JPS58214886A - Seal device for reactor well - 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 [Technical Field of the Invention] The present invention relates to a sealing device for a nuclear reactor well, which is disposed between a flange formed at the upper part of a nuclear reactor pressure vessel and an inner wall of the reactor well.

[Technical background 4 of the invention] Generally, in nuclear power plants, periodic inspection work is required to ensure the normal operation of the plant.
As part of this work, a dryer inside the reactor pressure vessel,
Work is underway to move the separator and replace spent fuel with new fuel.

This operation is carried out after filling the reactor well 1 with water as shown in FIG. That is, as shown in FIG. 1, a reactor well sealing device 5 is disposed between the flange portion 3 formed at the upper part of the reactor pressure vessel 2 and the reactor well inner wall 4, and this nuclear After the space formed by the reactor well sealing device 5 and the reactor well inner wall 4 is filled with water, the dryer 6 and separator 7 housed in the reactor pressure heavy equipment 2 pass through the reactor well 1 and are stored as equipment. Fuel transferred to the boule 8 and disposed in the reactor core 9 housed within the reactor pressure vessel 2 is transferred through the reactor well 1 into the fuel boule 10 .

FIG. 2 shows details of the above-mentioned reactor well sealing device 5 used during such water filling, and in the figure, reference numeral 3 indicates a flange formed at the upper end opening of the reactor pressure vessel 2. ing.

A basin seal 13 seals between the flange portion 3 and the reactor containment vessel 12 . This basin seal 13 has one end fixedly attached to the flange portion 3, and has a lower seal member 1 on which the basin seal drain pipe 14 is disposed.
5, and the bulkhead 1 fixedly installed in the reactor containment vessel 12.
6 and an upper seal member 17 having one end fixedly attached to the reactor pressure vessel 2 and the upper seal member 17. They are connected by a fuel exchange bellows 18 to absorb the differential thermal expansion. Note that the lower seal member 1
One fuel exchange bellows leak detection pipe is disposed outside the fuel exchange bellows 18 '5.

Further, a space between the reactor containment vessel 12 and the reactor well inner wall 4 is sealed by a reactor well seal 20. This reactor well seal 20 includes a lower seal member 22 having one end fixed to a head 21 fixed to the reactor containment vessel 12 and an upper seal member 23 having one end fixed to the reactor well inner wall 4. Between the lower seal member 22 and the upper seal member 23 where the reactor well seal train piping 24 is disposed, there is a seal between the reactor containment vessel 12 and the reactor main tube 4. A reactor well seal bellows 25 is provided to absorb the difference in thermal expansion due to the temperature difference between the two. A seal bellows leak drain 26 is disposed outside and below the reactor well seal bellows 25 .

[Problem in the Background Art 1 However, in the reactor well sealing device configured as described above, the reactor pressure vessel 2, the reactor containment vessel 1
A fuel exchange bellows 18 and a reactor well seal bellows 25 are used to absorb the difference in thermal expansion caused by the temperature difference between the reactor well 1 and the reactor well inner wall 4. Corrosion products, etc. that are present in the fuel exchange bellows 18 and the reactor well seal bellows 2
5 and increases over time.

That is, the water filled in the reactor well 1 is discharged from the reactor pressure vessel 2, the Payson shield drain pipe 14, and the reactor well seal drain pipe 24, and then, for example, in the flange portion 3 of the reactor pressure vessel 2. Installation of the head requires work, but radioactive crud such as corrosion products remains in the fuel exchange bellows 1 even after the water has been drained.
8 and the reactor well seal bellows 25, there is a problem in that the radiation dose to workers increases.

For this reason, conventionally, the radioactive crud adhering to the fuel exchange bellows 18 and the reactor well seal bellows 25 is removed by cleaning with jet water or a brush by an operator. However, even in such work, workers may be exposed to considerable radiation;
Since it is difficult to completely remove radioactive substances, there is a problem that the amount of attached radioactive substances gradually increases.

[Object of the Invention] The present invention has been made in response to such conventional circumstances,
The present invention aims to provide a sealing device for a nuclear reactor well that can reduce radiation exposure of workers as much as possible by making the sealing device removable.

[Summary of the Invention゛] That is, the present invention provides an annular plate that is removably disposed between a flange formed at the upper part of a reactor pressure vessel and an inner wall of a reactor well, and this annular plate. and a sealing mechanism disposed between the flange portion and the inner wall of the reactor well.

[Embodiment of the Invention] The details of the present invention will be described below with reference to an embodiment shown in the drawings.

FIGS. 3 and 4 show a reactor well sealing device according to an embodiment of the present invention. This reactor well sealing device connects a flange portion 3 formed at the top of a reactor pressure vessel 2 and a nuclear reactor well sealing device according to an embodiment of the present invention. An annular plate 27 that is detachably disposed between the reactor well inner wall 4 and a seal mechanism 28 that is disposed between the annular plate 27, the flange portion 3, and the reactor well inner wall 4, respectively. The main part consists of .29.

