JPS6055178A - Vibration-proof support structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a support structure for heavy objects capable of reducing earthquake input, and in particular to a support structure suitable for supporting huge heavy objects such as tank-type fast breeder reactors. Regarding anti-vibration support structure.

[Background of the invention]

Generally, in order to reduce external vibrations (particularly earthquake loads) to a structure, the support structure that supports the main structure must be constructed with a so-called flexible structure that has a natural frequency smaller than the natural frequency of the main structure. This method avoids resonance between the main natural vibration of the main structure and the natural vibration of the supporting structure, and the insertion of vibration damping materials such as rubber between the main structure and the supporting structure to reduce earthquake loads. Methods are being considered to achieve this.

FIG. 1 shows an example of a tank-type fast breeder reactor with a flexible support structure. In FIG. 1, a main vessel 10 is provided with a roof slab 14 in which a core 12 is disposed, a roof slab 14 on which a control rod drive mechanism and the like are disposed, and the inside thereof is sealed.

The roof slab 14 is provided with a support skirt 16, which is fixed to the upper part of a support structure 20 provided independently inside the reactor building 18, and which connects the main vessel 10 to the roof slab 14. It is suspended through the Also,
A safety container 22 is provided around the main container 10 to receive the coolant when it flows out from the main container 10. This safety container 22 includes a support structure 20
It is fixed to a support cylinder 24 provided inside the. and,
A cap 7-26 is mounted between the main container 10 and the safety container 22.

In a tank-type fast breeder reactor having such a structure, the carrier 26 is used to increase the horizontal natural vibration of the reactor structure, particularly the main vessel 10 that supports the reactor core 12. By transmitting the horizontal vibration load of the main container 0 to the support cylinder 24 of the safety container 22 through the carrier 26, the horizontal rigidity of the main container 10 is improved, and the main container 10 is The height and wall thickness of the support structure 20 are adjusted so that the horizontal natural frequency of the support structure 20 is p higher than the horizontal natural vibration of the support structure 20 that supports the entire reactor structure. Therefore, in the support structure of the nuclear reactor in such a structural form, resonance between the natural vibration of the reactor structure and the natural vibration of the support structure 20 can be avoided. Earthquake force entering the structure is reduced. However, in the nuclear reactor support structure described above, the damping vibration force of the support structure 20 is small.

That is, the vibration model of the nuclear reactor shown in FIG.
0 are provided independently, and the nuclear reactor structure 30 is attached to the ground 28 via the support structure 20. Therefore, the greater the distance between the natural frequency of the reactor structure 30 and the natural frequency of the support structure 20, the greater the vibration isolation effect. However, if there is a part in the huge reactor structure 30 that can resonate with the natural vibration of the support structure 20, the vibration amplitude of that part is large and has an unfavorable effect on the p1 reactor structure 30. There is a strong possibility. In addition, in the support structure of the nuclear reactor described above,
The techniques for assembly, inspection, maintenance, etc. of the carry 26 are extremely complex, and in a nuclear reactor that pursues economic efficiency, the cost associated with installing the carry 26 impairs the economic efficiency of the reactor.

FIG. 2 shows an example of a nuclear reactor support structure using vibration damping materials. In Figure 2, roof slab 1
The support skirt 16 provided at 4 is fixed to the stepped portion of the reactor building 18 via a vibration damping structure 32 made of rubber or the like.

A vibration model of such a structure can be applied to the reactor structure 3 through a vibration damping mechanism 34 in the reactor building 18, as shown in FIG.
The structure has a value of 0. Therefore, the earthquake internal force from the reactor building 18 to the reactor structure 30 is transmitted and attenuated via the vibration damping structure (vibration damping mechanism 34) 32. However, in this structure, since the vibration input to the nuclear reactor structure 30 is only from the reactor building 18, the phase shift of the vibration input by the vibration damping mechanism 34 cannot be effectively used for vibration isolation. Additionally, the vibration damping structure 32 generally uses a flexible support member to provide a vibration damping effect. This makes it difficult to set and align the installation structure. Particularly in the case of a nuclear reactor, the support member is altered by radiation, and its softness decreases over time, making it impossible to obtain the desired vibration damping effect. Moreover, since the vibration damping structure 32 constitutes a load transmission path of the nuclear reactor structure, it is extremely difficult to remove the vibration damping structure 32 and perform inspection and maintenance of the equipment.

FIG. 3 shows an example of a tank-type fast breeder reactor that uses liquid flow energy to damp vibrations. In FIG. 3, the main vessel 10 is suspended from the roof slab 14 by fixing a support skirt 16 provided on the roof slab 14 to a stepped portion of the reactor building 18. and,
A safety container 22 is provided around the main container 10. This safety container 22 is connected to the roof slab 1 like the main container 10.
4, and inside, that is, between the main container 10 and
Liquids such as + and K are contained. The vibration model of this structure is as shown in FIG. 4 (Q). In other words, the reactor structure 30 and the safety vessel 22
8, and has a structure in which a vibration damping mechanism 34 is provided between the reactor structure 30 and the safety vessel 22. Seismic input to the reactor structure 30 is then transmitted directly from the reactor building 18. Vibrations of the main container 10 due to earthquake input are attenuated by the flow of the liquid 36 placed between the main container 10 and the safety container 22. However, in such a structure, since the main container 10 and the safety container 22 are both suspended from the roof slab 14, the main container 10 and the safety container 22 will vibrate together during an earthquake. The flow energy of the liquid 36 is prevented from dissipating, and the vibration damping effect cannot be exhibited. Also, the liquid 36 is transferred to the main container 1
Not only are they in direct contact with 0 and are strongly affected by radiation, but they are also exposed to high temperatures, so the selection of materials is limited to a very narrow range, making it difficult to select materials that have a large vibration damping effect. It is.

