AIR CIRCULATING DEVICE BELOW STEAM GENERATOR OF NUCLEAR REACTOR

Abstract

The present invention provides an air circulating sleeve device that is provided below a steam generator to prevent thermal deformation of a sliding base that supports the steam generator of a nuclear reactor, the air circulating sleeve device comprising: a through-hole formed at the center of the sliding base; and a sleeve vertically mounted so as to be aligned with the through-hole, wherein thermal deformation of the sliding base is prevented by performing natural cooling by introducing external air below the sliding base into a stagnated air area inside the sliding base and a skirt support through the sleeve, and the skirt support includes at least one vent hole such that the stagnated air area inside the sliding base and the skirt support is exposed to the air outside the skirt support, and natural circulation of air is performed through the vent hole.

Claims

1. An air circulating sleeve device below a nuclear reactor steam generator, the device for preventing thermal deformation of a sliding base supporting the steam generator, and comprising: a through-hole formed at a center of the sliding base; and a sleeve vertically mounted to be aligned with the through-hole, wherein thermal deformation of the sliding base is prevented by performing natural cooling by introducing external air below the sliding base into a stagnated air area inside the sliding base and a skirt support through the sleeve, and the skirt support includes at least one vent hole such that the stagnated air area inside the sliding base and the skirt support is exposed to the air outside the skirt support, and natural circulation of air is performed through the vent hole.

2. The air circulating device below the steam generator of claim 1, wherein the sleeve has a one-piece configuration having top and bottom end portions thereof protruding upward and downward, respectively, from the sliding base and having a mounting flange formed at an outer surface center thereof, and fixed to the sliding base.

3. The air circulating sleeve device below the steam generator of claim 1, wherein the sleeve has an assemblable/disassemblable, two-piece configuration having an upper pipe protruding upward from the sliding base and a lower pipe protruding downward from the sliding base, connecting flanges are formed respectively at connecting portions of the upper and lower pipes and fixed through bolting, and the upper pipe is detachable/attachable in a state in which the lower pipe is fixed to the sliding base.

4. The air circulating sleeve device below the steam generator of claim 2, wherein the sleeve has a Venturi passage formed therein such that the Venturi Effect is imparted to air passing through the sleeve, and the speed of flowing air is accelerated to improve air circulating effects.

5. The air circulating sleeve device below the steam generator of claim 4, wherein the sleeve has a neck portion formed at and proximal to a top end portion of the sleeve and having a decreasing inner diameter, such that the Venturi Effect is imparted, and the speed of flowing air is accelerated to improve air circulating effects in the stagnated air area.

6. The air circulating sleeve device below the steam generator of claim 3, wherein the sleeve has a Venturi passage formed therein such that the Venturi Effect is imparted to air passing through the sleeve, and the speed of flowing air is accelerated to improve air circulating effects.

7. The air circulating sleeve device below the steam generator of claim 6, wherein the sleeve has a neck portion formed at and proximal to a top end portion of the sleeve and having a decreasing inner diameter, such that the Venturi Effect is imparted, and the speed of flowing air is accelerated to improve air circulating effects in the stagnated air area.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG. 1 is a cross-sectional view illustrating the lower structure of a steam generator according to the related art.

[0040] FIG. 2 is a bottom view illustrating a lower sliding base structure of a steam generator according to the related art.

[0041] FIG. 3 is a cross-sectional view illustrating a structure in which an air circulating sleeve device at the lower portion of a steam generator is mounted on a sliding base, according to the present invention.

[0042] FIG. 4 is an exploded view illustrating a coupling structure of an air circulating sleeve device and a sliding base at the lower portion of a steam generator, according to the present invention.

[0043] FIGS. 5a and 5b are a perspective view and a coupled cross-sectional view illustrating the structure of an air circulating sleeve device having a one-piece configuration at the lower portion of a steam generator, according to the present invention.

[0044] FIGS. 6a and 6b are a perspective view and a coupled cross-sectional view illustrating the structure of an air circulating sleeve device having a separable two-piece configuration at the lower portion of a steam generator, according to the present invention.

DETAILED DESCRIPTION

[0045] Hereinafter, preferred embodiments of the present invention will be described in further detail with reference to the drawings.

[0046] An air circulating sleeve device (100) at the lower portion of a steam generator according to the present invention is a device for preventing thermal deformation of a sliding base (30) supporting a nuclear reactor steam generator (1) and preventing vibrating of the nuclear reactor.

[0047] The air circulating sleeve device (100) at the lower portion of the steam generator according to the present invention, as illustrated in FIGS. 3 and 4, is a structure having a through-hole (110) formed in the center of the sliding base (30), and a sleeve (120) aligned with the through-hole (110) and mounted vertically.

[0048] In particular, the air circulating sleeve device (100) at the lower portion of the steam generator according to the present invention, as illustrated in FIG. 4, is a structure differing from existing structures in that the sleeve (120) is mounted vertically in the through-hole (110) in the center of the sliding base (30), and introduces external air from below the sliding base (30) into a stagnated air area (80) inside the sliding base (30) and a skirt support (20), and performs natural cooling.

[0049] The sleeve (120) may preferably have a pipe-shaped one-piece configuration or a two-piece configuration that divides vertically. When the sleeve (120) is a one-piece member (120a), which is illustrated in FIGS. 5a and 5b, the sleeve has a pipe shape of which the top and bottom end portions protrude a certain length upward and downward, respectively, from the sliding base (30), and which has a mounting flange (122) formed on the outer surface at the middle thereof so as to be fixed on the sliding base (30).

