JP5885949B2 - Steam generator - Google Patents

Description

  The present invention relates to an earthquake resistant structure of a portion where bent portions of a heat transfer tube included in a steam generator are gathered.

  The steam generator is formed by arranging a plurality of U-shaped heat transfer tubes having U-shaped bent portions. A portion where the U-shaped bent portions are gathered is called a U-bend portion. Structures for improving the resistance (earthquake resistance) of this part to an earthquake are known (Patent Documents 1 and 2).

US Pat. No. 6,772,732 US Pat. No. 5,692,557

  The technology of Patent Document 1 is a structure in which a support member fixes a member that holds a plurality of heat transfer tubes in a U bend portion, but the support member is not fixed to a container of a steam generator. There is a risk that sufficient earthquake resistance cannot be ensured. The technique of Patent Document 2 is a structure in which a heat transfer tube is fixed to a container of a steam generator via a support member. However, if the U-bend portion has a large restraining force, the resistance to flow vibration may be affected.

  An object of this invention is to ensure the earthquake resistance of a U bend part, and the tolerance with respect to a flow vibration.

  In order to solve the above-described problems and achieve the object, the present invention provides a tube that surrounds a U-bend portion where bent portions of a plurality of heat transfer tubes are gathered and surrounds an outer peripheral portion of the U-bend portion. A first support member provided between the outer tube and the U-bend portion at a predetermined interval; and a first support member provided between the first support member and the tube group outer tube. A steam generator comprising: a second support member; and a third support member that is attached to a body portion that houses the plurality of heat transfer tubes and supports the second support member.

  When the U-bend portion vibrates in a direction parallel to the radial direction of the trunk portion having a circular cross section due to an earthquake or the like, the steam generator has a first support member, a second support member, and a third support member. Therefore, the vibration of the U bend part can be received by the body part, so that the earthquake resistance of the U bend part is ensured. Moreover, since the 1st support member is arrange | positioned with a predetermined space | interval with respect to a U bend part, the restraining force of a U bend part can be reduced. For this reason, when the steam generator is in operation, vibration wear and the like of the heat transfer tube due to the secondary cooling water passing between the first support member and the U bend portion can be suppressed. It is possible to reduce the influence on the resistance to the flow vibration of and to ensure the resistance.

  In the present invention, the first support member includes a bridge that connects a plurality of holding members that connect end portions of a plurality of bracing members arranged between the heat transfer tubes in the U bend portion at a predetermined interval. It is preferable that they overlap each other to restrict the movement of the bridge. The restriction member attached to the first support member does not restrain the heat transfer tube supported by the bridge via the anti-vibration member and the holding member in the U bend portion. For this reason, when the steam generator is operated, vibration wear of the bridge due to the secondary cooling water passing through the gap formed between the regulating member and the U-bend portion can be suppressed. The influence which it has on the tolerance with respect to the flow vibration of can be reduced, and the fall of the said tolerance can be suppressed. In addition, when the U-bend portion and the bridge vibrate due to an earthquake or the like, the restriction member supported by the trunk portion via the first support member, the second support member, and the third support member causes the bridge vibration. regulate. Since the space | interval of a control member and a bridge is smaller than the space | interval of a 1st support member and the some heat exchanger tube of a U bend part, the vibration of a U bend part can be suppressed more effectively. As a result, by using the restricting member, the earthquake resistance of the U-bend portion can be ensured more reliably.

  In the present invention, it is preferable that the restricting member has an orifice in a portion facing the bridge. In this way, a damping action that attenuates the vibration of the bridge can be obtained, so that a sudden change in acceleration acting on the plurality of heat transfer tubes of the U bend part is alleviated, and the earthquake resistance of the U bend part is further improved. To do.

  In the present invention, a plurality of the second support members extend radially from the first support member toward the tube group outer tube and are fixed to the tube group outer tube, and a plurality of the third support members It is preferable that a support member extends radially from the tube group outer cylinder and connects the tube group outer cylinder and the body portion. In this way, the first support member is supported by the body of the steam generator via the second support member and the third support member, and the tube group outer tube is supported by the third support member. It is supported by the trunk | drum by a member. Furthermore, since the tube group outer cylinder is reinforced by the first support member and the second support member, the strength is improved. As a result, the heat transfer tube of the U-bend portion that has vibrated due to the earthquake is supported via the first support member, the second support member, the tube group outer tube, and the third support member. Improves.

