JP2723246B2 - Fast breeder reactor - Google Patents

Description

The present invention relates to a tank-type fast breeder reactor mounted on a base mat of a reactor building, and in particular, to reduce a design seismic load. A fast breeder reactor that can be used.

(Prior Art) FIG. 2 shows a schematic configuration of a conventional tank type fast breeder reactor. A core 2 for generating thermal energy by nuclear reaction is provided inside a bottomed cylindrical main container 1. Further, inside the main container 1, a liquid metal 17 as a primary coolant is provided.
A plurality of circulation pumps 3 for circulating (usually liquid sodium), a plurality of intermediate heat exchangers 4 for transmitting heat energy from a primary coolant to a liquid metal (not shown) as a secondary coolant (usually liquid sodium), and the like. Primary cooling system equipment is housed.

A core inlet plenum portion 44 is provided at a lower portion of the core 2,
The core 2 and the core inlet plenum 44 are supported by a core support 6 provided at the bottom in the main vessel 1. Core 2
A core upper mechanism 7 is disposed above the core.

A partition 8 supported by a partition support 8A is disposed in the main container 1 in a horizontal direction. The partition 8 divides the space in the main container 1 into an upper hot pool 9 and a lower cold pool 10.

The plurality of main circulation pumps 3 and the plurality of intermediate heat exchangers 4 are all arranged in the main vessel 1 at equal circumferential intervals. A furnace pipe 11 is connected to the lower end of each main circulation pump 3, and the lower end of the furnace pipe 11 is connected to the cold pool.
It extends from inside 10 to the core inlet plenum 44. Then, a thin cylinder 42 extends from the lower portion of each main circulation pump 3 to the furnace pipe 11 and the lower end of the cylinder 42 is
And is introduced into the cold pool 10 so that the inside of the cylindrical body 42 communicates with the internal space of the cold pool 10.

Outside the main container 1, a bottomed cylindrical safety container 13 is provided in case of a coolant leak accident.

The fast breeder reactor configured as described above is supported by the cavity wall 14 of the reactor building via a support member 47 provided on the outer periphery of the upper portion of the safety vessel 13.

The upper opening of the cavity wall 14 and the upper opening of the main container 1 are closed by a roof slab 45 serving as an upper lid.

A cavity 46 is formed in the roof slab 45. By circulating a cooling gas through the cavity 46, the roof
The slab 45 is prevented from overheating. The hot pool 9 and the cold pool 10 contain liquid metal 17 (usually liquid sodium) as a primary coolant, and a cover gas is provided between the liquid surface of the liquid metal 17 and the roof slab 45. Is filled.

Next, the operation of the conventional tank type fast breeder reactor will be described.

First, the liquid metal 17 as the primary coolant receives heat energy from each reaction while passing upward through the core 2 and becomes high in temperature, and enters the hot pool 9 through a window (not shown) of the core upper mechanism 7. Inflow. Then, it flows into the intermediate heat exchanger 4 from above and flows down into the cold pool 10 while lowering the temperature by transmitting heat energy to the liquid metal as the secondary coolant. On the other hand, the liquid metal 17 in the cold pool 10 is pressurized by the main circulation pump 3 and returned to the core inlet plenum 44 through the furnace piping 11. In addition, the medium heat exchanger 4
The liquid metal as the secondary coolant heated in the step (1) is led to the outside of the main container 1 and heats the steam for driving the turbine.

(Problems to be Solved by the Invention) In the conventional fast breeder reactor configured as described above, the entire fast breeder reactor is supported by the cabinet and the support member 47.
Since it is supported by the wall 14, the input ground motion during the earthquake is amplified by the vibration of the cavity wall 14 and enters the fast breeder reactor. Due to the increase of the input seismic power, the design seismic load must be increased, which leads to an increase in the thickness of the main vessel 1, an increase in the rigidity of the core support 6, an increase in the rigidity of the roof slab 45, and the like. This leads to an increase in the amount of structural members and an increase in plant construction costs.

As a solution to such a problem, a fast breeder reactor equipped with a main vessel and a safety vessel provided outside thereof, and mounted on a base beam on a base mat of a reactor building via rollers is known. (Soviet Union, BN-600). There is also known a fast breeder reactor equipped with a main container and a safety container, which is mounted on a base mat of a reactor building via a support skirt provided below the safety container (USSR, BN- 8
No. 00).

Since these are not supported by the cavity wall but mounted on the base mat, the amplification of the input seismic power can be prevented.However, the bottom plates of the main vessel and the safety vessel each have a single arc-shaped vertical cross section. Therefore, there is a problem that the thermal stress applied to the bottom of the main container and the bottom of the safety container cannot be sufficiently absorbed by the arc portion.

On the other hand, there is known a fast breeder reactor in which various machines inside the main container are supported by the main container via a steel material, and the main container is mounted via a roller on a concrete pile on a base mat (Japanese Patent Application Laid-Open No. 61-1986) -791).

Since this is also placed on the base mat, it is possible to prevent the amplification of the input seismic load.However, the bottom plate of the main container is formed in a flat plate shape, and the thermal stress applied to the bottom of the main container can be sufficiently reduced. There is a problem that it cannot be absorbed.

The present invention has been made in view of such a point, and a fast breeder reactor capable of reducing the design seismic load and sufficiently reducing the thermal stress applied to the bottom of the main container and the safety container. The purpose is to provide.

[Configuration of the invention]

(Means for Solving the Problems) The present invention accommodates a core, a core upper mechanism, a main circulation pump and an intermediate heat exchanger inside, and partitions the inside into a hot pool and a cold pool by partition walls arranged substantially horizontally. A fast breeder reactor provided with a partitioned cylindrical main container having a bottom and a safety container disposed so as to cover the outside of the main container, wherein the reactor building has a lower side than a bottom plate periphery of the main container. A main vessel supporting skirt mounted on the base mat is vertically provided, and a core supporting skirt mounted on the base mat of the reactor building is provided downward from a periphery of the core,
The bottom plate of the main container and the bottom plate of the safety container in the core support skirt,
The cross section of the cutting plane passing through the center axis of the main vessel is formed into a curved surface so as to have an arc shape having both ends of the core support skirt on both sides, and a main vessel bottom plate between the core support skirt and the main vessel support skirt; The safety vessel bottom plate is characterized in that it is formed in a curved shape such that a cross section in a cutting plane passing through the central axis of the main vessel has an arc shape having both ends of the core support skirt and the main vessel support skirt.

(Operation) According to the present invention, the input seismic motion entering the base mat of the reactor building is transmitted through the main vessel supporting skirt and the core supporting skirt, and therefore, amplification of the seismic motion can be prevented.

When pressure is applied to the main container bottom plate, internal stress is generated inside the bottom plate. However, when the main container bottom plate is formed in a flat shape, stress concentrates near the joint between the bottom plate and the skirt. However, in the present invention as described above, since the bottom plate of the main container is formed in a curved surface, a film stress is generated in the radial direction and the circumferential direction, and the internal stress is dispersed. Therefore, the stress can be uniformly generated as a film stress as a whole, and the strength and life of the joint can be improved. A similar effect is exerted also on the safety container bottom plate.

In addition, since the main vessel bottom plate is connected and fixed to the core support skirt and the main vessel support skirt, when thermal expansion occurs in a high temperature state, if the bottom plate is flat, stress concentrates on the joint with the skirt. I do. However, in the present invention as described above, since the bottom plate of the main container is formed in a curved surface, thermal stress can be reduced and dispersed by the flexibility of the curved surface. A similar effect is exerted on the bottom plate of the safety container.

Further, the main container bottom plate is formed in an arc shape having the skirt at both ends. That is, the arc-shaped curved surface portion is directly connected to the skirt, and no flat portion or the like is interposed between the curved surface portion and the skirt. Therefore, even when pressure is applied to the bottom plate, stress does not concentrate on this portion as in the case where a flat plate portion exists. Therefore, the film stress is uniformly generated including the portion near the skirt of the bottom plate, and the stress can be prevented from being concentrated on the portion near the skirt. Further, even when thermal expansion occurs, stress does not concentrate on this portion as in the case where a flat plate portion exists. Therefore, the stress due to the expansion is dispersed throughout the bottom plate including the vicinity of the skirt of the bottom plate, and the concentration of the stress on the portion of the bottom plate near the skirt can be prevented. A similar effect is exerted also on the safety container bottom plate.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a view showing one embodiment of a fast breeder reactor according to the present invention.

In FIG. 1, a core 2 for generating thermal energy by a nuclear reaction is provided inside a bottomed cylindrical main container 1. A plurality of main circulation pumps 3 for circulating liquid metal 17 (usually liquid sodium) as a primary coolant inside the main container 1 and liquid metal (not shown) as a secondary coolant from the primary coolant (usually) A primary cooling system including a plurality of intermediate heat exchangers 4 for transmitting thermal energy to the liquid sodium is accommodated.

The core 2 is supported by a core support 6 fixed to a bottom plate 21 in the main vessel 1. A core upper mechanism 7 is provided above the core 2.

A partition 8 is arranged in the main container 1 in a substantially horizontal direction. The partition 8 divides the space in the main container 1 into an upper hot pool 9 and a lower cold pool 10.

A plurality of main circulation pumps 3 and a plurality of intermediate heat exchangers 4
Are arranged in the main container 1 at equal intervals in the circumferential direction. A core pipe 11 is connected to a lower end of each main circulation pump 3, and a lower end of the furnace pipe 11 is connected to the cold pool 10.
It extends to the core 2 inside.

In addition, a safety container 13 having a bottomed cylindrical shape is provided outside the main container 1 in case of a coolant leakage accident, and a heat insulating material 15 is provided to cover the safety container 13.

The main container bottom plate 21 has a main container supporting skirt 20 and a core supporting skirt in a longitudinal section passing through the central axis of the main container 1.
19, and between the core support skirts 19, are formed in a curved surface so as to draw a total of three arcs, each of which is a downwardly convex portion (FIG. 1). Further, the safety container bottom plate 22 is also formed in a curved shape substantially similar to the main container bottom plate 21.
In addition, the main container bottom plate 21 formed in a curved surface, the safety container bottom plate
Numeral 22 is directly connected to the core support skirt 19 and the main vessel support skirt 20 so that the ends thereof are the skirts.

A support cylinder is provided on the upper flat plate head 30, which forms the upper lid of the main container 1.
25, 26 and 27 project upward. This support cylinder 2
The main circulation pump 3 is supported by 5, the intermediate heat exchanger 4 is supported by the support cylinder 26, and the core upper mechanism 7 is supported by the support cylinder 27.

These support cylinders 25, 26 and 27 are mounted on the upper flat plate head 30 of the main container 1 and radially disposed radial webs 28, and also mounted on the upper flat plate head 30 and circumferentially disposed. It is connected to a tangential web (not shown). For this reason, support cylinder 2
The loads on 5, 26 and 27 are
28 and transmitted to the main container 1 side by the tangential web. Further, the rigidity of the upper flat plate head 30 is increased by the radial web 28 and the tangential web. On the other hand, the load applied to the inner peripheral side of the upper flat plate head 30 is transmitted from the support structure 6 of the core 2 to the head support 29 extending upward and supported by the core support skirt 19.

Next, the operation of the present embodiment having such a configuration will be described.

The liquid metal 17 as the primary coolant is sent to the intermediate heat exchanger 4 as in the conventional apparatus, and the liquid metal as the secondary coolant heated by the intermediate heat exchanger 4 is guided to the outside of the main container 1. Heats steam for turbine drive.

The input ground motion during an earthquake enters the base mat 18 of the reactor building from the ground. Next, the input seismic motion entering the base mat 18 is transmitted to the main vessel bottom 21 via the core support skirt 19 and the main vessel support skirt 20.

The seismic motion transmitted to the main vessel bottom 21 is the core 2,
The liquid metal 17 is propagated to the main circulation pump 3 and the intermediate heat exchanger 4.

Thus, according to the present embodiment, the conventional base mat 18
From the cavity wall 14, the support member 47 and the safety container
As compared with the path for transmitting the seismic motion to the main container 1 via the thirteen, the seismic ground transmission path is greatly shortened. For this reason, the input seismic motion is not amplified by the cavity wall 14 and transmitted to the main container 1, and it is not necessary to increase the design seismic load of the main container, so that the plant construction cost can be reduced.

Also, when pressure acts on the main container bottom plate 21, the main container bottom plate
Due to the curved surface formed in 21, a film stress is generated in the circumferential direction and the meridian direction of the main container bottom plate. Main container bottom plate 21
When is a flat plate, stress concentrates on the joint between the flat plate and the cylindrical portion. However, by generating film stress using the main container bottom plate 21 as a curved surface, the stress can be made uniform.

Also in the safety container bottom plate 22, the stress can be made uniform as in the main container bottom plate 21.

The main container bottom plate 21 thermally expands in the radial direction due to the high temperature. In this case, the main container bottom plate 21 is connected and fixed to the core support skirt 19 and the main container support skirt 20, but the main container bottom plate 21 is formed in a curved shape, so that the flexibility of the curved surface causes heat. Stress can be sufficiently reduced.

