JPS61223579A - 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 improvements in fast breeder reactors.

[Technical Background of the Invention] A conventional example will be described below with reference to FIG. FIG. 3 is a longitudinal sectional view showing the configuration of a tank-type fast breeder reactor. Figure middle mark @
1 is a main container, and a safety container 2 is installed on the outer circumferential side of this main container 1. The main container 1 above is a ring garter 3
The safety vessel 2 is supported by the reactor building 4 via a skirt portion 5 . A roof slab 6 is installed to close the upper opening 1A of the main container 1. This roof slab 6 includes a fixed plug 6A, a large rotation plug 6B rotatably installed on the inner circumference of the fixed plug 6A, and a small rotation plug 6C rotatably installed on the inner circumference of the large rotation flag 6B. It consists of Also, inside the main container 1,
A coolant 7 and a reactor core 8 are housed therein. This core 8 is composed of a plurality of fuel assemblies, control rods, etc.
It is suspended from the roof slab 6 via a core support mechanism 9 and a suspension shell 10. The reason for this structure in which the roof slab 6 is suspended through the suspension shell 10 is that even if the roof slab 6 vibrates, the core 8 and the core support mechanism 9 vibrate together with the roof slab 6, and the relative displacement between them is prevented. It is completely waterproof.

A core upper mechanism 11 is installed directly above the core 8 so as to pass through the small rotation plug 6C of the roof slab 6. A control rod drive mechanism (CRD) (not shown) is installed in the upper core mechanism 11, and the CHD controls the output of the core 8 by withdrawing or inserting the control rods from within the core 8. A partition W12 is installed between the main vessel 1 and the core support mechanism 9, and a vibration damping wall 13 is erected from the bottom of the main container 1 continuously from the inner peripheral end of the partition wall 12. The interior of the main container 1 is divided into upper and lower halves by the above-mentioned distance W112, with the upper part being an upper plenum (hot plenum) 14 and the lower part being a lower plenum (cold plenum) 15. Further, a horizontal vibration damping member 16 is installed below the partition wall 12, and this horizontal vibration damping member 16
This suppresses the horizontal vibration of the core support mechanism 9 when a horizontal earthquake occurs.

On the outer peripheral side of the core support mechanism 9, an intermediate heat exchanger 17 and a circulation pump 18 are installed alternately at equal intervals in the circumferential direction, passing through the fixing plug 6A of the roof slab 6 and the partition wall 12. Further, a space 19 between the liquid surface 7A of the coolant 7 and the roof slab 6 is filled with an inert gas such as argon gas.

According to the above configuration, the coolant 7 flows through the reactor core 8 from below to above, is heated by the heat of nuclear reaction in the reactor core 8, and flows out into the upper plenum 14. Then, it flows out to the outer circumferential side of the suspension shell 1o through the opening 10A formed in the suspension shell 10, and flows into the intermediate heat exchanger 17. It is cooled by exchanging heat with the secondary side coolant in the intermediate heat exchanger 17, and the lower brenum 1
It flows out within 5. It is then sucked and pressurized by the circulation pump 18 and supplied to the lower part of the reactor core 8 via the in-furnace piping (discharge piping) 21. The same cycle is repeated thereafter.

Next, a mechanism for preventing vibrational displacement of the reactor core 8 will be explained. As described above, on the outer periphery of the core support mechanism 9, a damping wall 13 is erected from the bottom of the main vessel 1. This vibration control! For example, there are 10 to 30 shoes between 13 and the core support mechanism 9.
A gap of m is formed, so that the core support mechanism 9 and the damping wall 13 do not come into mechanical contact. With this configuration, for example, during normal operation, vertical displacement of the core support mechanism 9 due to thermal deformation or the like is absorbed, and excessive thermal stress is prevented from being generated in each structure. Furthermore, if an earthquake or the like occurs and a horizontal load acts on the core support mechanism 9 and the core support mechanism 9 attempts to displace in the horizontal direction, the flow resistance of the coolant 7 in the gap will cause the core support mechanism 9 to displace horizontally. The vibrations are suppressed, and as a result, the horizontal vibration displacement of the core support mechanism 9 and the reactor core 8 is suppressed.

Further, a main container thermal protection structure 22 is installed on the inner peripheral side of the main container 1 above the partition wall 12, and a hanging l1
The hanging body thermal protection structure 2 is installed on the inner and outer circumferential sides of i10.
3 and 24 are provided.

Each of these thermal protection structures 22, 23 and 24 has a structure in which a plurality of heat insulating materials are laminated in the radial direction.

These thermal protection structures 22, 23 and 24 prevent the main container 1 and the suspension shell 10 from becoming too hot.