  In the present invention, it is preferable that a plurality of the first support members overlap each other toward the top of the U-bend portion. By doing in this way, the vibration of a U bend part can be suppressed more reliably and an earthquake resistance can be improved.

  In the present invention, among the plurality of first support members, the plurality of second support members and the plurality of second members are viewed from the direction in which the plurality of first support members are arranged. In some cases it is preferred that they overlap. If it does in this way, disorder of the flow of the secondary cooling water which goes to the top part of a U bend part from a pipe support plate can be controlled.

  The present invention can ensure the earthquake resistance of the U-bend part and the resistance to flow vibration.

FIG. 1 is a schematic view of a steam generator according to this embodiment. FIG. 2 is a diagram illustrating a bent portion of the heat transfer tube. FIG. 3 is a perspective view of the U-bend portion. FIG. 4 is a perspective view showing the earthquake-resistant structure of the steam generator according to this embodiment. FIG. 5 is a plan view of the earthquake-resistant structure of the steam generator according to this embodiment. FIG. 6 is an enlarged view of a part of the earthquake-resistant structure of the steam generator according to the present embodiment. FIG. 7 is a diagram illustrating a relationship between the restriction member and the bridge in the earthquake-resistant structure of the steam generator according to the present embodiment. FIG. 8 is a plan view showing an earthquake resistant structure according to a modification of the present embodiment. FIG. 9 is a diagram illustrating a modification of the restricting member. FIG. 10 is a diagram illustrating a modification of the restricting member. FIG. 11 is a diagram illustrating a modification of the restricting member. FIG. 12 is a diagram illustrating a modified example of the restricting member.

  DESCRIPTION OF EMBODIMENTS Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the constituent elements described below can be appropriately combined. In addition, various omissions, substitutions, or changes of components can be made without departing from the scope of the present invention. In this embodiment, the bottom is the vertical direction (direction in which gravity acts), and the top is the opposite side to the vertical direction.

  FIG. 1 is a schematic view of a steam generator according to this embodiment. FIG. 2 is a diagram illustrating a bent portion of the heat transfer tube. FIG. 3 is a perspective view of the U-bend portion. The steam generator 1 is used, for example, in a pressurized water reactor (PWR: Pressurized Water Reactor). The pressurized water reactor uses light water as a reactor coolant and neutron moderator. The pressurized water reactor uses light water as the primary coolant. The pressurized water reactor sends a primary coolant (primary cooling water) to the steam generator 1 as high-temperature high-pressure water that does not boil over the entire core. In the steam generator 1, the heat of the high-temperature and high-pressure primary cooling water is transmitted to the secondary coolant (secondary cooling water), and the secondary cooling water is used as steam. This steam is sent to the steam turbine to drive it. Since the input shaft of the generator is connected to the output shaft of the steam turbine, the generator driven by the steam turbine generates electric power.

  The steam generator 1 has a trunk portion 2. The trunk | drum 2 is a hollow cylindrical shape extended in the up-down direction and sealed, Comprising: The lower half part is a structure with a smaller diameter with respect to an upper half part. As for the trunk | drum 2, the water chamber 7 is arrange | positioned at the one end part side, and the steam discharge port 12 is arrange | positioned at the other end part side. The steam generator 1 is installed with the water chamber 7 facing downward and the steam outlet 12 facing upward.

  A cylindrical tube group outer tube (wrapper tube) 3 disposed at a predetermined distance from the inner wall surface of the body part 2 is provided from the lower half part to the upper half part of the body part 2. The lower end portion of the tube group outer tube 3 extends to the tube plate 4 disposed below in the lower half of the body portion 2. In the tube group outer cylinder 3, a heat transfer tube group 51 having a plurality of heat transfer tubes 5 having a U-shaped bent portion 5U as shown in FIG. 2 is provided. Each heat transfer tube 5 is arranged with the U-shaped portion of the bent portion upward, that is, toward the steam outlet 12, and the lower portion, that is, the end facing the water chamber 7 side is supported by the tube plate 4, The part is supported by a plurality of tube support plates 6. A portion where the U-shaped bent portions of the plurality of heat transfer tubes 5 are gathered is a U-bend portion 18. The U-bend portion 18 is disposed above the heat transfer tube group 51, that is, on the steam discharge port 12 side. A large number of through holes are formed in the tube support plate 6, and the heat transfer tubes 5 pass through the through holes in a non-contact state.

