JPH0339760Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a sealing device for a nuclear reactor well.

"Prior Art" Generally, nuclear fuel replacement work in a nuclear power plant is carried out with the top cover of the reactor pressure vessel open. It is necessary to submerge the nuclear fuel in the reactor pressure vessel and to provide a layer of seal water above the reactor containment vessel and the reactor pressure vessel.

Figure 3 shows a liquid-tight partition between the upper part of the reactor containment vessel and the upper part of the reactor pressure vessel. This figure shows one conventional example of a sealing device that separates the two.

This sealing device includes an annular bulkhead 3 integrally provided on the upper inner circumferential surface of a reactor containment vessel 2 provided inside a shielding wall 1;
A rib 4 provided between the lower surface and the reactor containment vessel 2 to support the bulkhead 3; and a bellows 6 provided between the inner peripheral edge of the bulkhead 3 and the outer periphery of the reactor pressure vessel 5. , a cylindrical guard ring 7 and a bucking ring 8 that cover the inner and outer circumferences of the bellows 6, respectively. Further, a sealing device including a bellows 9 is also provided in the space between the shielding wall 1 and the reactor containment vessel 2.

The sealing device includes a reactor containment vessel 2.
The reactor well 10 above the reactor pressure vessel 5 and the dry well 11 in the reactor containment vessel 2 are separated in a liquid-tight state, and the weight of seal water W injected into the reactor well 10 during fuel exchange is becoming increasingly popular.

"Problems to be Solved by the Invention" By the way, the bellows 6 has sufficient flexibility to allow relative displacement between the reactor containment vessel 2 and the reactor pressure vessel 5, for example. thickness 2
Since it is formed of a thin stainless steel plate of about a millimeter size, its mechanical strength tends to be insufficient, and there is a possibility that seal water W may leak during repeated fuel exchange operations.

This idea was proposed in view of the above circumstances.
Seal water W is also used when cracks etc. occur in the bellows.
The purpose of this invention is to obtain a seal structure that can reliably prevent leakage of .

"Means for Solving the Problems" In order to achieve the above object, the reactor reactor well sealing device according to the present invention provides a liquid-tight seal between the reactor well and dry well of the reactor containment vessel. A bellows to be sealed and a bucking ring attached to the lower part of the bellows and covering the outer periphery of the bellows with a gap are arranged, and the buckling ring is placed in the upper part of the bellows to elastically contact the inner peripheral surface of the buckling ring to seal the gap. The spring seal is configured to include a spring seal having an outwardly curved shape and a spring seal dam that contacts and supports the outside of the spring seal when the spring seal is deformed to expand outward due to an increase in pressure in the gap. There is.

When water is stored in the reactor well, if a leak occurs at the bellows part, when the spring seal receives water pressure, it deforms in the direction of expansion and comes into strong contact with the bucking ring, creating a seal in this part. . Furthermore, when the deformation of the spring seal becomes large, the curved outer side of the spring seal contacts the spring seal dam, suppressing the deformation of this contact part.
The deformation of the spring seal due to water pressure is concentrated near the contact area between the spring seal and the bucking ring, improving sealing performance. Therefore, water flowing down into the dry well due to leakage of the bellows is suppressed.

"Embodiment" Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 and 2. In the figure, parts common to the conventional example are given the same reference numerals to simplify the explanation.

That is, the sealing device of the present invention includes an upper end ring 12 provided at the connection between the bulkhead 3 and the bellows 6, and a lower end ring 14 supported by the reactor pressure vessel 5 via the support frame 13. The bellows 6 is attached between the bellows 6 and the upper end of the bucking ring 7 covering the inner periphery of the bellows 6 is fixed to the bulkhead 3, and the lower end of the outer buckling ring 8 is attached to the support frame 13. attached.

