JPH11125685A - Support device of reactor pressure vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve productivity and placement, absorb thermal expansion of reactor pressure vessel in operation without restricting and ensure stable aseismicity. SOLUTION: In between the outer surface of a reactor pressure vessel 1 and the inner surface of reactor shield wall 2 covering around it, a plurality of vibration damper mechanisms 10 are installed with specific intervals in the circumference direction in this device. In this case, the vibration damper mechanisms 10 are provided with a plurality of metal plate springs 17 layered in the radial direction of the reactor pressure vessel 1 and each of vibration damper mechanisms 10 forms a slope B constituted of the ratio of each displacement so that the displacement due to thermal expansion of the reactor pressure vessel 1 in radial direction and axial direction in the plane where the vessel side support part 22 fixed on the outer surface of the reactor pressure vessel 1 and the support part 20 co-working with each plate spring 17 face to each other becomes free. Each plate spring 17 is provided with a specific spring constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration control mechanism for a nuclear pressure vessel, and more particularly to a support for a nuclear reactor pressure vessel suitable for absorbing thermal expansion without restraint and absorbing horizontal force during an earthquake. Related to the device.

[0002]

2. Description of the Related Art In a conventional apparatus for supporting a reactor pressure vessel, as shown in FIG. 7, a reactor pressure vessel 1 is a vessel for accommodating a reactor core containing nuclear fuel therein, A hollow cylinder is set up vertically on a pedestal 8 in a container 7. The reactor containment vessel 7 is covered with a living body shielding wall 6 formed of a concrete wall, and is installed on a reactor building foundation 9. Further, the reactor shield wall 2 is erected around the reactor pressure vessel 1 so as to cover up to the top, and the top plate 4 is connected to the inner surface of the reactor containment vessel 7 at the upper end of the reactor shield wall 2 to secure rigidity. It is supposed to.

As a seismic support device for the reactor pressure vessel 1, a plurality of stabilizers (vibration control mechanisms) 5 are provided along the outer periphery as shown in FIGS. That is, the stabilizer 5 has a bracket 5C welded to a sole plate 4A fixed on the top plate 4 of the reactor shield wall 2, and the bracket 5C holds the stabilizer bracket 3 projecting from the outer surface of the reactor pressure vessel 1. Then, the stabilizer bracket 3 is tightened via the disc springs 5J stacked in the circumferential direction to suppress horizontal vibration of the reactor pressure vessel 1 during an earthquake. This stabilizer 5
Are provided at equal intervals on the outer circumference of the reactor pressure vessel 1, and can cope with earthquakes in all directions. As shown in FIGS. 9 and 10, one stabilizer 5 has two brackets 5 </ b> B whose lower end surfaces are welded to a bracket 5 </ b> C and provided opposite to each other, and two stabilizers 5 are welded to both ends between the two brackets 5 </ b> B. A bracket 5A, a yoke 5H provided between the two brackets 5A and having a through hole for the stabilizer bracket 3, and a bracket 5A
The two washers 5 at both ends facing the yoke 5H through the
G, a plurality of disc springs 5J at both ends in contact with the washer 5G and laminated in the circumferential direction, sleeves 5F at both ends contacting the disc spring 5J, and two rods inserted through the bracket 5A, the washer 5G, and the disc spring 5J. 5D and two nuts 5E screwed to the rod 5D and abutting against the sleeve 5F. FIG. 11 schematically shows a simplified mechanism for controlling the horizontal seismic intensity during an earthquake. The arrow in the figure indicates the direction of the earthquake, and the spring 34 corresponds to the disc spring 5J.

As shown in FIGS. 12 to 14, a plurality of rubber bearings (damping mechanisms) 30 are provided between the inner surface of the reactor shield wall 2 and the outer surface of the reactor pressure vessel 1. It is disclosed in JP-A-59-75188.
The rubber bearing 30 is formed by alternately laminating a metal plate 32 and a hard rubber 31, and welding one end surface of the rubber plate 30 to the sole plate 29. There is a gap 35 between the outer surface of the reactor pressure vessel 1 and the inner surface of the reactor shield wall 2,
In the gap 35, a pedestal 28 is protruded from an upper portion of the inner surface of the reactor shield wall 2, and a sole plate 29 is fastened to the pedestal 28. The rubber bearing 30
The direction of the laminated structure faces outward in the radial direction of the reactor pressure vessel 1, and the front end face 33 faces the outer surface of the reactor pressure vessel 1 via a slight gap 39. A plurality of the rubber bearings 30 formed as described above are arranged at equal intervals in a circumferential direction of the reactor pressure vessel 1,
It is configured as a seismic support device. FIG. 15 schematically illustrates this seismic support device. The arrow in the figure indicates the direction of the earthquake, and the spring 34 corresponds to the rubber bearing 30.