Further, during normal operation and when starting and stopping the nuclear reactor, a large discontinuous temperature distribution occurs in the coolant 7 in the height direction. The thermal protection structures 22, 23 and 24 prevent thermal stress from occurring in the main container 1 and the suspension shell 10 due to such discontinuous temperature distribution.

[Problems with background technology] According to the above configuration, there were the following problems.

That is, the thermal protection structures 22, 23 and 24 have the following three configurations.

(1) First, as described above, there is a configuration in which heat insulating materials are installed in multiple layers.

(2) A configuration in which a partition wall is installed on the inner peripheral side of the main container 1, and an inert gas is filled between the partition wall and the main container 1 to perform gas insulation.

(3) A configuration in which the low-temperature coolant at the outlet of the circulation pump 18 is made to flow inside the main container 1 and inside and outside the suspension shell 1o.

However, in any case, the configuration is complicated and requires a large amount of material. In particular, when the configuration (3) above is adopted, the coolant 7 is stored on the inner peripheral side of the main container 1 and inside the suspension shell 10. There was a problem in that the route introduced to the periphery/outer periphery side became complicated.

That is, in the conventional case, the coolant 7 discharged from the circulation pump 21 flows into the lower part of the core support mechanism 9. Then, a part of it is introduced further downward, and a route is taken to introduce it to the main container 1 at the upper plenum 14 via between the main container 1 and a liner installed on the inner peripheral side of the main container 1. The route was complicated.

[Object of the Invention] The present invention has been made based on the above points, and its object is to distribute the low-temperature coolant at the outlet of the circulation pump to the inner circumferential side of the main container and the inner circumferential and outer circumferential sides of the hanging body. If a configuration is adopted, the introduction route can be effectively simplified,
An object of the present invention is to provide a fast breeder reactor equipped with a thermal protection structure capable of achieving an effective thermal protection function with a simple configuration.

[Summary of the Invention] That is, the fast breeder reactor according to the present invention comprises: a main vessel that accommodates a coolant and a reactor core; a shielding lid that closes an upper opening of the main vessel; a core support mechanism that accommodates and supports the core; a suspension shell that suspends the core support mechanism from the shielding lid; a partition installed between the core support mechanism and the main vessel that divides the inside of the main vessel into upper and lower halves; a damping wall that is erected on the side with a gap from the core support mechanism and whose upper end is connected to the partition wall and to which the tip of the discharge piping of the circulation pump is fixed; A main vessel cooling liner stands upright with a gap from the main vessel, and a hanging shell inner cooling liner stands from the upper end of the core support mechanism on the inner peripheral side of the hanging shell with a gap from the hanging shell. a hanging cylinder outer cooling liner installed on the outer circumferential side of the hanging cylinder with a gap between the hanging cylinder and the hanging cylinder and whose lower end is connected to the lower end of the hanging cylinder, and a cooling liner formed on the upper end of the vibration damping wall. a main vessel cooling coolant introduction hole for introducing a part of the coolant rising between the damping wall and the core support mechanism through the lower part of the partition wall and between the main vessel and the main vessel cooling liner; A coolant for cooling the inside of the suspension shell, which introduces a part of the coolant formed at the lower end of the suspension shell and rising between the damping wall and the core support mechanism between the suspension shell and the suspension shell inner cooling liner. A portion of the coolant that is formed in the hanging shell above the connection position between the introduction hole and the hanging shell and the hanging shell outer cooling liner and rising between the hanging shell and the hanging shell inner cooling liner is transferred to the hanging shell and a coolant introduction hole for cooling the outside of the hanging body introduced between the hanging body outside cooling liner, a lower sealing mechanism installed between the lower end of the core support mechanism and the damping wall;
The present invention is characterized by comprising an upper sealing mechanism installed between the upper end of the vibration damping wall and the suspension barrel.

