JP3110901B2 - Fast breeder reactor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-sized fast breeder reactor, and more particularly to a fast breeder reactor for preventing an excessive rise in temperature of a reactor support for supporting a reactor vessel.

[0002]

2. Description of the Related Art Generally, a reactor vessel is accommodated in a reactor vessel room formed in a reactor containment structure, and air for cooling the reactor vessel is introduced into the reactor vessel room into a wall of the reactor containment structure. A furnace that has an air supply duct, and an exhaust duct that is located slightly above the air supply duct to discharge high-temperature air that has cooled the reactor vessel, and that forms a long air flow path between the air supply duct and the exhaust duct 2. Description of the Related Art A fast breeder reactor is known in which a vessel air cooling cylinder is provided, and cooling air is circulated through an air flow path formed by the reactor vessel air cooling cylinder to cool the reactor vessel.

FIG. 4 shows a configuration of a conventional fast breeder reactor. The conventional fast breeder reactor 21 has a reactor vessel 22, which is housed inside a reactor containment structure 23 constructed of concrete. Inside the reactor containment structure 23, a reactor vessel chamber 24 for accommodating the reactor vessel main body 22 and a reactor upper chamber 26 for containing a containment dome 25 covering the upper part of the reactor vessel 22 are formed. A step is formed at the boundary between the furnace upper chamber 26 and the furnace container chamber 24,
A reactor support plate 27 is fixed to this step, and constitutes a reactor support 28 that supports the reactor vessel 22. The upper end of the reactor vessel 22 is fixed on the reactor support plate 27, and the reactor vessel 22 is supported so as to be thermally expandable and contractible in the vertical direction about the reactor support plate 27. Inside the concrete wall of the containment structure 23 around the reactor chamber 24,
An air supply duct 29 for introducing cooling air into the furnace chamber 24 is formed. An exhaust duct 30 for discharging high-temperature air that has cooled the reactor vessel 22 is formed inside the concrete wall of the reactor containment structure 23 at a position slightly above the air supply duct 29. A projecting portion 31 that projects inward is formed on the inner wall of the furnace chamber 24 between the air supply duct 29 and the exhaust duct 30. A reactor vessel air-cooled cylinder 32 having a diameter larger than that of the reactor vessel 22 is fixed to the protruding portion 31 by a flange portion 32a formed at the upper end thereof. The furnace vessel air cooling cylinder 32 forms a long cooling air flow path between the air supply duct 29 and the exhaust duct 30. In this conventional fast breeder reactor 21, the temperature of the reactor vessel 22 rises with the fission of the nuclear fuel inside, so that the air flows through the air supply duct 29, the cooling air flow path, and the exhaust duct 30 so that the atomic It is necessary to prevent the temperature of the furnace vessel 22 from rising excessively. Cooling air is introduced from the air supply duct 29 into the furnace vessel chamber 24, and as shown by the arrow in FIG.
It descends along the air flow path formed between 2 and the inner wall of the furnace chamber 24, and cools the inner wall of the furnace chamber 24. Next, the cooling air flows into the air flow path formed between the reactor vessel air-cooling cylinder 32 and the reactor vessel 22 from the open end below the reactor vessel air-cooling cylinder 32, and rises while cooling the reactor vessel 22. I do. The high-temperature air that has cooled the reactor vessel 22 reaches the upper space 24a of the reactor vessel chamber 24, and is discharged outside through an exhaust duct by natural convection or forced blast pressure.

[0004]

However, in the above-mentioned conventional small-sized fast breeder reactor, the cooling air rises in the air flow path between the reactor vessel air-cooled cylinder and the reactor vessel to absorb the heat of the reactor vessel. And becomes temporarily hot and stagnates temporarily in the upper space of the furnace vessel, so structural members (concrete) on the upper part of the furnace vessel
However, the temperature sometimes increased due to the influence of high-temperature air. The concrete in the upper part of the reactor vessel room constitutes the reactor support that supports the reactor vessel, so if the temperature rises excessively, the structural strength of the concrete will decrease and the safety and reliability of the reactor will be reduced. There was a loss. This means that even if the reactor containment structure is made of steel, the safety of the
Impairs reliability. On the other hand, in the conventional fast breeder reactor,
In order to prevent a rise in the temperature of the upper part of the reactor vessel chamber, a heat insulating material was provided on the wall surface of the reactor vessel chamber, and equipment such as a local cooler for locally cooling the concrete of the reactor support was provided. However, these measures are not effective enough,
In addition, there is a problem that the structure of the fast breeder reactor is complicated. Therefore, an object of the present invention is to solve the above-mentioned problems of the conventional fast breeder reactor, to prevent an excessive rise in temperature of the structural members of the reactor containment structure, and to provide a fast breeder reactor having a simple structure. .