However, the prior art does not consider the following points. The first point is that the stabilizer and its surrounding parts are enlarged because the stabilizer bracket is sandwiched in addition to the large number and shape of the parts forming the stabilizer. For this reason, installation work on site was complicated, and this point was not considered. Also, the load acting on the stabilizer bracket during the earthquake may act as a moment and generate high stress, and the strength of the stabilizer bracket has not been considered.

On the other hand, the gap between the outer surface of the reactor pressure vessel and the tip surface of the rubber bearing differs between the reactor pressure vessel during operation and the stopped state. That is, the gap during operation is smaller than that in the stopped state, there is a possibility that it is not possible to maintain a constant gap consistently from the stopped state to the operation to the stopped state, and in terms of securing the earthquake resistance constant, Was not considered.

[0007]

The conventional apparatus for supporting a reactor pressure vessel has a problem that the number of parts of the stabilizer is large and large, and the manufacturability, on-site installation and workability are not good. was there. In addition, there is a problem that high stress may be generated in the stabilizer bracket.
Further, there is a problem that the rubber bearing may not be able to maintain a constant earthquake resistance consistently during stop and during operation.

It is an object of the present invention to improve manufacturability and installation, absorb the thermal expansion of a reactor pressure vessel during operation without restraint, and improve the seismic resistance of the reactor pressure vessel during operation and at rest. It is an object of the present invention to provide a reactor pressure vessel support device that can maintain a constant level and effectively support horizontal force during an earthquake.

[0009]

In order to achieve the above-mentioned object, a support apparatus for a reactor pressure vessel according to the present invention comprises a reactor pressure vessel having an outer surface and an inner surface of a reactor shielding wall surrounding the reactor pressure vessel. In the meantime, in a reactor pressure vessel support device in which a plurality of vibration damping mechanisms are interposed at predetermined intervals in the circumferential direction, each of the vibration damping mechanisms is formed of a plurality of metal layers stacked in the radial direction of the reactor pressure vessel. It is configured to have a disc spring. With this configuration, a predetermined spring constant required for earthquake resistance can be obtained. Since the laminating direction is one direction, the entire supporting device is simplified and downsized, and the manufacturability and the installation property are improved.

[0010] Each of the vibration damping mechanisms includes a reactor side support portion fixed on the outer surface of the reactor pressure vessel and a support portion cooperating with each disc spring. A configuration may be employed in which a gradient is formed by the ratio of the respective displacement amounts so that the displacement due to thermal expansion in the radial direction and the axial direction of the container becomes free, and each disc spring has a predetermined spring constant. With this configuration, thermal expansion in the radial and axial directions of the reactor pressure vessel can be freely displaced, and contact between the vessel-side support portion and the support portion is suppressed, so that stress due to moment is reduced.

Each of the disc springs may have a configuration in which one end face is inserted into a support cylinder having a fixed end face, so that the support cylinder can receive an earthquake load in a direction intersecting with the lamination direction of the disc springs. The number of mechanisms is reduced.

Further, in the reactor pressure vessel, a support device for any one of the above-mentioned reactor pressure vessels is provided, and a vessel-side support portion opposed to a support portion of each vibration damping mechanism is fixed. In addition, stress due to seismic load and the like is reduced, and seismic resistance is improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1 to 4, a plurality of vibration damping mechanisms 10 are provided at predetermined intervals in the circumferential direction between the outer surface of the reactor pressure vessel 1 and the inner surface of the reactor shielding wall 2 surrounding the reactor pressure vessel 1. This is a supporting device for a mounted reactor pressure vessel, and each vibration damping mechanism 10 includes a plurality of metal disc springs 17 stacked in the radius R direction of the reactor pressure vessel 1. Each vibration damping mechanism 10 includes a container-side support portion (container-side slope support) 22 fixed on the outer surface of the reactor pressure vessel 1 and a support portion (slope support) 20 that cooperates with each disc spring 17. A gradient B having a ratio ΔR / ΔV of the respective displacement amounts ΔR and ΔV is formed on each of the opposing surfaces so that the displacement due to the thermal expansion in the radial direction and the axial direction of the reactor pressure vessel 1 becomes free. Thus, a predetermined gap A is formed between the respective surfaces, and each disc spring 17 has a predetermined spring constant.

The method of manufacturing the vessel-side support portion 22 is to form the same material as the material of the reactor pressure vessel 1 and to fix or integrally mold the outer surface of the reactor pressure vessel 1 in advance by welding or the like. After the heat treatment together with the container 1, the outer surface thereof is subjected to surface processing at a predetermined gradient B. The support portion 20 is also formed of substantially the same material, and after the outer periphery and the concave portion are processed, the other end surface is finally surface-processed with a predetermined gradient B. The disc spring 17 is formed in a dish shape using spring steel or the like so as to have a predetermined spring constant. It is desirable to assemble each part at one end and adjust at least the length dimension according to the gap between the actual outer surface of the reactor pressure vessel 1 and the inner surface of the reactor shielding wall 2. I will do it.

