JPS6298084A - Containment vessel piping penetration structure - 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] [Field of Application of the Invention] The present invention relates to a structure of a piping penetration part of a containment vessel, and is particularly suitable for a containment vessel of a fast breeder reactor (hereinafter simply referred to as F or BR). Pertaining to things.

[Background of the invention]

The structure of the piping penetration part in the FBR containment vessel is as shown in FIG.

That is, inside the steel containment vessel 5, the inner concrete 6 is arranged in parallel with the containment vessel 5. or.

A protective wall 2 is arranged on the outside of the containment vessel 5 in parallel. A plumber penetrates the inner concrete 6, the containment vessel 5, and the protective wall 2. A penetration sleeve 8a fixed to the outside of the pipe 1 is provided with penetration sleeves 8 connected by a multi-stage bellows mechanism 4, which is a telescopic sealing device. This penetration sleeve 8 is fixed to the containment vessel 5.

It penetrates the containment vessel 5 and the inner concrete 6. The guard pipe 12 has a penetration sleeve 8,
8a and the plumber, and its containment vessel 5
An end plate 10 is installed at the inner end.

According to such a structure, even if the piping 1 expands or contracts due to thermal effects or the like, no strain is applied to the containment vessel 5 or the piping 1 itself due to the expansion and contraction of the bellows mechanism 4, which is an extensible sealing device. In order to check that the space between the penetration sleeve 8° 8a and the guard pipe 12 is airtight with respect to the outside, gas is introduced into the space to perform a gas leak test.
At this time, as shown in FIG. 4, the gap between the end plate 1o and the penetration sleeve 8 is made airtight by tightening the rubber packing 16 with the fastening fitting 15.

A penetrating portion having such a structure has the following drawbacks.

1) When a sodium fire occurs inside the containment vessel 5, the heat of the sodium fire may directly reach the containment boundary containment vessel 5, sleeve 8, etc. The design condition of the containment boundary is that the temperature is low compared to the sodium temperature, so if high-temperature sodium leaks near the pipe penetration and a sodium fire occurs, high-temperature sodium mist will be generated between the penetration sleeve 8 and the endpoint 10, There is a risk that the temperature will reach the containment boundary from between the sleeve 8 and the inner concrete 6 and the temperature of the containment boundary will exceed the design temperature.

2) If sodium leaks in containment vessel 5 and a sodium fire occurs, the pressure inside containment vessel 5 will be
However, like the temperature in (1) above, the influence of the pressure increase in the containment vessel 5 directly propagates to the containment boundary, making it impossible to maintain the design conditions of the containment boundary.

3) Even in the event of a small-scale sodium leak accident, sodium mist enters the space between the guard pipe 12 and the penetration sleeve 8 and the space between the I-made containment vessel 5 and the inner concrete 6 and comes into direct contact with the containment boundary. do. For this reason, there was a possibility that the steel containment vessel wall 5, guard pipe 10, etc. that constitute the containment boundary would suffer alkali corrosion from inside.

4) After a sodium leak accident, it is necessary to inspect the containment boundary, but it is extremely difficult to inspect the space between the inner concrete 6 and the steel containment vessel 5 from the inside.

5) After the sodium leak accident, regarding the containment boundary,
It becomes necessary to clean the inside, but as with the above inspection, the cleaning work is tedious.

6) In the event of a large-scale sodium leak accident, it was necessary to drain the sodium accumulated inside the containment boundary.

7) During a containment boundary leakage test, it is necessary to form a test chamber between the penetration sleeve 8 and the guard pipe 12, so it becomes necessary to install a seal as shown in the test seal 17 in FIG. The number of workers working inside the containment vessel room, where radiation levels are high, was increased, increasing the amount of radiation exposure. Furthermore, the test seal needs to be removed after the test, and the amount of radiation exposure increases during the removal process, which may make one task difficult as it may exceed the permissible value.

[Purpose of the invention]

An object of the present invention is to provide a structure for a pipe penetration whose containment boundary is less susceptible to accidents.

[Summary of the invention]

The basic structure of the present invention includes a containment vessel, an inner concrete provided for the containment vessel, a penetration sleeve attached to the containment vessel and penetrating the containment vessel and the inner concrete, and a penetration sleeve attached to the containment vessel and penetrating the containment vessel and the inner concrete. A structure comprising a guard pipe provided inside a sleeve, and piping passing through the guard pipe and penetrating the inner concrete and the containment vessel,
A piping penetration structure for a containment vessel characterized by comprising an inner concrete sleeve attached to the inner concrete and an expandable sealing device provided between the inner concrete sleeve and the penetration sleeve, the pipe penetration structure preventing the movement of the piping. It is possible to reliably maintain the storage boundary while allowing for

[Embodiments of the invention]

Hereinafter, the principle of an embodiment of the present invention will be explained using FIG. In FIG. 1, a guard pipe 14 is connected to the pipe 1. The penetration sleeve 8 is the containment vessel 5
A telescopic sealing device 7 is installed between the penetration sleeve 8 and the inner concrete sleeve 22. A telescopic sealing device 121 is installed between the penetration sleeve and the guard pipe 8 within the containment vessel chamber. In this system, the elastic seal V device 7 has a function of absorbing relative displacement between the inner concrete 6 and the containment vessel 5, and separates the nitrogen atmosphere in the containment vessel chamber from the air atmosphere pressure in the annulus. The expandable sealing device 21 prevents the influence of a sodium fire from directly reaching the containment boundary when a sodium fire occurs in the containment chamber, absorbs the relative displacement between the guard pipe 12 and the containment vessel 5, and performs a Class B leak test on the containment boundary. It has the function of configuring a test chamber during

The extensible sealing devices 7 and 21 are expandable and retractable by installing flexible sealing plates in a convex manner between the sealing parts.

