Earthquake resistance support device for nuclear power plant, and nuclear power plant

Abstract

To suppress horizontal vibration of a nuclear pressure vessel during an earthquake, and make a dynamic vibration absorber compact to suppress an installation space of the dynamic vibration absorber, in a nuclear power plant.SOLUTION: An earthquake resistance support device for a nuclear power plant is arranged in a reactor containment vessel, and suppresses horizontal vibration of a reactor pressure vessel supported by a pedestal when an earthquake occurs. The earthquake resistance support device comprises a horizontal beam that is arranged between the reactor containment vessel and the reactor pressure vessel, and the pedestal, and extends in the radial direction of the reactor pressure vessel and the pedestal; and a dynamic vibration absorber installed on the horizontal beam. The dynamic vibration absorber comprises a hollow weight extrapolated to the horizontal beam and movable in an axial direction of the horizontal beam, and a coil spring device that elastically supports the hollow weight in the axial direction of the horizontal beam, to allow the hollow weight to vibrate in the axial direction of the horizontal beam.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a seismic support device for a nuclear power plant having a reactor pressure vessel supported by a pedestal within a nuclear reactor containment vessel, and to the nuclear power plant. [Background technology]

[0002] Conventionally, inside a reactor building, a reactor pressure vessel (hereinafter referred to as the "pressure vessel"), a reactor pressure vessel pedestal (hereinafter referred to as the "pedestal") that supports the pressure vessel, and a reactor containment vessel that houses the pressure vessel and the pedestal are installed.

[0003] In such a reactor containment vessel, an earthquake-resistant support device is provided to suppress vibrations of the pressure vessel and the pedestal in the event that a large shaking occurs in the reactor building due to an earthquake.

[0004] For example, Patent Document 1 describes a pedestal support structure that can reduce the load generated at the base of a reactor pressure vessel pedestal due to an earthquake, and that includes a load transfer part fixed to the outer peripheral surface of the pedestal and a support arm rotatably supported on the load transfer part, and the containment vessel side end of the support arm is supported on the containment vessel so that it can rotate or move circumferentially.

[0005] Also described is an embodiment in which an extension section that can be extended and retracted in the longitudinal direction is arranged on the support arm (FIG. 12), and an embodiment in which a compression coil spring and a damper are arranged on the support arm (FIG. 13).

[0006] On the other hand, dynamic vibration absorbers for suppressing vibrations are disclosed in Patent Documents 2 and 3.

[0007] The dynamic vibration absorber described in Patent Document 2 consists of a long support handle that is attached in a cantilevered manner to a vibrating body that is subjected to forced vibrations, a weight that is movably attached to the support handle so that the distance from the fulcrum of the support handle can be changed and that can increase or decrease the natural frequency k2 of the support handle vibration system as it moves, and a means for moving the weight in response to changes in the frequency ω of the vibrated body, thereby allowing the natural frequency to accurately follow changes in the frequency of the ship's engine and reliably stopping the vibration of the vibrated body, that is, the hull, i.e., the structure.

[0008] Patent Document 3 describes a columnar vibration control device as a dynamic vibration absorber, which comprises a cylindrical weight inserted at a distance from the lightning rod, and a spring member that connects the lightning rod and the weight and allows the weight to swing, thereby making it possible to suppress the vibration of a columnar body with a simple structure. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 2019-2728 [Patent Document 2] Japanese Patent Application Publication No. 59-50243 [Patent Document 3] Japanese Patent Publication No. 2022-27181 Summary of the Invention [Problem to be solved by the invention]

[0010] The response characteristics of a nuclear power plant during an earthquake are affected by the characteristics of the ground on which the plant is located, etc. Therefore, the response of major equipment such as the pressure vessel inside the reactor containment vessel also changes, so the structure of major equipment must be designed to suit the location.