The assembly of the vibration damping mechanism is performed by using the reactor shielding wall 2
A plurality of disc springs 17 having a predetermined spring constant are inserted through a rod 14 having one end welded to a sole plate 11 fixed to an inner surface of the sole plate 11 and laminated, and a sleeve 16 for holding the disc spring 17 is abutted on the other end. Then, the nut 15 screwed to the other end of the rod 14 is screwed, and the laminated disc springs 17 are completely adhered to each other to eliminate the gap between the disc springs 17. Each disc spring 1
Numeral 7 has a disc spring height D, and the concave surface is laminated toward the reactor pressure vessel 1. Then, a shim 21 is attached to the other end surface of the sleeve 16.
The slope support 20 is attached via the. At this time, the other end of the rod 14 and the nut 15 are inserted into the recess formed therein.
To accommodate.

The vibration damping mechanism is installed by installing each component in a state before installing the slope support 20 and the shim 21 after the installation of the reactor pressure vessel 1 and the anchor bolt 12 and the nut 1.
3 attaches to the inner surface of the reactor shield wall 2. Thereafter, the gap A between the vessel-side slope support 22 fixed to the outer surface of the reactor pressure vessel 1 and the slope support 20 is set to a predetermined gap, and the vessel-side slope support 22 is bolted through the shim 21. By attaching the vibration damping mechanism 10 to the sleeve 16 with the nut 18 and the nut 19, the installation of the vibration damping mechanism 10 is completed. The opposite surfaces of the slope support 20 and the vessel-side slope support 22 have a thermal expansion amount ΔR with respect to a radial radius R and a thermal expansion amount with respect to an axial length V during operation of the reactor pressure vessel 1. ΔR / ΔV = gradient B determined by the relationship with ΔV is provided. The gradient B is generally provided in the axial direction, but may be provided in other directions according to displacement due to thermal expansion. Also, slope support 2
A gap C having a predetermined size is provided between the inner surface of the recessed portion of No. 0 and the other end surface of the rod 14. This gap C is formed by the disc spring 17
To ensure the elastic function of the disc spring height D
It is necessary to set the above values.

The operation of this embodiment for thermal expansion will be described. The reactor pressure vessel 1 starts operation from a stopped state, and the reactor pressure vessel 1 extends in the radial direction and the axial direction due to thermal expansion. Since the gap A is provided, this elongation extends along a preset gradient B.
The reactor pressure vessel 1 can be freely displaced without restricting the thermal expansion of the reactor pressure vessel 1 throughout the operation from the time of installation. This state is simplified and schematically shown in FIG. The solid line shows the state when the nuclear pressure vessel is installed or stopped, and the broken line shows the state during operation. The spring 36 corresponds to the disc spring 17.
Therefore, since the load due to thermal expansion does not act on the support device including the plurality of vibration damping mechanisms, the strength and soundness of the support device are not affected at all. When the elongation in the radial and axial directions is more than a predetermined amount, the slope support may come into contact with the container-side slope support, but the abutment converts the elongation into horizontal force and absorbs the spring force of the disc spring. Therefore, there is an effect that the reliability of the supporting device is improved.

Next, the operation of this embodiment in response to an earthquake will be described. When an abrupt horizontal load occurs in the reactor pressure vessel 1 during an earthquake, the load is transmitted from the vessel-side slope support 22 to the contacted slope support 20. Then, the vibration is transmitted from the shim 21 through the sleeve 16 to the disc spring 17 from the longitudinal direction of the sleeve 16, and the load is absorbed by the spring force of the disc spring 17, so that the vibration damping mechanism exhibits the anti-seismic function. Therefore, during an earthquake, the moment acting on the vessel-side slope support 22 is reduced, so that the stress is also reduced, and the strength soundness of the reactor pressure vessel 1 is improved.

According to this embodiment, the mechanism can be simplified and the cost can be reduced. In addition, since the gap between the slope support and the vessel-side slope support can be kept constant throughout the operation of the reactor pressure vessel from the stopped state to the operation, the reactor pressure vessel can be maintained even during the stopped state and during operation. Seismic resistance can be ensured, and reliability can be improved. In addition, the size is made smaller than before, and the inspection workability during the service period from the space between the reactor pressure vessel and the reactor shield wall and the workability at the time of periodic inspection are improved.