  A water chamber 7 is provided at the lower end of the body 2. The water chamber 7 is divided into an entrance chamber 71 and an exit chamber 72 by a partition wall 8. One end of each heat transfer tube 5 communicates with the entrance chamber 71, and the other end of each heat transfer tube 5 communicates with the exit chamber 72. In addition, an inlet nozzle 711 leading to the outside of the trunk portion 2 is formed in the entrance chamber 71, and an outlet nozzle 721 leading to the outside of the trunk portion 2 is formed in the exit chamber 72. The inlet nozzle 711 is connected to a cooling water pipe through which primary cooling water is sent from the pressurized water reactor. The outlet nozzle 721 is connected to a cooling water pipe for sending the primary cooling water after heat exchange to the pressurized water reactor.

  In the upper half of the body portion 2, a moisture separator 9 that separates the feed water W into steam S and hot water, and moisture separation in which the moisture of the separated steam S is removed to make it close to dry steam. A vessel 10 is provided. Between the steam / water separator 9 and the heat transfer tube group 51, a water supply pipe 11 for supplying secondary cooling water into the body 2 from the outside is inserted. Further, a steam discharge port 12 is formed at the upper end portion of the body portion 2. Further, in the lower half of the body part 2, the secondary cooling water supplied from the water supply pipe 11 into the body part 2 is caused to flow down between the body part 2 and the tube group outer tube 3 by the tube plate 4. A water supply path 13 that is folded back and raised along the heat transfer tube group 51 is provided. The steam outlet 12 is connected to a cooling water pipe for sending steam to the turbine, and the water supply pipe 11 is used to supply secondary cooling water in which steam used in the turbine is cooled by a condenser. Cooling water piping is connected.

  In such a steam generator 1, the primary cooling water heated in the pressurized water reactor is sent to the entrance chamber 71, circulates through a large number of heat transfer tubes 5, and reaches the exit chamber 72. On the other hand, the secondary cooling water cooled by the condenser is sent to the water supply pipe 11 and rises along the heat transfer pipe group 51 through the water supply path 13 in the trunk portion 2. At this time, heat exchange is performed between the high-pressure and high-temperature primary cooling water and the secondary cooling water in the body portion 2. Then, the cooled primary cooling water is returned from the outlet chamber 72 to the pressurized water reactor. On the other hand, the secondary cooling water heat-exchanged with the high-pressure and high-temperature primary cooling water rises in the body portion 2 and is separated into steam and hot water by the steam separator 9. The separated steam is sent to the turbine after moisture is removed by the moisture separator 10.

  In the steam generator 1, when the primary cooling water passes through each heat transfer tube 5, fluid excitation vibration is generated in the inverted U-shaped bent portion 5 </ b> U. Therefore, a bent member 5U of the heat transfer tube 5 is provided with a bracing member. The upper end of the heat transfer tube group 51 is the U-bend portion 18. The bend portion 18 is a portion where a plurality of inverted U-shaped bent portions 5U of the heat transfer tubes 5 are arranged. As shown in FIG. 3, the heat transfer tubes 5 are arranged such that the bent portion 5U has a large radius of curvature toward the outside (upper side), and the curved radius of the bent portion 5U is changed while overlapping the arranged ones. Thus, the upper end portion of the heat transfer tube group 51 is formed in a hemispherical shape. That is, the U bend portion 18 has a hemispherical shape, and the portion closest to the steam discharge port 12 shown in FIG.

  The bracing member 14 is inserted between the stacked rows of the heat transfer tubes 5. The bracing member 14 is a member in which a bar-shaped member having a rectangular cross section is formed in a substantially V shape. The bracing member 14 has bent portions disposed at the same diameter portions (predetermined positions) in the stacked rows of the heat transfer tubes, and both ends of the bent portion outside the arc portion of the heat transfer tube 5 having the largest curvature radius. The part is projected. For this reason, the end of the bracing member 14 is arranged in a line along the arc of the heat transfer tube group 51.

