JPH0128918B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention provides a prestressed concrete pressure vessel that accommodates a gas-cooled nuclear reactor, and which extends from the interior space to the exterior of the pressure vessel, and which extends from the interior space side of the pressure vessel to the exterior side tip and the exterior side tip of the pressure vessel. The present invention relates to a penetrating device for a prestressed concrete pressure vessel, which has a sheathing tube that is provided with a closing portion at each end and defines an internal space between the two ends.

A penetration device of the above type is already known from the West German patent application DE-OS 2828973.

Penetration devices are generally provided inside prestressed pressure vessels as passages for transporting machinery and equipment in and out, passages for workers to enter and exit, and for passing wiring and piping, and various sizes and shapes are selected depending on the purpose of use. . However, since this penetration device extends from the inside of the high-temperature, high-pressure prestressed concrete pressure vessel to the outside, it must be sealed during operation of the nuclear reactor. Furthermore, this sealing must be extremely reliable in order to prevent environmental pollution caused by reactor operation. It is particularly difficult to seal large-sized penetration devices because the cover attached to the outside is often welded.

The penetration device described in the above-mentioned West German gazette is a prestressed concrete pressure vessel (hereinafter referred to as PCPV) that is formed using a metal outer pipe surrounded by concrete in a gas-tight manner. As mentioned above, this armored tube forms a passage for goods and workers, and also serves to reduce the pressure exerted by the high pressure inside the PCPV on the concrete surrounding the armored tube during reactor operation. In addition, to prevent the exterior tube and surrounding concrete from overheating beyond the allowable temperature during normal reactor operation, a cooling pipe is wrapped around the outer wall of the exterior tube, and the exterior tube is connected to the liner of the PCPV. A flow restrictor is attached to the end of the cooling gas to regulate the flow of cooling gas. Moreover, a sealing cover is attached to the other end of the outer tube in an airtight manner by welding.
In a penetration device with such a configuration, if the above-mentioned sealing cover is damaged and high-temperature, high-pressure cooling gas of approximately 800°C and 40 bar flows out from inside the PCPV, the exterior pipe and the surrounding concrete will be damaged. The concrete will be heated above the allowable temperature, causing damage to the concrete. One way to prevent this is to use a heat insulating material in the outer tube in addition to the cooling tube. During normal operation of a nuclear reactor, the cooling pipes maintain a sufficiently low temperature for the exterior pipes and concrete, so providing the above-mentioned expensive insulation materials, which are not always necessary, is not necessary in order to reduce costs. This is an issue that should be considered.

An example of a case where the sealing cover is damaged as described above is when a heavy object is being transported or installed outside the PCPV, or when a heavy object is accidentally collided with it.

The object of this invention is to have a cooling pipe for gas cooling that is wrapped around the outer pipe, and also to prevent the concrete surrounding the outer pipe from exceeding the allowable value even if the sealing cover attached to the outer end of the PCPV is damaged. An object of the present invention is to provide a penetrating device for a prestressed concrete pressure vessel equipped with an insertion tube that can prevent the temperature from rising to a high temperature.

In order to achieve the above object, in the penetration device of the present invention, an insertion tube is arranged inside the exterior tube, a gap is formed between the exterior tube and the insertion tube, and the insertion tube is inserted into the inner space of the PCPV. The inner end toward the outer tube is hermetically connected to the inner wall of the outer tube, and a space, that is, an adiabatic space is formed between the outer tube and the insertion tube.

In the penetrating device of this invention, as in the West German published specification, the internal space of the sheathing pipe and the internal space of the PCPV are at almost the same pressure during normal operation of the nuclear reactor. High-temperature, high-pressure cooling gas does not flow through the closure, and the outer pipe and surrounding concrete are
The temperature is almost the same as other parts of the PCPV wall. The penetration device and the adjacent concrete therefore do not become overheated. However, the outer tube
If the closing part, that is, the sealing cover at the tip facing the outside of the PCPV is damaged and the internal space of the armored tube communicates with the outside, the pressure in the internal space will decrease, and High pressure is applied to the closed part, that is, the flow restrictor, and the high-temperature, high-pressure cooling gas in the internal space of the PCPV is ejected into the exterior pipe and flows out of the PCPV from its tip.

However, since the above-mentioned heat-insulating space formed between the outer pipe and the insertion pipe is formed airtight on the inner space side of the PCPV, the above-mentioned high-temperature and high-pressure cooling gas does not flow through the heat-insulating space. The cooling gas within acts as a thermal insulator between the sheathing tube and the insertion tube and does not significantly increase the temperature of the sheathing tube and therefore of the surrounding concrete. Although such effects do not last for a long time, in actual nuclear reactors, emergency measures are taken automatically or manually as soon as an accident occurs, so there is no problem in practice.

