JPH0126435B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a device for sealing a penetration portion of a pipe that penetrates a nuclear reactor containment vessel.

(Prior art) For example, the reactor containment vessel of a boiling water reactor is
As an example, as shown in FIG. 1, the outside of a reactor containment vessel b made of a steel plate and containing a reactor pressure vessel a is surrounded by a biological shielding wall c made of concrete. Various piping d, such as a main steam pipe, led out from the pressure vessel a penetrate the containment vessel b and the shielding wall c and are led to the power generation turbine and other external equipment.

Conventionally, a penetrating part assembly e as shown in FIG. 2, for example, is provided in the penetrating part of the pipe d. That is, the outside of the pipe d is surrounded by a telescopic outer pipe g via a protective pipe f, one end of the telescopic outer pipe g is airtightly fixed to the containment vessel b, and the other end of the telescopic outer pipe g is It is airtightly fixed to the pipe d via a flange plate h. Further, the telescopic outer tube g is provided with telescopic bellows i and j,
These bellows i and j make it possible to absorb relative movement between the pipe d and the containment vessel b due to earthquakes or thermal causes. moreover,
A gap k is provided between the expandable outer tube g and the shielding wall c so that relative displacement due to earthquakes or heat can be absorbed.

Conventional penetrating part assembly e configured as above
In this case, if a rupture accident occurs in the pipe d outside the flange plate h, the influence of the accident will extend to the outer periphery of the containment vessel through the gap k. In particular, in the case of an accident involving a high-temperature, high-pressure piping such as a main steam pipe, high-pressure steam passes through the gap k and acts as external pressure on the containment vessel b, adversely affecting the structural integrity of the containment vessel b.
Therefore, conventionally, in order to protect the containment vessel b, a blowout panel n is provided at the boundary of the space m housing the penetration assembly e, and the steam pressure in this space m is equal to the allowable external pressure of the containment vessel b. The structure is such that the blowout panel n is destroyed before the steam reaches the point where the steam escapes to another space, such as the reactor building or the turbine building, and the pressure is reduced.

(Problem to be solved by the invention) However, when this pressure drop exceeds the allowable external pressure of the containment vessel b, it is necessary to release the pressure to the atmosphere through a blowout panel installed on the outer wall of the building, which poses a problem in terms of preventing exposure. Ta.

This invention was made based on the above circumstances, and its purpose is to prevent external pressure from acting on the reactor containment vessel even in the unlikely event of a pipe rupture accident, and to prevent radioactive gas from being released outside the building. An object of the present invention is to provide a piping penetration sealing device that can prevent discharge.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides piping that penetrates a reactor containment vessel made of steel plates and a shielding wall made of concrete surrounding the outside thereof, and a pipe provided outside the piping. A protective pipe that surrounds and protects the piping and a shielding wall that is provided outside the piping and penetrates through the shielding wall with a gap and one end is fixed to the piping airtight outside the shielding wall. an outer pipe whose other end is airtightly fixed to the reactor containment vessel; a first expansion/contraction mechanism provided on the outer pipe that is expandable and retractable in the axial direction of the piping; A partition pipe which is airtightly fixed to the pipe and whose other end is airtightly fixed to a shielding wall or a partition wall connected to the shielding wall; A telescopic mechanism, an exhaust chamber connected to an outside space partitioned by a partition pipe, an exhaust device for exhausting the gas in the exhaust chamber to the outside, and a purification device for purifying the exhaust gas. This is a piping penetration sealing device that aims to achieve this purpose.

(Function) By providing such a means, when a relative displacement occurs between the reactor containment vessel and the piping, the first expansion and contraction mechanism provided in the outer pipe and the second expansion mechanism provided in the partition pipe The expansion and contraction mechanism expands and contracts to absorb the relative displacement. This maintains the sealing of the piping penetration. Furthermore, even if the pipe breaks outside the shielding wall, the ejected gas will be blocked by the partition pipe and the outer pipe and will not flow into the reactor containment vessel.

(Embodiment) The present invention will be described below based on a first embodiment shown in FIGS. 3 and 4. In the figure, reference numeral 1 denotes a reactor containment vessel made of a steel plate, and a reactor pressure vessel (not shown) is accommodated within this containment vessel 1. Further, the outside of the containment vessel 1 is surrounded by a biological shielding wall 2 made of concrete. Note that these containment vessel 1 and shielding wall 2 are constructed within the reactor building.