That is, the plate 27 has an annular shape, and the inner peripheral edge 30 of the plate 27 extends from the support member 3 formed to protrude from the flange 3 formed at the upper part of the reactor pressure vessel 2.
It is placed on 1.

On the other hand, a support member 33 in the shape of a rectangle is disposed on the outer peripheral edge 32 of the plate 27, and a vertical part of the support member 33 is made of stainless steel, for example, in order to absorb thermal distortion in the vertical direction. A bellows 34 is provided.

A bellows 35 is disposed in the middle of the plate 27 to absorb thermal distortion in the horizontal direction.
is supported by reinforcing members 36 on both sides. Note that the lower end of the reinforcing member 36 is placed on the upper surface of the bulkhead 16 supported by the reactor containment vessel 12.

Furthermore, this plate 27 is connected to the reactor containment vessel 12.
is supported by a reinforcing member 38 placed on the upper end of the
Three handles 40 are arranged at equal angles on the inner and outer upper surfaces of the bellows 35 of the plate 27, respectively.

FIG. 5 shows the inner peripheral edge 30 of the plate 27, and there is a gap between the inner peripheral edge 30 and the support member 31, for example.
A pair of sealing members 41 made of rings are provided, and these sealing members 41 are inserted and supported in mounting grooves 42 formed on the lower surface of the plate 27, respectively. The inner peripheral edge 30 of the plate 27 is located between the seal members 41 and 41.
A mounting bolt 43 is provided for pressing the support member 31 against the support member 31, and this mounting bolt 43 is screwed into a screw hole 44 formed in the support member 31.

FIG. 6 shows the outer peripheral edge portion 32 of the plate 27, and the horizontal portion of the box-shaped support member 33 is placed on a fixing member 45 formed on a stepped portion of the inner wall 4 of the reactor well. A set of sealing members 4 is provided between the supporting member 33 and the fixing member 45.
6 are disposed, and these seal members 46 are inserted and supported in mounting grooves 47 formed on the lower surface of the support member 33, respectively. A mounting bolt 48 for fixing the support member 33 to the fixing member 45 is disposed between the seal members 46 and 46, and the mounting bolt 48 is screwed into a screw hole 46 screwed into the fixing member 45. has been done.

In the reactor well sealing device configured as described above, after the top cover of the reactor containment vessel 12 is removed when the reactor is shut down, the plate 27 is moved to the flange portion 3 by a crane or the like using the handles 39 and 40. After being placed between the plate 27 and the reactor well inner wall 4, the inner circumferential edge 30 and outer circumferential edge 32 of the plate 27 are attached to the support member 31 and the fixing member 45 with mounting bolts 43 and 48, respectively. The upper cover of the reactor pressure vessel 2 is removed and the reactor well 1 is filled with water. Thereafter, the water filled in the reactor well 1 from the reactor pressure vessel 2 is discharged, and then, for example, a head installation work is performed on the flange portion 3 of the reactor pressure vessel 2. After completing the work, plate 27
The mounting bolts 43, 48 that attach the plate 27 to the support member 31 and the fixing member 45 are removed, and the plate 27 is
The handles 39 and 40 are suspended by a crane or the like and moved to a cleaning room where they are cleaned to completely remove radioactive deposits and then stored in a predetermined storage location.

Therefore, in the reactor well sealing device configured as described above, unlike the conventional reactor well sealing device, radioactive crud such as corrosion products gradually adheres to the bellows, etc., and this does not increase. The radiation exposure of workers can be significantly reduced.

[Effects of the Invention] As described above, according to the reactor well sealing device of the present invention, radiation exposure of workers can be significantly reduced by eliminating the increase in adhesion of radioactive substances to the device. .

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing the vicinity of a conventional reactor well sealing device, FIG. 2 is a vertical cross-sectional view of the reactor well sealing device shown in FIG. 1, and FIG. 4 is a top view of FIG. 3, FIG. 5 is an enlarged view of the inner peripheral edge of the plate in FIG. 3, and FIG.
The figure is an enlarged view of the outer peripheral edge of the plate in FIG. 3. 2・・・・・・・・・・・・Reactor pressure vessel 3・
・・・・・・・・・・・・・・・Flange part 4・・・・・・
......Reactor well inner wall 27...
Plate 28.29 Seal Mechanism Agent Patent Attorney Sa Suyama - Figure 1 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] (1) An annular plate disposed such that it can be sharpened between a flange formed at the upper part of the reactor pressure vessel and the inner wall of the reactor well, and the annular plate, the flange, and the reactor. 1. A sealing device for a nuclear reactor well, comprising: a sealing mechanism disposed between each well and an inner wall of the well.