JPS62177493A - 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 in which propeller blades for primary sodium circulation are installed in an intermediate heat exchanger.

[Technical overview of invention]

Tank-type fast breeder reactors generally use liquid total flex sodium as the primary and secondary coolant, and the primary sodium heated in the reactor core is introduced into an intermediate heat exchanger placed in the reactor vessel to convert it into secondary sodium. After heat exchange, the cooled primary sodium is sent back to the reactor core.

FIG. 6 shows a schematic configuration of a conventional tank-type fast breeder reactor. The inside of a reactor vessel 1 containing primary sodium is partitioned into an upper plenum 3 and a lower plenum 4 by a partition wall 2. A reactor core section 8 consisting of a reactor core assembly 1 5, a blanket combustion assembly 6 J5, and a reflector 7 is installed in the central part.

Four core upper mechanisms 10 are installed in the center of a roof slab 9 that closes off the upper end of the reactor vessel 1, and
A plurality of intermediate heat exchangers 11, a plurality of circulation pumps 12, etc. are installed independently around the intermediate heat exchanger 11, respectively.

13 indicates a motor that drives the circulation pump 12, and
The discharge side of the circulation pump 12 is connected to a high pressure plenum 15 via an inlet pipe 14 .

The intermediate heat exchanger 11 includes a shroud 20, a secondary sl-lium inlet pipe 21 and a secondary sodium outlet pipe 22 coaxially arranged in the center thereof, and a secondary sl-lium inlet pipe 21 and a secondary sodium outlet pipe 22 arranged coaxially in the center thereof. -Multiple heat transfer tubes 2 inserted between the liumium outlet pipe 22 and the shroud 20
3, and a lower tube sheet 24 and a lower tube sheet 25 that support these heat exchanger tubes 23.

Further, the shroud 20 is provided with a through hole 26 for sucking in primary sodium, and the outlet pipe 22 is provided with a through hole 27 for allowing secondary sodium to enter and leave the outside of the heat transfer tube 23.
28 are provided. Two show no primary 1-lium outlet.

In the tank-type fast breeder reactor configured as described above, primary sodium in the upper plenum 3 (flows into the shura rad 20 through the through holes 26, flows from the upper tube sheet 24 through the heat transfer tubes 23, and flows through the lower tube sheet 25 J'i and primary sodium flows into the lower plenum 4 through Taguchi 29.

The primary sodium in the lower plenum 4 is fed into the inlet pipe 14 by a circulation pump 12 driven by a motor 13, and is sent to the core fuel assembly 5 through the high-pressure plenum 15.
The area near the plankera 1 to the fuel assembly 6 is placed in the soil and heated.

The primary sodium thus heated collides with the lower end of the core upper mechanism 10, changes its flow in a radial direction, and flows into the intermediate heat exchanger 11 through the through holes 26 again.

On the other hand, secondary sodium flows through the inlet pipe 21 in the outlet pipe 22 toward the lower tube plate, flows between the outlet pipe 22 and the shroud 20 through the through hole 27 provided near the lower end of the outlet pipe, and flows into the heat exchanger tube 23. After flowing outside the lithium and exchanging heat with the primary 1-lium, it flows through the through hole 28 into the outlet pipe 22 and is led to a secondary heat exchanger (not shown), where it radiates heat. It is pressurized by a secondary pump (not shown) and sent into the inlet pipe 21 again.

[Problems with front shoulder 1 technology] In the tank-type fast breeder reactor configured as described above,
Since a plurality of medium IFU heat exchangers 11 and a plurality of circulation pumps 12 are arranged in the upper blemish 3, the primary sodium flow path is 'Fj, HE. Especially the circulation pump 12
There is no suction part around the plenum, and the temperature distribution due to stagnation of the coolant causes excessive static thermal stress on the shroud wall of the intermediate heat exchanger 1, the wall of the furnace vessel 311, etc. in the entire upper plenum. may cause this to occur.

Furthermore, the partition wall 2 includes an intermediate heat exchanger 11 and a circulation pump 12.
However, since the total weight of these intermediate heat exchangers and circulation pumps is considerable, the wall thickness of the partition wall 2 should be 200 to 30 mm in terms of h''+1 structural strength.
0mm is also required.

In addition, the roof slab 9 is provided with holes for passing through the intermediate heat exchanger 11, the core upper mechanism 10, and the circulation pump 12, which improves structural strength 1α and heat shielding efficiency.
The furnace vessel 9 needs to have a thick plate structure.