In other words, part of the low-temperature coolant discharged from the circulation pump,
The coolant is raised between the core support mechanism and the control wall, is introduced between the main vessel and the main vessel cooling liner through the main vessel cooling coolant introduction hole, and is introduced between the main vessel and the main vessel cooling liner. Introduced between the hanging shell and the hanging shell through the coolant introduction hole for cooling the inside of the hanging shell, and between the hanging shell and the outer cooling liner of the hanging shell through the coolant introduction hole for cooling the outside of the hanging shell. It is.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Note that parts that are the same as those in the prior art are denoted by the same reference numerals, and their explanations will be omitted. A gap A exists on the inner peripheral side of the main container 1 and above the partition wall 12, and the main container cooling liner 1
22 are installed. The lower end of the main vessel cooling liner 122 is connected to the outer peripheral end of the partition wall 12. Allocation I again! 13 includes a circulation pump 18 and a discharge pipe (furnace pipe) 21
The tip is fixed. The inner peripheral end of the partition wall 12 is the vibration damper! 13 is formed continuously with the upper end of the vibration damping!
A coolant introduction hole 131 for cooling the main container is formed at the upper end of the main container 113 . With this configuration, a part of the low-temperature coolant 7 pressurized by the circulation pump 18 flows out from the in-furnace piping 21 and passes through the gap between the damping wall 13 and the core support mechanism 9. The coolant rises, flows radially outward under the partition wall 12 through the main container cooling coolant introduction hole 131, and flows into the gap 111A. This configuration effectively cools the main container 1. In addition, the lower end of the core support mechanism 9 and vibration damping! 13, there is a lower seal mechanism 13 between the
2 is installed, and the upper end of the damping wall 13 and the hanging 11
An upper sealing mechanism 133 is also installed in the area with 10'. Each of these seal mechanisms 132 and 133 employs a piston ring type in order to allow displacement of the core support mechanism 9 in the vertical and horizontal directions. By installing the seal mechanisms 132 and 133, leakage of the coolant 7 is prevented and horizontal movement of the core support mechanism 9 is restricted.

On the other hand, a cooling liner 123 for cooling the inside of the suspension shell 123 is provided upright from the upper end of the core support mechanism 9 with a gap B on the inner peripheral side of the suspension shell 10, and a gap W is provided on the outside of the suspension shell 10.
A cooling liner 124 on the outside of the suspension barrel is installed via the UC. The lower end of this hanging barrel outer cooling liner 124 is connected to the lower end of the hanging barrel 10. A coolant introduction hole 141 for cooling the inside of the hanging cylinder is provided at the lower end of the hanging cylinder 10.
In addition, a coolant introduction hole 142 for cooling the outside of the hanging drum is formed in the hanging lR10 above the connecting portion between the hanging drum 1 and the hanging drum outer cooling liner 124. With this configuration, a portion of the low-temperature coolant pressurized by the circulation pump 18 is transferred to the gap 1! ID, and introduced into the gap B through the cooling material introduction hole 141 for cooling the inside of the hanging drum, and into the gap C through the cooling material introduction hole 142 for cooling the outside of the hanging drum, Hanging trunk 10
to effectively cool it from the inside and outside.

The operation will be explained based on the above configuration. First, as described in the explanation of the conventional example, the coolant 7 flows upward through the reactor core 8, and at that time, its temperature rises due to the heat of nuclear reaction in the reactor core 8, and the coolant 7 flows into the upper plenum 14.
leaks inside. The coolant 7 that has flowed out is poured into the opening 1 of the suspension shell 10.
It flows out of the suspension shell 10 via 0A and flows into the intermediate heat exchanger 17. There, it exchanges heat with the secondary coolant, is cooled, and flows out into the lower plenum 15. It is then sucked and pressurized by the circulation pump 18 and supplied to the lower part of the reactor core 8 via the in-furnace piping 21. At that time, part of the coolant 7 is F
Vibration damping wall 13 and core support mechanism 9 via JIllID
The coolant rises between the main vessel cooling coolant introduction hole 131, flows below the gap W112, and is further introduced into the gap A. At the same time, the coolant flows into the gap IRIS through the cooling material introduction hole 141 for cooling the inside of the hanging drum, and is introduced into the gap 1!1c through the cooling material introduction hole 142 for cooling the outside of the hanging drum. Through the circulation of the coolant 7, the main container 1 and the suspension shell 10 can be effectively cooled, and thermal stress can be alleviated.

As described above, the following effects can be achieved by the fast breeder reactor according to this embodiment.

(1) First, in a configuration in which the low-temperature coolant 7 discharged from the circulation pump 18 is introduced into the inner circumferential side of the main container 1 and the inner circumferential side and the outer circumferential side of the suspension shell 10 to cool the coolant 7, the coolant 7 is cooled. The introduction route is simplified, making it possible to achieve the desired cooling function with a simple configuration.

(2) Next, since the upper and lower ends of the gap 111D are sealed by the seal mechanisms 131 and 132, leakage of the coolant 7 can of course be effectively prevented.
It is also possible for the seal mechanisms 131 and 132 to exhibit a vibration damping function, and horizontal vibrations of the core support mechanism 9 can be suppressed more effectively.