  Further, the anti-rest member 14 is paired with a small V-shaped member disposed inside a large substantially V-shaped member. In the present embodiment, three pairs of the bracing members 14 are arranged in the semicircular portion of the heat transfer tube 5. Furthermore, the part inserted between the row | line | columns of the piled heat exchanger tube 5 is formed with the material (for example, SUS405) preferable for suppressing the vibration.

  As shown in FIG. 3, the holding member 16 is welded to the end of the anti-vibration member 14 to connect the ends of the plural anti-vibration members 14. The holding member 16 is an arc-shaped rod-shaped member attached along the outer periphery of the U-bend portion 18, that is, the hemispherical outer periphery of the heat transfer tube group 51. The holding member 16 extends in a direction orthogonal to the direction in which the plurality of heat transfer tubes 5 are stacked. The bridges 17 are connected to the plurality of holding members 16. The bridge 17 is an arc-shaped and plate-shaped member disposed along the outer periphery of the U-bend portion 18, that is, the hemispherical outer periphery of the heat transfer tube group 51. The bridge 17 extends along the direction in which the heat transfer tube 5 extends in the U-bend portion 18. Although one bridge 17 is shown in FIG. 3, a plurality of bridges 17 are arranged in a direction parallel to the direction in which the plurality of heat transfer tubes 5 are stacked. Next, the earthquake-resistant structure of the steam generator according to this embodiment will be described.

  FIG. 4 is a perspective view showing the earthquake-resistant structure of the steam generator according to this embodiment. FIG. 5 is a plan view of the earthquake-resistant structure of the steam generator according to this embodiment. FIG. 6 is an enlarged view of a part of the earthquake-resistant structure of the steam generator according to the present embodiment. FIG. 7 is a diagram illustrating a relationship between the restriction member and the bridge in the earthquake-resistant structure of the steam generator according to the present embodiment. The seismic structure (hereinafter referred to as seismic structure) 20 of the steam generator includes an annular member 21 (21A, 21B) as a first support member, a second support member 22 (22A, 22B), and a third support. Member 23 (23A, 23B). The earthquake-resistant structure 20 has two annular members 21, two second support members 22, and three third support members 23, respectively. In the following, when distinguishing these, the code A is added to the pipe support plate 6 side, and the code A is added to the top 18T side of the U bend part 18. When these are not distinguished, the symbols A and B are not added.

  The annular member 21 surrounds and surrounds the U bend portion 18 where the bent portions 5U of the plurality of heat transfer tubes 5 are gathered. The annular member 21 is provided with a predetermined distance from the U bend portion 18 between the tube group outer cylinder 3 surrounding the outer periphery of the U bend portion 18. The second support member 22 is provided between the annular member 21 and the tube group outer cylinder 3 to support the annular member 21 on the tube group outer cylinder 3. The third support member 23 is attached to the body 2 (more specifically, the inner peripheral surface of the body 2) that houses the plurality of heat transfer tubes 23, and supports the second support member 22. Since the tube group outer cylinder 3 is interposed between the second support member 22 and the third support member 23, the third support member 23 is connected to the annular member 21 via the tube group outer cylinder 3. Is supported by the body 2. The annular member 21 is a structure having a circular plan view. The annular member 21 may form a hollow circular tube in an annular shape, or may form a solid rod-like member having a circular cross section in an annular shape.

  As shown in FIG. 6, the plurality of second support members 22 are provided on the radially outer side of the annular member 21, and extend radially from the annular member 21 toward the tube group outer tube 3. The plurality of third support members 23 extend in a direction parallel to the radial direction of the body portion 2 from the inner surface of the body portion 2 having a circular cross section toward the tube group outer tube 3. That is, the plurality of third support members 23 extend radially from the tube group outer tube 3.

  The end of the second support member 22 opposite to the annular member 21 side is fixed to the tube group outer tube 3 via a pedestal 27. The 2nd support member 22 and the base 27 are joined and joined by welding, for example. The base 27 is fixed to the tube group outer cylinder 3 by fastening means such as bolts. With such a structure, the second support member 22 is fixed to the tube group outer tube 3.