[Purpose of the invention]

The present invention has been made in order to eliminate the drawbacks of the prior art, and an object of the present invention is to provide a vibration-proof support structure that can effectively suppress vibrations of a huge heavy object.

[Summary of the invention]

The present invention provides a support member that supports a huge heavy object in the air, and a vibration damping mechanism is interposed between the building and the huge heavy object, so that vibrations from the outside are transmitted through the supporting member to the huge heavy object. transmitting it to the object, and transmitting phase-delayed vibration from the building to the heavy object via a vibration damping mechanism, so that the vibration transmitted from the support member and the vibration transmitted from the vibration damping mechanism interfere; It is constructed to be able to dampen the vibrations of M sights.

[Embodiments of the invention]

Preferred embodiments of the anti-vibration support structure according to the present invention will be described in detail with reference to the accompanying drawings. Note that the same reference numerals are given to the parts corresponding to the parts explained in the prior art, and the explanation thereof will be omitted.

FIG. 5 shows an example in which the basic concept of the anti-vibration support structure according to the present invention is applied to a tank-type nuclear reactor. In FIG. 5, a main vessel 10 housing a reactor core 12 is suspended from a roof slab 14.

The roof slab 14 is fixed onto the support structure 20 via the support skirt 16 and is connected to the side wall of the reactor building 18 via the vibration area Ra structure 34.

The height, wall thickness, material, etc. of the support structure 20 are adjusted so that the natural frequency is approximately the same as or slightly lower than the natural frequency of the reactor structure including the main vessel 10, the reactor core 12, etc. Designed. Therefore, the vibration energy of the reactor structure is converted into the vibration energy of the support structure 20, and
It is dissipated via the vibration damping mechanism 3≠. In addition, vibration input from the outside such as an earthquake is transmitted from the support structure 20 to the roof slab 14 via the support skirt 16, and from the reactor building 18 to the roof slab 14 via the vibration damping mechanism 34. be done. The vibration input transmitted through the vibration damping mechanism 34 interferes with the vibration input transmitted to the roof slab 14 through the support structure 20 because the wavelength of the input wave is delayed by a half wavelength. It has a counteracting effect.

FIG. 6 shows a specific example of the vibration damping mechanism described above. The vibration damping mechanism shown in this example is constructed by filling an annular space 38 formed by the reactor building 18 and the support structure 20 with a viscous fluid 40 such as oil or grease. The upper part of the annular space 38 is a labyrinth seal 4.
It is sealed by 2. Furthermore, the inner wall of the reactor building 18 and the outer wall of the support structure 20 that constitute the annular space 38 are
Each liner 44,46 is attached. The annular space 38 is provided with a supply port 48 at the lower end, and a discharge port 50 near the top so that the viscous fluid 40 within the annular space 38 can be circulated.

The liners 44 and 46 are made of a material with low thermal conductivity, and have shock absorbers such as synthetic rubber provided on their surfaces. The liner 44 is connected to structural reinforcing bars 52 that constitute the reactor building 18, as shown in FIG. Liner 46 is also connected to structural reinforcing bars 54 that make up support structure 20 . Further, the support structure 20 has a liner 56 attached to its inner peripheral surface, and a support structure top plate 58 is provided at the top, and the support skirt 16 is fixed to the top surface of the support structure top plate 58. It is.

In the labyrinth seal 42 described above, a plurality of sealing plates 60 are alternately attached to the support structure upper plate 58 of the support structure 2o and the ring-shaped support plate 62 provided in the reactor building. These sealing plates 60 are mounted in a stacked manner so that some parts overlap, and
A spring seal 64 is fixed to the upper surface of each sealing plate 60. The upper surface of the spring seal 64 is in contact with the lower surface of the upper sealing plate 60, and the spring seal 64 of the uppermost sealing plate 60 is connected to the presser plate 66 provided on the upper surface of the support structure upper plate 58. It is touching the bottom surface. Furthermore, a bellows 68 is attached between the presser plate 66 and the ring-shaped support plate 62 to seal the annular space 38.

The vibration model using the support structure configured in this way is
It is shown in Figure ■. That is, the nuclear reactor structure 30 is attached to the support structure 20, and the vibration damping mechanism 34 is interposed between the support structure 20 and the reactor building 18.

