JPS61225501A - Steam generator - 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 steam generator for a fast breeder reactor.

[Technology of invention 1? il Conventionally, this type of steam generator has a heat exchanger tube 2 raised up inside an ll1i1 whose both ends are closed, as schematically shown in FIG. At the same time, the upper end of the heat transfer tube 2 is connected to the water/steam outlet header 4 opened at the upper end of the shell 1, and the sodium inlet nozzle 5 is connected to the top 1a of the Ml. A sodium outlet main pipe 6 is connected to the lower end 1b of the body 1. The sodium flows into the interior of the tube 111 from the inlet nozzle 5 and flows out from the outlet nozzle 6 at the bottom, and while the sodium passes through the shell 1, it exchanges heat with water and steam in the heat transfer tube 2. is held on Wednesday.
Steam is taken out from the steam outlet header 4.

In addition, in general, sodium-based equipment, as shown schematically in Fig. 3, sodium flowing out of the steam generator 7 is sent in the direction of the arrow to an intermediate heat exchanger 9 by a circulation pump 8 for heat exchange. is also returned to the steam generator 7. Sodium, which is a coolant, is purified by a purification unit 10 attached to the outlet of the steam generator 7.

[Problems with the Background Art] As shown in FIG. 3, in the conventional fast breeder reactor, a purification unit 10 is installed outside the steam generator 7, which increases the amount of piping and This requires a large space for installation, contributing to the increased cost of fast breeder reactors.

[Object of the Invention] The present invention has been made in view of the above points, and in order to reduce the need for auxiliary sodium system piping and storage in the secondary cooling system, a purification unit is provided in the shell of the steam generator, and a fast breeder reactor is equipped with a purification unit. An object of the present invention is to provide a steam generator that can reduce costs.

[Summary of the Invention] The present invention provides an inlet and an outlet for sodium as a heat exchange fluid at the top of the steam generator, closes the lower end of the barrel, and connects the upper end of the return pipe with its lower end open inside the barrel. It is connected to the above sodium outlet so that the sodium that enters the cylinder from the top inlet and has completed heat exchange rises in the return pipe and is discharged from the top outlet, and a purification unit is installed at the top outlet. This is a steam generator characterized by being installed.

[Embodiments of the Invention] Hereinafter, a steam generator according to the present invention will be described with reference to FIG. Note that the same parts in FIG. 1 as in FIG. 2 are designated by the same reference numerals.

FIG. 1 is a cross section W1 schematically showing an embodiment of the present invention. That is, in FIG. 1, heat exchanger tubes 2 are placed inside the shell 1
The lower end of the tube bundle of heat transfer tubes is connected to the water/steam inlet header 3 connected to the lower end of the shell 1, and the tube bundle of heat transfer tubes 2 is connected to the water/steam outlet header 4 connected to the upper end of the shell 1. In the structure in which the sodium inlet and outlet nozzles 5 are installed at the top of the shell 1, the upper end of a sodium return pipe 11 arranged parallel to the axis of the shell 1 is connected to the sodium outlet nozzle 6. The sodium inlet nozzle holder 5 is positioned so that sodium flows downward between the inner surface of the shell 1 and the outer surface of the sodium return pipe 11, and a lower plenum 1 is provided at the lower end of the shell 1.
2 is installed, and the sodium descending in W41 is reversed in the lower plenum 12 and rises in the return pipe 11 to reach the outlet nozzle 6.
Make sure to reach the following. A sodium inlet pipe is connected to the sodium inlet nozzle 5, and a sodium outlet pipe is connected to the sodium outlet nozzle 6. Note that the reference numeral 13 is a skirt that supports the torso 1. Sodium outlet nozzle 6
A purification unit 14 is inserted inside the tank to purify the coolant.

With the above configuration, when water and steam are allowed to flow in through the water and steam inlet header 3, and sodium is allowed to flow into the shell 1 from the top through the sodium inlet pipe and the sodium inlet nozzle stub 5, the sodium flows into the heat transfer-2. It descends while exchanging heat with the rising water and steam.

The water/steam that has exchanged heat with the sodium is heated and turned into steam, which is taken out from the outlet header 4'. On the other hand, the sodium that has descended after completing heat exchange with water and steam is reversed in the lower plenum 12 and enters the return pipe 11.
After being partially purified in the purification unit 14, the sodium flows out from the sodium outlet nozzle 6.

Therefore, not only does the piping connecting the purification unit 14 become unnecessary, but also impurities that permeate through the steam generator heat exchanger tubes are quickly purified.

Note that the purification unit 14 in the steam generator in the present invention
Since the method removes oxygen and hydrogen compounds by cooling sodium and taking advantage of the difference in solubility,
It is efficient to install it in the low temperature part of -.

Furthermore, since the purification unit 14 needs to be replaced periodically due to the capture of impurities, it is necessary to provide it in a location that is easy to maintain.

Therefore, it is desirable to provide the purification unit 14 in the sodium outlet tube stub 6 of the center return type steam generator.

When installing the purification unit 14 in the part of the thorium outlet tube stand 6, the end plate of the top part 1a of i11 is made slightly larger, the diameter of the sodium outlet tube stand 6 is increased, and the upper part is made into a seven-lunge structure. It is desirable to install the purification unit 14 at the same time.゛Also, the purification unit 14
The structure includes a mesh that precipitates hydrogen compounds and oxides that penetrate through the i-thermal tube 2 of the steam generator by cooling the sodium, and the hydrogen compounds and oxides are deposited in this mesh. It is designed to attach and remove.

Furthermore, by using low alloy steel with a relatively low chromium content, such as 90r-1 MO steel, as the material for the steam generator, the amount of permeation of hydrogen is small, so that the purification unit 14 can be effectively made compact.

[Effects of the Invention] As described above, according to the steam generator of the present invention, the return pipe through which the heated fluid rises is located in the space in the center of the body, and the inlet nozzle and outlet nozzle of the heated fluid are are all installed in the upper part of the cylinder, and after the heating fluid that entered the cylinder through the heating fluid inlet nozzle descends, it reverses and ascends in the return pipe, and when it flows out from the heating fluid outlet nozzle, it passes through the purification unit. Since the system is purified, the piping that conventionally connected each device is removed, reducing the installation space. At the same time, it is possible to reduce costs.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view diagrammatically showing an embodiment of a steam generator according to the present invention, FIG. 2 is a longitudinal sectional view schematically showing a conventional steam generator, and FIG. 3 is a longitudinal sectional view schematically showing a conventional steam generator. FIG. 2 is a system diagram showing an example of how a generator is used. １・・・・・・・・・・・・Torso

Claims (1)

[Claims] (1) Arrange a heat transfer tube inside the shell, connect the lower end of the heat transfer tube to the water/steam inlet header at the lower end of the shell, and connect the upper end of the heat transfer tube to the water/steam outlet header at the upper end of the shell. In a steam generator, an inlet and an outlet for the heat exchange fluid are installed at the top of the shell, and the upper end is connected to the heat exchange fluid outlet, and the lower end is connected to the heat exchange fluid outlet. 1. A steam generator characterized in that a return pipe opening inward is provided in the body, and a purification unit is installed in the upper end fluid outlet pipe.