Steam dryer for boiling water reactor

Abstract

To provide a boiling-water reactor steam dryer that enables rigidity of the hood thereof to be secured not thickening a hood plate itself, thereby enabling avoidance of prolongation of a manufacturing time and complication of a manufacturing procedure.SOLUTION: A boiling-water reactor steam dryer is provided, comprising a hood for leading to a steam dryer unit, steam separated by a steam-water separator installed above a reactor core consisting of a plurality of fuel assemblies arranged inside a reactor pressure vessel, wherein the boiling-water reactor steam dryer is comprised of: the hood; a support ring; a skirt; and a steam dryer unit that has a corrugated plate inside. The hood is comprised of: a first hood plate arranged in a vertical direction; a reinforcing plate attached to the first hood plate; a second hood plate that is arranged vertically above the first hood plate and the reinforcing plate; and a side plate arranged between the first hood plate and the steam dryer unit, wherein the reinforcing plate has a cross section formed in a projected-recessed shape.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a steam dryer for a boiling water reactor, and more particularly to a steam dryer for a boiling water reactor having a hood installed to guide steam separated by a steam separator installed above a reactor core consisting of a plurality of fuel assemblies arranged in a reactor pressure vessel to a steam dryer unit. [Background technology]

[0002] In a boiling water reactor, a core consisting of multiple fuel assemblies is placed inside a reactor pressure vessel. A part of the reactor coolant water heated by the nuclear reaction in the core turns into steam, and the two-phase flow containing the reactor coolant water and the steam is separated into the reactor coolant water and steam by a steam separator installed above the reactor core. The steam separated by the steam separator is led to a steam dryer installed above the steam separator.

[0003] The steam dryer is provided with a steam dryer unit including a corrugated sheet, and the moisture contained in the steam is removed by passing the steam through the steam dryer unit. In addition, the steam dryer is provided with a hood at a position facing the steam dryer unit to guide the steam separated by the steam-water separator to the steam dryer unit.

[0004] A steam dryer equipped with the above-mentioned hood structure is described in Patent Document 1.

[0005] Patent Document 1 describes a steam dryer that has a structure in which the increase in labor costs is low compared to the labor costs required to increase the number of workers required to manufacture the steam dryer unit, without increasing the diameter of the steam dryer or the reactor pressure vessel, and that increases the rigidity of the parts that receive vibration loads.The steam dryer described in Patent Document 1 includes a corrugated plate assembly in which multiple corrugated plates for collecting droplets are attached to spacer rods, a side plate to which the spacer rods are fixed, a unit support fixed to the lower part of the side plate, a top plate fixed to the upper part of the side plate, a hood support fixed to the side plate, a hood fixed to the hood support and the top plate, and a support plate arranged between the corrugated plates and fixed to the unit support and the top plate. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2007-17244 A Summary of the Invention [Problem to be solved by the invention]

[0007] Incidentally, the above-mentioned hood needs to ensure structural soundness (not break) against loads such as pressure acting from outside the hood. In Patent Document 1, structural soundness is ensured by increasing the rigidity of the hood plate, but if it is necessary to ensure more sufficient structural soundness against loads such as pressure acting from outside the hood, it can be considered to make the hood plate itself thicker.

[0008] However, if the hood plate itself is made thicker, the amount of welding heat input from welding when attaching the hood plate increases, resulting in greater deformation of the parts that make up the steam dryer, such as the hood plate, due to the welding heat. This results in additional work being required to correct the deformation due to this welding heat, which results in longer manufacturing time and more complicated manufacturing procedures.

[0009] The present invention has been made in consideration of the above-mentioned points, and its first object is to provide a steam dryer for a boiling water reactor which can ensure the rigidity of the hood without making the hood plate thicker in order to ensure the structural integrity of the hood against loads such as pressure acting from outside the hood, thereby avoiding longer manufacturing times and more complicated manufacturing procedures.

[0010] A second object of the present invention is to provide a steam dryer for a boiling water reactor that can ensure the structural integrity of the hood as a hood structure that can deflect loads due to fluid acting from outside the hood. [Means for solving the problem]

[0011] In order to achieve the first object described above, the steam dryer in a boiling water reactor of the present invention is provided with a hood for guiding steam separated by a steam separator installed above a core consisting of a plurality of fuel assemblies arranged in a reactor pressure vessel to a steam dryer unit, and is a steam dryer for a boiling water reactor comprising the hood, a support ring, a skirt, and a steam dryer unit having a corrugated plate inside, wherein the hood comprises a first hood plate arranged vertically, a reinforcing plate attached to the first hood plate, a second hood plate arranged vertically above the first hood plate, and a side plate arranged between the first hood plate and the steam dryer unit, and the reinforcing plate is formed in an uneven shape having a rectangular or arcuate cross section.

[0012] In addition, in order to achieve the first object described above, the steam dryer in a boiling water reactor of the present invention is provided with a hood for guiding steam separated by a steam separator installed above a core consisting of a plurality of fuel assemblies arranged in a reactor pressure vessel to a steam dryer unit, and is characterized in that the hood is divided into several parts and arranged vertically, and is composed of a first hood plate arranged in a stepped manner so that the distance from the steam dryer unit becomes wider from top to bottom in the vertical direction, a second hood plate arranged vertically above the first hood plate, a side plate arranged between the first hood plate and the steam dryer unit, and a reinforcing plate attached to the first hood plate and extending vertically to the steam dryer unit.

[0013] Furthermore, in order to achieve the second object described above, the steam dryer in a boiling water reactor of the present invention comprises a hood for guiding steam separated by a steam separator installed above a core consisting of a plurality of fuel assemblies arranged in a reactor pressure vessel to a steam dryer unit, and is a steam dryer for a boiling water reactor comprising the hood, a support ring, a skirt, and a steam dryer unit having a corrugated plate therein, wherein the hood comprises a first hood plate arranged vertically and a second hood plate arranged vertically above the first hood plate, and the first hood plate has a triangular structure or an arc structure having a vertex in a direction perpendicular to the load acting by the fluid. Effect of the Invention

[0014] According to the present invention, in order to ensure the structural soundness of the hood against loads such as pressure acting from outside the hood, the rigidity of the hood can be ensured without making the hood plate itself thicker, thereby avoiding longer manufacturing times and more complicated manufacturing procedures, or the structural soundness of the hood can be ensured by providing a hood structure that deflects loads from fluids acting from outside the hood. [Brief description of the drawings]

[0015] [Figure 1] 1 is a diagram showing an overall configuration of a boiling water reactor in which a steam dryer for a boiling water reactor according to the present invention is adopted; [Diagram 2] FIG. 1 is a perspective view showing a first embodiment of a steam dryer for a boiling water reactor according to the present invention. [Diagram 3] FIG. 3 is a view seen from the direction of arrow A in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view taken along line BB in FIG. [Diagram 5] FIG. 5 is a diagram showing a modification of the first embodiment of the steam dryer for a boiling water reactor according to the present invention, and corresponds to FIG. 4. [Figure 6] FIG. 5 shows a second embodiment of the steam dryer for a boiling water reactor according to the present invention, and corresponds to FIG. 4. [Figure 7] FIG. 4 shows a third embodiment of the steam dryer for a boiling water reactor according to the present invention, and corresponds to FIG. [Figure 8] 8 is a partial cross-sectional view taken along the direction of the arrow C in FIG. 7. [Figure 9] FIG. 4 shows a fourth embodiment of the steam dryer for a boiling water reactor according to the present invention, and corresponds to FIG. [Figure 10] FIG. 10 is a cross-sectional view taken along line DD in FIG. [Figure 11] FIG. 11 is a view showing a modification of the fourth embodiment of the steam dryer for a boiling water reactor according to the present invention, and corresponds to FIG. 10. [Figure 12] FIG. 11 is a diagram showing another modified example of the steam dryer for a boiling water reactor according to the fourth embodiment of the present invention, which corresponds to FIG. [Figure 13] FIG. 11 shows a fifth embodiment of the steam dryer for a boiling water reactor according to the present invention, and corresponds to FIG. 10. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The steam dryer for a boiling water reactor according to the present invention will be described below based on the illustrated embodiments. In each embodiment, the same components are designated by the same reference numerals.

