JPS60114792A - Tank type fast breeder reactor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a tank type fast breeder reactor.

[Technical background of the invention]

Figure 1 shows the schematic configuration of a tank-type fast breeder reactor.
Reference numeral 1 denotes a main container, and the upper opening of the main container 1 is closed by a roof slab 2. Further, reference numeral 3 denotes a core provided within the main vessel 1, and this core 3 is supported by a core support structure 4.

A core upper mechanism 7 is supported on the roof slab 2 along with a circulation pump 5 and an intermediate heat exchanger 6. The upper core mechanism 7 is positioned above the reactor core 3 and controls the reactor output by inserting and withdrawing control rods from the reactor core 3.

Further, the core support structure 4 is suspended and supported from the roof slab 2 by a cylindrical suspension shell 8. This is caused by vertical vibrations caused by earthquakes, etc., which causes the roof slab 2 and core 3 to
This is to completely prevent the control rods supported by the roof slab 2 from being pulled out of the reactor core 3 by changing the vertical distance between them and the positive reactivity from being inserted. and the circulation pump 5
Both the intermediate heat exchanger 6 and the intermediate heat exchanger 6 are located outside the hanging cylinder 8. In addition, a plurality of 70-holes 8a are provided in the peripheral wall of the hanging cylinder 80.

On the other hand, a horizontal support structure 9 is provided to prevent the reactor core 3 from swinging in the horizontal direction due to horizontal vibrations caused by an earthquake or the like. Therefore, when external vibration in the horizontal direction occurs due to an earthquake or the like, the reaction force from the core 3 due to the horizontal vibration is transmitted to the main vessel 1 through the horizontal support structure 9 (f). The outside is protected by a guard vessel 10, and a radial key 11 provided on the outside of the main container 1 and a key receiver 12 provided in the guard vessel 10 are fitted.

Therefore, the reaction force from the reactor core 3 transmitted to the main vessel 1 is transmitted to the guard vessel 10 via these radial keys 11 and key receivers 12, and is further transmitted to the wall of the reactor vessel chamber 13 housing the main vessel 1. The structure is such that horizontal vibration of the core 3 is prevented.

Here, a difference in thermal expansion occurs between the core support structure 4 and the horizontal support structure 9 due to a temperature difference. Therefore, the horizontal support structure 9 must be able to absorb this difference in the amount of thermal expansion and prevent the horizontal vibration of the reactor core 3.Shaky is generally used to satisfy these needs. It is being Furthermore, the contact portions between the horizontal support structure 9 and the core support structure 4 are configured to slide against each other in order to cope with vibrations in the vertical direction.

In addition, liquid sodium 14, which is a coolant, is housed in the main vessel 1, and a partition wall 15 is provided. It is separated from the low-temperature lunum 17 below. In addition, a high-pressure blemish 1 is located below the core 3.
8 is provided. The outer periphery of the circulation bong f5 is surrounded by an outer cylinder 19 communicating with the low-temperature plenum 17, and the lower end discharge port of the circulation pump 5 is connected to the high-pressure plenum 18 via a pressure guiding pipe 20f. Further, the intermediate heat exchanger 6 has an inlet 21 communicating with the high temperature plenum 16 and an outlet 22 communicating with the low temperature plenum 17 .

A 7-run section 23 is provided at the upper end of the main container 1, and an outer 7-run section 24 of the roof slab 2 is placed on this flange section 23. And the Franz part 2 of the main container 1
4 is a ring girder attached to the wall of the furnace vessel chamber 13;
25, and the load of the main vessel 1, its contents, and the roof slab 2 is supported by the wall of the furnace vessel chamber 13. Further, a guard vessel 10 outside the main vessel 1 is also supported by the wall of the furnace vessel chamber 13. In addition,
In the figure, 26 is a secondary cooling phase inflow pipe connected to the intermediate heat exchanger 6, and 27 is a secondary coolant outflow pipe. Also, 2 in the diagram
8 is a motor that drives the circulation pump 5.

In the above configuration, the liquid in the still pressure plenum 18)
IJum 14 flows through the reactor core 3 from below to above.
The temperature rises due to the heat of nuclear reaction. The liquid sodium 14 flowing from the reactor core 3 into the suspension shell 8 in the high-temperature blemish 16 passes through the entire flow hole 8a and passes through the suspension shell 8.
, flows into the intermediate heat exchanger 6 through the inlet 21 , and exchanges heat with the secondary coolant inside the intermediate heat exchanger 6 . After that, from the outlet 22, the low-temperature gleam 17
The liquid sodium 14 that has flowed out passes through the outer cylinder 19 and flows into the circulation pump 5, and passes through the entire pressure impulse pipe 20 to the cylinder pressure solenum 1.
8.