In other words, this curved surface is formed so as to draw three arcs in a vertical section passing through the central axis of the main container 1, and these arcs have the core supporting skirt 19 and the main container supporting skirt 20 as ends. is there. For this reason, the main container bottom plate 21
Are the core support skirt 19 and the main vessel support skirt
20 or an arc portion of the main vessel bottom plate 21 which is not directly connected to the core support skirt 19 and the main vessel support skirt 20 but is connected to the skirt via a flat plate-like portion. In comparison, especially the core support skirt
The stress due to thermal stress and pressure of the main container bottom plate 21 in the vicinity of the main container support skirt 19 and the main container can be reduced. Furthermore, since the main container bottom plate 21 is formed so as to draw three arcs, it is possible to increase the degree of thermal stress by increasing the number of thermal stress relaxation points as compared with a single arc. Can be.

In the safety container bottom plate 22, as in the case of the main container bottom plate 21, the arc-shaped portion of the bottom plate has the skirts 19 and 20 at both ends, so that the stress can be relieved. Relaxation can be achieved.

The main container supporting skirt 20 and the core supporting skirt
Since 19 is fixed to the base mat 18, it is possible to stably support especially the input earthquake motion in the vertical direction.

The loads of the main circulation pump 3, the intermediate heat exchanger 4, and the upper core mechanism 7 having the rotary plug 7a are transmitted to the support cylinders 25, 26, and 27, and are transmitted through the radial web 28 and the tangential web. And transmitted to the main container 1 and the head support 29 as a uniform distribution. These loads are transferred from the main container 1 and the head support 29 via the main container support skirt 20 and the core support skirt 19 to the base mat.
It is transmitted to 18.

As described above, since the upper flat plate head 30 can be reinforced by the radial web 32 and the tangential web, the thickness of the upper flat plate head 30 can be reduced.

〔The invention's effect〕

According to the present invention, the seismic motion that has entered the base mat during an earthquake is transmitted to the main container bottom plate without being amplified by a shorter transmission path as compared with conventional equipment. Therefore, the design seismic load can be reduced and the construction cost can be reduced without the input seismic motion being amplified. Further, the thermal stress applied to the main container bottom plate and the safety container bottom plate can be sufficiently reduced by the curved surfaces formed on the main container bottom plate and the safety container bottom plate, so that it is possible to provide a high-speed amplification furnace safe against the thermal stress. . Further, the bottom plate of the main container and the bottom plate of the safety container are formed in an arc shape having the skirt at both ends. Therefore, even if thermal stress or pressure is applied to the bottom plate, stress does not concentrate on this portion as in the case where a flat plate portion exists. Accordingly, it is possible to prevent stress from being concentrated on the portion near the skirt of the bottom plate, and to provide a safer fast breeder reactor.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a fast breeder reactor according to the present invention, and FIG. 2 is a sectional view showing a conventional fast breeder reactor. , 1 ... Main vessel, 2 ... Core, 3 ... Main circulation pump, 4 ... Intermediate heat exchanger, 7 ... Core upper mechanism, 8 ... Partition wall, 9 ... Hot pool, 10 ... Cold pool , 13 Safety container, 18 Base mat, 21 Core support skirt, 20 Main container support skirt, 21 Bottom plate of main container, 22 Bottom plate of safety container.

Continued on the front page (72) Inventor Thomas, Mikle, Carlson California, United States of America, San Francisco, Fifty, Beer, Street, Pee, Oh, Box 3965 Vectel, National, Inc. United States California, San Francisco, Fifty, Beer, Street, Pee, Oh, Box 3965 in Vector, National, Inc. (72) Inventor Joseph, Fredrick, Petrozelli California, United States of America, San Francisco, Fifty, Beer, Street, Pee , Oh, Box 3965 Bectel, National, Inc. (56) References JP-A-63-210697 (JP, A) JP-A-57-194393 (JP, A)

Claims (1)

(57) [Claims] 1. A bottomed cylindrical shape having a core, a core upper mechanism, a main circulation pump, and an intermediate heat exchanger housed therein, and a hot-water pool and a cold pool defined by a partition disposed substantially horizontally. In a fast breeder reactor including a main container and a safety container disposed so as to cover the outside of the main container, the fast breeder reactor is placed on a base mat of a reactor building downward from a peripheral edge of a bottom plate of the main container. A main vessel supporting skirt is vertically provided, and a core supporting skirt mounted on the base mat of the reactor building is provided downward from a periphery of the core, and a main vessel bottom plate in the core supporting skirt and The safety container bottom plate is formed in a curved shape so that a cross section of the cut surface passing through the center axis of the main container has an arc shape having both ends of the core support skirts on both sides, and the core support skirt and the main The cross section of the main container bottom plate and the safety container bottom plate between the container support skirt and the safety container bottom plate taken along a central axis of the main container has an arc shape having both ends of the core support skirt and the main container support skirt. A fast breeder reactor characterized by having a curved surface.