The insertion tube is usually formed of a thin metal plate, and in order to maintain an appropriate distance between the outer tube and the insertion tube, the surface of the insertion tube is provided with a protrusion that protrudes toward the inner surface of the outer tube. .

The protrusions mentioned above may be corrugated or ribbed on the surface of the insertion tube, or may be bolts or rivets attached to the insertion tube.

The advantage obtained by this invention is that the above-mentioned insertion tube having a simple structure is placed inside the sheathing tube without using expensive insulation material to prevent overheating of the concrete surrounding the sheathing tube. The aim is to achieve the same purpose by creating a heat-insulating space.

Next, an embodiment of the present invention will be described with reference to FIG. FIG. 1 shows a longitudinal section of a penetration device 1 according to the invention. Cooling pipes 14, 15, 16, 1 on the outer periphery
An insertion tube 3 is inserted coaxially into the outer tube 2 wound with 7 and spaced apart from each other by 4 in the radial direction. The outer tube 2 usually has a circular cross section, and its inner diameter is about 100 to 2300 mm in the case of a gas-cooled nuclear reactor.
The tip of the internal space 7 of the PCPV of the outer tube 2 is
It is hermetically coupled to a liner 6 that covers the interior space 7 of the PCPV and extends further into the interior space 7. A step 9 is provided inside the sheathing tube 2 extending into the internal space of the PCPV, and a flow restrictor 8 forming a closed section is placed on this step 9. The flow restrictor 8 includes a disc-shaped lid 24 and a seal member 100 fitted around the lid 24. The sealing member 100 separates the internal space 7 of the PCPV and the internal space 101 of the sheathing tube 2 to prevent leakage during operation of the nuclear reactor.

Further, a sealing cover 12 forming a closing portion is airtightly attached to an end portion of the outer tube 2 opposite to the internal space 7, that is, an outer end 10, by a welding portion 11. This sealing cover 12 completely separates the exterior tube 2 and the inside of the sealing cover 12 from the outside of the PCPV. The reason for using welding in this way is to completely cut the shears, and when using the penetration device, the welded portion is removed, the sealing cover 12 is removed from the sheathing pipe 2, and the flow restrictor 8 is removed. After removing it to the inner space 7 side and completing the necessary work, the outer tube 2 and flow restrictor 8 are reattached as shown in FIG. 1, and the sealing cover 12 is welded to the outer tube 2. In the figures, the sealing cover 12 is depicted as having a large internal volume, but this is merely an example. This example is an example in which a measuring instrument is housed inside the sealing cover 12. Penetration devices are frequently used during the construction of a nuclear reactor to transport goods into the PCPV and to allow personnel to enter and exit the PCPV, but they are closed once operations begin.
It is only used when a breakdown occurs or when it is necessary to access the interior for maintenance and inspection. However, the reactor must be constantly monitored to see if it is operating under normal conditions, and the measuring instruments necessary for this purpose are placed in the insertion tube 3, the sealing cover 12, or both. A sensor of a measuring device (not shown) is guided through a flow restrictor 8 to a measuring position inside the PCPV. In this case, sensors that can withstand high temperature and high pressure have been developed, but it is not desirable to place the measuring device that receives the output and performs measurements inside the high temperature and high pressure PCPV. It is preferable to keep the distance between the sensor and measuring device as close as possible in order to perform stable measurements, but since nuclear reactor equipment is generally extremely large, placing the measuring device outside the PCPV will shorten the distance to the sensor. It gets bigger and I don't like it. However, in the case of the penetration device of the present invention, during steady operation of the nuclear reactor, a place with a lower temperature than the internal space 7 is formed inside the insertion tube 3 and in the sealing cover 12, so the measuring device is placed here. , the stable output from the measuring instrument is derived through the sealing cover 12,
The data is sent to a computing device (not shown) located at an appropriate location outside the PCPV. In this case, a wiring (not shown) that sends an output signal from the measuring instrument to the outside of the PCPV passes through the sealing cover 12, but since this wiring is formed relatively thin, it can be airtightly routed from the sealing cover 12 to the outside. There is no particular difficulty in withdrawing. As you can see from the above explanation,
The shape and size of the sealing cover 12 are appropriately selected depending on the number and size of measuring devices to be placed inside, such as temperature measuring devices, pressure measuring devices, etc. A plate-like sealing cover may be used for the device.

The exterior pipe 2 has a cooling pipe 1 wrapped around its outer wall 13.
4, 15, 16, 17,
An insertion tube 3 provided inside the sheathing tube 2 is arranged coaxially with the sheathing tube 2 and spaced apart from the sheathing tube by a distance 4. The distance 4 is defined by a protrusion, ie, a corrugation 20 or a ridge 21 formed on the surface of the insertion tube 3, or by a bolt 22 or rivet 23 attached to the wall of the insertion tube 3.

In the penetration device of this embodiment, when the reactor is in normal operation, the internal space 7 of the PCPV and the internal spaces of the outer tube 2 and the sealing cover 12 are under approximately the same pressure. When the pressure in the other two spaces is lower than that in the inner space 7, the high temperature and high pressure cooling gas in the PCPV inner space 7 leaks from the sealing member 100 of the flow restrictor 8 and enters the two spaces until the pressure is almost balanced. It is from. Therefore, during normal operation of the nuclear reactor, high-temperature, high-pressure cooling gas does not flow into the two spaces from the internal space 7 of the PCPV. As a result, the temperature of the cooling gas in both the above-mentioned spaces is reduced to
5, 16, and 17, the temperature is significantly lower than that of the cooling gas in the internal space of the PCPV, and the concrete surrounding the exterior pipe 2 will not be damaged by the high temperature.

In a nuclear reactor operating normally under the above conditions, even if the sealing cover 12 is damaged due to an unexpected accident and a portion of the sealing cover communicates with the outside, the concrete surrounding the exterior pipe 2 may be damaged. Explain that there will be no large temperature rise. Sealing cover 12
If damaged, the high-pressure cooling gas in the interior space 101 of the exterior tube 2 and the space inside the sealing cover 12 will be damaged.
Outflows to the outside of the PCPV and flows into the flow restrictor 8 through the outer pipe 2.
The pressure acting from the internal space 101 side of the PCPV decreases rapidly, and the high-temperature, high-pressure gas in the internal space 7 of the PCPV enters the internal space of the outer tube 2 through the outer periphery of the sealing member 100 and passes through the damaged part of the sealing cover. It then squirts outside. Since this ejection continues for a while, the inner pipe 2 is heated to a high temperature. However, the tip or inner end 19 of the insertion tube 3 is
Since it is airtightly attached to the inner wall 18 of
The high-temperature, high-pressure cooling gas that has flowed in from the internal space 7 of the PCPV does not enter into the heat insulating space 102 formed between the exterior tube 2 and the insertion tube 3, and the high-temperature and high-pressure cooling gas that has flowed in from the interior space 7 of the PCPV does not enter the insulation space 102 formed between the exterior tube 2 and the insertion tube, which has become hot. Insulating space 10 between 3 and
The cooling gas in 2 acts as an insulator thermally separating both tubes 2 and 3. The protrusions 20, 21, 22, 23 provided on the insertion tube 3 are connected to the inner wall 18 of the outer tube 2.
However, since the contact area is small, it has little effect on increasing the temperature of the armored tube 2. Therefore, even if such damage occurs, the concrete in contact with the exterior pipe 2 will not be damaged.

As explained above, if the penetrating device of the present invention is used, when work is performed outside the PCPV,
For example, if the sealing cover is accidentally damaged when transporting heavy objects or moving objects using a crane device, the concrete that makes up the PCPV will receive high heat and the reactor will suddenly become in a dangerous state. It won't happen. In such a case, it goes without saying that the emergency shutdown device will then operate to stop the reactor operation.

[Brief explanation of drawings]

FIG. 1 shows a longitudinal sectional view of the penetration device of the invention. 2... Exterior tube, 3... Insertion tube, 7... Inner space, 8... Closing part, 12... Closing part, 18... Inner wall, 19... Inner end part, 20... Waveform, 21... Stick shape, 22... Bolt, 23... Rivet, 10
1...Internal space, 102...Insulating space.

Claims (1)

[Claims] 1. Extending from the internal space 7 of a prestressed concrete pressure vessel housing a gas-cooled nuclear reactor to the outside of the pressure vessel, at the tip of the internal space 7 side and the tip of the external side of the pressure vessel, respectively. Closing part 8, 12
In the penetrating device for a prestressed concrete pressure vessel, which has an exterior pipe 2 forming an internal space 101 between the two ends, an insertion pipe 3 is disposed inside the exterior pipe 2, and the insertion pipe 3 is inserted into the exterior pipe 2. It is characterized in that a spacing 4 is formed between the tubes 3, and said insertion tube 3 is attached in a gas-tight manner to the inner wall 18 of the outer tube 2 at its inner end 19 towards the inner space 7 of the prestressed concrete pressure vessel. Penetration equipment for prestressed concrete pressure vessels. 2. The penetration device according to claim 1, wherein the insertion tube 3 is made of a thin metal plate. 3. The distance 4 between the insertion tube 3 and the exterior tube 2 is determined by the protrusions 20, 21, 22, 23 that protrude from the wall of the insertion tube 3 toward the exterior tube 2. A penetrating device according to any one of claims 1 and 2. 4 The protrusions 20, 21, 22, 23 are the insertion tube 3
The corrugations 20 and ridges 21 formed on the wall, the bolts 22 and rivets 2 attached to the outer circumference of the inner tube 3
3. The penetrating device according to any one of claims 1 and 2, characterized in that: