JPH0461571B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention mainly relates to an electric wire penetration part that penetrates a partition wall that requires airtight sealing, such as a containment vessel of a nuclear power plant.

[Prior art]

In preparation for the future depletion of oil resources, the switch from thermal power generation to nuclear power generation is being gradually carried out today. The heart of nuclear power generation, the nuclear reactor, is housed in a containment vessel, also known as a pressure vessel.
To control and monitor the internal furnace,
For example, several wire penetration parts are provided for wires such as inorganic insulated metal sheathed wires (hereinafter referred to as MIC). Note that MIC is an electric wire in which the conductor is insulated with an inorganic material such as magnesium oxide, and the outside is protected with a metal sheath such as SuS. Such wire penetrations are required not only to have an airtight structure to prevent internal radioactive substances from leaking through the wire penetrations, but also to have various strict characteristics including fire resistance, heat resistance, and earthquake resistance.

Now, what has been proposed in the past has been proposed as shown in FIG. 1. As shown in FIG. The end plates 3 and 5 are airtightly attached to the outer cylinder 1 with the straight pipes 6 facing outward. After that, the conductor 16 is taken out from one end of the straight pipe 6 attached to both end plates 3 and 5, which are opposed to each other and whose center axes are substantially the same, and the taken out conductor 16 is made of glass or other material from the other end. A crimping sleeve 19 is attached to a lead 18 which is insulated with a heat-resistant insulator 17 such as ceramic in an airtight structure.
Connect the MIC4 connected to the lead 18
Insert it from the straight pipe opening on the side A in Figure 1, with the end connected to it as the rear end. At this time, the MIC is connected to the B section side of the other end.
The metal eyelet 20, which airtightly encloses the insulator 17, is pushed into the metal tube 6 while being inscribed therein until the conductor 16 of No. 4 comes out enough to be connected to the lead 18. Next, on the part B side, the lead 18, which is airtightly insulated by the insulator 17, and the conductor 16 of the MIC 4 are connected with a crimp sleeve 19, and then the metal eyelet 20, which airtightly encloses the insulator 17, is connected. When the metal eyelet 20 protrudes from the end of the metal tube 6 on the A section side and the B section side almost equally, the connection point 20 is opened.
a and 20b are welded or brazed to airtightly connect them, and then the outer cylinder 1 is airtightly attached to the through wall 11 of the containment vessel by welding or the like at the connecting portion 11a.

Note that the valve 7, pressure gauge 8, and communication hole 9 provided in the outer cylinder 1 supply pressurized nitrogen gas to the airtight space C constituted by the outer cylinder 1, the end plates 3 and 5, etc. The purpose is to encapsulate the gas and constantly monitor its pressure fluctuations. In other words, if you look at this pressure fluctuation, you can detect a break in the airtightness. Now, the drawback of the conventional electric wire penetration part made in this way is that it is not a problem at room temperature, but if the temperature inside the containment vessel suddenly rises due to, for example, a cooling pipe rupturing inside the containment vessel, Thermal stress is generated due to the temperature difference between the inside and outside and the difference in thermal expansion coefficient between the wire penetration part main body consisting of the outer cylinder 1 and end plates 3 and 5, etc. and the MIC 4, and the connection part between the conductor 16 and the lead 18 of the MIC 4 and the lead 18. The thermal stress is concentrated at the joint between the conductor 16 and the insulator 17 made of glass, ceramic, etc., and as a result, accidents occur such as buckling of the conductor 16 and the lead 18 and breakage of the airtightness between the lead 18 and the insulator 17. . Also, as shown in Figure 1, MIC
4 is supported in the straight pipe 6 only by the lead 18, which is fixed in an airtight structure with an insulator 17 at both ends.
The MIC 4 shakes within the straight pipe 6, and the conductor 16 or lead 18 may be damaged due to fatigue.

[Purpose of the invention]

In view of the above-mentioned problems, the object of the present invention is to provide electric wires that will not break airtight or break even if exposed to high temperatures due to an accident inside a containment vessel or subjected to severe vibrations such as an earthquake. The purpose is to provide a penetration part.

[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 airtightly attached to both ends of the outer cylinder, and metal tubes are airtightly attached to the end plates so as to protrude to the outside of the end plates into the through holes of the end plates. A MIC is inserted across the metal tube attached to both end plates, and a lead insulated in an airtight structure by an insulator made of glass or ceramic is connected to the conductor of the MIC at both ends of the MIC. further, a metal eyelet airtightly enclosing the insulator is airtightly connected to the metal tube at a protruding side opening of the metal tube, and the outer tube is airtightly attached to the through wall. The metal tube that is the penetration part and is attached to at least one end plate of the metal tubes that are attached to the end plate has flexibility and elasticity, and the wire penetration part has a fixture whose one end is connected to the metal sheath of the MIC and whose other end is fixed to the flexible and stretchable metal tube, and the connection between the conductor of the MIC and the lead is It is characterized by a movable connection.

