder 4 and the first stage outer cylinder 5 is the first stage. Since the drainage flow path 12 is formed, the liquid film formed on the inner wall of the first stage inner cylinder 4 after being centrifuged from the gas-liquid two-phase flow W by the swirler 80 reaches the top of the first stage inner cylinder 4. The first stage annular plate 7 is returned to the downcomer 52 via the first stage drain pipe 12 between the first stage inner cylinder 4 and the first stage outer cylinder 5.

  The movement of water and steam in the steam separator 54 will be described in more detail.

  The gas-liquid two-phase flow W from the core 53 introduced into the gas-water separator 54 having the configuration shown in FIG. 5 has a quality of about 15%, and the gas-liquid two-phase flow W flowing into the stand pipe 1 is When the swirl speed is given by the swirler 80, water and steam are separated by the difference in centrifugal force due to the gas-liquid density difference, and the water that has moved to the wall surface forms a liquid film.

  The liquid film formed on the wall surface of the first stage inner cylinder 4 passes through the first stage drainage flow path 12 formed by the first stage inner cylinder 4 and the first stage outer cylinder 5 by the first stage pick-off ring 6. And discharged to the outside of the steam separator 54. The water discharged from the first-stage drain flow channel 12 flows again into the downcomer 52 and is sent to the core 53 by the internal pump 57.

  On the other hand, the steam entrained in the first-stage drainage flow path 12 is guided to the downcomer 52 and the internal pump 57 together with the water, and the impeller of the internal pump 57 may have an adverse effect such as cavitation.

  Carry under is a numerical value representing the amount of steam entrained in the first stage drainage channel 12 as described above, and is defined as the weight ratio of steam contained in the fluid discharged downward from the steam separator 54, It is one of the indices that represent water separation performance.

When the vapor mass flow rate is Wg [kg / s] and the liquid mass flow rate is Wl [kg / s], the carry under (CU) is expressed by the following equation.
[Equation 1]
CU = Wg / (Wg + Wl) × 100 (%) (1)
By the way, the droplets in the vapor that have not reached the wall surface in the first stage inner cylinder 4 reach the inner cylinder wall surface in the second stage inner cylinder 8 or the third stage inner cylinder 72, and the second stage pick-off ring 79 or The water is discharged from the third stage pick-off ring 73 through the second stage drainage flow path 76 or the third stage drainage flow path 77 to the outside of the steam / water separator 54. The droplets that have not reached the wall surface of the inner cylinder before passing through the third stage pick-off ring 73 flow out from the steam / water separator outlet 78 to the steam dryer 55 together with the steam.

(1) Carry-over as an index of the separation efficiency of the steam / water separator along with the carry under is defined as the weight ratio of the liquid contained in the fluid flowing out of the steam / water separator, and the steam mass flow rate is expressed as Wg. If [kg / s] and the liquid mass flow rate are Wl [kg / s], the carryover (CO) is expressed by the following equation.
[Equation 2]
CO = Wl / (Wg + Wl) × 100 (%) (2)
Next, the mechanism in which the circumferential distribution occurs in the thickness of the liquid film formed on the inner wall surface of the diffuser 9 or the inner wall surface of the first stage inner cylinder 4 will be described with reference to FIGS.

  As shown in the figure, when the gas-liquid two-phase flow W rising in the stand pipe 1 reaches the swirler 80, it collides with the curved surface 13 of the swirl vane 3. Then, the collision separation of water and steam occurs, and it has been confirmed by analysis that a liquid film is formed on the curved surface 13 that has collided. The formed liquid film moves in the radial direction due to the centrifugal force obtained from the twisted structure of the swirl vane 3 while rising on the curved surface 13 of the swirl vane 3 due to the upward velocity component originally possessed, and the diffuser 9 Reaches the inner wall of A liquid film 35 exists on the inner wall surface of the diffuser 9 in FIG. 2, but the liquid film formed on the curved surface 13 moves in the vicinity of the curved surface 13 of the swirl blade 3, so that a thickened portion 36 is generated.

