JPH026038B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inner tube with a ring-shaped cross section, which is embedded in the wall of a prestressed concrete pressure vessel of a nuclear reactor system and which enables communication between the internal space and the external space of the pressure vessel.

In a prestressed concrete pressure vessel for a nuclear reactor (hereinafter referred to as a pressure vessel), an inner tube fitted into a duct that penetrates the wall of the pressure vessel measures the differential pressure between the pressure inside the pressure vessel and the pressure outside. It is necessary to prevent the portion of the cannula that covers the inner surface of the duct and the members connected thereto from deforming. The inner tube airtightly covers the duct and is used as a passage for workers to enter and exit the pressure vessel and for carrying in and out various members, instruments, and machines. The lid attached to the outer end of the inner tube serves to seal the internal space of the pressure vessel from communicating with the outside through the inner tube during reactor operation. When used as a passageway, it is removed after the reactor operation is stopped.

Generally, during the construction of the pressure vessel, changes occur in the concrete structure during the drying stage of the concrete, which causes forces to act on the pressure vessel as well as the steel attached to the liner attached to the pressure vessel, such as the inner tube. In addition, due to the high pressure generated during reactor operation, force acts on the pressure vessel and the above-mentioned steel members, and force is applied to members such as the connection between the anchor bolt and the inner tube used to fix the inner tube to the wall. , which may cause mechanical damage to the connection.
Therefore, in such a case, the function of the anchor bolt may deteriorate and the inner tube may be pushed out due to the high pressure within the pressure vessel. Furthermore, when a nuclear reactor is operated, differential expansion occurs between the inner tubes of the pressure vessel due to temperature changes, which may impair the effectiveness of the anchor bolts.

Although various improvement measures have been considered in order to prevent the above-mentioned disadvantages, they are still not sufficient.

The purpose of the present invention is to prevent an internal tube attached to a duct in the wall of a pressure vessel of a nuclear reactor from being pushed out due to the high pressure inside the pressure vessel, and to prevent the temperature between the concrete and the liner from being pushed out. It is an object of the present invention to provide an internal intubation tube that can avoid stress concentration and local curvature due to differences in expansion.

In order to achieve the above object, the inner intubation tube for a pressure vessel of the present invention has a first circular tube portion with a large diameter formed on the inner space side, and a second circular tube portion with a small diameter formed on the outer space side. A tube portion is formed integrally with the two circular tube portions, and has a diameter that gradually decreases from the first circular tube portion to the second circular tube portion, and has a diameter within the internal space. a conical tube part that causes the wall body to support the external space-directed force applied to the inner tube by high pressure; and a conical tube part fixed to the surfaces of the first and second circular tube parts,
It is formed of a plurality of anchor members that allow the wall to support and release the force that causes the inner cannula to curve due to the difference in temperature expansion between the wall and the inner cannula.

One of the preferred examples of the internal intubation tube is:
The end of the pressure vessel projecting into the internal space is provided with a flange that is fixed to a liner that airtightly surrounds the internal space.

The advantage obtained by the invention is that the force applied to the cannula, i.e. the extremely large force acting to push the cannula due to the high pressure in the interior space of the pressure vessel, is transferred to the conical part or support. and the force that acts to curve the inner tube due to the difference in thermal expansion between the concrete forming the pressure vessel and the inner tube is transmitted to the pressure vessel through the anchor bolt and supported. This is what I did. As a result, the anchor bolt can be formed into a much smaller and simpler structure than when there is no support part used in the present invention and both of the above forces are supported only by the anchor bolt. That's true.

Next, an embodiment of the present invention will be described with reference to FIG. Figure 1 shows a prestressed concrete pressure vessel (hereinafter referred to as pressure vessel) used in a nuclear reactor.
a part of the wall 10 of the pressure vessel; a liner 12 that covers the inside of the pressure vessel and seals the internal space 35 of the pressure vessel;
An intubation tube 20 is shown passing through the wall 10 and communicating between the interior space 35 and the exterior space 36 of the pressure vessel.