[0011] The support structure in Patent Document 1 has an extension section on the support arm and is equipped with a compression coil spring and a damper. However, since it is not a dynamic vibration absorber that controls vibration by the vibration of a weight, it is insufficient to suppress the vibration of major equipment in a nuclear power plant, such as the reactor pressure vessel, during an earthquake.

[0012] Furthermore, the support structure of Patent Document 1 rotatably supports a support arm on a load transmission part fixed to the outer peripheral surface of the pedestal, and the containment vessel side end of the support arm is supported on the containment vessel so that it can rotate or move circumferentially, and furthermore, an expansion part or a compression coil spring and a damper are arranged on the support arm, which results in a large support structure. However, various equipment is arranged inside the reactor containment vessel, and if the support structure becomes large, it becomes difficult to secure a large space to arrange the support structure.

[0013] Furthermore, in nuclear power plants, it is necessary to suppress horizontal vibrations caused by earthquakes, but the dynamic vibration absorber in Patent Document 2 is for ships and is specialized for suppressing vertical vibrations, and the dynamic vibration absorber in Patent Document 3 is for lightning rods and is specialized for suppressing vibrations of vertical supports, and there was a problem that neither of them could be applied to suppressing horizontal vibrations such as earthquake-resistant support devices in nuclear power plants.

[0014] An object of the present invention is to provide an earthquake-resistant support device for a reactor pressure vessel, and a nuclear power plant, which can suppress horizontal vibrations of the reactor pressure vessel during an earthquake, and which uses a compact dynamic vibration absorber that can reduce the installation space required for the dynamic vibration absorber. [Means for solving the problem]

[0015] In order to solve the above problems and achieve the objects, the present invention has the following configuration: That is, the present invention provides an earthquake-resistant support device for a nuclear power plant that is disposed within a reactor containment vessel and that suppresses horizontal vibrations of a reactor pressure vessel supported by a pedestal in the event of an earthquake, the support device comprising: a horizontal beam that is disposed between the reactor containment vessel, the reactor pressure vessel, and the pedestal and extends in a radial direction of the reactor pressure vessel and the pedestal; and a dynamic vibration absorber that is attached to the horizontal beam, the dynamic vibration absorber comprising: a hollow weight that is extrapolated to the horizontal beam and is movable in the axial direction of the horizontal beam; and a coil spring device that elastically supports the hollow weight in the axial direction of the horizontal beam, allowing the hollow weight to vibrate in the axial direction of the horizontal beam.

[0016] As a result, when an earthquake occurs, the hollow weight vibrates in the axial direction (horizontal direction) of the horizontal beam due to the coil spring device, thereby suppressing horizontal vibration of the reactor pressure vessel.

[0017] Furthermore, since the hollow weight and the coil spring device are arranged side by side in the axial direction (horizontal direction) of the horizontal beam, the dynamic vibration absorber has a compact structure and the installation space for the dynamic vibration absorber can be reduced. [Effects of the Invention]

[0018] According to the present invention, it is possible to suppress horizontal vibrations of a reactor pressure vessel when an earthquake occurs, and the dynamic vibration absorber is compact, so that the installation space for the dynamic vibration absorber can be reduced. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a cross-sectional view of a nuclear power plant equipped with an earthquake-resistant support device for a reactor pressure vessel according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view showing the arrangement of earthquake-resistant support devices in a reactor containment vessel. [Figure 3] 2 is a diagram showing the details of the structure of the dynamic vibration absorber 3 in the first embodiment of the present invention. FIG. [Figure 4A] 4 is a cross-sectional view of the AA section of FIG. 3 as viewed from the direction of the arrow. [Figure 4B] 4 is a cross-sectional view of the cross section BB in FIG. 3 as viewed from the direction of the arrow. [Figure 4C] 4 is a cross-sectional view of the CC section of FIG. 3 as seen from the direction of the arrow. [Figure 4D] 4 is a cross-sectional view of the DD cross section of FIG. 3 as seen from the direction of the arrow. [Figure 5] 1 is a model diagram of a vibration system for explaining the operating principle of the earthquake-resistant support device of this embodiment. FIG. [Figure 6] FIG. 10 is a diagram showing details of a horizontal beam 2 and a dynamic vibration absorber 3 in a second embodiment of the present invention. [Figure 7A] 7 is a cross-sectional view of the AA section of FIG. 6 as seen from the direction of the arrow. [Figure 7B] 7 is a cross-sectional view of the cross section BB in FIG. 6 as seen from the direction of the arrow. [Figure 7C] 7 is a cross-sectional view of the CC section of FIG. 6 as seen from the direction of the arrow. [Figure 7D] 7 is a cross-sectional view of the DD cross section of FIG. 6 as seen from the direction of the arrow. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0021] First Embodiment FIG. 1 is a cross-sectional view of a nuclear power plant equipped with an earthquake-resistant support device for a reactor pressure vessel according to a first embodiment of the present invention.