  The thickness of the liquid film 35 formed on the inner wall surface of the diffuser 9 or the inner wall surface of the first stage inner cylinder 4 according to the principle as described above has a distribution in the circumferential direction, and the curved surface 13 of the swirl vane 3 and the diffuser 9 The vicinity of the intersection line 14 with the inner wall surface is particularly thick. The thick portion 36 of the liquid film continues immediately after passing through the swirler 80 and becomes a streaky liquid film 32. However, the circumferential distribution of the thickness of the liquid film 30 rises as the inner wall surface of the first stage inner cylinder 4 is smoothed, and the streaky liquid film 32 disappears.

  The distribution in the circumferential direction of the liquid film thickness will be described in more detail using the numerical analysis results of FIG.

  9 is a cross-sectional view taken along the line CC ′ of the steam separator 54 shown in FIG. 5, and FIG. 8 shows a circumferential distribution of the liquid film thickness on the inner wall surface 15 of the diffuser 9 shown in FIG. is there. The horizontal axis of FIG. 8 represents the inner wall surface 15 of the diffuser 9 in FIG. 9, and points A, A, and C in FIGS. 8 and 9 correspond to each other.

  According to the analysis result, the circumferential distribution of the thickness of the liquid film 35 in the cross section along the line CC ′ in FIG. 5 is as shown by the solid line in FIG. 8, and the liquid in the cross section along the line DD ′ in FIG. The circumferential distribution of the thickness of the film 30 is as shown by the broken line in FIG. According to the analysis, the intersection of the solid line and the broken line in FIG. 8 is about 10 mm from point a.

  The characteristics of the present invention obtained in consideration of the above description will be described with reference to FIGS.

  In the present invention, as shown in FIGS. 6 and 7, the opening includes the intersection line of the swirling blade surface and the inner wall surface of the diffuser 9 or the intersection line of the swirling blade surface and the inner wall surface of the first stage inner cylinder 4 in the opening. Or the slit 11 is provided. That is, a hole or a slit 11 is provided on the inner wall surface of the diffuser 9 including the side on the side where the gas-liquid two-layer flow on the end surface of the swirl blade 3 facing the inner wall surface of the diffuser 9 contacts.

  The position of the “intersection line between the swirling blade surface and the inner wall surface of the diffuser 9, or the intersecting line between the swirling blade surface and the inner wall surface of the first stage inner cylinder 4” will be described in detail with reference to FIG.

  In FIG. 10, in order to confirm the swirler 80, the first-stage outer cylinder 5, the first-stage inner cylinder 4, the diffuser 9, and the stand pipe 1 are cut on a half axis for convenience. Further, in FIG. 10, there are four swirl vanes 3.

  In FIG. 10, the surface of the swirling blade refers to the curved surface 13 of each swirling blade 3 on which the upward flow of the gas-liquid two-phase flow W collides. The inner wall surface of the diffuser 9 refers to the inner wall surface 15 of the diffuser 9.

  Therefore, the “intersection line between the surface of the swirl blade and the inner wall surface of the diffuser 9” is an intersection line 14 indicated by a thick line in FIG. 10 where the two surfaces intersect. In FIG. 10, since the swirl vanes 3 are four, the number of intersection lines 14 is also four. Further, the “intersection line between the surface of the swirl blade and the inner wall surface of the first stage inner cylinder 4” means that the swirler 80 is not installed in the diffuser 9 as shown in FIG. 10 but is installed in the first stage inner cylinder 4. The crossing line 14 is indicated.

  The above is the description of the position of “the intersecting line between the swirling blade surface and the inner wall surface of the diffuser 9, or the intersecting line between the swirling blade surface and the inner wall surface of the first stage inner cylinder 4”.

  Since the position on the intersection line 14 is a portion where the liquid film becomes thicker as described above, if a hole or slit 11 is provided at that position, the gas-liquid two-phase is supplied to the first-stage drainage flow path 12. Only the liquid film can be discharged without discharging the vapor in the stream W.

  The optimum size of the hole or slit 11 shown in FIGS. 6 and 7 of this embodiment will be described.