[0005]

In order to achieve the above object, a fast breeder reactor according to the present invention comprises a reactor vessel housed in a reactor containment structure and a reactor vessel housed therein. The reactor vessel is supported by a reactor support portion formed in a part of the reactor containment structure through, and a reactor vessel air-cooled cylinder that forms an air flow path around the reactor vessel is provided. In a fast breeder reactor that cools a reactor vessel by flowing cooling air through an air flow path, the reactor vessel air-cooled cylinder forms a continuous high-temperature air flow path and a low-temperature air flow path inside and outside thereof, respectively. The reactor support ring has a through hole for inflow of air, and is disposed at an air inflow portion of the low temperature air flow passage. The air discharge portion of the high temperature air flow passage is provided with the reactor vessel air cooling cylinder and the low temperature air flow passage. Air discharger that discharges high-temperature air to the outside through To have is characterized in.

[0006]

In the fast breeder reactor according to the present invention, the space inside the reactor vessel chamber is partitioned by a reactor vessel air-cooled cylinder having a diameter larger than that of the reactor vessel.
A high-temperature air flow path is formed on the outer peripheral part in contact with the reactor vessel, and a low-temperature air flow path is formed on the outside of the reactor vessel air-cooling cylinder. The low-temperature air flow path and the high-temperature air flow path are connected to each other. In addition, a reactor support ring provided with a through hole for air inflow is arranged in the air inflow section of the low temperature air flow path, and the furnace vessel air cooling cylinder and the low temperature air flow path pass through the air discharge section of the high temperature air flow path. And an air discharging means for discharging high-temperature air to the outside. With the above configuration, in the fast breeder reactor of the present invention, the cooling air first flows through the low-temperature air flow path through the reactor support ring and the reactor support, then flows through the high-temperature air flow path, and finally flows. The air is discharged to the external space through the air discharging means. Since the cooling air has not yet been heated in the air inlet of the low-temperature air flow passage, the temperature of the reactor support and the reactor support ring can be maintained at a low temperature. Also, since the low-temperature air flow path is formed to include the high-temperature air flow path,
The inner wall of the furnace chamber does not come into direct contact with hot air. Also, in the high-temperature air flow path, the air has a lower temperature than the reactor vessel, so that it has a sufficient cooling effect, and
The air that has become hot at the air discharge section at the end of the high-temperature air flow path is directly discharged to the outside by the air discharge means and does not affect the low-temperature air flow path or the reactor support section. By the above-described operations, in the fast breeder reactor of the present invention, the heat of the reactor vessel is directly released to the external space without affecting the strength of the structural members of the reactor containment structure. The strength of the structural member of the product is maintained, and the safety and reliability of the reactor can be improved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a reactor support in which a high-temperature air flow path and a low-temperature air flow path are respectively formed inside and outside by a furnace vessel air-cooled cylinder, and a low-temperature environment is required at the air inlet of the low-temperature air flow path. And an air discharge means for directly discharging the high-temperature air to the outside without transmitting heat to the reactor containment structure at the air discharge portion of the high-temperature air flow path where the air has the highest temperature. Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows a configuration of a fast breeder reactor according to a first embodiment of the present invention. The fast breeder reactor generally denoted by reference numeral 1 has a reactor vessel 2 that houses a reactor core. The reactor containment structure 3 is entirely made of concrete, and includes a reactor vessel chamber 4 for housing the main body of the reactor vessel 2 therein and a furnace upper chamber 6 for containing a containment dome 5 for covering the upper part of the reactor vessel 2. Is formed. A step is formed at the boundary between the furnace upper chamber 6 and the reactor vessel chamber 4, and this step constitutes a reactor support 7 for supporting the reactor vessel 2. The reactor vessel 2 is fixed on a reactor support ring 8 fixed on a reactor support section 7 and is supported so as to be vertically expandable and contractible about the reactor support ring 8. An air supply duct 9 communicating with an upper part of the furnace upper chamber 6 and an exhaust duct 10 communicating with an upper part of the reactor vessel chamber 4 are formed inside the concrete wall of the reactor containment structure 3. A reactor vessel air-cooled cylinder 11 surrounding the outer peripheral wall of the reactor vessel 2 is provided around the reactor vessel 2 at an interval. The furnace vessel air-cooled cylinder 11 has an upper end connected to the upper part of the reactor vessel 2 and a lower end opened to a lower space of the furnace vessel chamber 4. As clearly shown in FIG. 2, an exhaust bellows 12 having one end connected to the exhaust duct and the other end communicating with the space inside the furnace container air cooling cylinder 11 is provided at the upper part of the furnace container air cooling cylinder 11. . As shown in FIG. 2, the reactor support ring 8 has a cylindrical portion 8 having a predetermined height.
The cylindrical portion 8a has a through hole 13 through which a plurality of air flows.