  A base 27 is attached to both ends of the third support member 23. The third support member 23 and the pedestal 27 are attached by being joined by welding, for example. The pedestal 27 on the one end portion side of the third support member 23 is fixed to the trunk portion 2 by fastening means such as a bolt, for example. Further, the pedestal 27 on the other end side of the third support member 23 is attached to the tube group outer tube by a bolt that fixes the pedestal 27 attached to the second support member 22 to the tube group outer tube 3. Fixed. With such a structure, the third support member 23 connects the body portion 2 and the tube group outer tube 3. The annular member 21 is supported by the trunk portion 2 via the second support member 22 and the third support member 23. In the present embodiment, the annular member 21A on the tube support plate 6 side and the annular member 21B on the top portion 18T side of the U-bend portion 18 have different diameters, but the second support members 22A and 22B and the third member respectively. It is supported by the trunk | drum 2 by support member 23A, 23B.

  When the U-bend portion 18 vibrates in a direction parallel to the radial direction of the trunk portion 2 having a circular cross section due to an earthquake or the like, the annular member 21, the second support member 22, and the third support member 23 are interposed. Since the vibration of the U-bend portion 18 can be received by the body portion 2, the earthquake resistance of the U-bend portion 18 is ensured. Further, since the annular member 21 is disposed with a predetermined interval with respect to the U bend portion 18, the restraining force of the U bend portion 18 can be reduced. In this embodiment, since the annular member 21 does not restrain the heat transfer tube 5 of the U bend portion 18, the restraining force is zero. For this reason, when the steam generator 1 is operated, vibration wear of the heat transfer tube 5 and the like due to the secondary cooling water passing between the annular member 21 and the U bend portion 18 can be suppressed. As a result, the earthquake-resistant structure 20 having the annular member 21 can reduce the influence on the resistance against the flow vibration of the heat transfer tube 5 and ensure the resistance. Moreover, since the seismic structure 20 can attach the annular member 21, the 2nd support member 22, and the 3rd support member 23 by repair work also with respect to the existing steam generator 1, the existing steam generator 1 is attached. Can improve the earthquake resistance.

  In the present embodiment, the annular member 21 of the earthquake-resistant structure 20 has a regulating member 24 shown in FIGS. As shown in FIGS. 6 and 7, the restricting member 24 is a bridge 17 that connects a plurality of holding members 16 that connect end portions of the plurality of bracing members 14 disposed between the heat transfer tubes 5 in the U bend portion 18. Is sandwiched at a predetermined interval C to restrict the movement of the bridge 17. More specifically, the holding member 16 restricts the movement of the bridge 17 in the direction in which the heat transfer tubes 5 are overlapped.

  The restricting member 24A has a groove 24S. The bridge 17 is sandwiched between the grooves 24S with a predetermined interval C. The restricting member 24A is attached to the annular member 21A and the restricting member 24B is attached to the annular member 21B, for example, by joining means such as welding. Since the regulating member 24 and the bridge 17 have a predetermined distance C (about 5 mm to 10 mm), a gap is generated between them.

  With such a structure, the regulating member 24 attached to the annular member 21 does not restrain the heat transfer tube 5 supported by the bridge 17 via the bracing member 14 and the holding member 16 in the U bend portion 18. The binding force of the heat transfer tube 5 is zero. For this reason, when the steam generator 1 is operated, vibration wear of the bridge 17 due to the secondary cooling water passing through the gap formed between the regulating member 24 and the U bend portion 18 can be suppressed. . As a result, the earthquake-resistant structure 20 having the annular member 21 can reduce the influence on the resistance against the flow vibration of the heat transfer tube 5 and can suppress the decrease in the resistance. Further, when the U-bend portion 18 and the bridge 17 vibrate due to an earthquake or the like, the regulating member 24 supported by the trunk portion 2 via the annular member 21, the second support member 22, and the third support member 23 is The vibration of the bridge 17 is regulated. Since the bridge 17 supports the plurality of heat transfer tubes 5 of the U-bend portion 18, these vibrations are also restricted by the restriction member 24. Since the spacing between the regulating member 24 and the bridge 17 is smaller than the spacing between the annular member 21 and the plurality of heat transfer tubes 5 of the U bend portion 18, if the regulating member 24 is used, the vibration of the U bend portion 18 can be more effectively performed. Can be suppressed. As a result, the earthquake resistant structure 20 having the regulating member 24 can ensure the earthquake resistance of the U bend portion 18 more reliably.