[0022] In FIG. 1, a nuclear power plant 100 of this embodiment includes a reactor building 101, a reactor containment vessel 102 constructed in the reactor building 101, a reactor pressure vessel (hereinafter sometimes simply referred to as the "pressure vessel") 103 which is disposed in the reactor containment vessel 102 and which is the main equipment of the nuclear power plant 100 and which houses a reactor core 103a, and a reactor pressure vessel pedestal (hereinafter sometimes simply referred to as the "pedestal") 104 which supports the pressure vessel 103.

[0023] The containment vessel 102 is formed in a cylindrical shape to be airtight. The pedestal 104 is erected upward from the floor formed at the bottom of the containment vessel 102, and the pressure vessel 103 is supported on the upper end of the pedestal 104.

[0024] Furthermore, the nuclear power plant 100 of this embodiment is provided with an earthquake-resistant support device 1 that is disposed inside the reactor containment vessel 102 and that suppresses horizontal vibration of the pedestal 104 in the event of an earthquake, thereby suppressing horizontal vibration of the reactor pressure vessel 103 supported by the pedestal 104.

[0025] FIG. 2 is a perspective view showing the arrangement of earthquake-resistant support devices in the reactor containment vessel.

[0026] In Figure 2, the nuclear power plant 100 of this embodiment has multiple seismic support devices 1, which are arranged radially in the radial direction of the pressure vessel 103 and the pedestal 104 to surround the pressure vessel 103 and the pedestal 104.

[0027] As shown in FIG. 1, each of the multiple earthquake-resistant support devices 1 is disposed between the reactor containment vessel 102 and the pressure vessel 103 and pedestal 104, and includes a horizontal beam 2 extending in the radial direction of the pressure vessel 103 and pedestal 104, and a dynamic vibration absorber 3 installed on the horizontal beam 2.

[0028] In this embodiment, the outer ends of the horizontal beams 2 are joined to the inner circumferential surface of the containment vessel 102 by welding or the like, and the inner ends are joined to the outer circumferential surface of the steel plate covering the concrete of the pedestal 104 by welding or the like.

[0029] In addition, a shield wall that covers the periphery of the pressure vessel 103 may be installed at the upper end of the pedestal 104. In this case, the inner end of the horizontal beam 2 may be joined to the outer peripheral surface of the shield wall so that the horizontal beam 2 indirectly supports the pedestal 104.

[0030] FIG. 3 is a diagram showing the details of the structure of the dynamic vibration absorber 3 in the first embodiment of the present invention.

[0031] 4A is a cross-sectional view of the AA section of FIG. 3 as seen from the direction of the arrow shown, FIG. 4B is a cross-sectional view of the BB section of FIG. 3 as seen from the direction of the arrow shown, FIG. 4C is a cross-sectional view of the CC section of FIG. 3 as seen from the direction of the arrow shown, and FIG. 4D is a cross-sectional view of the DD section of FIG. 3 as seen from the direction of the arrow shown.

[0032] In Figures 3 and 3A to 3D, the dynamic vibration absorber 3 is extrapolated to the horizontal beam 2 and includes a hollow weight 5 that is movable in the axial direction of the horizontal beam 2, and a coil spring device 10 that elastically supports the hollow weight 5 in the axial direction of the horizontal beam 2 and allows the hollow weight 5 to vibrate in the axial direction of the horizontal beam 2.

[0033] By arranging the hollow weight 5 and the coil spring device 10 relative to the horizontal beam 2 in this manner, the hollow weight 5 is caused to vibrate in the axial direction (horizontal direction) of the horizontal beam 2 by the coil spring device 10 when an earthquake occurs, thereby suppressing horizontal vibration of the reactor pressure vessel 103.

[0034] In addition, the hollow weight 5 is extrapolated to the horizontal beam 2, and the coil spring device 10, which elastically supports the hollow weight 5 in the axial direction of the horizontal beam 2, is positioned juxtaposed to the hollow weight 5 in the axial direction (horizontal direction) of the horizontal beam 2, so that the configuration of the dynamic vibration absorber 3 is compact and the installation space for the dynamic vibration absorber 3 can be reduced.

[0035] The coil spring device 10 also includes a first coil spring assembly 6 and a second coil spring assembly 7, which are arranged on both axial sides of the hollow weight 5 and elastically support the hollow weight 5 in the axial direction of the horizontal beam 2.

[0036] When the coil spring assemblies of the coil spring device 10 are arranged on both sides of the hollow weight 5 in this way, the configuration of the dynamic vibration absorber 3 becomes symmetrical in the axial direction of the horizontal beam 2. This simplifies the design of the dynamic vibration absorber 3, stabilizes the vibration of the weight 5, and provides good vibration-damping action. Furthermore, because the coil springs are distributed and the amount of deflection of each individual coil spring due to its own weight is reduced, this also stabilizes the vibration of the weight 5 and provides good vibration-damping action.

[0037] In addition, in this embodiment, the first coil spring assembly 6 includes three coil springs 6a, 6b, and 6c arranged at equal intervals in the circumferential direction of the horizontal beam 2, and the second coil spring assembly 7 similarly includes three coil springs 7a, 7b, and 7c arranged at equal intervals in the circumferential direction so as to surround the horizontal beam 2.

[0038] Here, if the first coil spring assembly 6 and the second coil spring assembly 7 are each constructed from a single coil spring, the coil spring will need to be large in order to ensure the rigidity required as a dynamic vibration absorber to suppress vibrations of the main equipment inside the reactor containment vessel 102, making it difficult to manufacture.

[0039] Furthermore, if the first coil spring assembly 6 and the second coil spring assembly 7 are each composed of two coil springs, asymmetric vibrations (vibrations in directions other than the direction in which the two coil springs are aligned) are more likely to occur in the direction perpendicular to the axis of the horizontal beam 2 (direction perpendicular to the axial direction of the horizontal beam 2).

[0040] In this embodiment, the first coil spring assembly 6 and the second coil spring assembly 7 are each composed of three coil springs arranged at equal intervals in the circumferential direction so as to surround the horizontal beam 2. As a result, when viewed in a cross section perpendicular to the axis, the three coil springs are located at the vertices of a triangle, with two coil springs lined up in three directions along the three sides of the triangle, thereby increasing the symmetry of vibration in the direction perpendicular to the axis. As a result, vibrations that are dominant in a specific direction do not occur, and the coil springs can expand and contract stably, allowing the hollow weight 5 to vibrate stably. In addition, the design of the dynamic vibration absorber 3 is simplified.

[0041] For these reasons, it is desirable that each of the first coil spring assembly 6 and the second coil spring assembly 7 is made up of three or more coil springs.

[0042] The dynamic vibration absorber 3 also includes a rectangular (square) first end plate 8a and a second end plate 8b joined to the horizontal beam 2 and spaced apart in the axial direction of the horizontal beam 2, and a rectangular (square) first intermediate plate 9a and a second intermediate plate 9b extrapolated between the first end plate 8a and the second end plate 8b so as to be movable horizontally relative to the horizontal beam 2 and spaced apart in the axial direction of the horizontal beam 2, and the coil springs 6a, 6b, and 6c of the first coil spring assembly 6 have one end joined to the first end plate 8a and the other end joined to the first intermediate plate 9a, the coil springs 7a, 7b, and 7c of the second coil spring assembly 7 have one end joined to the second end plate 8b and the other end joined to the second intermediate plate 9b, and the hollow weight 5 has one end joined to the first intermediate plate 9a and the other end joined to the second intermediate plate 9b.

[0043] As shown in Figures 4A to 4D, the horizontal beam 2 is a steel plate with an H-shaped cross section, and the first end plate 8a and the second end plate 8b and the first intermediate plate 9a and the second intermediate plate 9b have rectangular (e.g., square) holes 8a-1, 8b-1, 9a-1, and 9b-1 formed therein through which the H-shaped cross section steel plate of the horizontal beam 2 passes.

[0044] The rectangular holes 8a-1 and 8b-1 in the first end plate 8a and the second end plate 8b have approximately the same dimensions as the H-shaped rectangular cross section of the horizontal beam 2, as shown in Figures 4A and 4D, and the first end plate 8a and the second end plate 8b are joined by welding or the like to the top and bottom surfaces of the horizontal beam 2. The rectangular holes 9a-1 and 9b-1 in the first intermediate plate 9a and the second intermediate plate 9b are slightly larger than the H-shaped rectangular cross section of the horizontal beam 2, as shown in Figures 4B and 4C, and are formed so that a gap will be created between the first intermediate plate 9a and the second intermediate plate 9b and the horizontal beam 2 when the horizontal beam 2 moves due to an earthquake.

[0045] In addition, the hollow weight 5 is joined by welding or the like to the first intermediate plate 9a and the second intermediate plate 9b so as to surround the radial outside of the rectangular holes 9a-1, 9b-1 in the first intermediate plate 9a and the second intermediate plate 9b, and can move in the axial direction of the horizontal beam 2 integrally with the first intermediate plate 9a and the second intermediate plate 9b relative to the horizontal beam 2.

[0046] With this configuration, even if the lower edges of the holes 9a-1 and 9b-1 in the first intermediate plate 9a and the second intermediate plate 9b are in contact with the horizontal beam 2 under normal circumstances, when an earthquake occurs, the first intermediate plate 9a and the second intermediate plate 9b will rise from the lower edges of the holes 9a-1 and 9b-1 in the horizontal beam 2 due to the expansion and contraction of the coil springs 6a to 6c and 7a to 7c of the first coil spring assembly 6 and the second coil spring assembly 7, creating a gap between the first intermediate plate 9a and the second intermediate plate 9b and the horizontal beam 2 along all sides of the rectangular holes 9a-1 and 9b-1. This allows the hollow weight 5 to vibrate smoothly in the axial direction of the horizontal beam 2 due to the expansion and contraction of the coil springs 6a to 6c and 7a to 7c of the first coil spring assembly 6 and the second coil spring assembly 7, thereby achieving good vibration control.

[0047] FIG. 5 is a model diagram of a vibration system for explaining the operating principle of the earthquake-resistant support device of this embodiment.

[0048] In Figure 5, the lower vibration system VS1 represents the vibration system of the main equipment to be damped in the nuclear plant 100 excluding the dynamic vibration absorber 3, such as the pressure vessel 103 and its supporting member, the pedestal 104, and the upper vibration system VS2 represents the vibration system of the dynamic vibration absorber 3 of this embodiment.