Also, since the circulation pump 12 is located in the upper plenum 3, the motor 13 for driving the pump and its power supply system are not connected. There is an inconvenience that it becomes UM.

[Purpose of the invention]

The present invention was made in order to eliminate the above-mentioned drawbacks of the previous technology.The circulation pump was removed, and a fluid pump and propeller blades were installed in the intermediate heat exchanger to provide the primary heat exchanger. It is designed to circulate sodium.

[Summary of the invention]

The tank-type fast breeder reactor of the present invention is a tank-type fast breeder reactor in which the interior of the reactor vessel is partitioned into an upper plenum and a lower plenum by a partition wall, and an intermediate heat exchanger is installed in the reactor vessel through the partition wall t′1. It is characterized by the provision of propeller blades in the intermediate heat exchanger that feed primary sodium from the upper plenum side to the lower plenum side.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail with reference to FIGS. 1 to 5. In these figures, the same parts as J3 in FIG. 6 are denoted by the same reference numerals, and detailed explanation will be omitted unless necessary.

FIG. 1 shows an embodiment using a fluid pump, in which a pump shaft 30 is arranged in the center of the secondary sodium outlet pipe 22 at a position below the lower end of the secondary sodium inlet pipe 21 inserted therein. ing.

This pump shaft is arranged with its lower half protruding toward the primary sodium outlet 29 side of the shroud 20, and a bearing 3 provided in the secondary sodium outlet pipe 22 is located near the upper end of the pump shaft.
1, and a portion near the middle thereof is rotatably supported by a bearing 32. Note that the bearing 31 is configured to allow secondary 1-lium to flow through, and the bearing 32 is configured to prevent secondary 1-lium from flowing through.
It has a seal configuration.

A pump blade 33 is attached to the pump shaft 30 between bearings 31 and 32, and a propeller blade 35 is attached at a position below the bearing 32 to constitute a fluid pump. 36 indicates a casing.

In the tank-type fast breeder reactor of FIG. 1 constructed as described above, the secondary sodium lithium flowing in from the secondary sodium inlet pipe 21 is pumped as it flows downward in the secondary sodium outlet pipe 22. After applying rotational force to the blade 33, the sodium flows out from the through hole 27 to the outside of the secondary sodium outlet pipe 22,
It rises while exchanging heat with the primary sodium in the heat transfer tube 23, returns to the secondary sodium outlet tube 22 through the through hole 28, and is discharged to the outside of the furnace vessel 1.

On the other hand, the primary sodium is given a downward thrust by the propeller blades 35, so it is sent to the lower plenum 4 side from the primary sodium outlet 29, enters the reactor core 8 from the high-pressure plenum 15, and while rising there, it is sent to the lower plenum 4 side. It absorbs heat, reaches a high temperature, reaches the upper plenum 3, is sucked into the shroud 20 of the intermediate heat exchanger 11 through the through holes 26, and as it flows through the heat transfer tubes 23, it exchanges heat with the secondary sodium outside the tubes. After being cooled, the primary sodium outlet leads to the lower plenum.

Therefore, even if the circulating I pump 12 and the motor 13 described in FIG. 6 are omitted, the primary sodium can be circulated by the fluid pump built into the intermediate heat exchanger.

FIG. 2 shows an embodiment in which the high-pressure plenum 15 and two primary sodium outlets are connected by an inlet pipe 40, and the other configurations are the same as in FIG. 1. In this embodiment, high pressure on the discharge side of the fluid pump can be prevented from being applied to the partition wall 2.

In FIG. 3, a mirror plate-shaped lower partition wall 50 is provided below the partition wall 2, which prevents the primary sodium pressure on the lower plenum 4 side caused by the fluid pump from acting on the partition wall 2.
The thickness of the partition wall 2 can be reduced.

In FIG. 4, the propeller blades 35 are rotated by a drive motor 60 instead of a fluid pump driven by secondary sodium. The pump shaft 61 airtightly seals the seal member 62 fixed to the furnace vessel 1.
A propeller blade 35 is attached near the upper end of the casing 36 of the primary sodium outlet.