A pipe 3, for example a main steam pipe, is provided which penetrates the containment vessel 1 and the shielding wall 2. There is an isolation valve 4 such as a main steam isolation valve in the middle of this piping 3.
is provided. Further, the piping 3 is fixed to a support base 6 via a fixing device 5, and this support base 6 has a side wall 7 connected to the shielding wall 2.
It is attached to a and 7b. A penetrating part assembly 10 is provided at the penetrating part of the pipe 3.

This penetrating part assembly 10 will be explained below.
That is, a telescopic outer pipe 11 is provided on the outside of the pipe 3. This telescopic outer pipe 11 has one end hermetically fixed to a flange 12 fixed to the piping 3 and the other end hermetically fixed to the containment vessel 1. Further, the telescopic outer tube 11 passes through the shielding wall 2 with a gap 13 between the telescopic outer tube 11 and the shielding wall 2 . And telescopic outer tube 11
A bellows 1 is shown as an example of the first expansion/contraction mechanism.
4 and 15 are provided so that it can expand and contract in the tube axis direction.

Furthermore, inside the telescopic outer tube 11, a protective tube 16 surrounding the piping 3 is fixed to the flange 12. This protective tube 16 has a function of preventing the impact when the pipe 3 breaks from directly hitting the telescopic outer tube 11.

Furthermore, a partition pipe 17 is provided on the outside of the telescopic outer pipe 11. This partition pipe 17 has a bellows 18 as a second expansion/contraction mechanism that can be expanded and contracted in the tube axis direction, and one end is airtightly fixed to the extensible outer tube 11, and the other end is attached to the shielding wall 2. It is airtightly fixed to an annular receiving member 19.

The penetrating part assembly 10 is constructed as described above, and is housed in a compartment 21 surrounded by the shielding wall 2, the side walls 7a and 7b, and the partition wall 20. In this compartment 21, a blowout panel 23 is provided at the boundary of the space 22 on the side of the penetration part assembly 10.
When the internal pressure of the exhaust chamber 2 exceeds a predetermined value, the blowout panel 23 is blown through and the pressure is increased to the exhaust chamber 2 below.
It seems to be running away to the 6th side.

The divided chamber 21 communicates with an exhaust chamber 26 via a communication hole 25 provided in the partition wall 20.
This exhaust chamber 26 is hermetically sealed on all four sides by partition walls 27. This exhaust chamber 26 has an exhaust device 28.
is provided. Further, on the discharge side of the exhaust device 28, a filter assembly 29 is provided as a purification device for removing radioactive substances, etc. contained in the exhaust gas.
and an exhaust pipe 30 is connected.

The piping penetration sealing device for the reactor containment vessel configured as described above is configured such that when a relative displacement occurs between the containment vessel 1 and the piping 3 due to an earthquake or heat, for example, the bellows 14 provided on the retractable outer pipe 11 ,15
By expanding and contracting the bellows 18 provided on the partition pipe 17, this relative displacement can be absorbed, and the sealing of the piping penetration portion can be maintained. In addition, the relative displacement that occurs between the containment vessel 1 and the shielding wall 2 is
This is permissible due to the existence of the gap 13.

Since the partition pipe 17 is provided at a position to partition between the telescopic outer pipe 11 and the shielding wall 2, even if the pipe 3 breaks outside the penetration part assembly 10, the high pressure steam etc. that spout out will be prevented from entering the partition. It is blocked by the pipe 17 and the telescopic outer pipe 11 and does not flow into the containment vessel 1 side. Therefore, external pressure due to ejected steam or the like does not act on the containment vessel 1, and the structural integrity of the containment vessel 1 can be maintained. When the internal pressure of the space 22 on the side of the penetration part assembly 10 reaches a predetermined pressure, for example, the allowable external pressure of the partition pipe 17 or the telescopic outer pipe 11 due to the ejected steam, etc., the pressure is blown through the blowout panel 23 and exhausted. Escape to room 26 side. Then, the exhaust device 28 is activated in the exhaust chamber 26, radioactive gas and the like are removed by the filter assembly 29, and clean exhaust gas is discharged to the outside of the reactor building through the exhaust stack 30. Therefore, it is extremely effective in preventing radiation exposure.

Furthermore, since the partition pipe 17 is provided with a bellows 18, even if a relative displacement occurs between the shielding wall 2 and the penetration part assembly 10 due to earthquakes or thermal effects, the bellows 18 Therefore, relative displacement can be absorbed and the gap 13 can always be kept in a partitioned state.