[Problems with background technology]

In the tank-type fast breeder reactor configured as shown in FIG. 1, the core support structure 4 and the horizontal support structure 6 come to slide together in liquid sodium contained in the main vessel 1 as a coolant. However, smooth sliding may be hindered, leading to scratches or sticking to the sliding portion, and maintenance and inspection of the sliding portion is also difficult.

[Purpose of the invention]

The present invention was made based on these circumstances, and
The purpose is to eliminate the horizontal support structure that slides into the core support structure, to prevent the horizontal shaking of the core by using the coolant in the main vessel, and to provide a highly reliable tank-type fast breeder reactor. There is a particular thing.

[Summary of the invention]

In order to achieve the above objects, the tank-type fast breeder reactor of the present invention is provided with a cylindrical wall that surrounds the outer periphery of the core support structure with an annulus-shaped gap formed between the bottom of the main vessel and the core support structure. At the same time, a low-temperature plenum bottom wall is installed along the inner surface of the bottom with a gap between the cylindrical wall and the bottom of the main container, and the cylindrical wall and the low-temperature plenum bottom wall are joined by a flat plate structure. A low-temperature solenum is formed between the blemish bottom wall and the flat plate structure, and a gap between the main vessel bottom and the low-temperature blenum bottom wall is passed between the high-temperature plenum above the flat plate structure and the lower solenum below the core. are configured by communicating with each other.

[Embodiments of the invention]

2 and 3 show an embodiment of the present invention,
FIG. 2 shows a schematic configuration of a tank-type fast breeder reactor, and FIG. 3 shows a part thereof in an enlarged manner. - Also, in these figures, the same parts as in FIG. 1 are given the same reference numerals.

Subject g? The bottom of i1 is a spherical mirror plate 29,
A lower support flange (30) is provided on the inner surface of the spring board (29) in an annular manner and projects from the center of the axis of the main container (1). Further, on the peripheral wall of the main container 1, an annular upper support 7 run 31 is provided at the position of the inner surface 1 of the radial gear 11.

A cylindrical wall 32 is attached to the lower support flange 3o so as to surround the core support structure 4 with an annulus-shaped gap between it and the core support structure 4. Also, the lower support flange 3o and the upper support flange 3
1 is connected to the low-temperature blenheim bottom wall 33.

This low-temperature lunum bottom wall 33 is provided with a gap t between it and the end plate 29 at the bottom of the main container 1, and is installed along the inner surface of the end plate 2g. Further, the entire front a-pi circle I#i 32 and the low temperature plenum bottom wall 33 are connected by a flat plate structure 34 arranged at the height of the upper support flange 31. The cylindrical wall 32, the low-temperature plenum bottom wall 33, and the flat plate structure 34 form an annular low-temperature blemish container, and a low-temperature lunum 35 is formed between the annular walls.

The cylindrical wall 32 and the low-temperature plenum bottom wall 33 both extend upward from the flat structure 34, and the extended portions are connected to a reinforcing member 36 horizontally arranged inside the main container 1. ing. In addition, the flat plate structure 34 is a high-temperature solenum 1
The outer cylinder 19 and the intermediate heat exchanger 6 are passed through this flat plate structure 34, and the VK heat exchanger 5 is arranged inside the outer cylinder 19. are doing. And the outlet 21'f of the intermediate heat exchanger 6
: The liquid sodium 14 that has passed flows into the low temperature lunum 35, and is further sucked into the circulation bomb f5 through the outer periphery 19,
It is configured so that it passes through the entire pressure impulse pipe 2o and is fed under pressure into the cylinder pressure plenum 18 below the reactor core 3.

Also, below the core 3, that is, the core support structure 4 and the end plate 2
A space surrounded by 9 and the cylindrical wall 32 is defined as a lower lunum 3-7.

The lower support flange 3o and the upper support flange 31 are provided with communication ports 38, 39, respectively, which are ft6 in diameter. The lower plenum 32 and the high temperature solenum 16 are communicated with each other.

In the above configuration, when horizontal vibration occurs due to an earthquake or the like, a reaction force from the core 3 due to the vibration is present in the annulus-shaped gap between the core support structure 4 and the cylindrical wall 32. The liquid sodium 14 is transmitted to the liquid sodium 14, and collision between the core support structure 4 and the cylindrical wall 32 is prevented. The reaction force from the core 3 transmitted to the cylindrical wall 32 is transmitted to the main vessel 1 via the flat plate structure 34, and is also transmitted to the guard vessel 10 via the radial key 1 and key receiver 12, and then This is transmitted to the wall of the reactor vessel chamber 13, thereby preventing the core 3 from shaking in the horizontal direction.

Here, the fluid force of the liquid sodium 14 existing in the annulus-shaped gap is calculated by the following equation.