[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 invention. As shown in FIG. 2, the wire penetration part of the present invention is provided with a spiral tube or a wire in advance in at least one of the end plates 3 and 5 having a plurality of opposing through holes 2, for example, in the end plate 5 in FIG. A flexible metal tube 24 having flexibility and stretchability, such as a loose tube, is connected airtightly, and a straight metal tube 6 is airtightly connected to the other end plate 3. The end plates 3 and 5, on which the metal tubes 6 and 24 have been attached in advance, are attached to the outer cylinder 1 in an airtight manner with the metal tubes 6 and 24 both facing outward.
Here, the straight tube 6 and flexible metal tube 24 attached to the end plates 3 and 5 are arranged so that the central axes of the opposing metal tubes 6 and 24 are substantially coincident. Next, the MIC 4, which has been previously cut to an appropriate length, terminal-treated at both ends, and the conductor 16 has been taken out, is inserted into the MIC 4 with its small diameter portion as described above.
It is passed through a fixture 25 which circumscribes the metal sheath of the MIC 4 and whose collar part is inscribed inside the flexible metal tube 24, and is connected to the metal sheath at one end of the MIC 4 by welding, brazing, etc. at a connection point 25a. After connecting the fixture 25 in this way, insert the MIC 4 into the flexible metal tube 24 from the side A in FIG.
to reach the outer opening of the straight pipe 6 at the other end opposite to. Here, first, the collar portion of the fixture 25 is fixed to the inside of the flexible metal tube 24 on the A section side using a snap spring 26 or the like. Next, the lead 18, which is hermetically insulated by an insulator 17 with excellent heat resistance such as glass or ceramic, whose adhesive surface is hermetically enclosed by a metal eyelet 20 on the side of part A, is fitted inside. Connector 1 of MIC4 to matching hole 15
Insert 6. Here, conduction between the lead 18 and the conductor 16 is completely ensured by the contact 14 provided in the fitting hole 15. When the conductor 16 and the lead 18 are movably fitted in the axial direction to make a movable connection, if an allowance length e is provided between the conductor 16 and the conductor 16 in the fitting hole 15, thermal stress, which will be described later, can be avoided. It is convenient because it can absorb stress when subjected to stress. Subsequently, the metal eyelet 20 is connected to the flexible metal tube 24 at the connection part 20b.
Connect airtightly. After completing the connection on the A part side, connect the conductor 1 in the same way on the B part side at the other end.
6 and lead 18 are movably connected. At this time, as with the A section, it is convenient to provide an allowance length f between both sides when thermal stress is applied for the same reason as mentioned above. When the connection between the conductor 16 and the lead 18 is completed, the metal eyelet 2
0 and the straight pipe 6 are hermetically welded or brazed at the connecting portion 20a. Finally, attach the outer cylinder 1 to the through wall 11 of the containment vessel.
The connecting point 11a is airtightly connected to the connecting point 11a. In addition, in Fig. 2, the MIC4 is fixed to the end plate 3 through the spacer 28 at the through hole 2 of the end plate 3 where the straight pipe 6 is attached, but this is because the through hole 2 and the MIC4 are connected to each other. This spacer 28 is installed when there is a large gap between the spacers and the fixture 25 on the A side is insufficient to support and fix the MIC4, and there are concerns about earthquake resistance.
When using MIC4, connect flexible metal tube 24,
Before inserting into the straight pipe 6, this spacer 28 is attached by welding or the like on the metal sheath of the MIC 4, and when passing through the through hole 2 of the end plate 3, insert the screw previously cut into the through hole 2. Screw in the screw provided on the outside of the spacer 28. In addition, the outer cylinder 1 is provided with a valve 7, a pressure gauge 8, and a communication hole 9 that communicates with these.As mentioned above, this is done by filling the airtight space C with pressurized nitrogen gas and constantly monitoring the pressure fluctuations. This is to monitor and check for any breaks in airtightness.
Therefore, if there is a possibility that the airtight space C is divided by the fixing tool 25 and the spacer 28 and independent airtight spaces D and E are formed, a penetration part 27 that communicates the space C and the space D is installed in the fixing tool 25 in advance. A penetrating portion 29 connecting C and space E may be provided in the end plate 3.

According to the electric wire penetration part of the present invention constructed in this way, since the fixture is connected to the metal sheath of the MIC4 and fixed to the flexible metal tube, it is possible to prevent an accident from occurring inside the containment vessel. Even if this wire penetration part were to be exposed to high temperatures, the thermal stress caused by the high temperatures would be transferred from the MIC 4 to the fixture 25 and from the fixture 25 to the flexible metal tube 24. It is transmitted and finally absorbed by the elasticity of the flexible metal tube 24. Furthermore, conductor 1
Since the connection between the conductor 16 and the lead 18 is also a movable connection, it is convenient to provide an extra length between the tip of the conductor 16 and the fitting hole 15 of the lead 18, since thermal stress can be absorbed here as well. Furthermore, the fixture 25 supports the MIC 4 within the metal tubes 6 and 24, and prevents the MIC 4 from shaking even if it is hit by severe vibrations such as an earthquake.
This prevents fatigue failure from occurring in the conductor 16 and lead 18 at both ends. Incidentally, the spacer 28 is also one of the measures against earthquakes, but this spacer 28 and
By fixing the metal sheath of MIC4, straight pipe 6
The thermal stress of the MIC 4 and the lead 18 inside the straight pipe 6 will no longer be transmitted to the flexible metal tube 24 on the A section side, and the flexible metal tube 24 cannot be expected to have a thermal stress absorption effect. The thermal stress applied to the MIC 4 and the lead 18 is absorbed by the extra length f provided in the fitting hole 15 of the lead 18. Therefore, as a matter of course, the margin lengths e and f, especially f, are determined in consideration of the expected thermal stress, in other words, the expected maximum elongation of the conductor 16, lead 18, etc. In FIG. 2, a flexible metal tube is used only on one side, but if both end plates 3 and 5 are provided with flexible metal tubes, the thermal stress absorption effect will be increased.
In this case, the spacer 28 is not required, and the structure on the end plate 3 side in FIG. 2 is almost the same as the end plate 5 side in FIG. 2. In addition, another one of the flexible metal tubes 24
One effect is that when connecting the metal eyelets 20 to the tips of the flexible metal tubes 24 by welding, if there are too many flexible metal tubes 24, adjacent objects will get in the way, making it difficult to maintain a constant welding position. Although it is difficult to perform the work, since it is a flexible pipe, it is possible to bend the adjacent object that gets in the way to escape, or to bend the flexible metal pipe 24 to a position where it is easy to work. Furthermore, from this point of view, when a plurality of flexible metal tubes 24 are arranged in a row, the lengths of the outermost tubes should be made shorter, so that when connecting the metal eyelet 20 to the tip of the flexible metal tube 24, It has the advantage of having a wide working space. As described above, the electric wire penetration part of the present invention has a structure that can sufficiently absorb thermal stress, so that buckling of the conductor and lead due to thermal stress can be prevented, and furthermore, the airtightness between the lead and the insulator is less likely to be broken. It also has excellent earthquake resistance and is less susceptible to fatigue failure.

〔Effect of the invention〕

As described above, according to the present invention, even if exposed to high temperatures due to an accident inside the containment vessel or subjected to severe vibrations such as an earthquake, the reliability is maintained without breaking the airtight or breaking the electric wire. It is possible to obtain an excellent wire penetration part.

[Brief explanation of the drawing]

FIG. 1 is a partial vertical cross-sectional view of a conventional electric wire penetration part, and FIG. 2 is a partial vertical cross-sectional view showing an embodiment of the electric wire penetration part of the present invention. 1... Outer cylinder, 3, 5... End plate, 4... MIC,
6... Straight pipe, 11... Penetration wall, 14... Contact,
15... Fitting hole, 16... Conductor, 17... Insulator, 18... Lead, 20... Metal eyelet,
24... Flexible metal tube, 25... Fixture, 28...
Spacer.

Claims (1)

[Scope of Claims] 1. End plates each having a through hole facing each other are airtightly attached to both ends of the outer cylinder, and a metal plate is provided in the through hole of the end plate so as to protrude to the outside of the end plate. The tubes are each airtightly attached, and an inorganic insulated metal sheathed electric wire is inserted across the metal tubes attached to both end plates, and both ends of the inorganic insulated metal sheathed electric wire are covered with an insulator made of glass or ceramic. A lead insulated with an airtight structure is connected to the conductor of this inorganic insulated metal sheathed wire, and a metal eyelet airtightly enclosing the insulator is airtightly connected to the metal tube at the opening on the protruding side of the metal tube. an electric wire penetration part connected to the metal tube and having the outer tube airtightly attached to the penetration wall, the metal tube being attached to at least one end plate of the metal tubes attached to the end plate; has flexibility and stretchability, and one end of the wire penetration portion is connected to the metal sheath of the inorganic insulated metal sheath wire, and the other end is connected to the metal tube having flexibility and stretchability. An electric wire penetration part characterized in that the electric wire penetration part has a fixture fixed to the inorganic insulated metal sheath electric wire, and the connection between the conductor of the inorganic insulated metal sheath electric wire and the lead is a movable connection. 2. A patent claim characterized in that the inorganic insulated metal sheath electric wire is fixed in the through hole of the end plate on which the flexible and stretchable metal tube is not attached. The electric wire penetration portion described in item 1.