[0017] Furthermore, the following is merely an example, and is not intended to limit the contents of the invention to the specific embodiments described below. EXAMPLES

[0018] FIG. 1 shows the overall configuration of a boiling water reactor in which the boiling water reactor steam dryer of the present invention is adopted.

[0019] As shown in FIG. 1, a boiling water reactor 1 is roughly constructed by arranging at least a shroud head 11, an upper lattice plate 7, a core shroud 5, control rod guide tubes 9, and a core support plate 6 within a reactor pressure vessel 2.

[0020] The above-mentioned core shroud 5 surrounds the reactor core 3 in which a plurality of fuel assemblies 4 are loaded, and a core support plate 6 is attached to the core shroud 5 at the lower end of the reactor core 3.

[0021] An upper grid plate 7 attached to the core shroud 5 is disposed at the upper end of the reactor core 3, and the upper ends of the fuel assemblies 4 are supported by this upper grid plate 7. A plurality of control rods 8 that are moved in and out between the fuel assemblies 4 are each connected to a control rod drive mechanism (not shown) installed in each control rod drive mechanism housing 10.

[0022] Further, a plurality of control rod guide tubes 9 are installed below the reactor core 3 inside the reactor pressure vessel 2, and the control rods 8 withdrawn from the reactor core 3 are guided by the control rod guide tubes 9.

[0023] Meanwhile, a shroud head 11 is attached to the upper end of the upper lattice plate 7, a steam-water separator 12 is attached above the shroud head 11, and a steam dryer 13 is disposed above the steam-water separator 12.

[0024] FIG. 2 is an isometric perspective view of the configuration of the steam dryer 13 of this embodiment.

[0025] 2, the steam dryer 13 of this embodiment includes a support ring 14, a skirt 15, a steam dryer unit 16 having a corrugated plate (not shown) therein, and a hood 17. The steam dryer unit 16 and the hood 17 are attached to the upper part of the steam dryer 13, and a plurality of them are arranged in parallel.

[0026] Next, an example of the hood 17 employed in the steam dryer 13 of this embodiment will be described with reference to Figs.

[0027] As shown in Figures 3 and 4, the hood 17A of this embodiment is generally composed of a first hood plate 17a arranged in the vertical direction (up and down direction), a first reinforcing plate 17d attached to the first hood plate 17a, a second hood plate 17b arranged vertically above the first hood plate 17a and the first reinforcing plate 17d, and a side plate 17c arranged between the first hood plate 17a and the steam dryer unit 16.

[0028] The above-mentioned first reinforcing plate 17d is formed in an uneven shape with a rectangular (trapezoidal) cross section as shown in FIG. 4, and is attached to the first hood plate 17a at a plurality of points by welded portions 17e.

[0029] By configuring hood 17A as described above in this embodiment, the first reinforcing plate 17d is formed in an uneven shape with a rectangular (trapezoidal) cross section, and by attaching it to first hood plate 17a, the rigidity of first hood plate 17a is increased, making it possible to improve the rigidity of hood 17A without increasing the thickness of first hood plate 17a itself.

[0030] Therefore, the rigidity of the first hood plate 17a of the steam dryer 13 against loads such as pressure acting from outside the hood 17A is improved without making the first hood plate 17a itself thicker, so that the structural integrity of the hood 17A in the steam dryer 13 can be ensured and it is possible to avoid lengthening the manufacturing time and complicating the manufacturing procedure.

[0031] In addition, in the hood 17A shown in Figures 3 and 4, the first hood plate 17a and the first reinforcing plate 17d are attached at a welded portion 17e. However, it goes without saying that the attachment of the first hood plate 17a and the first reinforcing plate 17d is not limited to the welded portion 17e shown in Figure 4, and other fastening means such as rivets or bolts can also be used.

[0032] In addition, the structure of first reinforcing plate 17d is shown in a representative example in Figure 4 (a structure formed in an uneven shape with a rectangular (trapezoidal) cross section and attached to first hood plate 17a at multiple points by welds 17e), but it goes without saying that the horizontal length L of the attachment position between first hood plate 17a and first reinforcing plate 17d (the up and down direction in Figure 4, which is the B-B cross section of Figure 3, is the horizontal direction, and "the horizontal length of the attachment position between first hood plate 17a and first reinforcing plate 17d" means the horizontal contact distance between first hood plate 17a and first reinforcing plate 17d, which are fixed by one weld 17e in Figure 4) is not limited to that shown in Figure 4, and the horizontal length of the attachment position between first hood plate 17a and first reinforcing plate 17d can be changed.

[0033] In addition, the structure of the first reinforcing plate 17d is shown in Figure 4 as a representative example (a concave-convex structure having a rectangular (trapezoidal) cross section), but it goes without saying that it is not limited to what is shown in Figure 4 and can be applied to any other polygonal concave-convex structure.

[0034] In addition, the first reinforcing plate 17d in the hood 17A shown in Figures 3 and 4 is uniformly attached to the first hood plate 17a, but the attachment range is not limited to that shown in Figures 3 and 4, and it is possible to divide it vertically and horizontally or to attach it to a part of the first hood plate 17a.

[0035] Furthermore, as shown in Fig. 5, in addition to the structure of the hood 17A shown in Fig. 4, by providing a support 17f extending vertically from a welded portion 17e of the first reinforcing plate 17d to the first hood plate 17a to the steam dryer unit 16, the rigidity of the first hood plate 17a can be further improved. Note that the mounting structure of the support 17f is not limited to that shown in Fig. 5.

[0036] Also, although different from the structure of hood 17A described above, it is possible to eliminate the need for first reinforcing plate 17d by devising the structure of first hood plate 17a itself and configuring it so that steam is guided to steam dryer unit 16 only by first hood plate 17a. That is, by configuring first hood plate 17a itself to have the structure of first reinforcing plate 17d as shown in Fig. 4 or 6 (a rectangular cross-sectional shape or an uneven cross-sectional shape with an arc-shaped cross-section), not only can the same effect as the above-described configuration be obtained, but also the first hood plate 17a serves as the first reinforcing plate 17d, making first reinforcing plate 17d unnecessary. EXAMPLES

[0037] FIG. 6 shows another example of the hood 17 employed in the steam dryer 13 of this embodiment.

[0038] Hood 17B shown in FIG. 6 differs from hood 17A of Example 1 only in the structure of first reinforcing plate 17d. The characteristic parts of hood 17B of Example 2 will be described in detail, but overlapping descriptions will be omitted.

[0039] The structure of the first reinforcing plate 17d in the hood 17B of the second embodiment shown in FIG. 6 is characterized in that the cross section of the first reinforcing plate 17d in the first embodiment is an arc-shaped, uneven shape, as compared to the rectangular cross section of the first reinforcing plate 17d in the first embodiment.

[0040] By adopting such a structure for hood 17B in this embodiment, it is possible to improve the rigidity of hood 17 by only changing the structure of first reinforcing plate 17d, without making first hood plate 17a itself thicker, and an effect similar to that of Example 1 can be obtained.

[0041] In hood 17B of Example 2, a representative example of first reinforcing plate 17d having an arc-shaped cross section is shown in Figure 6. However, it goes without saying that the arc-shaped cross section of first reinforcing plate 17d is not limited to that shown in Figure 6, and can be applied to any other uneven shape having an arc-shaped cross section. EXAMPLES

[0042] The hood 17C employed in the steam dryer 13 of this embodiment will be described with reference to Figs.

[0043] Example 3 shown in Figures 7 and 8 differs from hood 17A of Example 1 only in the structure of hood 17C. The characteristic parts of hood 17C of Example 3 will be described in detail, but overlapping descriptions will be omitted.

[0044] As shown in Figures 7 and 8, hood 17C of this embodiment is obtained by dividing first hood plate 17a shown in Examples 1 and 2 into multiple parts in the vertical direction (up and down direction) (in this embodiment, into first divided hood plate 17a1, second divided hood plate 17a2, and third divided hood plate 17a3), and moreover, first divided hood plate 17a1, second divided hood plate 17a2, and third divided hood plate 17a3 are arranged in a stepped manner so that the distances between first divided hood plate 17a1, second divided hood plate 17a2, and third divided hood plate 17a3 and steam dryer unit 16 become wider from top to bottom in Figure 7.