Further, a ring-shaped spring seal dam 15 is attached to the outer periphery of the upper end ring 12 located at the upper side in FIG. It covers the top of the space. Further, a spring seal 16 is provided on the outer periphery of the upper end ring 12 to close the gap between the spring seal dam 15 and the outer buckling ring 8. This spring seal 16 is a curved thin plate-like flexible member as shown in the figure.
One end thereof is fixed to the outer periphery of the upper end ring 12, and the other end is slidably pressed against the inner periphery of the bucking ring 8.

In the seal structure constructed in this way, the bellows 6 is elastically deformed as in the conventional case, and the spring seal 1 is deformed as shown by the solid line in FIG.
Relative displacement between the reactor containment vessel 2 and the reactor pressure vessel 5 is allowed by sliding it on the inner periphery of the bucking ring 8 while closely contacting the buckling ring 8 with its own elastic force. be done. Also,
In the event that the bellows 6 is damaged, seal water W will enter between the bellows 6 and the outer buckling ring 8, but the water pressure of this seal water W will cause the inside of the curved part of the spring seal 16 to As a result, the curved portion is deformed in the direction of expansion, and the spring seal 16 comes into strong contact with the inner surface of the bucking ring 8, creating a sealing property and preventing the seal water W from flowing into the dry well 11. To prevent.

If the water pressure is high, the spring seal 16
The amount of deformation increases against the elastic force of the spring seal 16, and the curved outer portion of the spring seal 16 comes into contact with the spring seal dam 15, as shown by the chain line in FIG. However, after that, the spring seal 16 by water pressure
The deformation is concentrated in the gap between the bucking ring 8 and the spring seal dam 15, the contact between the spring seal 16 and the bucking ring 8 is strengthened, and the sealing performance is improved. Therefore, water flowing down into the dry well 11 due to leakage of the bellows 6 is further suppressed.

"Effects of the Invention" As is clear from the above explanation, the present invention provides a structure in which a buckling ring is provided between a bellows and a buckling ring that is spaced apart in the radial direction from the reactor well to the drywell. Since it is equipped with a spring seal that is elastically deformed by pressure, in the event that a leak occurs in the bellows, the water pressure of the seal water leaking from the bellows is applied to the spring seal to elastically deform the spring seal. , the gap inside the bucking ring can be sealed to prevent seal water from leaking from the reactor well to the dry well.

In addition, if the internal pressure between the bellows and bucking ring is high and the curvature of the spring seal is about to widen, the curved outside of the spring seal contacts the spring seal dam, which suppresses the curvature from widening. Pressure is concentrated at the contact portion between the spring seal and the bucking ring, which is allowed to deform, thereby improving sealing performance and reducing the flow of seal water.

Furthermore, since the spring seal, which ensures sealing performance through deformation, is smaller than a bellows or a buckling ring, it is easy to manufacture and install, and has excellent practicality.

[Brief explanation of the drawing]

Figures 1 and 2 show an embodiment of the reactor wel in which the structure according to the present invention is adopted.
FIG. 1 is a longitudinal sectional view, FIG. 2 is a detailed view of a spring seal portion, and FIG. 3 is a longitudinal sectional view of a reactor well equipped with a conventional sealing device. 1... Shielding wall, 2... Reactor containment vessel, 3...
Bulk head, 5... Reactor pressure vessel, 6... Bellows, 7... Guard ring, 8... Backing ring, 10... Reactor well, 11... Dry well, 12, 14... End ring, 15...
...Spring seal dam, 16...Spring seal.

Claims (1)

[Scope of utility model registration request] A bellows 6 is provided between the reactor well 10 and the dry well 11 of the reactor containment vessel 1 to seal them liquid-tightly, and a bucking ring 8 is attached to the lower part of the bellows and covers the outer periphery of the bellows with a gap. A spring seal 16 is arranged on the top of the bellows and has an outwardly curved shape that elastically contacts the inner peripheral surface of the buckling ring to seal the gap.
and a spring seal dam 15 that contacts and supports the outside of the spring seal when the spring seal is deformed to expand outward due to an increase in pressure in the gap. Device.