(3) Furthermore, the core support mechanism 9 and the reactor internal wiring IF21 are not mechanically connected, so in the unlikely event that the core support mechanism 9
Alternatively, even if a problem occurs in the suspension shell 10, the suspension shell 10 can be easily removed from above after removing the rotary plug 6A and the upper core mechanism 11, and maintenance and inspection work can be easily performed. .

(4) As mentioned above, the in-core piping 21 and the core support mechanism 9 are not mechanically connected, so even if an earthquake occurs and the core support mechanism 9 vibrates, for example, The load acting on the in-furnace piping 21 is extremely small, so that the structural integrity of the in-furnace piping 21 can be improved.

(5) Further, the horizontal vibration damping member 16 has a relatively thick structure, and therefore it is not preferable that a large concentration difference occurs between its upper and lower surfaces. In this regard, in the case of this embodiment, the low-temperature coolant 7 is introduced below the partition wall 12 as described above, and the concentration of the low-temperature coolant 7 and the lower plenum 15 below the horizontal vibration damping member 16 are As a result, the temperature difference between the upper and lower surfaces of the horizontal vibration damping member 16 is extremely small, and the structural integrity of the horizontal vibration damping member 16 can be improved. .

[Effects of the Invention] As detailed above, according to the present invention, it is possible to simplify the coolant introduction route, facilitate maintenance (tl. inspection work), and further improve the structure of the horizontal vibration damping member. The effects are great, such as making it possible to improve soundness.

[Brief explanation of drawings]

1 and 2 are diagrams showing one embodiment of the present invention, in which FIG. 1 is a longitudinal cross-sectional view of a tank-type fast breeder reactor, FIG. 2 is a cross-sectional view showing the part ■ in FIG. 1 in detail, FIG. 3 is a longitudinal sectional view of a conventional tank-type fast breeder reactor. 1... Main vessel, 7... Coolant, 8... Core, 9...
... Core support mechanism, 10 ... Suspension shell, 12 ... Partition wall, 13 ... Damping wall, 14 ... Upper plenum, 15.
...Lower plenum, 16...Horizontal vibration damping member, 122.
... Liner for cooling the main vessel, 123 ... Liner for cooling inside the hanging shell, 124 ... Liner for cooling outside the hanging shell, 131
...Coolant introduction hole for main container cooling, 132, 133...
- Seal mechanism, 141... Coolant introduction hole for cooling the inside of the hanging drum, 142... Coolant introduction hole for cooling the outside of the hanging drum. Applicant's agent Patent attorney Takehiko Suzue JI2 prisoner

Claims (2)

[Claims] (1) A main vessel that accommodates coolant and the reactor core, a shielding lid that closes the upper opening of the main vessel, a core support mechanism that accommodates and supports the core, and a suspension that suspends the core support mechanism from the shielding lid. a partition wall installed between the core support mechanism and the main vessel and dividing the inside of the main vessel into upper and lower halves, and a gap between the core support mechanism and the core support mechanism on the outer peripheral side of the core support mechanism from the bottom of the main vessel. a vibration damping wall which is erected and whose upper end is connected to the partition wall and to which the tip of the discharge piping of the circulation pump is fixed, and which is erected from the outer peripheral end of the partition wall to the inner peripheral side of the main container with a gap between it and the main container. a cooling liner for cooling the main vessel, a liner for cooling the inside of the hanging shell, which stands upright on the inner circumferential side of the hanging shell from the upper end of the core support mechanism with a gap between the hanging shell and the hanging shell; a hanging body side cooling liner installed with a gap between the hanging body and the hanging body and having its lower end connected to the lower end of the hanging body;
A main body is formed at the upper end of the vibration damping wall and introduces a portion of the coolant rising between the vibration damping wall and the core support mechanism into the space between the main vessel and the main vessel cooling liner via the lower part of the bulkhead. A part of the coolant rising between the vessel cooling coolant introduction hole and the suspension shell lower end and the vibration damping wall and core support mechanism is transferred between the suspension shell and the suspension shell inner cooling liner. A coolant introduction hole for cooling the inside of the hanging shell to be introduced and a cooling material formed in the hanging shell above the connection position between the hanging shell and the cooling liner on the hanging shell side, and rising between the hanging shell and the cooling liner for inside the hanging shell. A coolant introduction hole for cooling the outside of the suspension shell, through which a part of the coolant is introduced between the suspension shell and the suspension shell outside cooling liner, and a damping wall installed between the lower end of the core support mechanism and the damping wall. A fast breeder reactor comprising: a lower sealing mechanism; and an upper sealing mechanism installed between the upper end of the vibration damping wall and the hanging barrel. (2) The fast breeder reactor according to claim 1, wherein the lower seal mechanism and the upper seal mechanism are constituted by piston rings.