The operation of this embodiment will be described below based on the above structure. In the fast breeder reactor 1 of the present embodiment, a reactor core (not shown) composed of an assembly of nuclear fuel is accommodated in a reactor vessel 2, and the core is fissioned to generate heat,
This heat is taken out to the outside by a primary coolant such as liquid sodium and a secondary coolant such as water, and converted into power. Therefore, during operation, the temperature of the reactor vessel 2 becomes high, and it is necessary to keep it cooled. The arrows in FIGS. 1 and 2 indicate the flow of cooling air. As shown in FIG. 1, the cooling air flows from the air supply duct 9 through the filter 14 into the furnace upper chamber 6, then flows into the reactor vessel chamber 4 through the through hole 13 of the reactor support ring 8, Next, the air is flown up between the furnace vessel air-cooled cylinder 11 and the reactor vessel 2 and is discharged to the external space through the exhaust bellows 12 and the exhaust duct 10. The flow of the air is configured to be able to be performed by both forced ventilation and natural ventilation. In this case, the space between the outside of the furnace vessel air cooling cylinder 11 and the inner wall of the furnace vessel chamber 4 forms a low-temperature air flow path L, and the space between the inside of the furnace vessel air cooling cylinder 11 and the outside of the reactor vessel 2 is The high-temperature air flow path H is configured. After flowing through the furnace upper chamber 6, the cooling air flows into the low-temperature air flow path L of the reactor vessel chamber 4 while cooling the reactor support ring 8 and the reactor support 7. In the low-temperature air flow path L, air flows by interrupting the transfer of heat between the wall surface of the furnace chamber 4 and the high-temperature air flow path H. Next, the air flows into the high-temperature air flow path H from the lower end of the reactor vessel air-cooled cylinder 11 and rises in the high-temperature air flow path H while cooling the reactor vessel 2. The high-temperature air that has reached the air discharge portion Ha at the upper end of the high-temperature air flow path H is discharged to the exhaust duct 10 via the exhaust bellows 12 without affecting the reactor support ring 8 and the reactor support portion 7 thermally. You.
Due to the flow path of the cooling air described above, the reactor support 7 and the reactor support ring 8 are connected to the air inlet La of the low-temperature air flow path L.
Is cooled by low-temperature air at all times, and the high-temperature air that has been further cooled is discharged without heating the reactor support 7 and the reactor support ring 8. It is maintained at a low temperature, which can improve the safety and reliability of the reactor. In addition, since it is not necessary to provide any special equipment such as a local cooler for locally cooling the reactor support portion 7 or a heat insulating material, the fast breeder reactor 1 having a simple structure can be obtained.