In this embodiment, the lower plenum 4 has plenty of space.
Since the drive motor 60 is arranged below the propeller blade 3 in the intermediate heat exchanger 11, the design is easy.
5 will be easier to place. In addition, maintainability is also improved if the dimensions of the seal plate 63 are determined so that the pump shaft 61, propeller blade 35J5, and casing 36 can be handled as one unit. In this embodiment, as in the embodiment described in 1), a pump for circulating primary sodium is incorporated into the intermediate heat exchanger 11, so that improvements in thermal efficiency, compactness, and stability can be achieved. can be achieved.

In each of the above embodiments, the intermediate heat exchanger 11 with a circular cross section was used. However, if the intermediate heat exchanger 11 is shaped like an ellipse as shown in FIG. 5, the space factor can be reduced. It is also possible to make the furnace vessel 1 more compact.

〔Effect of the invention〕

As explained in each of the above embodiments, according to the tank-type fast breeder reactor of the present invention, the circulation pump, which was conventionally installed in the reactor vessel independently of the intermediate heat exchanger, and The drive motor that was installed on the roof slab can be removed, and the number of structures in the upper blennium can be reduced, making it possible to simplify the flow path bus. The stagnation that previously occurred in the reactor is reduced, the temperature in the lower brenum becomes uniform, the occurrence of thermal stress can be prevented, and the thermal efficiency of the entire reactor can be improved.

In addition, by housing the fluid pump or Pro S roller blade that circulates the primary sodium inside the shroud of the intermediate heat exchanger, the required materials can be significantly reduced compared to a conventional circulation pump. As a result, it is possible to reduce the structure of the partition wall (Δ) and its thickness.

Furthermore, since there is no need to provide a hole in the roof slab for passing the drive motor of the circulation pump through, the structural strength of the roof slab can be increased.

In addition, if the primary sl/lium outlet 29 of the intermediate heat exchanger and the high-pressure blennium 15 are not connected by inlet piping as shown in the embodiments shown in Fig. 1, Fig. 3, or Fig. 4, This solves the problem of pipe breakage in other areas, contributing to improved safety.

[Brief explanation of drawings]

1 to 4 are longitudinal cross-sectional views showing an embodiment of the tank-type fast breeder reactor of the present invention, and FIG. 5 conceptually shows an embodiment of the tank-type fast breeder reactor of the present invention. Plan, 6th
The figure does not show a conventional tank-type fast breeder reactor, but is an rlf top view. 1... Furnace vessel 2... Bulkhead 3... Upper Blenheim 4... Lower Blenheim 5... ......Core fuel assembly 6...Blanket fuel assembly 7...
...Reflector 8 ..... Core section 9 ..... Roof slab 10 ..... Core upper mechanism 11 .... ...Intermediate heat exchanger 12...Circulation pump 13...Drive motor 14.40...Inlet piping 15...・High pressure blemish 20...Shroud 21...Secondary sodium inlet pipe 22...
......Secondary sodium outlet pipe 23...
... Heat exchanger tube 24 ... ... Upper tube sheet 25 ... ... Lower tube sheet 26.27.28 ... Through hole 29 ......・Primary sodium outlet 30.61
... Pump shaft 31, 32 ... Bearing 33 ... Pump blade 35 ... Propeller blade 36 ... Casing 50 ... ...... Lower bulkhead 60 ... Drive motor 62 ... Sealing member 63 ... Seal plate agent Patent attorney Rules Written by Hiroshi Mitsumata, Chika Jza, Figure 1, Figure 4, Figure 5

Claims (4)

[Claims] (1) In a tank-type fast breeder reactor in which the interior of the reactor vessel housing the reactor core and primary sodium is partitioned by a partition into an upper plenum and a lower plenum, and an intermediate heat exchanger is installed inside the reactor vessel by penetrating the partition, A tank-type fast breeder reactor characterized by having a propeller blade installed in an intermediate heat exchanger to send primary sodium from the upper plenum side to the lower plenum side. (2) A fluid pump is installed in the secondary sodium inlet pipe, and includes a pump blade that is rotated by the flowing secondary sodium, and a propeller blade that is connected to the pump blade via a pump shaft and provides circulation force to the primary sodium. A tank-type fast breeder reactor according to claim 1, characterized in that the tank-type fast breeder reactor comprises: (3) A tank-type fast breeder reactor according to claim 1, wherein the propeller blades are connected to a drive motor provided on the lower side of the reactor vessel via a pump shaft. (4) A tank-type fast breeder reactor according to any one of claims 1 to 3, wherein the intermediate heat exchanger has an elliptical cross section.