The inner tube 20 is airtightly buried in concrete constituting the wall 10. The internal intubation tube 20 has a first circular tube section 31 with a large diameter and a second circular tube section 33 with a small diameter.
and a conical tube section 32 which connects the two circular tube sections and has a conical shape 24 that becomes narrower from the first circular tube section 31 to the second circular tube section 33; Anchor bolts 16 are provided on the outer peripheries of the circular tube portions 31 and 33, for example by welding, in a substantially radial direction of the circular tube portions. The first circular tube section 31, the second circular tube section 33, and the conical tube section 32 are arranged coaxially with the central axis 28 of the internal tube 20.

In FIG. 1, the first circular tube section 31 is arranged on the side of the internal space 35 (on the left side of the figure) which is at high temperature and high pressure during operation in the pressure vessel, and the second circular tube section 33 is located under almost normal pressure. It is arranged on the outside 36 side (right side in the figure). A flange 13 is formed at the left end of the first circular tube section 31, and this flange 13 is hermetically welded to the liner 12. During reactor operation, the lid 30 is airtightly attached to the right side of the second circular tube section 33.

One conical tube section 32 is shown in the figure, but if the pressure inside the internal space 35 is extremely high, a plurality of conical tube sections 32 may be installed in order of decreasing diameter in the longitudinal direction of the internal tube 20 for safety reasons. It can be provided so that
Further, the above-mentioned flange 13 may be omitted if structurally and functionally permitted. To take devices, instruments, members, etc. in and out of the internal space 35 of the pressure vessel from the outside, or to let workers in and out, stop the operation of the reactor, follow the prescribed procedures, remove the lid 30, and open the space inside the inner tube. can be used as a passageway.

As is clear from the embodiment described above, the pushing force acting on the inner tube 20 due to the high pressure in the interior space 35 is transmitted via the conical tube section 32 to the wall 10 of the pressure vessel. The inner space 35 side of the internal intubation tube 20 is also the end 1
The flange 13 formed in 4 also receives extrusion force,
It is transmitted to the wall 10 via the liner. Anchor bolts 16 fixed to the outer periphery of the illustrated inner tube 20 serve to prevent local curvature and stress concentration between the wall 10 and the inner tube 20 due to differences in temperature expansion.

[Brief explanation of drawings]

FIG. 1 is a partial vertical cross-sectional view of an internal tube and a wall of a pressure vessel having a reduced section, showing an embodiment of the fixation device of the present invention. 10... Wall body, 12... Liner, 13... Flange,
16... Anchor bolt, 20... Internal intubation tube, 24... Conical shape, 28... Central axis, 31... First circular tube part, 32
... Conical tube section, 33... Second circular tube section, 35... Internal space, 36... External space.

Claims (1)

[Scope of Claims] 1. In an inner tube with a ring-shaped cross section that is embedded in the wall of a prestressed concrete pressure vessel of a nuclear reactor equipment and that enables communication between the internal space and the external space of the pressure vessel, Intubation is carried out by inserting a first circular tube section with a large diameter formed on the inner space side, a second circular tube section with a small diameter formed on the outer space side, and between the two circular tube sections. It is formed integrally with both circular tube parts, and the diameter gradually becomes smaller from the first circular tube part to the second circular tube part, and the high pressure in the internal space causes the inner tube to be applied to the outer space. a conical tube portion for supporting the force on the wall; and a conical tube portion fixed to the surfaces of the first and second circular tube portions;
An inner tube for a pressure device, characterized in that it is formed of a plurality of anchor bolts that allow the wall to release and support the force that causes the inner tube to curve due to the difference in temperature expansion between the wall and the inner tube. Intubation. 2. The first circular pipe portion protruding into the internal space of the prestressed concrete pressure vessel is provided with a flange fixed to a liner that airtightly covers the inner surface of the pressure vessel. Internal intubation according to scope 1.