JPS58178291A - Seal device of 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 1] The present invention relates to a nuclear reactor vessel disposed between a flange formed at the upper part of a nuclear reactor vessel and an inner wall of the reactor vessel. related to the sealing device.

[Technical Background of the Invention 1 Generally, in nuclear power plants, it is the duty of a regular inspection authority to ensure the normal operation of the plant.
As a confirmation of work II;-t-f, the (ζ-), ear, and separator in the power vessel were moved and the spent fuel was replaced with new fuel. There is.

This work is carried out after filling the reactor chamber 1 with water as in the hob shown in FIG. As shown in Figure 1,
, a flange portion 3 formed in a part of the reactor pressure vessel 2
A sealing device 5 for the reactor well is disposed between the reactor well inner wall 4 and the space formed by the reactor well sealing device 5 and the reactor well inner wall 4. After being filled with water, the dry cell 6 and separator 7 housed in the reactor pressure vessel 2 are transferred through the atomic well 1 to the equipment storage pool 8, and are also housed in the reactor pressure vessel 2. The fuel placed in the reactor core 9 is in the reactor well 1
The fuel is transferred to the fuel pool 10 through the fuel tank.

FIG. 2 shows details of the sealing device 5 for the reactor unit used during such water filling. In the figure, the reference numeral 3 is formed at the -1 end opening of the reactor pressure vessel 2. The flange portion is shown.

A basin seal 13 seals between the flange portion 3 and the reactor containment vessel 12 . This payne seal 13 has one end fixed to the 7 flange portion 3, and has a lower seal member 15 on which the payne seal drain pipe 14 is disposed.
and a bulkhead 16 fixedly installed in the reactor containment vessel 12.
The lower seal member 15 and the upper seal member 17 have one end fixedly attached to the upper seal member 17. The fuel exchange bellows 18 is connected to absorb the difference in thermal expansion caused by the fuel exchange bellows 18. Note that the lower seal member 15
A fuel exchange bellow leak detection pipe 19 is disposed outside the fuel exchange rose 18.

Furthermore, a reactor well seal 20 seals between the reactor containment vessel 12 and the reactor core inner wall 4.

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 reactor containment vessel 12 and the reactor well inner wall 4, there is a A seal bellows 25 is provided in each reactor to absorb the difference in thermal expansion caused by the temperature difference. A seal bellows leak drain 26 is disposed outside and below the reactor well seal bellows 25 .

[Problems with Background Techniques] However, in the reactor well sealing device configured as shown below, the temperature difference between the reactor pressure vessel 2, the reactor containment vessel 12, and the reactor well inner wall 4 To absorb the difference in thermal expansion, a fuel exchange bellows 18 and a reactor well seal bellows 25 are used, and when the reactor well 1 is filled with water, corrosion products contained in reactor water are removed from the fuel exchange. Adhesion to the bellows 18 and reactor well seal bellows 25 is problematic.

That is, the water filled in the reactor well 1 is discharged from the reactor pressure vessel 2, payson shield drain piping 14, and reactor well seal drain piping 24, and then, for example, in the norange section of the reactor pressure vessel 2. 3, the head is installed, but even after the filling water has been drained, TLL-prone crud such as corrosion products is still attached to the fuel exchange bellows 18 and the reactor well seal bellows 25, so workers must There is a problem in that the number of victims of rape is increasing.

For this reason, conventionally, the radioactive crud adhering to the rose 18 and the reactor well seal bellows 25 during fuel exchange 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.

[Object of the invention] The present invention has been made in response to such conventional circumstances,
The present invention aims to provide a reactor well sealing device that can prevent radioactive substances such as cladding from adhering to payson seals 13, reactor well seals 20, etc., and can minimize the amount of radiation used by workers. .

[Summary of the Invention 1] In other words, the present invention includes a sealing mechanism that seals between a norange part formed in the upper part of a nuclear reactor vessel and an inner wall of a reactor well, and a sealing mechanism disposed to cover this sealing mechanism. There is a sealing device C for a nuclear reactor well characterized by comprising a pedestal having a pure water spout and a supply pipe for supplying the pure water between the sealing mechanism and the pedestal.

[Embodiment 1 of the Invention] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIGS. 3 and 4 show a reactor well sealing device according to an embodiment of the present invention, and in the figures, reference numeral 27 indicates a second
A pedestal is shown that is disposed above the payson seal 13 and the reactor well seal 2o described in the figure. One end of this pedestal 27 is mounted on a bracket 28 formed at the upper end of the seven flange portion 3 of the reactor pressure vessel 2, and the other end is mounted on the 14(7) stage 129a in the reactor well.