[0049] In the lower vibration system VS1, mm is the mass of the vibration-damping target of the nuclear plant 100 (for example, the pressure vessel 103 and the pedestal 104 that is its supporting member), and km is the spring constant of the vibration-damping target of the nuclear plant 100.

[0050] In the upper vibration system VS2, ma is the mass of the hollow weight 5 of the dynamic vibration absorber 3, and ka is the spring constant of the coil spring device 10 of the dynamic vibration absorber 3 (the first coil spring assembly 6 and the second coil spring assembly 7).

[0051] The mass ma of the hollow weight 5 and the spring constant ka of the coil spring device 10, which are the eigenvalues ​​of the dynamic vibration absorber 3, are set to match the natural frequency of the object to be damped, including the pressure vessel 103, so that when an earthquake occurs, the dynamic vibration absorber 3 resonates and can suppress the vibration of major equipment.

[0052] That is, the characteristics of the ground and the like differ depending on the installation location of the nuclear power plant 100. Furthermore, the input seismic waves used for seismic evaluation also differ. As a result, the building response input to the major equipment of the nuclear power plant 100 when an earthquake occurs differs. For this reason, if the dominant frequency of the response input to the major equipment is close to the natural frequency of the major equipment, the response frequency of the major equipment will be large. The mass ma of the hollow weight 5 of the dynamic vibration absorber 3 and the spring constant ka of the coil spring device 10 are set to match the natural frequency of the major equipment, including the pressure vessel 103, so as to attenuate such a response frequency.

[0053] In this way, by adding the dynamic vibration absorber 3 to the nuclear power plant 100 and setting the mass ma and spring constant ka of the dynamic vibration absorber 3 to appropriate values, it is possible to suppress horizontal vibrations of major equipment such as the pressure vessel 103 and pedestal 104 installed inside the reactor containment vessel 102 of the nuclear power plant 100 when an earthquake occurs.

[0054] In this embodiment, the coil spring device 10 that elastically supports the hollow weight 5 in the axial direction of the horizontal beam 2 is two sets of coil spring assemblies, the first and second coil spring assemblies 6 and 7, provided on both sides of the weight 5. However, as shown by one coil spring with a spring constant ka in the vibration system model diagram of Figure 5, the coil spring device 10 may also be one coil spring assembly (for example, the first coil spring assembly 6) having a spring constant ka.

[0055] ~Effects~ According to this embodiment, the following effects can be obtained. 1. The dynamic vibration absorber 3 is configured to include a hollow weight 5 that is extrapolated to the horizontal beam 2 and is movable in the axial direction of the horizontal beam 2, and a coil spring device 10 that elastically supports the hollow weight 5 in the axial direction of the horizontal beam 2 and allows the hollow weight 5 to vibrate in the axial direction of the horizontal beam 2.Therefore, when an earthquake occurs, the hollow weight 5 vibrates in the axial direction of the horizontal beam 2 (horizontal direction) due to the coil spring device 10, and horizontal vibration of the reactor pressure vessel 103 can be suppressed.

[0056] In addition, the hollow weight 5 is extrapolated to the horizontal beam 2, and the coil spring device 10, which elastically supports the hollow weight 5 in the axial direction of the horizontal beam 2, is positioned juxtaposed to the hollow weight 5 in the axial direction (horizontal direction) of the horizontal beam 2, so that the configuration of the dynamic vibration absorber 3 is compact and the installation space for the dynamic vibration absorber 3 can be reduced.

[0057] 2. The hollow weight 5 and the coil spring device 10, which are components of the dynamic vibration absorber 3, are metal parts, so there are few restrictions on the materials due to temperature conditions, making it easy to manufacture the dynamic vibration absorber 3.