Here, Ml-ρπa LK M2- ρπbL 5 [Also, Fy: Fluid force FX acting on the core support structure 4:
Fluid force a acting on cylinder M1.32: Core support structure 4
Outer radius 2: Inner radius V of cylindrical wall 32: Absolute displacement W of core support structure 4: Absolute displacement ρ of cylindrical wall 32: Density LK of fluid (liquid sodium 14): Core support structure 4 and cylindrical wall In addition to the above formula, the leakage effect of the liquid sodium 14 at the annulus between the core support structure 4 and the cylindrical wall 32 is also taken into consideration, and the exit direction 1o is determined.

When we analyzed the relationship between the initial clearance of the anneal section and the horizontal relative displacement of the core support structure 4 and the cylindrical wall 32 for a 10,000 kW class tank-type nuclear reactor, we obtained the results shown in Figure 4. That is, A in the figure is a limit line where the core support structure 4 and the cylindrical wall 32 geometrically collide. Therefore, the output 10
In a 00,000 kW class nuclear reactor, the initial gap in the annealed part is 10
~． 30+a+, but within this range, the relative displacement is smaller than the limit line A, and no collision occurs between the two. Therefore, the core support structure 4 can be supported in the horizontal direction by the fluid force of the liquid sodium 14.

In addition, when the roof slab 2 vibrates in the vertical direction during an earthquake, the core support structure 4
Since it is suspended via the suspension shell 8, it moves vertically together with the roof slab 2 as shown by the imaginary line in FIG. 3, thereby changing the volume of the lower plenum 37 below. However, when the volume of the lower plenum 37 decreases, the third
As shown by arrows in the figure, the liquid sodium 14 in the lower plenum 37 escapes into the high temperature plenum 16 through the gap between the low temperature plenum bottom wall 35 and the end plate 29, and the liquid sodium 14 escapes into the high temperature plenum 16 through the gap between the low temperature plenum bottom wall 33 and the bottom of the main vessel 1. The end plate 29 is elastically deformed downward, thereby suppressing internal pressure fluctuations in the lower plenum 37. For this reason, there is no need to make the end plate 29 or the suspension body 8 particularly thick to provide strength.

Furthermore, since the cylindrical wall 32, the low-temperature plenum bottom wall 33, and the flat plate structure 34 form a low-temperature plenum vessel, a partition wall is provided to connect the core support structure 4 and the main vessel 1 as in the conventional case. The high-temperature plenum 16 and the low-temperature plenum 35 can be partitioned without the need for a partition wall, and the reaction force from the reactor core 3 when horizontal vibrations occur is localized to the peripheral wall of the main vessel 1. It does not act as a concentrated load, and the integrity of the main container 1 is maintained. moreover,
Since the conventional horizontal support structure that slides on the core support structure 4 is also omitted, the problem of galling or sticking at the sliding portion is also solved.

〔Effect of the invention〕

As detailed above, according to the present invention, the horizontal support structure that slides into the core support structure is eliminated, and the horizontal swing of the core is prevented by the fluid force of the coolant. , a highly reliable tank-type fast breeder reactor can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical cross-sectional view of a tank-type fast breeder reactor showing a conventional example, FIG. 2 is a schematic vertical cross-sectional view of a tank-type fast breeder reactor showing an embodiment of the present invention, and FIG. The longitudinal cross-sectional view m1 and FIG. 4, which are partially enlarged, are diagrams showing the relationship between the initial gap between the core support structure and the cylindrical wall and the relative displacement thereof in the same embodiment. l...Main vessel, 2...Roof slab, 3...Reactor core, 8...Suspended shell, 14...Liquid sodium (coolant), 32...Cylindrical wall, 33... low temperature solenum bottom wall,
34... Flat plate structure, 35... Low temperature plenum, 37
...lower solenum.

Claims (1)

[Claims] A main container containing a coolant and having an open top, a roof slab that closes the top opening of the main container, and fj! A core provided in each vessel, a core support structure that accommodates and supports this core and forms a lower plenum below, and a suspension shell that suspends this core support structure from the roof slab;
A cylindrical wall that is attached to the bottom of the main vessel and surrounds the outer periphery of the core support structure with an annulus-shaped gap between the bottom of the main vessel and the bottom of the main vessel, a low-temperature plenum bottom wall installed along the inner surface of the bottom; a flat plate that joins the cylindrical wall and the low-temperature plenum bottom wall to form a low-temperature plenum container together with the cylindrical wall and the bottom wall; A tank-type fast breeder reactor, comprising: a structure, wherein the lower plenum and the high-temperature plenum are communicated through a gap between the bottom of the main vessel and the bottom wall of the low-temperature plenum.