JPH0461569B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention mainly relates to nuclear power plant containment vessels, etc.
This invention relates to an electric wire penetration part that penetrates a partition wall that requires an airtight seal.

[Prior Art] In preparation for the depletion of oil resources in the future, a switch to nuclear power generation is being gradually carried out today. Now, in nuclear power generation, the core, the reactor, is housed in a containment vessel, also known as a pressure vessel.
The bulkhead of the containment vessel has several wire penetrations for various wires used to control and monitor the internal furnace. Such a wire penetration part is strictly required to have an airtight structure so that radioactive substances do not leak through the wire penetration part. Now, as this type of wire penetration part, the one shown in FIG. 1 has been known in the past. FIG. 1 shows one end of the outer cylinder 1 that is airtightly attached to the through wall of the containment vessel. As this figure shows, a large number of When welding an end plate 3 having through holes 2 to airtightly seal the inorganic insulated metal sheathed electric wire 4 (hereinafter referred to as MIC) passed through each through hole 2, welding the outer periphery of the MIC 4. The entire part 2a must be uniformly welded. Here, MIC refers to a conductor insulated with an inorganic material such as magnesium oxide and a metal sheath such as SuS on the outside. Generally, the shorter the length of the wire penetration part to be welded or brazed, the fewer defects such as pinholes will occur, and as a result, the reliability of airtightness will be improved.
Therefore, it is also necessary that the wire penetration portion be as small as possible. Therefore, the surface of the end plate 3 having the through holes 2 is narrow, and the intervals between the through holes 2 are also narrow.
Therefore, when we welding MIC4 one by one,
Gradually, the items installed next to it become a nuisance, and the MIC
The welding operation becomes unstable and difficult, as it is impossible to weld while keeping the welding torch at the same angle over the entire circumference of the welding tube. In this way, in the conventional electric wire penetration part, between the end plate 3 and the MIC 4 passing through the through hole 2 provided in the end plate 3,
It is extremely difficult to create an airtight seal by welding or brazing. In particular, the greater the number of through holes 2, the greater the problem. In addition, apart from this, the first
There is also one in which the part corresponding to end plate 3 in the figure is solidified all at once with epoxy resin, etc., but it penetrates as described above.
If there are many MIC4 or solid conductors, all
It is extremely difficult to fill and solidify resin to maintain airtightness between the MIC4 and the solid conductor, and there is also the problem that if there is an airtight leak in even one place, the whole thing will have to be redone.

[Purpose of the invention]

In view of the above-mentioned problems, an object of the present invention is to provide a wire through-hole in the through-hole of both end plates having the through-hole.
It is an object of the present invention to provide an electric wire penetration part that is easy to perform sealing work such as welding when passing through a MIC and airtightly seals the gap therebetween, and therefore has a highly reliable airtightness.

[Structure of the invention]

