WO2022111428A1

WO2022111428A1 - Heat-pipe heat exchanger, and mounting method therefor

Info

Publication number: WO2022111428A1
Application number: PCT/CN2021/132229
Authority: WO
Inventors: 邢继; 李海涛; 刘天斌; 和丹; 王晓和; 赵英昆; 刘迎; 陈科; 徐岚
Original assignee: 中国核电工程有限公司
Priority date: 2020-11-27
Filing date: 2021-11-23
Publication date: 2022-06-02
Also published as: CN112611247A

Abstract

Provided are a heat-pipe heat exchanger and a mounting method therefor. The heat-pipe heat exchanger is used for passive after-heat removal of a spent fuel pool and comprises: an evaporation section (1) configured to absorb heat from a spent fuel pool (6) to evaporate a working medium; a collection section (8) connected to one end of the evaporation section (1); a connecting pipe (2), with one end of the connecting pipe (2) being connected to the collection section (8); and a condensation section (4), the condensation section (4) being configured to condense the evaporated working medium, with one end of the condensation section (4) being connected to the other end of the connecting pipe (2), and the other end of the condensation section (4) being connected to the evaporation section (1) by means of a return pipe (5).

Description

Heat pipe heat exchanger and installation method thereof

This application claims the priority of the Chinese patent application filed on November 27, 2020, entitled "A Passive Waste Heat Extraction Heat Pipe Heat Exchanger for Spent Fuel Pool" and the application number is 202011353252.4.

technical field

The invention relates to the technical field of passive safety equipment in nuclear power plants, in particular to a heat pipe heat exchanger used for passive waste heat extraction in spent fuel pools and an installation method thereof.

Background technique

At present, the heat transfer from the spent fuel pool of the nuclear power plant is realized by pumping the water in the spent fuel pool through the shell-and-tube heat exchanger to transfer the heat to the chilled water system. After the Fukushima nuclear accident in Japan in 2011, higher requirements have been placed on the inherent safety performance of nuclear reactor systems.

Heat pipe heat exchangers have the advantages of high heat transfer efficiency, small pressure loss, stable and reliable operation, compact structure and effective isolation of primary and secondary fluids, and have been widely used in many industrial fields.

The core component of the heat pipe heat exchanger is the heat pipe. The heat pipe is a typical passive heat exchange element. The heat transfer mainly depends ^on the vapor and liquid phase of the working medium. /(m·℃) order, while the thermal conductivity of copper, silver and other materials can only reach the order of 10 ² W/(m·℃).

SUMMARY OF THE INVENTION

There is a need to replace the currently used forced heat exchangers circulating by pumps with heat exchangers with higher safety performance. However, many problems are faced when replacing the current forced heat exchangers with heat pipe heat exchangers for passive waste heat transfer in spent fuel pools.

The purpose of the present invention is to provide a heat pipe heat exchanger that can solve these problems and an installation method thereof, so that the heat pipe heat exchanger can export the waste heat of the spent fuel pool under normal operation and accident conditions of the spent fuel pool.

For achieving the above object, the technical scheme adopted in the present invention is as follows:

A heat pipe heat exchanger, the heat pipe heat exchanger comprises: an evaporation section configured to absorb heat from a spent fuel pool to evaporate a working medium; a collection section, the connection between the collection section and the evaporation section is One end is connected; a connecting pipe, one end of the connecting pipe is connected with the collecting section; and a condensing section, the condensing section is configured to condense the evaporated working medium, one end of the condensing section is connected with the other end of the connecting pipe connected, and the other end of the condensation section is connected to the evaporation section through a return pipe.

In some embodiments, the return pipe may be connected to the evaporation section through the collection section.

In some embodiments, the diameter of the connecting pipe may be larger than the diameter of the return pipe.

In some embodiments, the evaporation section may be mounted on the outer surface of the pool wall of the spent fuel pool.

In some embodiments, the evaporation section may be integral with the pool wall of the spent fuel pool.

In some embodiments, the evaporation section may be disposed on a grid within the spent fuel pool.

In some embodiments, the evaporation section may be integral with the lattice within the spent fuel pool.

In some embodiments, the evaporation section can be designed with a modular structure.

In some embodiments, the connecting pipe and the return pipe may be arranged in the same pipe.

In some embodiments, the exterior of the condensation section may be provided with fins.

In some embodiments, a porous body may be provided in the return pipe.

In some embodiments, the collecting section can also be used as a distributor, so that the condensed medium in the return pipe is evenly distributed into each heat pipe through the distributor.

In some embodiments, a method of installing a heat pipe heat exchanger, comprising the steps of: providing an evaporation section to absorb heat from a spent fuel pool; providing a collection section and connecting one end of the evaporation section to the collection section; One end of the connecting pipe is connected to the collecting section; and one end of the condensing section is connected to the other end of the connecting pipe, and the other end of the condensing section is connected to the evaporation section through a return pipe.

Description of drawings

FIG. 1 is a schematic diagram of the basic operating principle of a heat pipe heat exchanger used for passive waste heat transfer in a spent fuel pool according to an embodiment of the present invention.

FIG. 2 is a schematic perspective view of a heat pipe heat exchanger used for passive waste heat transfer in a spent fuel pool according to an embodiment of the present invention.

In the picture:

1-evaporating section, 2-connecting pipe, 3-building, 4-condensing section, 5-return pipe, 6-spent fuel pool, 7-grid, 8-collecting section.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

Referring to FIG. 1 , the figure schematically shows the basic operation principle of a heat pipe heat exchanger used for passive waste heat transfer in a spent fuel pool; the heat pipe heat exchanger includes a heat exchanger body, and the heat exchanger body includes Evaporation section 1, connecting pipe 2, condensation section 4 and return pipe 5. The evaporation section 1 is arranged in the spent fuel pool 6 . One end of the evaporation section 1 is connected with the connecting pipe 2 . The connecting pipe 2 is connected to one end of the condensation section 4 through the building 3 , and the other end of the condensation section 4 is connected to the other end of the evaporation section 1 through the return pipe 5 . The evaporation section 1 has the function of absorbing heat from the spent fuel pool 6 to evaporate the working medium to generate steam. The vapor generated in the evaporation section 1 is sent to the condensation section 4 through the connecting pipe 2 . The condensation section 4 has the function of condensing the vapor of the working medium. The liquefied working medium is sent to the evaporation section 1 through the return pipe 5 . In some embodiments, a medium with high vapor pressure and high latent heat of vaporization may be used as the working medium. For example, ammonia, water, chlorofluorocarbons, alcohols, acetone, etc. can be used as the working medium.

During operation, the evaporation section 1 absorbs heat in the spent fuel pool to evaporate the working medium in the evaporation section 1 to generate steam, and the produced steam overcomes the pipeline resistance and/or gravity and moves along the connecting pipe 2 to reach the outdoor condensation. Section 4, and then exchange heat with air and condense, and the condensed medium (such as water and other fluids) flows back to the evaporation section 1 through the return pipe 5 under the action of gravity or capillary force, and circulates the waste heat of the spent fuel pool 6 to the outside of the building. The water in the spent fuel pool 6 meets the system requirements and ensures the safety of the spent fuel pool 6 .

Referring to FIG. 2 , this figure shows an embodiment of the heat pipe heat exchanger for passive waste heat transfer of spent fuel pools of the present invention. The heat pipe heat exchanger includes an evaporation section 1 , a collecting section 8 , a connecting pipe 2 , a condensation section 4 and a return pipe 5 .

As shown in FIG. 2 , the evaporation section 1 may be arranged in the spent fuel pool 6 . In some embodiments, the evaporation section 1 may also be arranged on the outer surface of the pool wall of the spent fuel pool 6 . One end of the evaporation section 1 is connected to the collecting section 8 . One end of the connecting pipe 2 is connected to the collecting section 8 , so that the medium evaporated in the evaporation section 1 is collected to the connecting pipe 2 through the collecting section 8 during operation. In the present invention, by using the collecting section 8, the number and volume of pipelines are reduced, and the integration degree of the system is improved, thereby ensuring that the heat pipe heat exchanger does not interfere with other devices.

