JPH0259698A - Dry well cooling device - Google Patents

Abstract

PURPOSE:To enhance cooling effect by dividing a space part between a nuclear reactor pressure vessel and a shielding wall by a separator, and executing cooling by an air supply and exhaust in each space part. CONSTITUTION:In the inside of a cylindrical shielding wall 3 provided on the periphery of a nuclear reactor pressure vessel 1, an annular separator 11 is attached in a position of about the center in the height direction. On the lowest part of each of the lower space part 5a and the upper space part 5b, annular air supply nozzles 12a, 12b are provided, and on the uppermost part of each of both the space parts 5a, 5b, annular exhaust nozzles 13a, 13b are provided. In this state, from a local cooler 8, cold air is fed to the air supply nozzles 12a, 12b through air supply ducts 7a, 7b, allowed to pass through each space part 5a, 5b, and drawn out by exhaust fans 15a, 15b through exhaust ducts 14a, 14b. In such a way, a passing distance of cold air is shortened and a temperature rise of cold air becomes small, and also, since an outflow of cold air becomes small, the cooling efficiency becomes high.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is directed to the inside of a reactor containment vessel in a nuclear couplant;
In particular, it relates to cooling of the space between the reactor pressure vessel and the shielding wall.

(Prior art) In the conventional reactor containment vessel in a nuclear coupler of a nuclear power plant, etc., as shown in the cross-sectional view of the main part in Fig. 2, a reactor pressure vessel 1 is installed in the center on a pedestal 2, and the A cylindrical shielding wall 3 is installed around the reactor pressure vessel 1 for the purpose of blocking radiation and heat from the reactor pressure vessel 1. Furthermore, the interior of the nuclear reactor containment vessel 4, which is constructed to cover the entire structure, is used as a dry well, and various equipment for operating the reactor is installed therein. Among these, the space 5 between the reactor pressure vessel 1 and the shielding wall 3 becomes a high temperature region due to the heat radiation of the reactor pressure vessel 1, so an annular air supply nozzle 6 is arranged at the lower part of the shielding wall 3. Cold air is supplied from a local cooler 8 through an air supply duct 7 that penetrates the shielding wall 3, and is blown out almost uniformly along the outer periphery of the reactor pressure vessel 1 within the space 5 for cooling. . This cold air cools the inside of the space 5 along the outer periphery of the reactor pressure vessel 1, rises, flows out from the top of the shielding wall 3, diffuses, passes through the inside of the reactor containment vessel 4, and passes through the reactor containment vessel 4. Together with the internal atmosphere, it is sucked into the suction port 8a of the local cooler 8 and cooled again.

(Problem to be Solved by the Invention) Since the space 5 between the reactor pressure vessel 1 and the shielding wall 3 is vertically long, the cold air supplied from the bottom of the shielding wall 3 reaches the top of the shielding wall 3. The temperature rises significantly by then, and the cooling effect decreases near the top.

Various nozzles 9 connected to the reactor pressure vessel 1 pass through the shielding wall 3, and openings 10 are provided in this portion for periodic inspection. Therefore, the cold air sometimes flows out of the shielding wall 3 through these gaps, and there is a drawback that the cold air does not reach the top of the shielding wall 3 sufficiently. In addition, high-temperature air remains near the top of the lX shield wall 3, increasing the temperature difference between it and the bottom of the reactor containment vessel 4 where the local cooler 8 is installed, resulting in equalization of the temperature inside the dry well. The problem was that it was difficult.

The present invention has been made in view of the above, and its purpose is to divide the space between the reactor pressure vessel and the shielding wall,
Cooling is carried out through air supply and exhaust, and heat is efficiently removed to prevent a high-temperature area from forming near the top of the shielding wall, and the temperature valves at the top and bottom of the reactor containment vessel are set appropriately. An object of the present invention is to provide a dry well cooling device.

[Structure of the Invention] (Means for Solving the Problem) An annular separator is provided at a position in the height direction in the space between the reactor pressure vessel and the shielding wall to divide the space into a plurality of parts,
At the bottom of each of these divided spaces, an air supply nozzle that discharges cold air supplied from a local cooler installed in the dry well is installed, and at the top, an exhaust nozzle that sucks the air from the space is installed. Then, an exhaust duct equipped with an exhaust fan is connected to this exhaust nozzle, and its tip is placed inside the dry well.

(Function) The space between the reactor pressure vessel, which is the heat source, and the shield wall, which is its heat shield, are divided into sections, and cold air is supplied and warmed air is exhausted separately. Since the temperature rise in the shielding wall is reduced and a cooling effect is obtained in a small manner, the thermal stress in the shielding wall is particularly reduced.

In addition, this exhaust gas is collected near the suction port of the local cooler to reduce high-temperature air retention at the top of the shielding wall and equalize the temperature within the dry well.

(Example> An embodiment of the present invention will be described with reference to the drawings.

