JP2000009887A - Direct contact heat transfer type steam generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a superheated steam superior in steam conditions by facilitating superheating generated saturated steam. SOLUTION: This steam generator 27 is provided with a vessel 29 in which a primary cooling system piping 28, wherein liquid sodium having passed a core and became a high temperature flows, passes from the top to the bottom, a secondary coolant 30 stored in the vessel and heated by the heat of liquid sodium, a water injection nozzle 6 directly injecting water into the secondary coolant 30, a steam generation part 3 generating steam by direct contact heat transfer between the secondary coolant 30 and the water injected from the injection nozzle 6 in it, a superheated steam generation part 31 exchanging heat between the separated steam from the secondary coolant 30 and the primary coolant flowing through the primary cooling system piping 28 and a steam outlet 7 provided at the upper part of the vessel 29. Steam is generated by the direct contact heat transfer between the secondary coolant 30 heated by the primary coolant in the steam generator 34 and water, and this steam or slightly superheated steam is superheated by the high temperature primary coolant flowing in the primary cooling system piping 28 during rising in the space in the superheated steam generator 31 so that superheated steam superior in steam conditions is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a direct contact heat transfer type steam generator. More specifically, the present invention relates to a direct contact heat transfer type steam generator suitable as a steam generator for a fast reactor using liquid sodium as a coolant.

[0002]

2. Description of the Related Art A conventional direct contact heat transfer type steam generator for a fast reactor is disclosed in, for example, JP-A-7-71703. As shown in FIG. 4, the direct contact heat transfer type steam generator includes a low-melting point alloy 103 as a secondary coolant through a pipe 102 for circulating a primary coolant (liquid sodium) in a lower half portion of a container 101. Is provided, and a water injection member 105 is provided above the low-melting-point alloy heat exchanging section 104 to inject water directly into the molten low-melting-point alloy 103. The water directly injected into the low melting point alloy 103 becomes steam in the steam generator 106 and is taken out from the steam outlet 108 through the steam space 107. The pipe 102 for circulating the primary coolant is disposed below the water injection member 105, and the low melting point alloy 103 rises inside the inner cylinder 109, and then moves to the inner cylinder 109.
Circulates down the outside of the tree. In such a direct contact heat transfer type steam generator, a secondary cooling system using liquid sodium, an intermediate heat exchanger, and the like are not required, so that the heat transport system of the power plant can be made compact, and the liquid sodium and water are separated. Since the contact is difficult, the construction cost of the fast reactor including such countermeasure equipment can be reduced.

[0003]

However, in the above-mentioned direct contact heat transfer type steam generator, after the low melting point alloy 103 is heated in the low melting point alloy heat exchange section 104, it flows together while changing water into steam. As the temperature rises, the temperature of the low melting point alloy 103 decreases as the temperature rises. For this reason, although it has excellent ability in the process of directly injecting water into the low melting point alloy 103 and generating saturated steam by liquid-liquid direct contact heat transfer, it is difficult to superheat the generated saturated steam, It was not suitable for obtaining superheated steam having excellent conditions.

An object of the present invention is to provide a direct contact heat transfer type steam generator suitable for obtaining superheated steam having excellent steam conditions.

[0005]

In order to achieve the above object, a direct contact heat transfer type steam generator according to the present invention is characterized in that a primary cooling system pipe through which a high temperature liquid sodium flows through a reactor core is arranged upward. , A secondary coolant that is stored in the container and heated by the heat of liquid sodium, a water injection member that directly injects water into the secondary coolant, and a secondary cooling device. A steam generating section that generates steam by direct contact heat transfer between the material and water directly injected from a water injection member therein, and a steam generated from the secondary coolant and the primary coolant flowing in the primary cooling system piping. A superheated steam generation section for exchanging heat between the superheated steams to generate superheated steam, and a steam outlet provided at an upper portion of the container are provided.

[0006] Therefore, liquid sodium, which is a primary coolant that has passed through the reactor core and has become high temperature, flows through the primary cooling system piping to heat the secondary coolant in the vessel by indirect heat exchange. In the steam generating section, the heated secondary coolant causes water directly injected into the secondary coolant to boil and evaporate by direct contact heat transfer. The generated saturated steam or slightly overheated steam rises in the space of the superheated steam generating section. The primary cooling system pipe passes through this superheated steam generation part from the top to the bottom, and the saturated steam released from the liquid surface of the secondary coolant or the slightly superheated steam rises around the primary cooling system pipe. While being superheated by the heat of the liquid sodium, it is taken out from the steam outlet as superheated steam. The primary cooling system piping is passed from top to bottom, and liquid sodium flows from top to bottom, so the generated steam is superheated by the hotter liquid sodium as the space in the superheated steam generator rises Is done.

In a direct contact heat transfer type steam generator according to a second aspect of the present invention, the primary cooling system pipe is a double pipe, liquid sodium flows through the inner pipe, and a secondary pipe is provided between the inner pipe and the outer pipe. This is for filling the coolant.

Accordingly, the heat of the liquid sodium flowing in the inner pipe of the double pipe is transmitted through the secondary coolant filled between the inner pipe and the outer pipe, and superheats the steam rising in the superheated steam generating section,
Further, the secondary coolant stored in the container is heated. The primary cooling system pipe is a double pipe, and does not come into contact with steam (water) rising outside the outer pipe even if liquid sodium flowing in the inner pipe leaks.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail based on the best mode shown in the drawings.

FIG. 1 shows an example of an embodiment of a direct contact heat transfer type steam generator to which the present invention is applied. FIG. 2 shows a direct contact heat transfer type steam generator to which the present invention is applied in a power plant of a fast breeder reactor. An example of a heat transport system when incorporated is shown. Direct contact heat transfer type steam generator (hereinafter simply referred to as steam generator)
Reference numeral 27 denotes a container 29 through which a primary cooling system pipe 28 through which liquid sodium, which is a high-temperature primary coolant having passed through the reactor core 16 flows, passes from above to below, and a primary cooling system stored in the container 29. A secondary coolant 30 that is warmed by the heat of the liquid sodium passing through the pipe 28, a water injection nozzle 6 that is a water injection member that directly injects water into the secondary coolant 30, a secondary coolant 30, Water injection nozzle 6 inside
Between the steam released from the secondary coolant 30 and the high-temperature liquid sodium flowing through the primary cooling system pipe 28, and a steam generator 34 that generates steam by direct contact heat transfer with water directly injected from the water. A superheated steam generator 31 for exchanging and generating superheated steam, and a steam outlet 7 provided at an upper portion of the container 29, wherein the secondary coolant 30 heated by the primary coolant in the steam generator 34 and water directly The steam is generated by the contact heat transfer, and the steam or the slightly superheated steam is superheated by the high-temperature primary coolant flowing through the primary cooling system piping 28 while ascending the space of the superheated steam generator 31.

The steam generator 27 is a so-called shell and tube type steam generator in which a number of primary cooling system pipes 28 pass through a vessel 29. Primary cooling system piping 28
Is a double pipe, in which liquid sodium flows through each inner pipe 2 and a secondary coolant 30 is provided between each inner pipe 2 and each outer pipe 4.
Is filled. The upper end of each inner pipe 2 is connected to the inlet header 1 connected to the main pipe 32 of the primary cooling system,
It is supported by a tube sheet 13. The upper end of each outer tube 4 is fixed to and supported by a tube sheet 14.

An inert gas is sealed between the inner pipe 2 and the outer pipe 4 of each primary cooling system pipe 28 and between the respective tube plates 13 and 14. By adjusting the gas pressure, the superheated steam is A liquid column 33 of the secondary coolant 30 is formed between the inner pipe 2 and the outer pipe 4 in a range corresponding to the generating section 31, whereby the inner pipe 2 and the outer pipe 4 are formed.
Is filled with the secondary coolant 30. Further, a detection port 12 is formed between each of the tube plates 13 and 14, and a gas component between each of the tube plates 13 and 14, such as moisture and a hydrogen component, is monitored through the detection port 12. , The damage of the outer tube 12 is detected.

The lower end of each primary cooling system pipe 28 is bent to be substantially horizontal, and the lower end of each outer pipe 4 is connected to the overflow weir 1.
5, each inner pipe 2 is opened in the descending flow path 10 outside.
Is connected to the outlet header 3 outside the container 29. A large number of fins 32 are provided on the outer peripheral surface of each outer tube 4 for promoting heat exchange with steam in the superheated steam generator 31.

The secondary coolant 30 is a low-melting alloy which is cooled by the liquid sodium (primary coolant) heated to a high temperature after cooling the core 16 and does not react violently with sodium or water, for example, a lead-bismuth alloy The use of is preferred. However, the invention is not limited to the lead-bismuth alloy, but may be, for example, mercury or another inert low melting point alloy. Secondary coolant 30 warmed by liquid sodium
Is stored to a height at which the overflow weir 15 is immersed, and this portion is a secondary coolant reservoir 11.

The water injection nozzle 6 is provided below the primary cooling system pipe 28. Water is supplied to the water injection nozzle 6 from the water supply pipe 5. Water heated to, for example, about 200 ° C. under high pressure by a feed water heater 22 is supplied to the feed water pipe 5, and the water is immediately boiled by direct heat transfer from the secondary coolant 30.

The liquid sodium heated to a high temperature by cooling the reactor core 16 is supplied from the main pipe 35 of the primary cooling system to the inlet header 1.
And distributed to the inner pipe 2 of each primary cooling system pipe 28.
The liquid sodium flowing into each of the inner tubes 2 first superheats the steam by a shell and tube type heat exchange system while passing through the superheated steam generator 31, and then passes through the secondary coolant reservoir 11. The secondary coolant 30 is heated by a shell and tube type heat exchange system. The liquid sodium which has become low in temperature thereby is guided to the outlet header 3 outside the container 29 through the overflow weir 15.
Then, at the outlet header 3, the low-temperature liquid sodium flowing through each inner pipe 2 of each primary cooling system pipe 28 joins, is pumped by the primary main circulation pump 17, and is circulated to the core 16.

The water supplied from the water supply pipe 5 is directly injected from the water injection nozzle 6 into the molten secondary coolant 30. Since a large number of nozzle holes are formed in the water injection nozzle 6, water is evenly injected into the inside of the overflow weir 15 of the secondary coolant reservoir 11. The injected water is heated by the liquid / liquid direct contact heat transfer in the secondary coolant 30, rises while evaporating, and is saturated steam or slightly overheated before reaching the liquid level of the secondary coolant 30. Turns into steam. Here, in the region where the water and the secondary coolant 30 are in direct contact heat transfer, the steam generator 3
4 are configured. The water injection nozzle 6 is located at the overflow weir 15
Of water in the primary cooling system pipes 28
Since the lower end of the outer pipe 4 is opened outside the overflow weir 15, water (steam) does not enter between each outer pipe 4 and the inner pipe 2, and liquid sodium and water (steam) Tube wall 1 of tube 2
It does not exist between the sheets. For this reason, it has a structure in which contact between sodium and water is extremely unlikely to occur.

The steam generator 3 in the secondary coolant reservoir 11
The saturated steam or slightly overheated steam generated in 4 rises around each primary cooling system pipe 28 of the superheated steam generation unit 31. At this time, the steam is supplied to the inner pipe 2 of each primary cooling system pipe 28.
The liquid sodium is heated by the heat of the liquid sodium flowing inside, and is taken out from the steam outlet 7 as superheated steam. Since the liquid column 33 of the secondary coolant 30 exists between the inner pipe 2 and the outer pipe 4 of each primary cooling system pipe 28, the heat of the liquid sodium is transmitted to the outer pipe 4 well. Further, since the liquid sodium flows downward from above, the higher the vapor is, the more the liquid sodium is heated by the high temperature liquid sodium.
Therefore, superheated steam having excellent steam conditions can be obtained.

The superheated steam taken out from the steam outlet 7 is
After being guided by the turbine 24 of the power generator 26 to generate power, the water is returned to water by the condenser 25, pumped by the water supply pump 23, and circulated again to the steam generator 27.

The secondary coolant 30 receives heat from the liquid sodium and gives heat to the water injected by the water injection nozzle 6. The secondary coolant 30 in the secondary coolant reservoir 11 has a reduced apparent density due to vapor bubbles generated by evaporation of water, and generates buoyancy. Therefore, the secondary coolant 3
At 0, a natural circulation flow is generated that rises inside the overflow weir 15 and descends outside. Since the liquid sodium flows from the inside of the overflow weir 15 downward from above, the secondary coolant 30 inside the overflow weir 15 becomes hotter upward.

That is, the water injected into the steam generating section 34 of the secondary coolant reservoir 11 is heated by the secondary coolant 30 having a higher temperature as it rises as steam in the secondary coolant 30 and is further heated. The higher the temperature of the steam generator 31 is, the higher the temperature of the liquid sodium is. As described above, since the temperature in the vicinity of the steam outlet 7 can be set to the highest temperature, very good heat exchange performance can be obtained for the steam generator 27 as a whole. That is, the heat exchange part is a counter-flow type heat exchange system, and the heat exchange efficiency is improved.

The steam generator 27 uses a liquid metal lead / bismuth alloy as the secondary coolant 30 and employs a good heat exchange method of liquid / liquid direct contact heat transfer between water and liquid metal.
The size of the equipment is made compact.

The location where the liquid sodium as the primary coolant heats the secondary coolant 30 and the location where the secondary coolant 30
Is the same as where water is heated by liquid-liquid direct contact heat transfer. Therefore, the heat exchange height required to generate saturated steam can be reduced.

Further, the primary cooling system pipe 28 has a double pipe structure, so that even if liquid sodium in the inner pipe 2 leaks, it does not come into contact with steam (water) flowing outside the outer pipe 4. , So that the contact between sodium and water hardly occurs. An inert gas is filled between the inner tube 2 and the outer tube 4 and between the tube plates 13 and 14, and the inert gas is monitored through a detection port 12 by a moisture or hydrogen component detector or the like. By doing so, breakage of the outer tube 4 can be detected.

By using this steam generator 27, as shown in FIG. 2, the heat transport system of the power plant of the fast breeder reactor can be greatly rationalized. For comparison, FIG. 3 shows the same heat transport system when the steam generator 27 is not used. In the case of FIG. 3, the intermediate heat exchanger 18, the evaporator 21, and the superheater 20, which were necessary in the case of FIG. 3, can be combined into one and replaced with the steam generator 27, and the secondary main circulation pump 19 is omitted. And can greatly streamline the heat transport system. In addition, the evaporator 21 and the superheater 20 have a structure in which liquid sodium and water (steam) flow through one tube wall, but these can be made unnecessary, so that safety against the reaction of liquid sodium and water is obtained. Can be further increased.

The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the gist of the present invention.

[0027]

As described above, in the direct contact heat transfer type steam generator according to the first aspect, the primary cooling system pipe through which the high temperature liquid sodium flows through the core passes from the top to the bottom. Container, a secondary coolant that is stored in the container and heated by the heat of liquid sodium, a water injection member that directly injects water into the secondary coolant, and a secondary coolant and water is injected therein. Superheated by exchanging heat between the steam generator that generates steam by direct contact heat transfer with water injected directly from the member and the steam separated from the secondary coolant and the primary coolant flowing in the primary cooling system piping As it has a superheated steam generator that generates steam and a steam outlet provided at the top of the vessel, it can be used as a direct contact heat transfer type steam generator that can make the heat transfer system of the power plant of the fast breeder reactor compact. , Steam It is possible to obtain an excellent superheated steam conditions.

Further, in the direct contact heat transfer type steam generator according to the second aspect, the primary cooling system pipe is a double pipe, liquid sodium flows through the inner pipe, and a secondary pipe is provided between the inner pipe and the outer pipe. Since the coolant is filled, even if the liquid sodium in the inner tube leaks, it does not come into contact with the steam flowing outside the outer tube, so that the reaction between sodium and water can be prevented. Further, since the secondary coolant filled between the inner pipe and the outer pipe transfers the heat of the liquid sodium to the outer pipe, deterioration of the heat transfer performance can be prevented even if the primary cooling system pipe is a double pipe. .

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of an embodiment of a direct contact heat transfer type steam generator of the present invention.

FIG. 2 is a schematic configuration diagram of a heat transfer system of a power plant of a fast breeder reactor using the direct contact heat transfer type steam generator of the present invention.

FIG. 3 is a schematic configuration diagram of a heat transfer system of a power plant of a fast breeder reactor when a direct contact heat transfer type steam generator is not used.

FIG. 4 is a schematic configuration diagram of a conventional direct contact heat transfer type steam generator.

[Explanation of symbols]

 2 Inner pipe 4 Outer pipe 6 Water injection nozzle (water injection member) 7 Steam outlet 16 Reactor core 27 Direct contact heat transfer type steam generator 28 Primary cooling system piping 29 Vessel 30 Secondary coolant 31 Superheated steam generator 34 Steam generator

Claims (2)

[Claims] 1. A container through which a primary cooling system pipe through which a high temperature of liquid sodium flows through a reactor core passes from above to below, and a container which is stored in the container and is heated by the heat of the liquid sodium. Secondary coolant, a water injection member for directly injecting water into the secondary coolant, and steam generated by direct contact heat transfer between the secondary coolant and water directly injected from the water injection member therein. A steam generating unit that generates heat by exchanging heat between the steam separated from the secondary coolant and the primary coolant flowing through the primary cooling system piping, and a superheated steam generating unit that generates superheated steam. A direct contact heat transfer type steam generator comprising a steam outlet provided at an upper portion. 2. The method according to claim 1, wherein the primary cooling system pipe is a double pipe, the liquid sodium flows through the inner pipe, and the secondary coolant is filled between the inner pipe and the outer pipe. Item 6. A direct contact heat transfer type steam generator according to item 1.