[0058] 3. The coil spring device 10 is configured to include a first coil spring assembly 6 and a second coil spring assembly 7, which are arranged on both axial sides of the hollow weight 5 and elastically support the hollow weight 5 in the axial direction of the horizontal beam 2, so that the configuration of the dynamic vibration absorber 3 can be symmetrical in the axial direction of the horizontal beam 2. This makes it easier to design the dynamic vibration absorber 3, stabilizes the vibration of the weight 5, and provides good vibration-damping action. Furthermore, because the coil springs are distributed and the amount of deflection of each individual coil spring due to its own weight is reduced, this also stabilizes the vibration of the weight 5 and provides good vibration-damping action.

[0059] 4. The first coil spring assembly 6 and the second coil spring assembly 7 are each composed of three coil springs arranged at equal intervals in the circumferential direction so as to surround the horizontal beam 2. When viewed in a cross section perpendicular to the axis, the three coil springs are located at the vertices of a triangle, so that two coil springs are lined up on each of the three sides of the triangle, resulting in high symmetry of vibration in the direction perpendicular to the axis. As a result, vibrations that predominate in a specific direction do not occur, and the coil springs can expand and contract stably, allowing the hollow mass 5 to vibrate stably. Furthermore, the design of the dynamic vibration absorber 3 becomes easier.

[0060] The same applies when each of the first coil spring assembly 6 and the second coil spring assembly 7 is made up of four or more coil springs, which is more than three.

[0061] 5. The outer end of the horizontal beam 2 is joined to the inner surface of the reactor containment vessel 102, and the inner end is joined to the outer surface of the pedestal 104, so the seismic support device 1 can be installed around the pedestal 104, which has relatively few restrictions inside the containment vessel 102.

[0062] 6. The mass of the hollow weight 5 and the spring constant of the coil spring device 10 are set to appropriate values ​​to match the natural frequency of the major equipment to be damped, such as the pressure vessel 103 and pedestal 104 installed in the containment vessel 102 of the nuclear plant 100, so that horizontal vibration of the major equipment can be suppressed when an earthquake occurs.

[0063] Second Embodiment A second embodiment of the present invention will be described with reference to FIGS. 6, 7A, 7B, 7C, and 7D.

[0064] FIG. 6 is a diagram showing details of the horizontal beam 2 and the dynamic vibration absorber 3 in the second embodiment of the present invention.

[0065] 7A is a cross-sectional view of the AA section of FIG. 6 as viewed from the direction of the arrow shown, FIG. 7B is a cross-sectional view of the BB section of FIG. 6 as viewed from the direction of the arrow shown, FIG. 7C is a cross-sectional view of the CC section of FIG. 6 as viewed from the direction of the arrow shown, and FIG. 7D is a cross-sectional view of the DD section of FIG. 6 as viewed from the direction of the arrow shown.

[0066] In this embodiment, as shown in Figures 7B and 7C, the first intermediate plate 9a and the second intermediate plate 9b are positioned farther from the axis of the horizontal beam 2 than the outer surface of the hollow weight 5, and multiple (four) guide holes 11 are formed near the four corners of the first intermediate plate 9a and the second intermediate plate 9b, and multiple (four) guide rods 12 are movably inserted into each of the multiple guide holes 11, and one end of each of the multiple guide rods 12 is joined to the first end plate 8a and the other end is joined to the second end plate 8b.

[0067] As a result, the hollow weight 5 moves in the axial direction only by the difference between the diameter of the guide hole 11 and the diameter of the guide rod 12, so that in the event of an earthquake, the vibration of the coil spring device 10 and the hollow weight 5 in the axial direction is suppressed, and the horizontal vibration of the reactor pressure vessel 103 can be reliably suppressed. [Explanation of symbols]