  In the present embodiment, a plurality of annular members 21 are arranged toward the top portion 18T of the U bend portion 18. More specifically, two annular members 21 </ b> A and 21 </ b> B are arranged from the tube support plate 6 toward the top portion 18 </ b> T of the U bend portion 18. By doing in this way, vibration of U bend part 18 can be controlled more certainly, and earthquake resistance can be further secured. The number of annular members 21 is not limited to two, and may be three or more. Further, if the single bend member 21 can ensure the earthquake resistance of the U-bend portion 18, the number of the ring members 21 may be one.

  When the earthquake-resistant structure 20 has a plurality of annular members 21, between the plurality of annular members 21, the plurality of second support members 22 and the plurality of second members 23 are arranged in a direction in which the plurality of annular members 21 are arranged. When viewed from above, it is preferable that they overlap. If it does in this way, disorder of the flow of the secondary cooling water which goes from pipe support plate 6 to top 18T of U bend part 18 can be controlled. The plurality of second support members 22 and the plurality of second members 23 do not exclude overlapping when viewed from the direction in which the plurality of annular members 21 are arranged.

  FIG. 8 is a plan view showing an earthquake resistant structure according to a modification of the present embodiment. In the seismic structure 20 shown in FIG. 5, the second support member 22 and the third support member 23 extend radially from the annular member 21. The difference is that the support member 22a and the third support member 23a do not extend radially from the annular member 21a. When the second support member 22 and the third support member 23 extend radially from the annular member 21, they extend in a direction parallel to the radial direction of the annular member 21. That is, the second support member 22 and the third support member 23 extend in a direction orthogonal to the tangent line of the outer peripheral portion of the annular member 21. In the present modification, the second support member 22a and the third support member 23a extend in directions other than orthogonal to the tangent line of the outer peripheral portion of the annular member 21a. Even in this case, the annular member 21a is supported by the body portion 2 via the second support member 22a and the third support member 23a.

  In the present embodiment, the annular members 21 and 21a have been described as an example of the first support member. However, the first support member is not limited to the annular member 21 and the like. In other words, the first support member surrounds the U bend portion 18 so as to surround the outer periphery of the U bend portion 18 and surrounds the outer periphery of the U bend portion 18 with respect to the U bend portion 18. Any member may be used as long as it is provided with an interval of. Therefore, the first support member may be a cage member that surrounds and covers the U-bend portion 18, for example.

(Modification example of restriction member)
9 to 12 are diagrams showing modifications of the restricting member. The restriction member according to this modification is different in that an orifice is provided in a portion facing the bridge. The regulating member 24a shown in FIGS. 9 and 10 has a plurality of orifices 25 penetrating from the portion facing the bridge 17a in the groove 24S to the outer portion 24Y. The bridge 17a has both side surfaces 17Sa sandwiched between the regulating members 24a. The regulating member 24a has an orifice 25 at a portion facing both the side surfaces 17Sa. In the bridge 17a, a portion (bridge end portion) 17Ta sandwiched between the groove portions 24S of the regulating member 24a has a width larger than the other portions. The restricting member 24a has an extending portion 24E that extends from both outer portions 24Y to the opening of the groove portion 24S. Since the dimension between the two extending portions 24E is smaller than the width of the bridge end portion 17Ta, the bridge 17a is prevented from falling off from the groove portion 24S. As shown in FIG. 10, the orifice 25 has a smaller inner diameter than the opening, but the orifice 25 is not limited to such a configuration.

  A predetermined interval Ca is provided between both side surfaces 17Sa of the bridge end portion 17Ta and the groove portion 24S of the regulating member 24a. In addition, a predetermined interval Cb is provided between the extending portion 24E and the bridge end portion Ta. Since the restriction member 24 has the orifice 25, when the bridge end portion Ta moves in the groove 24S, the secondary cooling water in the groove 24S flows in and out of the orifice 25. As a result, a damping action for attenuating the vibration of the bridge 17a is obtained, and a sudden change in acceleration acting on the plurality of heat transfer tubes 5 of the U-bend portion 18 is mitigated. As a result, the earthquake resistance of the U bend portion is further improved. The secondary cooling water also flows in and out from a predetermined distance Cb provided between the extending portion 24E and the bridge end portion Ta. As a result, the damping action of the vibration of the bridge 17a is also obtained by this, so that the earthquake resistance of the U-bend portion 18 is further improved.