  As described with reference to FIG. 8, when the distance from the intersection line 14 is about 10 mm on the inner wall surface 15 of the diffuser 9, the thickness of the liquid film is equal to the thickness of the liquid film 30 on the inner wall surface of the first stage inner cylinder 4. Therefore, the hole or the opening of the slit 11 may be within a distance of 10 mm from the intersection line 14. That is, the hole diameter or slit width may be within 10 mm. In addition, by setting the size of the opening as described above, the liquid film 35 on the opening of the hole or slit 11 becomes a sufficiently thick portion, so that the vapor in the gas-liquid two-phase flow W is removed from the first stage. It will not be discharged into the discharge channel 12.

  By adopting such a present embodiment, the first stage inner cylinder 4 that causes an increase in pressure loss and carryover while preventing steam from being mixed into the first stage drainage flow path 12 that causes an increase in carry under. The amount of liquid film on the inner wall surface can be reduced.

  Next, the configuration of the embodiment according to the present invention will be described using FIG. 11 in comparison with an example of a configuration not corresponding to the present invention.

  In FIG. 11, the intersection line 14 indicated by a bold line is the aforementioned “intersection line between the swirling blade surface and the inner wall surface of the diffuser 9, or the intersection line between the swirling blade surface and the inner wall surface of the first stage inner cylinder 4”. The holes or slits 90 to 95 are formed on the first stage inner cylinder 4 or the diffuser 9.

  The embodiment of the present invention corresponds to "a hole or a slit including an intersection line of the swirl blade surface and the inner wall surface of the diffuser 9 or an intersection line of the swirl blade surface and the inner wall surface of the first stage inner cylinder 4". The holes or slits are a hole 91, a slit 92, a hole 93, and a hole 95. The hole 91 and the hole 93 include the intersection line 14 on the edge of the opening, and the slit 92 and the hole 95 include the intersection line 14 in the opening. On the other hand, the hole 90 and the hole 94 correspond to “a hole or a slit including an intersection line of the swirling blade surface and the inner wall surface of the diffuser 9 or an intersection line of the swirling blade surface and the inner wall surface of the first stage inner cylinder 4”. It is not included in the present invention. The hole 90 and the hole 94 do not include the intersection line 14 at the opening.

  The hole 90 is likely to deviate from the trajectory of the liquid film 32 having a thick liquid film extending from the intersection line 14. This is because the locus of the streak-like liquid film 32 changes depending on the flow rate condition of the gas-liquid two-phase flow W and may move from the locus 33a to the locus 33b. When the locus of the streaky liquid film becomes 33b and deviates from the position of the hole 90, the liquid film becomes thin on the opening of the hole 90, and in addition to the liquid film, the vapor is also discharged to the first stage discharge flow path 12. However, there is a high possibility that the carry under will increase.

  Since the position of the hole 94 is off the intersection line 14 and the liquid film 35 is a thin part, the vapor is discharged similarly to the hole 90, and the carry under is increased.

  As shown in FIG. 3, the steam separator described in Patent Document 1 includes a slit 10 on the first stage inner cylinder 4, but the opening of the slit 10 does not include the intersection line 14. It is classified into the same case as the 11 holes 90. The position of the slit 10 deviates from the locus of the streak-like liquid film 32, and in addition to the liquid film, the vapor is also discharged to the first-stage discharge flow path 12, and there is a high possibility of increasing the carry under.

  In order to solve the above problem, as in the hole 91, the slit 92, the hole 93, and the hole 95 of the present embodiment, the opening of the slit 10 is “an intersection line between the swirl blade surface and the inner wall surface of the diffuser 9, or swirl. By moving the position of the slit 10 so as to be at a position including the intersection line of the blade surface and the inner wall surface of the first stage inner cylinder 4, the thick part of the liquid film and the opening of the slit 10 may be made to correspond to each other. .

  The present invention is applicable to a nuclear plant having a steam separator and a boiling water nuclear plant.