Another embodiment of the present invention is shown in FIGS. This embodiment differs from the embodiment shown in FIG. 2 in that a support cylinder is inserted around the outer periphery of the disc spring. Sleeve 2
A protruding portion 26A is provided on the side of the disc spring 17 of FIG.
The support cylinder 23 is inserted into the outer periphery of the protruding portion 26A, one end surface of the support cylinder 23 is welded to the sole plate 11, and between the other end surface of the sleeve 26 and one end surface of the support cylinder 23, and the protruding portion 26A. E between one end face of the support cylinder 23 and the other end face of the insertion portion of the support cylinder 23.
Is provided. As in the previous embodiment, the disc spring 17
In order to ensure the elastic function of the spring, the gap E is the height of the disc spring D
It is necessary to set the above values. The provision of the support cylinder 23 has the following effects in addition to the functions and effects described above.

That is, when an earthquake load acts in a direction perpendicular to the lamination direction of the disc springs, that is, in the direction of the arrow shown in FIGS. 5 and 6, for example, in the axial direction, the friction between the slope support and the container-side slope support is increased. When the load generated by the load acts on the support cylinder, the load can be received by the support cylinder, and the support cylinder also has an axial seismic function. Therefore, if the sum of the seismic loads generated in the reactor pressure vessel during an earthquake is the same (the seismic loads acting on all the supporting devices are the same), the required number of vibration damping mechanisms shown in Figs. 2
And the vibration reduction mechanism shown in FIG. 3 can be reduced.

As another embodiment of the present invention, in a reactor pressure vessel, a support device for any one of the above-mentioned reactor pressure vessels is provided, and the vessel side is located at a position opposed to a support portion of each vibration damping mechanism. The support portion is fixedly provided, and the surfaces facing each other are formed with a gradient.

According to the present embodiment, it is possible to provide a reactor pressure vessel in which stress against an earthquake load is reduced and seismic performance is improved.

[0024]

According to the present invention, a disk spring is laminated on the vibration damping mechanism, and a gradient is formed on the opposing surface of the support portion, so that thermal expansion in the radial and axial directions can be freely displaced. In addition, the earthquake resistance of the reactor pressure vessel during operation can be ensured, and the inspection workability during the service period, the workability and reliability at the time of regular inspection can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of a nuclear power plant.

FIG. 2 is a longitudinal sectional view showing one embodiment of the present invention.

FIG. 3 is a sectional view showing a section taken along line AA in FIG. 2;

FIG. 4 is a diagram schematically showing the vibration damping mechanism of FIG. 2;

FIG. 5 is a longitudinal sectional view showing another embodiment of the present invention.

FIG. 6 is a sectional view showing a section taken along line BB of FIG. 5;

FIG. 7 is a longitudinal sectional view showing a conventional technique.

FIG. 8 is a cross-sectional view showing a cross section taken along line CC of FIG. 7;

FIG. 9 is an enlarged view of a portion D in FIG. 8;

FIG. 10 is a sectional view showing a section taken along line EE in FIG. 9;

FIG. 11 is a diagram schematically showing a conventional vibration damping mechanism.

FIG. 12 is a longitudinal sectional view showing a conventional technique.

FIG. 13 is an enlarged view of a portion F in FIG. 12;

FIG. 14 is a view taken along line GG of FIG. 12;

FIG. 15 is a diagram schematically showing a conventional vibration damping mechanism.

[Description of Signs] 1 Nuclear Pressure Vessel 2 Reactor Shielding Wall 7 Reactor Containment Vessel 10 Vibration Suppression Mechanism 17 Disc Springs 20 Slope Support 22 Vessel Side Slope Support

Claims (4)

[Claims] A reactor pressure vessel having a plurality of vibration damping mechanisms interposed at predetermined intervals in a circumferential direction between an outer surface of the reactor pressure vessel and an inner surface of a reactor shielding wall surrounding the reactor pressure vessel. In the apparatus, each vibration damping mechanism includes a plurality of metal disc springs stacked in a radial direction of the reactor pressure vessel. 2. Each of the vibration damping mechanisms includes a container-side support portion fixed to an outer surface of a reactor pressure vessel, and a support portion cooperating with a respective disc spring. A gradient formed by the ratio of the respective displacement amounts is formed so that the displacement due to thermal expansion in the radial and axial directions of the furnace pressure vessel becomes free, and each disc spring has a predetermined spring constant. The support apparatus for a reactor pressure vessel according to claim 1, wherein 3. The reactor pressure vessel support device according to claim 1, wherein each of the disc springs is inserted into a support cylinder having one end surface fixed. 4. A nuclear reactor comprising the reactor pressure vessel support device according to claim 1 or 2, and a vessel-side support portion opposed to a support portion of each of the vibration damping mechanisms. Furnace pressure vessel.