Therefore, external vibrations are transmitted to the reactor structure 30 via the support structure 20, and vibrations with a half wavelength from the reactor building 18 are transmitted to the reactor structure 30 via the support structure 20. be done. Therefore, the seismic input transmitted from the ground 28 through the support structure 20 and the reactor building 18
The vibration input transmitted through the vibration damping mechanism 34 interferes with each other and is damped. It turns out. That is, when an earthquake occurs, the vibrations of the reactor building 18 are transmitted to the support structure 20 through the viscous fluid 40 filling the annular space 38, so that the vibrations of the reactor building 18 and the support structure 20 are transmitted to the support structure 20. The vibrations are caused to interfere with each other and are damped by the viscous fluid 40, which is a vibration damping mechanism. In particular, the liner 4.4 facing the radial dimension of the plate space or the annular space 38.
By adjusting the wall thickness of the shock absorber attached to 46, it is possible to achieve mechanical impedance matching that best absorbs vibration energy. By appropriately setting the damping constant of the vibration damping structure as described above, it is possible to obtain a large vibration damping effect as shown by the solid line in Figure 8, and the response vibration width of the reactor vessel is greater than that of the conventional structure. The ratio can be reduced to 1/2 to 1/3. Note that curve A shown in FIG.

B and C show the relationship between the frequency ratio and the reactor vessel response amplitude ratio for the vibration models of FIGS. 4(a), (b), and (Q), respectively.

As described above, according to this embodiment, the seismic input to the nuclear reactor structure can be significantly reduced with a simple structure. Moreover,
Due to the significant reduction in seismic input, the structural members of the reactor structure can be made thinner, reducing manufacturing costs and improving reliability.

In addition, since the viscous fluid 40 does not come into contact with the main container 10 and is separated from the main container 10 by the support structure 20, there is little change in the material due to radiation etc., increasing the degree of freedom in selecting the material. Moreover, maintenance and inspection of the vibration damping mechanism becomes easy. Furthermore, since the liner 44 is connected to the reinforcing bars 52 of the reactor building 18, it is possible to prevent the temperature of the viscous fluid 40 from rising. Moreover, by circulating the viscous fluid as necessary, the support structure 20 can be cooled, and the reactor can be cooled in the event of an accident or the like.

〔Effect of the invention〕

As explained above, according to the present invention, the vibrations transmitted to the heavy object from the support member and the building interfere with each other, so that the vibrations of the huge heavy object can be effectively suppressed.

[Brief explanation of the drawings] Fig. 1 shows an example of a conventional tank-type fast breeder reactor in which vibration is suppressed by a shaky structure, and Fig. 2 shows an example of a conventional tank-type fast breeder reactor in which vibration is suppressed by a vibration damping structure. Figure 3 shows an example of a conventional tank-type fast breeder reactor in which a liquid is placed between the main vessel and the safety vessel to prevent vibrations. Figure, Figure 4 Prisoner's), 0. (G) is a diagram showing a vibration model of a conventional tank-type fast breeder reactor and a duplex fast breeder reactor according to an embodiment of the present invention, and FIG. An explanatory diagram of an example shown,
FIG. 6 is an explanatory diagram of an embodiment of the vibration-proof support structure according to the present invention,
FIG. 7 is a partially enlarged view of the vibration damping mechanism of the above embodiment, and FIG.
The figure is a diagram showing the relationship between the frequency ratio and the reactor vessel response amplitude ratio corresponding to the vibration model shown in FIG. 4 (5), (T3), (Q, Q)). DESCRIPTION OF SYMBOLS 10... Main vessel, 12... Reactor core, 14''iζbu, 18... Reactor building, 20... Support structure, 22
... safety container, 26 ... carry, 30 ... reactor structure, 34 ... vibration damping mechanism, 38 ... annular space, 40 ... viscous fluid, 42 ... labyrinth 7-le ,
44, 46.56... Raina. Agent Patent Attorney Tatsuyuki Unuma 10 22 Mol + Diagram (A) (B) (C) (D) Da 8 Taku 8 Diagram 1 -1 Number of evil edicts Tohi

Claims (1)

[Scope of Claims] 1. A vibration-proof support structure for storing a heavy object in a building by reducing vibrations from the outside, including a support member provided in the building for supporting the heavy object in a hollow manner; A vibration-proof support structure comprising a vibration damping mechanism interposed between a heavy object and the building. 2. The vibration damping mechanism includes the supporting member formed in a cylindrical shape around the heavy object, an inner circumferential wall of the building forming an annulus space between the supporting member, and a height filled in the annulus space. The vibration isolation support structure according to claim 1, comprising a viscous fluid and a sealing member that seals the annulus space. 3. The outer circumferential surface of the supporting member forming the annulus space and the inner circumferential wall of the building are each covered with a liner that has corrosion resistance against the high viscosity fluid, and this liner is covered with the supporting member or the inner circumferential wall of the building. The vibration isolation support structure according to claim 2, wherein the vibration isolation support structure is fixed to reinforcing bars of the building. 4. The sealing members are movable relative to each other in a radial direction;
and two or more annular plates attached alternately to the support member and the inner circumferential wall of the building so as to have overlapping parts, and a leaf spring-shaped seal plate disposed between these annular plates; The vibration isolation support structure according to claim 2 or 3, characterized in that it is a bellows provided covering an annulus space.