[0050] Thus, when the sleeve (120) has a long pipe shape that protrudes certain lengths upward and downward from the sliding base (30), the height differences at the top and bottom end portions thereof are maintained, and the Chimney Effect is implemented in which a natural airflow is formed between the top and bottom end portions.

[0051] When the sleeve (120) is a two-piece member (120b), as illustrated in FIGS. 6a and 6b, the sleeve (120) is an assemblable/disassemblable structure having a two-piece pipe shape consisting of an upper pipe (126a) protruding upward from the sliding base (30) and a lower pipe (126b) protruding downward from the sliding base (30), and connecting flanges (128) are respectively formed at the connecting portions of the upper and lower pipes (126a and 126b) and fixed through bolting, such that the upper pipe (126a) may be detached/attached in a state in which the lower pipe (126b) is fixed to the sliding base (30).

[0052] Even in this structure in which the sleeve (120) is formed in two pieces, the upper and lower pipes (126a and 126b) are connected to each other to form a long pipe shape and provide the Chimney Effect.

[0053] Moreover, this two-piece member (120b) is particularly useful during inspection and maintenance and repair of the steam generator (1) equipment.

[0054] For example, various fault inspections such as weld inspections are performed regularly or arbitrarily for the welded portions of the stay cylinder (10) and the skirt support (20) of the steam generator (1) equipment, and various pieces of equipment are disposed at the center of the sliding base (30).

[0055] In such cases, the upper pipe (126a) is separated from the lower pipe (126b), enabling unimpeded use of inspection equipment. After the inspection is completed, the upper and lower pipes may be reassembled. Thus, the disassemblable structure of the two-piece member is extremely useful.

[0056] These sleeves (120) both have Venturi passages (130) formed therein for accelerating the circulation of air flowing therein, and a neck portion (132) having a reduced diameter is formed at the inner diameter side near the top end portion of the sleeve (120), so as to provide the Venturi effect at the top end portion of the sleeve (120), or adjacent to the stagnated air area (80).

[0057] This Venturi passage (130) is a standard structure and is typical in that the respective inner diameters from the top and bottom ends of the sleeve (120) gradually decrease toward the neck portion (132).

[0058] Resultantly, during the process in which air flows inside the Venturi passage (130), the speed builds to a maximum at the neck portion (132) to form a fast flow of air, which greatly diffuses high-temperature air inside the stagnated air area (80).

[0059] Thus, the sleeve (120) is capable of further improving air circulating effects and increasing natural cooling effects when airflow is accelerated at the top end of the sleeve (120) in the stagnated air area (80), when external air below the sliding base (30) is introduced into the stagnated air area (80) by virtue of a convection current brought about by a temperature difference between the stagnated air area (80) inside the sliding base (30) and the skirt support (20) and the external air below the sliding base (30).

[0060] Meanwhile, the air circulating sleeve device (100) below the steam generator according to the present invention includes at least one vent hole (140) in the skirt support (20), through which the stagnated air area (80) inside the sliding base (30) and the skirt support (20) is made to communicate with the air outside the skirt support (20).

[0061] This vent hole (140) may be configured in the form of open holes formed along the circumference of the skirt support (20), and such vent holes (140) may also function as man-ways through which workers enter the skirt support (20).

[0062] Accordingly, such a vent hole (140), together with the sleeve (120) provided on the sliding base (30), forms a natural circulation passage, through which external air below the sliding base (30) flows through the stagnated air area (80) to the outside of the skirt support (20).

[0063] The air circulating sleeve device (100) below the nuclear reactor steam generator according to the present invention as configured above, as illustrated in FIG. 3, has a through-hole (110) formed in the center of the sliding base (30), a sleeve (120) aligned with the through-hole and mounted vertically, and at least one vent hole (140) formed in the skirt support (20), such that high-temperature heat in the stagnated air area (80) is naturally circulated by external air and cooled.

[0064] Particularly, in such an air circulating and cooling process, the sleeve (120) has the Venturi passage (130) formed therein so as to impart the Venturi Effect to air passing through the sleeve (120) and accelerate the speed of flowing air to enable air circulating effects to be improved.

[0065] Therefore, according to the present invention, high-temperature heat transferred from the steam generator (1) to the sliding base (30) may be greatly reduced, which may effectively prevent thermal deformation of the sliding base (30), and may prevent structural vibration of the nuclear reactor so as to effectively prevent fretting wear of the steam generator (1) and wear of nuclear reactor coolant system equipment.

[0066] While the present invention has been described in detail above with respect to specific embodiments and with reference to the drawings, the present invention shall not be limited to such specific configurations. A person with ordinary skill in the art will be able to diversely modify or change the present invention without departing from the technical spirit and protective scope of the present invention as set forth in the scope of the claims below. For example, while one sleeve (120) has been illustrated and described as mounted at the center of the sliding base (30), the sleeve (120) may be provided in plurality instead of the singular. Also, instead of the technique of naturally circulating air through the Venturi Effect, a configuration may be employed in which a temperature sensor is mounted in the stagnated air area inside the skirt support, and when the temperature sensor senses that the temperature has reached a preset specific temperature, the air inside the skirt support is forcibly discharged. It shall be noted in advance, however, that such simple design modifications or structural changes will all clearly fall within the protective scope of the present invention.