FIG. 4 is a top view of this pedestal 27. This pedestal 27 is made of a shape 4k obtained by dividing an annular disk into six parts, and is arranged along a bracket 28 formed on the flange portion 3. There is. A pure water spout 29 is formed between each pedestal 27 with a small gap. Further, among these frames 27, the one located on the side of the fuel boule 10 has a floor portion made of lead. Upstream of the on-off valves 14a and 24a of the payson shield drain pipe 14 and the reactor single shield drain pipe 24 shown in FIG. 2, there is a supply pipe 31 in which an on-off valve 30 is inserted, as shown in FIG. Branch pipes 32a and 32b are connected to each other.

It should be noted that, except for the above-mentioned parts, the structure is the same as that of the reactor well sealing device shown in FIG. 2, so the same parts as in FIG.

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 pedestal 27 is moved to the bracket 28 by a crane or the like.
and the reactor well inner wall 4, the on-off valves 14a and 24a provided in the payson shield drain pipe 14 and the reactor well seal drain pipe 24 are closed, and the valves 14a and 24a provided in the supply pipe 31 are closed. The provided on-off valve 30 is opened, and pure water flows into the space between the pedestal 27, the payson seal 13, and the reactor well seal 20, and when the pure water reaches the lower part of the pedestal 27, the upper lid of the reactor pressure vessel 2 is closed. is removed and reactor tube 1 is filled with water.

Therefore, in the reactor well sealing device configured as described above, pure water always flows into the payson seal 13 and the reactor well seal 20 from the payson seal drain pipe 14 and the reactor well seal drain pipe 24. ,
Since this pure water is flowing upward from the spout 29 formed between the pedestals 27 and the pedestals 27, reactor water containing radioactive materials such as radioactive cladding flows into the lower part of the pedestals 27. There's nothing to do. Note that since water is always present at the bottom of the pedestal 27 when it is filled with water, there is no need to consider the weight in the water direction when designing the pedestal 27, and the pedestal 27 does not need to have a very sturdy structure. Further, water sealing is performed only by the basin seals 13 & 3 and the reactor well seal 20. Also, pedestal 2
Since the floor of the pedestal 27 on the fuel boule 10 side at the back of 7 is made of lead, it can provide radiation shielding when the fuel passes between the reactor well 1 and the fuel boule 10. Work can be carried out without any problem even at the lower part of No. 12.

Furthermore, in the reactor tube sealing device configured as described above, even when lowering the water level in the reactor well 1, the on-off valve 30 disposed in the supply pipe 31 remains open. The on-off valve 3 installed in the supply pipe 31 after the water level becomes lower than the upper end surface of the flange portion 3 of the reactor pressure vessel 2
0 is closed, and the on-off valve 1 is inserted into the Payson shield drain pipe 14 and the reactor tower shield drain 1 pipe 24.
4a and 24a are opened, and the pure water remaining in the payson seal 13 and the reactor well seal 20 flows into the payson seal drain pipe 14 and the reactor well seal drain pipe 24.
removed from

Therefore, it is possible to completely prevent radioactive materials such as radioactive cladding from flowing into payson seal 13 and reactor well seal 20.

Note that the pedestal 27 is removed during operation of the nuclear reactor.

[Effects of the Invention 1] As described above, according to the reactor well sealing device of the present invention, it is possible to prevent radioactive materials from landing on the payson seal and the reactor well seal, and to reduce the worker's P.I.
i Control line training fluid can be significantly reduced.

In addition, in the embodiment described above, an example was described in which the pedestal 27 was arranged over the entire surface of the payson seal 13 and the reactor well seal 20, but it is also possible to cover the payson seal 13 and the reactor well seal 20 with separate pedestals. Of course it's a good thing.

[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. FIG. 4 is a longitudinal sectional view showing a sealing device for a reactor well, and FIG. 4 is a top view of FIG. 3. 2... Reactor pressure vessel 3...
・・・・・・・・・7 Lunge part 4・・・・・・・・・・・・
・Reactor well inner wall 5...Seal mechanism 27... Frame 31...Supply piping agent patent attorney
Satoshi Suyama - Figure 1

Claims (1)

[Claims] (1) A sealing mechanism that seals between a flange formed at the top of the reactor FF force vessel and the inner wall of the reactor well;
An atom characterized by comprising: a pedestal provided with a pure water spout disposed to cover the seal; and a supply pipe for supplying the pure water between the seal mechanism and the pedestal. Furnace well sealing device.