In order to achieve the above object, the wire penetration part of the present invention has the following features:
end plates having opposing through holes are hermetically attached to both ends of the outer tube, the MIC is hermetically attached through the opposing through holes of each of the end plates, and the outer tube is airtightly attached to the through wall. In the wire penetration part attached to the wire penetration part, at least one of the end plates attached to both ends of the outer cylinder has a metal tube having flexibility and elasticity in the through hole on the outside. The metal tube is protruded from and airtightly attached to the MIC, and the metal tube and the metal sheath of the MIC passing through the metal tube are airtightly sealed.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 2 shows an embodiment of the present invention. As shown in this figure, in the end plates 3 and 5 having a plurality of through holes 2, a spiral metal tube or a metal loose tube or the like is inserted into the through holes 2 in advance. A flexible metal tube 6 having flexibility and stretchability is passed through and airtightly welded inside the end plate.
A welded portion 6a is formed. In FIG. 2, the inner surfaces of the end plates 3 and 5 and the end surface of the flexible metal tube 6 are welded almost flush, but the end surfaces of the flexible metal tube are spread out into a brim shape, and the end plates 3 and 5 are welded almost flush. It is preferable to weld or braze the insides of the welds 3 and 5 as shown in FIG. 3, since this improves the strength of the welded portion 6a. Now, in this way, the end plates 3 and 5 are welded or brazed on the inside,
After the flexible metal tube 6 protruding outward is attached airtightly, the end plates 3 and 5 with the flexible metal tube are attached to the outer tube 1 at the welded portions 3a and 5, respectively, with the flexible metal tube 6 facing outward. Weld 5a and install it airtight. Of course, it is not limited to welding as long as it can maintain airtightness. Regarding the through holes 2 of the end plates 3 and 5, the central axes of the opposing through holes do not necessarily have to coincide, but it is better to do so when passing the electric wire through them. It's convenient. In addition, in Fig. 2, pressurized nitrogen gas is sealed in the inner space formed by the outer cylinder 1 and the end plates 3 and 5, and internal pressure fluctuations are constantly monitored to detect the presence or absence of gas leakage. A ring 1 to which a valve 7 and a pressure gauge 8 are attached and has a pressure detection hole 9 communicating with the pressure gauge 8.
The outer cylinder 1 is formed by airtightly connecting the ring 1B and the welded part 1a to the main body part 1A, but in order to reduce the number of welded parts and improve the reliability of airtightness, the ring 1B and the main body part 1A are manufactured as one piece in advance. The outer cylinder 1 may also be formed by doing so.
Now, after attaching the end plates 3 and 5 to the outer cylinder 1 airtightly,
Pass the MIC 4 through the opening of one flexible metal tube 6,
The tip is brought out into the opening of the other flexible metal tube 6.
Of course, there is no problem in inserting it from either direction. After inserting MIC4 in this way,
The metal sheath of the MIC 4 and the flexible metal tube 6 are welded airtight. Therefore, by making the inner diameter of the opening of the flexible metal tube 6 slightly larger than the outer diameter of the MIC 4, the welding portion 4a can be easily formed. Further, if the adjacent flexible metal tube 6 is an obstacle when welding the welding portion 4a, the flexible metal tube 6 may be bent to escape. Here, if a through hole 15 is provided in the metal sheath as shown in FIG. 4 at the C part in FIG. 2 of the MIC 4 inserted into the flexible metal tube 6, the outer tube 1 and the end plate 3, The pressurized nitrogen gas sealed in the space surrounded by 5 is
It is possible to constantly check through the pressure gauge 8 whether there is any leakage through the MIC4, or conversely, whether radiation, etc. inside the containment vessel is leaking through the MIC4. In addition, to prevent leakage from terminal D of MIC4, conductor 1 is connected as shown in Figure 5.
Connect the lead 18 airtightly sealed with an insulator 17 such as glass or ceramic to the tip of the MIC 4 from which the MIC 6 has been taken out, using a crimp sleeve 19, cover it with a metal case 20, and connect the metal case 20 and the MIC 4.
The metal sheath and insulator 17 are hermetically sealed by welding or brazing.

After the MIC 4 is installed as described above, the outer cylinder 1 is finally attached airtightly, for example, by welding, to the through wall 11 having the through part of the containment vessel. The welded portion 11a in FIG. 2 is the welded portion.

FIG. 6 is an application example, but when inserting multiple MICs 4 into the flexible metal tube 6, it is not possible to airtightly seal the metal sheath of the MIC 4 and the opening of the flexible metal tube 6 as they are. Since it is difficult, use spacer 2.
If 1 is inserted and the parts 21a and 21b are sealed airtight, the work is easy and airtightness is easily achieved. Also the second
In the figure, flexible metal tubes 6 are attached to both end plates 3 and 5, but in some cases, one side may be combined with the conventional method as shown in FIG. 1 or 7. Good too. In Fig. 7, the metal case 22 is airtightly welded to the end plate 3 or 5 at either the 22a or 22b part, and the metal sheath of the MIC 4 is airtightly welded to the welded part 4a at the tip opening of the metal case 22. It is welded. When using the conventional method only on one side, there are cases where there is not enough space on one side and it is not possible to take a sufficient length l from the end plate to the tip of the MIC 4.

As described above, in the present invention, as a method of airtightly sealing between the MIC that passes through the wire penetration part and the through hole that the MIC passes through, we have developed a structure that is easy to weld or braze, that is, each penetration of the end plate. The structure is such that the MIC and the flexible metal tube are hermetically welded or brazed at the tip of the flexible metal tube that is airtightly fitted into the hole. Therefore, even if there are multiple through holes provided in the end plate and the flexible metal pipes are lined up in a row, it is necessary to bend the adjacent flexible metal pipes slightly so that they do not get in the way of welding or brazing work. It is possible to release the material to a location where it is easy to work on the material to be welded or brazed. Because the welding or brazing is performed at the tip of the flexible metal tube, and because the metal tube is flexible, this flexible metal tube
Welding or brazing work between MICs can always be done in a constant posture, making it easier to obtain high quality welding or brazing. In addition, if this flexible metal tube is attached to the end plate by welding or brazing on the inside of the end plate, that is, on the side opposite to the protruding side of the flexible metal tube, the adjacent flexible metal tube can be attached. This is preferable because it does not interfere with work. Furthermore, when there are multiple flexible metal pipes standing in a row as shown in Figure 8, the outer ones are made shorter so that the adjacent ones are less likely to get in the way. Workability such as welding at the tip of a metal tube is further improved. Further, in the present invention, as a method of airtight sealing, a sealing method by filling resin such as epoxy resin is not used at all, but a method of individually welding or brazing is adopted. Therefore, each connection made by welding or brazing can be tested for airtightness to ensure that there are no leaks before proceeding, and if a leak is found, it can be repaired at each step. At the same time, it has better fire and heat resistance than resin-filled types. In addition, from the viewpoint of heat resistance, even if the wire penetration part according to the present invention is exposed to high temperatures, the flexible metal tube absorbs the thermal stress that occurs due to this high temperature with its elasticity. Specifically, the flexible metal tube and MIC4
The thermal stress does not directly act on the connecting portion. It also has excellent heat resistance.

〔Effect of the invention〕

As described above, according to the present invention, when attaching the MIC that passes through the wire penetration part to the penetration part main body by welding or brazing, this workability is good, and therefore the airtight reliability of the connection part is high, and Further, a wire penetration portion having excellent fire resistance and heat resistance can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a partial longitudinal cross-sectional view showing a conventional electric wire penetration part, FIG. 2 is a partial vertical cross-sectional view showing an embodiment of the electric wire penetration part of the present invention, and FIG. 3 is a flexible metal in FIG. 2. FIG. 4 is a partial vertical cross-sectional view showing another example of the method for installing the pipe, FIG. 4 is a partial vertical cross-sectional view showing section C in FIG. 2, and FIG. 6 and 7 are partial longitudinal sectional views showing other embodiments of the present invention, and FIG. 8 is a schematic diagram of an example of flexible metal tube arrangement showing another embodiment of the present invention. be. 1A, 1B... Outer cylinder, 3, 5... End plate, 4...
Inorganic insulated metal sheathed electric wire, 6...Flexible metal tube, 1
DESCRIPTION OF SYMBOLS 1... Penetration wall, 17... Insulator, 20... Metal case, 21... Spacer.

Claims (1)

[Scope of Claims] 1. End plates having opposing through holes are hermetically attached to both ends of the outer cylinder, and inorganic insulated metal sheathed electric wires are hermetically attached through the opposing through holes of each end plate. and in which the outer tube is airtightly attached to the through wall, one side of at least one end plate of the end plates attached to both ends of the outer tube has a flexible plate attached to the through hole. A metal tube having elasticity and elasticity protrudes outward and is airtightly installed, and a space between the metal tube and the metal sheath of the inorganic insulated metal sheathed electric wire passing through the metal tube is airtightly sealed. An electric wire penetration part characterized by the following. 2. In the case of a plurality of through-holes, the length of the flexible metal tube installed in the through-hole is shorter as the through-hole is installed in the outermost through-hole. An electric wire penetration portion according to claim 1.