  DESCRIPTION OF SYMBOLS 1 ... Stand pipe, 2 ... Hub, 3 ... Swirling blade, 4 ... First stage inner cylinder, 5 ... First stage outer cylinder, 6 ... First stage pick-off ring, 7 ... First stage annular plate, 8 ... Second Step inner cylinder, 9 ... Diffuser, 10 ... Slit, 11 ... Hole or slit, 12 ... First stage drainage channel, 13 ... Curved surface of swirl vane, 14 ... Intersection line between swirl vane curved surface and diffuser inner wall, 15 ... Inner wall surface of diffuser, 30 ... liquid film, 31 ... droplet, 32 ... stripe-like liquid film, 33a, 33b ... locus of stripe-like liquid film, 34 ... path of vapor, 35 ... liquid film on inner wall surface of diffuser 36 ... Thick portion of liquid film on the inner wall of the diffuser, 50 ... Core shroud, 51 ... Reactor pressure vessel, 52 ... Downcomer, 53 ... Core, 54 ... Steam separator, 55 ... Steam dryer, 56 ... Main Steam piping, 57 ... internal pump, 70 ... second stage outer cylinder, DESCRIPTION OF SYMBOLS 1 ... Second stage annular plate, 72 ... Third stage inner cylinder, 73 ... Third stage pick-off ring, 74 ... Third stage outer cylinder, 75 ... Third stage annular plate, 76 ... Second stage drainage flow path, 77 ... third-stage drainage flow path, 78 ... gas / water separator outlet, 79 ... second-stage pick-off ring, 80 ... swirler, 90, 94 ... hole not corresponding to the present invention, 91, 93, 95 ... corresponding to the present invention Hole, 92 ... slit corresponding to the present invention.

Claims (7)