According to the present invention, a high-temperature air flow path and a low-temperature air flow path are formed inside and outside a reactor vessel air-cooled cylinder, and a reactor support is disposed at an air inlet of the low-temperature air flow path. Air discharge means for discharging high-temperature air may be provided at the end of the flow path, and is not limited to the positions of the air supply duct and the exhaust duct and the specific configuration of the air discharge means. Hereinafter, a second embodiment of the present invention in which an air supply duct is connected to a through hole of a reactor support ring will be described. FIG. 3 shows a configuration of a second embodiment of the present invention in which an air supply duct is directly connected to a through hole of a reactor support ring. In FIG. 3, in which the same reference numerals are given to the same parts as in FIG. 1 and the description is omitted, the reactor support ring 15 is buried in the concrete of the reactor containment structure 3 at the upper end of the reactor chamber 4, and the cylindrical part 15a Is provided with a through hole 16 for inflow of air at a predetermined location. Further, an air supply duct 17 whose outlet is aligned with the through hole 16 is formed in the concrete wall of the reactor containment structure 3. According to this embodiment, since the cooling air first cools the reactor support ring 15 without being heated, the reactor support portion 7 can be effectively cooled at a low temperature due to the good heat radiation of the reactor support ring 15 by the metal. Can be maintained.

[0010]

As is apparent from the above description, the fast breeder reactor according to the present invention forms a high-temperature air flow path around the reactor vessel by a reactor vessel air-cooled cylinder having a diameter larger than that of the reactor vessel.
A low-temperature air flow path is formed outside the high-temperature air flow path, a reactor support section and a reactor support ring are arranged at an air inlet of the low-temperature air flow path, and high-temperature air is supplied to an air discharge section of the high-temperature air flow path. Is provided, the reactor support and the reactor support ring are continuously cooled by low-temperature air during operation, and are reliably maintained at a low temperature. As a result, the safety and reliability of the entire reactor can be improved without the structural strength of the reactor support ring and the reactor support being reduced by the high temperature. Further, in the fast breeder reactor of the present invention, since the reactor support portion and the like are continuously cooled by low-temperature air, there is no need to provide special equipment such as a local cooler, and a fast breeder reactor having a simple structure can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a fast breeder reactor according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a reactor support according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a fast breeder reactor according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a conventional fast breeder reactor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fast breeder reactor 2 Reactor vessel 3 Reactor containment structure 4 Reactor vessel room 7 Reactor support part 8 Reactor support ring 11 Reactor vessel air-cooled cylinder 12 Exhaust bellows 13 Through hole L Low temperature air flow path La Low temperature air flow path Air inlet H High temperature air channel Ha Air outlet of high temperature air channel

──────────────────────────────────────────────────続 き Continued on the front page (72) Hiroshi Nakamura 2-4, Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside Keihin Plant, Toshiba Corporation (72) Inventor Sadao Hattori Otemachi, Chiyoda-ku, Tokyo No. 6-1 in the Central Research Institute of Electric Power Industry (56) References JP-A-63-58291 (JP, A) JP-A-3-18792 (JP, A) JP-A-3-18793 (JP, A) JP-A-4-232496 (JP, A) JP-A-5-196778 (JP, A) JP-A-5-196779 (JP, A) JP-A-5-196780 (JP, A) (58) Int.Cl. ⁷ , DB name) G21C 15/12 G21C 1/02 G21C 13/02

Claims (1)

(57) [Claims] A reactor vessel is housed in a reactor vessel chamber formed inside a reactor containment structure, and a reactor support portion formed on a part of the reactor containment structure via a reactor support ring. The reactor vessel is supported by the reactor vessel, and a reactor vessel air-cooled cylinder forming an air flow path is provided around the reactor vessel, and cooling air is circulated through the air flow path to cool the reactor vessel. In the fast breeder reactor, the reactor vessel air-cooled cylinder forms a continuous high-temperature air flow path and a low-temperature air flow path inside and outside thereof, and the reactor support ring has a through hole for air inflow, and the low-temperature air flow is provided. The high-temperature air flow passage has an air discharge unit that is disposed at an air inflow portion and that discharges high-temperature air to the outside through the furnace vessel air-cooling cylinder and the low-temperature air flow passage. A fast breeder reactor characterized in that: