JPS61218989A - 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 the Invention] The present invention relates to a tank-type fast breeder reactor with improved 111N walls within the reactor vessel.

[Technical background of the invention and its problems]

A conventional tank-type fast breeder reactor has a reactor vessel 1 as shown in FIG. 5, and a reactor core 2 is disposed slightly below the center of the reactor vessel 1. This core 2
is surrounded by a core barrel 3, and a pair of upper and lower partition plates 4.5 are provided between the core barrel 3 and the reactor vessel 1. This partition plate 4.5 divides the inside of the furnace into a high temperature plenum 6 and a low humidity plenum 7. Each plenum 6.7 is filled with liquid metal sodium. An intermediate plenum 8 is formed between the partition plates 4 and 5, and this intermediate plenum 8 is also filled with liquid metal sodium.

The liquid metal sodium in this intermediate plenum 8 is adiabatic II
This prevents heat transfer from the high-temperature plenum 6 to the low-humidity plenum 7.

A roof slab 10 equipped with a rotating plug 9 is disposed on the top of the reactor vessel 1, and the reactor vessel is hermetically sealed by the roof slab 10. Also, this roof slab 10
A pump 11 and an intermediate heat exchanger 12 are installed vertically. The pump 11 guides the liquid metal sodium in the low-humidity plenum 7 to the reactor core 2 . On the other hand, intermediate heat exchanger 1
2 exchanges heat between the liquid metal sodium in the high temperature plenum 6 and the secondary sodium circulating in the secondary cooling system. Further, the rotating plug 9 is equipped with a core upper mechanism 13 and a fuel exchanger. Note that the reactor vessel 111 is surrounded by concrete W115.

Incidentally, during nuclear reactor operation, the upper partition plate 4 reaches a high temperature of about 500° C., and undergoes large thermal deformation due to thermal expansion of the material. Since the upper bulkhead plate 4 is attached to the inner wall of the reactor vessel 1 and the core barrel 3 by welding, thermal deformation is restricted and large thermal stress is generated. In order to alleviate this thermal stress, the upper partition plate 4 is configured to form a curved surface. However, increasing the bending of the upper bulkhead plate 4 to further improve its reliability against thermal stress has the problem of making it very difficult to install the upper bulkhead plate 4, manufacturing and assembling the upper bulkhead plate 4, etc. be.

[Object of the Invention] The present invention has been made to overcome the above-mentioned problems, and it is an object of the present invention to provide a tank-type fast breeder reactor having a bulkhead structure that has improved reliability against thermal stress and is easy to manufacture and assemble. With the goal.

[Summary of the invention]

In order to achieve the above object, the present invention includes a partition plate installed in a reactor vessel which encloses a reactor core and is sealed with a roof slab, and divides the inside of the reactor vessel into a high temperature plenum, a low humidity plenum and an intermediate plenum. At the same time, in a tank-type fast breeder reactor in which each plenum is filled with liquid metal, the partition plate is divided into an annular shape in the circumferential direction, and the divided parts are joined with flexible seals. It is characterized by being configured to be supported by a plurality of partition wall plate support plates attached to a wall surface.

This flexible seal has the effect of absorbing displacement due to thermal deformation and relieving thermal stress in the partition plate.

[Embodiments of the invention]

A first embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a sectional view showing an example of a tank-type fast breeder reactor according to the present invention. Note that the same parts in the figure as in FIG. 5 are designated by the same reference numerals.

The reactor vessel 1 houses a reactor core 2 therein and is filled with liquid metal sodium, and has a concrete wall 1.
Supported within 5. Further, a roof slab 10 is disposed on the upper part of the reactor vessel 1, and the reactor vessel 1 is configured to have a closed structure.

Furthermore, inside the reactor vessel 1, there are a pair of upper and lower partition plates 1.
6 and 5 are installed. The interior of the reactor vessel 1 is divided into a high-temperature plenum 6 and a low-humidity plenum 7 by the partition plates 16 and 5, and each plenum 6 and 7 is filled with liquid metal sodium.

Further, an intermediate plenum 8 is formed surrounded by the partition plates 16 and 5, and this intermediate plenum 8 is also filled with liquid metal sodium. The liquid metal sodium in this intermediate plenum 8 provides insulation mrra between the hot plenum 6 and the low humidity plenum 7.

On the other hand, a pump 11 and an intermediate heat exchanger 1112 are vertically installed on the roof slab 10. Further, the rotating plug 9 is equipped with a core upper mechanism 13 and a fuel exchange 1114.

Pump 11 and intermediate heat exchanger 12 are connected to both corner wall plates 1
6 and 5, each end leading into a low humidity plenum 7. The tip of the pump 11 is connected to a high-pressure blenum 17 provided at the lower part of the reactor core 2 via a pump outlet pipe 18. Therefore, the liquid metal sodium in the low-humidity plenum 7 is pressurized by the pump 11 and guided into the high-pressure plenum 17 , and from within the high-pressure plenum 17 to the reactor core 2 to cool the reactor core 2 .

In addition, the inlet 19 and outlet 20 of the intermediate heat exchanger 12
are located in the hot plenum 6 and the low humidity plenum 7, respectively. Further, a secondary sodium supply mechanism 21 is connected to the intermediate heat exchanger 12 to supply secondary sodium into the intermediate heat exchanger 12 . As a result, the liquid metal sodium flowing through the intermediate heat exchanger 12 from the inlet 19 to the outlet 20 is cooled by exchanging heat with the secondary sodium, and flows out from the outlet 20 into the low-humidity plenum 7.

Furthermore, the core upper mechanism 13 is located above the core 2,
Equipped with a control rod drive mechanism. The control rods within the reactor core 2 are controlled by this control rod drive mechanism.

Fuel exchange! 6114 is provided on the rotary plug 9 and has the function of exchanging spent fuel assemblies in the core 2 with new fuel assemblies during fuel exchange.

The partition plates 16 and 5 are provided in the reactor vessel 1 and the core barrel 3, as shown in FIG. That is, the upper bulkhead plate 16 is attached to the wall of the reactor vessel 1 and the wall of the core tank 3 by welding. The upper bulkhead plate 16 is divided in the circumferential direction near the wall of the reactor vessel 1 and near the wall of the core barrel 3, and has an annular gap 22. A flexible seal 23 is joined to the entire circumference of the divided gap 22.

Partition plate support plates 24 provided below the flexible seal 23 are attached to the wall of the reactor vessel 1 and the wall of the core tank 3 at several to several dozen locations. The top part contacts the upper partition plate 16 and has a structure that extends past the annular dividing part. Since the partition plate support plate 24 is not welded to the upper partition plate 16, thermal deformation of the upper partition plate 16 is not restrained by the partition plate support plate 24. The thermal deformation of the upper bulkhead plate 16 is absorbed by the deformation of the flexible seal 23. Since the flexible seal 23 is joined to the annular divided portion 22 of the upper partition plate 16 over the entire circumference, no leakage flow occurs between the high temperature plenum 6 and the low humidity plenum 7.

In this way, thermal deformation of the upper partition plate 16 is absorbed by the deformation of the flexible seal 23, so that no large thermal stress is generated in the upper partition plate 16. Therefore, the reliability of the upper partition plate 16 against thermal stress can be improved without impairing the sealing performance of the upper partition plate 16, and the safety of the nuclear reactor can be improved. Further, since there is no need to bend the upper partition plate 16, manufacturing and assembly operations can be simplified.

FIG. 3 partially shows only the essential parts of the second embodiment of the present invention, and the same parts as in the first embodiment are designated by the same reference numerals and the explanation thereof will be omitted.

In this second embodiment, a flexible seal 23 is joined to the lower surface side of the upper partition plate 16, and a notch 2 is provided in the partition plate support plate 24 so as not to come into contact with the flexible seal 23.
5 was established. By attaching the flexible seal 23 to the lower surface side of the upper bulkhead plate 16 in this manner, the margin against buckling of the flexible seal 23 caused by the differential pressure between the high temperature plenum 6 and the intermediate plenum 8 is improved, and the flexibility is increased. This has the effect of reducing the thickness of the flexible seal 23.

FIG. 4 shows a third embodiment of the invention. Similar to the second embodiment, the same parts as in FIG. 2 are denoted by the same reference numerals, and the explanation thereof will be omitted.

In this third embodiment, the portion where the flexible seal 23 is joined to the upper partition plate 16 is connected upward to a protrusion 26, and the flexible seal 23 is attached to the protrusion 26. According to this embodiment, since the flexible seal 32 can be made small, the flexible seal 23 can be manufactured easily.

(Effects of the Invention) As described above, according to the tank-type fast breeder reactor according to the present invention, the partition plate inside the reactor vessel is divided into an annular shape in the circumferential direction, and flexible The seal is joined and the partition plate is supported by a partition plate support plate. Therefore, the reliability of the partition plate against thermal stress can be improved without impairing the sealing performance between the high-temperature plenum and the low-humidity plenum. Further, there is an effect that the process of bending the partition plate becomes unnecessary, making manufacturing and assembly easier, and that the space occupied by the partition plate can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a first embodiment of a tank-type nuclear reactor according to the present invention, FIG. 2 is a partial sectional view showing an enlarged main part of FIG. 1, and FIGS. 3 and 4 are FIG. 5 is a sectional view showing only the essential parts of the second and third embodiments of the present invention, and FIG. 5 is a sectional view not showing a conventional tank type nuclear reactor. 1...Reactor vessel, 2...Reactor core, 4.5.16...
- Partition plate, 6... High temperature plenum, 7... Low humidity plenum, 8... Intermediate plenum, 23... Flexible seal, 24... Partition plate support plate. Representative Patent Attorney Noriyuki Chika (and 1 other person) Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] A pair of upper and lower bulkhead plates are installed in a reactor vessel that encloses the reactor core and is sealed with a roof slab, and the inside of the reactor vessel is divided into a high temperature plenum, a low humidity plenum, and an intermediate plenum, and the upper bulkhead plate is It is divided into multiple annular parts along the circumferential direction between the reactor vessel and the core barrel, and these divided parts are joined by flexible seals, and a bulkhead plate support is installed at the bottom of the flexible seals. A tank-type fast breeder reactor characterized by being provided with a plate.