Embodiments of the present invention will be described in more detail below with reference to FIG. In FIG. 5, a guard pipe 12 is connected to the piping 1, and a storage boundary bellows 4 is installed between the guard pipe 12 and the penetration sleeve 8 within the annulus space. The penetration sleeve 8 is connected to the steel containment vessel 5, and an atmosphere separation bellows 7 is installed between the penetration sleeve 8 and the inner concrete 6.

Between the penetration sleeve and the guard pipe, there is a bellows 9 that forms a test chamber in the containment vessel room.
is installed.

In this system, even if sodium leaks in the containment vessel room and a sodium fire occurs, the inner concrete sleeve 22 and penetration sleeve 8
The influence of temperature and pressure increases caused by the sodium fire is propagated to the steel containment vessel 5 and the penetration containment boundary due to the two bellows: the atmosphere seal bellows 23 between the two, the penetration sleeve 8, and the bellows 9 between the guard pipe 12. This makes it possible to maintain the design temperature and pressure conditions of the storage boundary.

In addition, even in the event of a small-scale sodium leak accident inside the containment vessel, by preventing sodium mist from entering the test chamber and the space between the inner concrete 6 and the steel containment vessel wall 5, the containment boundary can be protected. This makes it possible to prevent alkali corrosion from occurring on the inside.

In addition, since sodium mist does not enter the test chamber, there is no need to inspect the inside of the containment boundary, which is difficult to inspect due to its narrow and complex shape. can be kept to a minimum. Furthermore, even in the event of a large-scale sodium spill accident, shallow water sodium will not enter the penetration sleeve and inner concrete sleeve, making shallow water sodium dosing equipment unnecessary and the equipment simplified.

During a Class B leak test during regular inspections, the guard pipe 12 and penetration sleeve are opened by opening the test gas supply valve (not shown) connected to the test gas supply pipe (not shown) in the annulus space. The space between 8 supplies test gas and performs a leak test of the containment boundary. After the test, loosen the test gas drain plug (not shown) to release the test gas into the containment vessel. In the conventional method, a test seal 17 consisting of a rubber gasket 16 and a fastening fitting 15 as shown in Figure 4 is attached during the test, and a test gas supply pipe (
The test seal 17 and the test gas supply pipe (not shown) were removed after the test was completed.

By adopting the present invention, it becomes unnecessary to install and remove the test seal 17 and to install and remove the test gas supply piping, and by simplifying the work in the containment vessel where the radiation dose is high, it is possible to reduce radiation exposure. can. Furthermore, by simplifying the shallow water test work, it becomes possible to significantly improve maintenance efficiency, and the efficiency of periodic inspections can be improved.

Furthermore, the present invention is not limited to the above embodiment.

For example, when a rubber boot 18 is used in the test chamber forming bellows portion as shown in FIG. 6, a sleeve structure may be used as shown in FIG. 7. In either case, as in the case of FIG. 1, there is a telescopic sealing device, ie, two functions capable of achieving the sealing function while allowing expansion and contraction.

〔Effect of the invention〕

According to the present invention, in the storage boundary piping penetration part,
In the event of an accident within the containment boundary, it is possible to prevent the impact from directly reaching the containment boundary.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a storage boundary piping penetration part showing the principle of the present invention, and FIG. 2 is a sectional view of an embodiment of the present invention in which a bellows is used as the sealing mechanism. FIG. 3 is a sectional view of a conventional containment boundary pipe penetration part, FIG. 4 is a sectional view of a test seal attachment part during a leak test in the conventional plan, and FIG. 5 is a sectional view of a pipe penetration part of an embodiment of the present invention.
Fig. 6 shows an embodiment of the present invention, which is a sectional view of a pipe penetration part when a rubber skirt is used, and Fig. 7 shows an embodiment of the invention, which shows a sectional view of a pipe penetration part when a sleeve structure with a rubber seal is used. It is a diagram. 1... Piping, 5... Containment vessel, 6... Inner concrete + 7.21... Expandable seal device, 8...
・Penetration sleeve, 12... Guard pipe, 18... Rubber boots, 19... Rubber packing,
22...Inner concrete sleeve.

Claims (1)

[Scope of Claims] 1. A containment vessel, an inner concrete provided for the containment vessel, a penetration sleeve attached to the containment vessel and penetrating the containment vessel and the inner concrete, and the penetration sleeve. In a structure comprising a guard pipe provided inside a ration sleeve, and piping passing through the inner concrete and the containment vessel passed through the guard pipe, an inner concrete sleeve attached to the inner concrete; A piping penetration structure for a containment vessel, comprising an elastic sealing device provided between the inner concrete sleeve and the penetration sleeve. 2. A pipe penetration structure for a containment vessel according to claim 1, characterized in that a telescopic sealing device is provided between the penetration sleeve and the guard pipe. 3. The piping penetration structure for a containment vessel according to claim 1 or 2, wherein the expandable seal device has a bellows structure.