[0068] 1 Seismic support equipment 2 horizontal beams 3 Dynamic vibration absorber 5 hollow weight 6 First coil spring assembly 6a, 6b, 6c Coil springs 7 Second coil spring assembly 7a, 7b, 7c Coil springs 8a 1st end plate 8a-1 Rectangular hole 8b 2nd end plate 8b-1 Rectangular hole 9a 1st intermediate plate 9a-1 Rectangular hole 9b 2nd intermediate plate 9b-1 Rectangular hole 10 Coil spring device 11 Guide hole 12 Guide rod 100 Nuclear Plants 101 Reactor Building 102 Reactor containment vessel 104 Reactor Pressure Vessel Pedestal VS1 vibration system VS2 vibration system

Claims

1. An earthquake-resistant support device for a nuclear power plant that is arranged inside a reactor containment vessel and suppresses horizontal vibrations of a reactor pressure vessel supported by a pedestal in the event of an earthquake, a horizontal beam disposed between the reactor containment vessel and the reactor pressure vessel and the pedestal, and extending in a radial direction of the reactor pressure vessel and the pedestal; a dynamic vibration absorber installed on the horizontal beam, The dynamic vibration absorber is A hollow weight that is extrapolated to the horizontal beam and is movable in the axial direction of the horizontal beam; and a coil spring device that elastically supports the hollow weight in the axial direction of the horizontal beam and allows the hollow weight to vibrate in the axial direction of the horizontal beam.

2. 2. The earthquake-resistant support device for a nuclear power plant according to claim 1, the coil spring device includes a first coil spring assembly and a second coil spring assembly that are arranged on both axial sides of the hollow weight and elastically support the hollow weight in the axial direction of the horizontal beam.

3. 3. The earthquake-resistant support device for a nuclear power plant according to claim 2, 1. An earthquake-resistant support device for a nuclear power plant, wherein the first coil spring assembly and the second coil spring assembly each include three or more coil springs arranged at equal intervals in a circumferential direction so as to surround the horizontal beam.

4. 3. The earthquake-resistant support device for a nuclear power plant according to claim 2, The dynamic vibration absorber is a first end plate and a second end plate joined to the horizontal beam and spaced apart in the axial direction of the horizontal beam; a first intermediate plate and a second intermediate plate that are inserted onto the horizontal beam between the first end plate and the second end plate and spaced apart in the axial direction of the horizontal beam, and that are movable in the axial direction of the horizontal beam; The coil spring of the first coil spring assembly has one end joined to the first end plate and the other end joined to the first intermediate plate, The coil spring of the second coil spring assembly has one end joined to the second end plate and the other end joined to the second intermediate plate, 10. An earthquake-resistant support device for a nuclear power plant, wherein one end of the hollow weight is joined to the first intermediate plate and the other end is joined to the second intermediate plate.

5. 5. The earthquake-resistant support device for a nuclear power plant according to claim 4, The first intermediate plate and the second intermediate plate have a plurality of guide holes formed at positions farther from the axis of the horizontal beam than the outer circumferential surface of the hollow weight, a plurality of guide rods are movably inserted into the plurality of guide holes, one end of each of the plurality of guide rods being joined to the first end plate and the other end being joined to the second end plate.

6. 2. The earthquake-resistant support device for a nuclear power plant according to claim 1, 10. The earthquake-resistant support device for a nuclear power plant, wherein the horizontal beam has an outer end joined to an inner peripheral surface of the reactor containment vessel and an inner end joined to an outer peripheral surface of the pedestal.

7. 2. The earthquake-resistant support device for a nuclear power plant according to claim 1, a mass of the hollow weight and a spring constant of the coil spring device are set in accordance with the natural frequency of an object to be damped, the object including the reactor pressure vessel installed in the containment vessel of the nuclear plant.

8. A nuclear power plant including a reactor containment vessel and a reactor pressure vessel disposed in the reactor containment vessel and supported by a pedestal, A plurality of earthquake-resistant support devices according to claim 1 are provided, a plurality of earthquake-resistant support devices disposed radially around the reactor pressure vessel and the pedestal in a radial direction of the reactor pressure vessel and the pedestal, the earthquake-resistant support devices being disposed radially around the reactor pressure vessel and the pedestal;

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