  The regulation member 24b shown in FIG. 11 has an intermediate support member 26 having a U-shaped cross section facing the both side surfaces 17S of the bridge 17 in the groove 24S. A spring 27 is disposed between the intermediate support member 26 and the regulating member 24b. The spring 27 applies a force toward the bridge 17 to the intermediate support member 26. In addition, the regulating member 24b has a plurality of orifices 25 penetrating from the portion facing the bridge 17 in the groove 24S to the outer portion 24Y, similarly to the regulating member 24a shown in FIGS. With such a structure, the restricting member 24 b can obtain an impact absorbing action by the spring 27 in addition to the damping action of the vibration of the bridge 17 by the orifice 25. As a result, the restricting member 24b can further improve the earthquake resistance of the U-bend portion 18.

  The restriction member 24c shown in FIG. 12 has an intermediate support member 26c facing the both side surfaces 17S of the bridge 17 in the groove portion 24S, like the restriction member 24b shown in FIG. The difference is that the bridge end 17Tc is clamped by the support member 26c. For this reason, the two intermediate supporting members 26c are in contact with the bridge end portion 17Tc. The bridge end 17Tc has a circular cross section. By doing so, the inclination of the bridge 17c with respect to the intermediate support member 26c can be allowed.

  A spring 27 is disposed between each intermediate support member 26c and the regulating member 24c. The spring 27 applies a force toward the bridge 17 to the intermediate support member 26. With such a structure, the restricting member 24c can obtain an impact absorbing action by the spring 27 in addition to the damping action of the vibration of the bridge 17c by the orifice 25, similarly to the restricting member 24b described above. As a result, the regulating member 24c can further improve the earthquake resistance of the U-bend portion 18.

DESCRIPTION OF SYMBOLS 1 Steam generator 2 Body 3 Tube group outer cylinder 4 Tube plate 5 Heat transfer tube 5U Bending part 6 Tube support plate 7 Water chamber 8 Partition 9 Steam-water separator 10 Humidity separator 11 Water supply pipe 12 Steam discharge port 13 Water supply path 14 Bracing member 16 Holding member 17, 17a, 17c Bridge 17Ta, 17Tc Bridge end portion 17S, 17Sa Side surface 18 U bend portion 18T Top portion 20, 20a Seismic structure 21, 21A, 21B, 21a Annular member (first support member)
22, 22A, 22B, 22a 2nd support member 23, 23A, 23B, 23a 3rd support member 24, 24A, 24B, 24a Control member 24E Extension part 24Y Outer part
24S groove 25 orifice 26, 26c intermediate support member 27 pedestal

Claims (6)

A predetermined interval with respect to the U-bend portion between the outer periphery of the U-bend portion and surrounding the U-bend portion where the bent portions of the plurality of heat transfer tubes are gathered A first support member provided with
A second support member provided between the first support member and the tube group outer cylinder;
A third support member that is attached to a body portion that houses the plurality of heat transfer tubes and supports the second support member;
A steam generator characterized by comprising:   The first support member sandwiches a bridge that connects a plurality of holding members that connect end portions of a plurality of bracing members arranged between the heat transfer tubes in the U bend portion with a predetermined interval. The steam generator according to claim 1, further comprising a regulating member that regulates movement of the bridge.   The steam generator according to claim 2, wherein the restriction member has an orifice at a portion facing the bridge. A plurality of the second support members extending radially from the first support member toward the tube group outer tube and fixed to the tube group outer tube;
The steam according to any one of claims 1 to 3, wherein a plurality of the third support members extend radially from the tube group outer cylinder and connect the tube group outer cylinder and the body portion. Generator.   The steam generator according to any one of claims 1 to 4, wherein a plurality of the first support members are arranged toward the top of the U-bend portion. Between a plurality of said first support member, a plurality of said second support member What happened, the steam generator according to claim 5 which overlap when viewed from a direction in which the plurality of the first support member are arranged vessel.