A stand pipe that guides the gas-liquid two-phase flow from below to above, and a flow path that communicates with the upper end surface of the stand pipe to form a flow path. A diffuser that expands the area, a first stage inner cylinder that communicates with the upper end surface of the diffuser to form a flow path, and an annular flow path that surrounds the first stage inner cylinder in a concentric manner to form an annular flow path A first-stage outer cylinder, a first-stage annular plate that closes the inner periphery of the upper end surface of the first-stage outer cylinder, and that has a circular hole having a smaller diameter than the first-stage inner cylinder, and the first-stage outer cylinder At least a first stage pick-off ring that rises in a cylindrical shape from the inner peripheral edge forming the circular hole of the annular plate downward and forms the circular hole as a flow path to the second stage inner cylinder, A hub that passes through the axial center of the gas-liquid two-phase flow path and a radial mounting centered on the hub. The inner edge of the swirl vane is fixed to the hub in the radial direction, and the outer edge is fixed to the inner wall of the diffuser or the inner wall of the first stage inner cylinder in the radial direction of the swirl vane. In the steam separator with a swirler,
An air / water separator, wherein a hole or a slit is provided on the inner wall surface of the diffuser including an intersection between the surface of the swirl vane and the inner wall surface of the diffuser. A stand pipe that guides the gas-liquid two-phase flow from below to above, and a flow path that communicates with the upper end surface of the stand pipe to form a flow path. A diffuser that expands the area, a first stage inner cylinder that communicates with the upper end surface of the diffuser to form a flow path, and an annular flow path that surrounds the first stage inner cylinder in a concentric manner to form an annular flow path A first-stage outer cylinder, a first-stage annular plate that closes the inner periphery of the upper end surface of the first-stage outer cylinder, and that has a circular hole having a smaller diameter than the first-stage inner cylinder, and the first-stage outer cylinder At least a first stage pick-off ring that rises in a cylindrical shape from the inner peripheral edge forming the circular hole of the annular plate downward and forms the circular hole as a flow path to the second stage inner cylinder, A hub that passes through the axial center of the gas-liquid two-phase flow path and a radial mounting centered on the hub. The inner edge of the swirl vane is fixed to the hub in the radial direction, and the outer edge is fixed to the inner wall of the diffuser or the inner wall of the first stage inner cylinder in the radial direction of the swirl vane. In the steam separator with a swirler,
A steam / water separator, wherein a hole or a slit is provided on the inner wall surface of the first stage inner cylinder including an intersection line between the surface of the swirl vane and the inner wall surface of the first stage inner cylinder in an opening. . A stand pipe that guides the gas-liquid two-phase flow from below to above, and a flow path that communicates with the upper end surface of the stand pipe to form a flow path. A diffuser that expands the area, a first stage inner cylinder that communicates with the upper end surface of the diffuser to form a flow path, and an annular flow path that surrounds the first stage inner cylinder in a concentric manner to form an annular flow path A first-stage outer cylinder, a first-stage annular plate that closes the inner periphery of the upper end surface of the first-stage outer cylinder, and that has a circular hole having a smaller diameter than the first-stage inner cylinder, and the first-stage outer cylinder At least a first stage pick-off ring that rises in a cylindrical shape from the inner peripheral edge forming the circular hole of the annular plate downward and forms the circular hole as a flow path to the second stage inner cylinder, A hub that passes through the axial center of the gas-liquid two-phase flow path and a radial mounting centered on the hub. The inner edge of the swirl vane is fixed to the hub in the radial direction, and the outer edge is fixed to the inner wall of the diffuser or the inner wall of the first stage inner cylinder in the radial direction of the swirl vane. In the steam separator with a swirler,
A gas or a slit is provided on the inner wall surface of the diffuser including an opening on the side of the swirl vane that faces the inner wall surface of the diffuser on the side facing the gas-liquid two-layer flow. Water separator. The steam-water separator according to any one of claims 1 to 3,
The steam separator is provided on the first-stage annular plate and forms a flow path, and the second-stage inner cylinder surrounds the second-stage inner cylinder at a concentrically spaced interval to form an annular second A second-stage outer cylinder that forms a stage discharge passage, and a second-stage annular plate that closes the inner peripheral edge of the upper end surface of the second-stage outer cylinder and forms a circular hole having a smaller diameter than the second-stage inner cylinder; A third-stage inner cylinder that is installed on the second-stage annular plate and forms a flow path; and an inner peripheral edge that forms the circular hole of the second-stage annular plate, and is raised in a cylindrical shape downward. A second-stage pick-off ring that forms the circular hole as a flow path to the third-stage inner cylinder, and an annular third-stage discharge flow path that surrounds the third-stage inner cylinder in a concentrically spaced manner. A third-stage outer cylinder to be formed, a third-stage annular plate that closes the inner peripheral edge of the upper end surface of the third-stage outer cylinder, and that has a circular hole with a smaller diameter than the third-stage inner cylinder; A third-stage pick-off ring that rises in a cylindrical shape downward from the inner peripheral edge forming the circular hole of the third-stage annular plate and forms the circular hole as a steam-water separator outlet channel; A steam separator that is characterized by The steam-water separator according to claim 1 or 2,
The opening of the hole or slit is at a distance within 10 mm from the line of intersection of the surface of the swirl vane and the inner wall surface of the diffuser, or the line of intersection of the surface of the swirl vane and the inner wall surface of the first stage inner cylinder. A steam separator characterized by that. The steam-water separator according to claim 1 or 2,
The surface of the swirl vane is a curved surface where a gas-liquid two-phase upward flow of a plurality of swirl vanes collides. A reactor pressure vessel, a core provided in the reactor pressure vessel and loaded with a plurality of fuel assemblies, a shroud in which the core is disposed, and a plurality of the reactor pressure vessel above the core in the reactor pressure vessel A steam-water separator that is arranged in parallel and separates the steam-water mixture flow generated in the core into steam and water, and is located above the steam-water separator and separated by the steam-water separator. A steam dryer for drying the wet steam, a main steam pipe for supplying steam dried by the steam dryer to the turbine, and formed between the reactor pressure vessel and the shroud and separated by the steam separator. A boiling water reactor comprising a downcomer through which water is circulated and an internal pump that is disposed below the downcoma and supplies water in the downcoma to the core.
The boiling water reactor according to claim 1, wherein the steam separator is the steam separator according to claim 1.

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