Note that the same components as those in the prior art described above are denoted by the same reference numerals, and detailed explanations will be omitted.

FIG. 1 is a cross-sectional view of the main parts inside the reactor containment vessel, with a reactor pressure vessel 1 installed on a pedestal 2 in the center and a cylindrical shielding wall 3 provided around it. An annular separator 11 is installed at approximately the center in the height direction inside this shielding wall 3 with a gap between the reactor pressure vessel 1 and the reactor pressure vessel 1 to avoid deformation due to thermal expansion. The space with the wall 3 is divided into two parts, an upper space part 5a and an upper space part 5b. Air supply nozzles 12a and 12b which blow out cold air in an annular shape are installed at the lowest part of the shielding wall 3 in the upper space part 5a, and directly above the separating plate 11 in the upper space part 5b, and air supply ducts 7a and 7b are installed respectively. Connect to supply cold air from the local cooler 8. In addition, the air supply nozzles 12a and 12b are located below the separating plate 11 at the top of the upper space 5a and at the tip of the shielding wall 3 at the top of the upper space 5b.
Similarly, annular exhaust nozzles 13a and 13b are installed, and exhaust ducts 14a and 14b are connected to each of them.

Exhaust fans 15 are installed in the exhaust ducts 14a and 14b.
a and 15b, and their tips are arranged near the suction port 88 of the local cooler 8.

Next, the effects of the above configuration will be described. Heat from the reactor pressure vessel 1 is shielded by the shielding wall 3 and divided into the upper space part 5a and the upper space part 5b, but heat is supplied from the local cooler 8 to the upper space part 5a and the upper space part 5b, respectively. Cold air is blown out from the supply air nozzles 12a and 12b, cools the inside of the upper space part 5a and the upper space part 5b, rises, is exhausted from the exhaust nozzles 13a and 13b), and is sucked out by the local cooler 8. It is discharged near the suction port 8a, sucked into the suction port 8a, and cooled again by the local cooler 8. Therefore, the lower space part 5a and the upper space part 5b
Since the passage distance of the cold air in J5 is shortened, the temperature rise in the exhaust nozzles 13a and 13b is small and the cooling effect is large. Furthermore, since the exhaust air is sucked in from the exhaust fans 15a and 15b of the exhaust ducts 14a and 14b, the pressure inside the shielding wall 3 is reduced, so there is less cold air flowing out from the openings 10, and the cooling efficiency is increased. Furthermore, since the high temperature air is discharged near the local cooler 8, it is effectively sucked into the suction port 8a and does not stay in the upper part of the shielding wall 3, so that the temperature distribution in the dry well is equalized. Therefore, in combination with the above-mentioned improvement in cooling efficiency, it becomes possible to reduce the capacity of local coolers installed at various locations. Moreover, when the temperature rise in the upper space part 5a and the upper space part 5b becomes smaller, the thermal stress applied to the shielding wall 3 is reduced and deterioration is also prevented.

Although the above-mentioned embodiment shows that the space 5 is divided into two, it is of course possible to divide the space into two or more if necessary to obtain the same or better effect.

[Effects of the Invention] According to the present invention, the cooling effect of the nuclear reactor, pressure vessel, and shielding wall is improved, so thermal stress is reduced and deterioration can be prevented. Furthermore, the temperature rise of the cooling air in each space is low, and high-temperature air does not diffuse into the reactor containment vessel, which has the effect of equalizing the temperature in the dry well and thereby making it possible to downsize the cooling device.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part inside a reactor containment vessel according to an embodiment of the present invention, and FIG. 2 is a sectional view of a main part inside a conventional reactor containment vessel. 1... Reactor pressure vessel, 3... Shielding wall, 4...
Reactor containment vessel, 5...Space part, 5a...Upper space part, 5b...Upper space part, 7.7a, 7b...
・Air supply 'J') I~, 8...Local cooler, 8a
... Suction port, 9... Nozzle, 10...
Opening, 11... Separation plate, 12a112b...
Air supply nozzle, 13a, 13b...exhaust nozzle, 14a, 14b...exhaust duct, 15a, 15b...exhaust fan. Agent Patent Attorney Norio Ogo Figure 1

Claims (1)

[Claims] In a dry well formed by installing a cylindrical shielding wall that blocks radiation and heat by opening a space around the reactor pressure vessel and covering the whole with a reactor containment vessel, the reactor pressure vessel and An annular separator is provided at one or more locations in the height direction of the space between the shielding wall and the space is divided into a plurality of parts, and a local plate is installed in the dry well at the bottom of each of the divided spaces. An air supply nozzle is installed to discharge cold air supplied from the cooler through the air supply duct, and an exhaust nozzle is installed at the top to suck air from the space, and an exhaust fan is installed in this exhaust nozzle. A dry well cooling device characterized in that an exhaust duct is connected to the dry well and its tip is disposed within the dry well.