[0045] In addition, a second reinforcing plate 17g is arranged between the first and second divided hood plates 17a1 and 17a2, and is attached to the first and second divided hood plates 17a1 and 17a2 and extends vertically to the steam dryer unit 16, while a third reinforcing plate 17h is arranged between the second and third divided hood plates 17a2 and 17a3, and is attached to the second and third divided hood plates 17a2 and 17a3 and extends vertically to the steam dryer unit 16.

[0046] As shown in FIG. 8, the second reinforcing plate 17g and the third reinforcing plate 17h are formed with a plurality of steam passing holes 17i through which steam passes.

[0047] By configuring hood 17C as described above in this embodiment, it is possible to improve the rigidity of hood 17C without making first separate hood plate 17a1, second separate hood plate 17a2, and third separate hood plate 17a3 themselves thicker, and an effect similar to that of embodiment 1 can be obtained.

[0048] It goes without saying that the mounting positions and the number of the second reinforcing plates 17g and the third reinforcing plates 17h in the vertical direction are not limited to those shown in FIG.

[0049] Furthermore, it goes without saying that the installation angles of the second reinforcing plate 17g and the third reinforcing plate 17h (angles θ1, θ2 between the second reinforcing plate 17g and the third reinforcing plate 17h' and the third reinforcing plate 17h' in the shifted positions when the steam dryer unit 16 side is shifted upward from the vertically arranged positions of the second reinforcing plate 17g and the third reinforcing plate 17h in Figure 7) are not limited to the angles shown in Figure 7.

[0050] Moreover, it goes without saying that the structure of the plurality of steam passing holes 17i through which the above-mentioned steam passes is not limited to the structure shown in FIG. EXAMPLES

[0051] The hood 17D employed in the steam dryer 13 of this embodiment will be described with reference to FIGS. 9, 10, 11 and 12. FIG.

[0052] Hood 17D of Example 4 differs from hood 17A of Example 1 only in the structure of hood 17D. The characteristic portions of hood 17D of Example 4 will be described in detail, but overlapping descriptions will be omitted.

[0053] As shown in Figs. 9 and 10, the hood 17D of this embodiment is composed of a first hood plate 17a, a second hood plate 17b, and a side plate 17c.

[0054] By making the structure of this first hood plate 17a a triangular structure having a vertex 17a' in a direction perpendicular to the load acting on the fluid, this load can be diverted toward the side plate 17c, thereby ensuring the structural soundness of the hood 17D.

[0055] That is, when a fluid hits the apex 17a' of the triangular first hood plate 17a in FIG. 10, the load can be diverted to the upper and lower side plates 17c, thereby ensuring the structural soundness of the hood 17D.

[0056] Furthermore, by configuring the above-mentioned first hood plate 17a so that it is directly attached to the steam dryer unit 16 without using a side plate 17c, as shown in Figure 11 (by eliminating the side plate 17c in Figure 10 and attaching the horizontal end of the first hood plate 17a directly to the steam dryer unit 16), it is also possible to eliminate the need for side plate 17c to form a hood 17D structure that deflects the load acting on the fluid.

[0057] 12, it is also possible to provide supports 17f that extend vertically to the steam dryer unit 16 side on the first hood plate 17a. Note that the mounting positions and number of supports 17f are not limited to those shown in FIG. EXAMPLES

[0058] The hood 17E employed in the steam dryer 13 of this embodiment will be described with reference to FIG.

[0059] Hood 17E of Example 5 shown in Figure 13 differs from hood 17D of Example 4 only in the structure of the first hood plate 17a. The characteristic parts of hood 17E of Example 5 will be described in detail, but overlapping descriptions will be omitted.

[0060] The structure of the first food plate 17a in hood 17E of Example 5 is characterized in that, compared to the first food plate 17a in hood 17D of Example 4, the first food plate 17a has an arc structure rather than a triangular structure having an apex 17a'.

[0061] This allows the load acting on the hood 17E due to the fluid to be diverted to the side plate 17c, thereby ensuring the structural soundness of the hood 17E.

[0062] The present invention is not limited to the above-mentioned embodiment, but includes various modified examples. For example, the above-mentioned embodiment has been described in detail to clearly explain the present invention, and is not necessarily limited to those including all of the configurations described. It is also possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add, delete, or replace a part of the configuration of each embodiment with another configuration. [Explanation of symbols]

[0063] 1... boiling water reactor, 2... reactor pressure vessel, 3... reactor core, 4... fuel assembly, 5... core shroud, 6... core support plate, 7... upper grid plate, 8... control rod, 9... control rod guide tube, 10... control rod drive mechanism housing, 11... shroud head, 12... steam separator, 13... steam dryer, 14... support ring, 15... skirt, 16... steam dryer unit, 17A, 17B, 17C, 17D, 17E... hood, 17a...first food plate, 17a1...first divided food plate, 17a2...second divided food plate, 17a3...third divided food plate, 17a'...apex of triangular first food plate, 17b...second food plate, 17c...side plate, 17d...first reinforcing plate, 17e...welded portion, 17f...support, 17g...second reinforcing plate, 17h...third reinforcing plate, 17i...steam passage hole.

Claims

1. A steam dryer for a boiling water reactor, comprising: a hood for guiding steam separated by a steam separator disposed above a reactor core composed of a plurality of fuel assemblies arranged in a reactor pressure vessel to a steam dryer unit, the steam dryer comprising the hood, a support ring, a skirt, and a steam dryer unit having a corrugated plate therein, the hood is composed of a first hood plate arranged in a vertical direction, a reinforcing plate attached to the first hood plate, a second hood plate arranged vertically above the first hood plate and the reinforcing plate, and a side plate arranged between the first hood plate and the steam dryer unit; 13. A steam dryer for a boiling water reactor, wherein the reinforcing plate has an uneven cross section.

2. 2. The steam dryer for a boiling water reactor according to claim 1, 2. A steam dryer for a boiling water reactor, wherein the cross section of the reinforcing plate has an uneven shape, the cross section being rectangular or arc-shaped.

3. 3. The steam dryer for a boiling water reactor according to claim 1, 2. A steam dryer for a boiling water reactor, comprising: a support extending vertically from said reinforcing plate to said steam dryer unit.

4. A steam dryer for a boiling water reactor, comprising: a hood for guiding steam separated by a steam separator disposed above a reactor core composed of a plurality of fuel assemblies arranged in a reactor pressure vessel to a steam dryer unit, the steam dryer comprising the hood, a support ring, a skirt, and a steam dryer unit having a corrugated plate therein, a second hood plate arranged vertically above the first hood plate; a side plate arranged between the first hood plate and the steam dryer unit; and a reinforcing plate attached to the first hood plate and extending vertically to the steam dryer unit, the side plate having a plurality of steam passage holes through which steam passes.

5. A steam dryer for a boiling water reactor, comprising: a hood for guiding steam separated by a steam separator disposed above a reactor core composed of a plurality of fuel assemblies arranged in a reactor pressure vessel to a steam dryer unit, the steam dryer comprising the hood, a support ring, a skirt, and a steam dryer unit having a corrugated plate therein, the hood comprises a first hood plate disposed vertically, a second hood plate disposed vertically above the first hood plate, and a side plate disposed between the first hood plate and the steam dryer unit; 2. A steam dryer for a boiling water reactor, wherein the first hood plate is formed in an uneven shape having a rectangular or arcuate cross section.

6. A steam dryer for a boiling water reactor, comprising: a hood for guiding steam separated by a steam separator disposed above a reactor core composed of a plurality of fuel assemblies arranged in a reactor pressure vessel to a steam dryer unit, the steam dryer comprising the hood, a support ring, a skirt, and a steam dryer unit having a corrugated plate therein, the hood comprises a first hood plate disposed vertically, a second hood plate disposed vertically above the first hood plate, and a side plate disposed between the first hood plate and the steam dryer unit; 13. A steam dryer for a boiling water reactor, wherein the first hood plate has a triangular structure having a vertex in a direction perpendicular to a load acting on the fluid, or a circular arc structure.

7. 7. The steam dryer for a boiling water reactor according to claim 6, 2. A steam dryer for a boiling water reactor, comprising: a support disposed on said first hood plate and extending vertically to said steam dryer unit.

8. The steam dryer for a boiling water reactor according to claim 6 or 7, 2. A steam dryer for a boiling water reactor, comprising: a first hood plate having a horizontal end portion directly attached to said steam dryer unit;

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