Since the gap 13 can be blocked by the partition pipe 17 and the interior of the compartment 21 can be kept in a sealed state, for example, by connecting a suction mechanism such as a blower to the compartment 21, the interior of the compartment 21 can be opened as a passage. can be maintained at a negative pressure with respect to the external space. Therefore, it is effective in preventing leakage of contaminated air to the outside, and has the advantage that negative pressure control for air conditioning is facilitated.

It should be noted that FIG. 5 shows a second embodiment of the present invention, and since the basic configuration is the same as the first embodiment, common parts are given the same reference numerals and explanations are omitted. Explain the parts. That is, in this second embodiment, a partition wall 31 made of concrete is formed in the compartment 21, and a fixing device 5 for supporting the pipe 3 is attached to a base plate 32 provided on the partition wall 31.
At the same time as attaching the flange 1 installed on the pipe 3
A partition pipe 17 is airtightly fixed between the partition wall 2 and an annular receiving plate 33 provided on the partition wall 31. That is, the inner space 22a on the containment vessel 1 side is separated by the partition wall 31, the partition pipe 17, the flange 12, etc.
and an outer space 22b. Note that, like the first embodiment shown in FIG. 3, this outer space 22b communicates with an exhaust chamber 26 equipped with a purifying device such as an exhaust device 28 and a filter assembly 29. On the other hand, the inner space 22a is formed by the telescopic outer tube 11.
It is also used as a maintenance area for the partition pipe 17. Furthermore, a protective tube 34 is fixed to the flange 12 inside the partition pipe 17, so that the partition pipe 17 can be protected from the impact generated when the pipe 3 breaks.

According to the second embodiment, the inner space 22a on the side of the containment vessel 1 and the outer space 22b are separated by the partition wall 31, the partition pipe 17, the flange 12, etc.
Since the outer space 22b is partitioned off, even if the pipe 3 breaks in this outer space 22b, high pressure steam etc. will not flow out to the containment vessel 1 side, and the containment vessel 1 can be protected as in the first embodiment. It is.

As explained above, this invention uses a partition pipe to partition the gap existing between the telescopic outer tube and the shielding wall, so that the gas ejected when the pipe breaks flows out into the reactor containment vessel through the gap. This prevents external pressure from acting on the containment vessel, which is effective in maintaining the structural integrity of the containment vessel. In addition, gas leaking from the piping is led to the exhaust chamber, where it can be purified and discharged, which prevents the pressure inside the building from increasing and prevents contaminated gas from being released outside the building. Its effects are significant, including being effective in preventing radiation exposure.

[Brief explanation of drawings]

1 and 2 show conventional examples, FIG. 1 is a sectional view of a reactor containment vessel, FIG. 2 is a sectional view of a conventional piping penetration, and FIGS. FIG. 3 is a sectional view schematically showing the entire pipe penetration sealing device, FIG. 4 is a sectional view of the pipe penetration, and FIG. 5 is a second embodiment of the present invention. It is a sectional view of a piping penetration part. 1... Reactor containment vessel, 2... Shielding wall, 3...
Piping, 11... Telescopic outer pipe, 13... Gap, 14,
15... Bellows (first expansion and contraction mechanism), 16...
Protection tube, 17... Partition pipe, 18... Bellows (second expansion mechanism), 26... Exhaust chamber, 28... Exhaust device, 29... Filter assembly (purification device),
31... Bulkhead.

Claims (1)

[Scope of Claims] 1. Piping that penetrates a reactor containment vessel made of steel plates and a shielding wall made of concrete that surrounds the outside thereof, and a protection pipe that is provided outside of this piping and surrounds and protects the piping. is provided outside the piping and penetrates the shielding wall with a gap between the piping and the shielding wall, and one end is airtightly fixed to the piping outside the shielding wall, and the other end is attached to the nuclear reactor. an outer pipe airtightly fixed to the containment vessel; a first expansion/contraction mechanism provided on the outer pipe and extendable in the axial direction of the pipe; a partition pipe, the other end of which is airtightly fixed to the shielding wall or a partition wall connected to the shielding wall;
A second expansion and contraction mechanism provided in the partition pipe and capable of expanding and contracting in the axial direction of the pipe; an exhaust chamber connected to the outer space partitioned by the partition pipe; and a gas in the exhaust chamber to be discharged to the outside. What is claimed is: 1. A pipe penetration sealing device comprising: an exhaust device for purifying the exhaust gas; and a purification device for purifying the exhaust gas. 2. The piping penetration sealing device according to claim 1, wherein the piping is fixed to the partition wall via a fixing device. 3. The piping penetration sealing device according to claim 1 or 2, wherein the first and second expansion and contraction mechanisms are bellows.