The connecting pipe 2 is connected to one end of the condensation section 4 through the building 3 , and the other end of the condensation section 4 is connected to the evaporation section 1 through the return pipe 5 . The return line 5 is connected to the plurality of evaporation sections 1 via the collecting section 8 .

In the present invention, the heat pipe heat exchanger used for the passive waste heat export of the spent fuel pool absorbs the heat in the spent fuel pool 6 through the evaporation section 1, so that the working medium in the evaporation section 1 is evaporated to generate steam, and the generated steam It is collected into the connecting pipe 2 through the collecting section 8, overcomes the resistance of the pipe and/or gravity, moves along the connecting pipe 2, reaches the outdoor condensation section 4, and then exchanges heat with the air to condense, and the condensed medium acts under the action of gravity or capillary force It passes through the return pipe 5 to the collection section 8, and flows back to the evaporation section 1 through the collection section 8, and circulates in sequence to transfer the waste heat of the spent fuel pool to the atmosphere outside the building, so that the water temperature of the spent fuel pool meets the requirements and ensures that Safety of spent fuel pools.

In some embodiments, the installation position of the condensation section 4 may be higher than the installation position of the evaporation section 1 . In this case, the above-described circulation of the working medium can be achieved by means of gravity. In some embodiments, the installation position of the condensation section 4 may not be higher than the installation position of the evaporation section 1; in some embodiments, the condensation section 4 may have many curved parts so that the working medium cannot be circulated by gravity. In this case, a porous body (not shown in the figure) extending from the condensation section 4 to the evaporation section 1 along the length direction of the return pipe 5 may be provided in the return pipe 5 . The porous body promotes the condensed (liquefied) working medium in the condensation section 4 to be guided to the evaporation section 1 by the capillary force it generates. In some embodiments, the porous body may have a large number of pores (not shown in the figures) that serve as flow channels for the condensed working medium to flow.

In some embodiments, the collecting section 8 also acts as a distributor, so that the condensed medium (fluid) in the return pipe 5 is evenly distributed to each heat pipe through the collecting section 8 . In addition, in some embodiments, the medium pressure in the connecting pipe 2 is made lower than the medium pressure in the return pipe 5 , so as to ensure that the medium in the evaporation section 1 can enter the connecting pipe 2 through the collecting section 8 after being evaporated. In some embodiments, the diameter of the connecting pipe 2 can be made larger than the diameter of the return pipe 5 .

The evaporation section 1 can be installed in a number of different ways. Referring to FIG. 2 , in some embodiments, the evaporation section 1 is installed on the outer surface of the pool wall of the spent fuel pool 6 . This installation method does not occupy space in the spent fuel pool 6 and ensures that the heat pipe heat exchanger does not interact with the spent fuel pool 6 . Various devices in the spent fuel pool 6 interfere, and it is ensured that the natural convection in the spent fuel pool 6 does not have a detrimental effect; This installation method further improves the system integration; in some embodiments, the evaporation section 1 is arranged on the rack 7 in the spent fuel pool 6 . In some embodiments, it is integral with the grid 7 within the spent fuel pool 6 . Setting the grid 7 can also improve the seismic performance of the equipment and further improve the safety. It is also conceivable that these different installations described above can be combined in various suitable ways.

In some embodiments, each or more of the evaporation sections 1 may be designed in a modular structure. Referring to FIG. 2 , the evaporation section 1 can be designed as a plurality of modular structures, thereby simplifying installation and improving the flexibility of installation of the evaporation section 1 relative to the spent fuel pool 6 .

The medium evaporated in the modular evaporation section 1 is collected by the collecting section 8 to the connecting pipe 2 and passed through the building 3 by means of penetrations (not shown in the figures). In order for the heat pipe heat exchanger to pass through the penetration in the building 3, in some embodiments, the connecting pipe 2 and the return pipe 5 are arranged in the same duct. By arranging the connecting pipe 2 and the return pipe 5 in the same pipeline, the penetration of the building 3 is reduced, thereby ensuring the integrity of the boundary more easily and preventing the occurrence of leakage.

In order to improve the heat exchange efficiency and increase the air flow rate, in some embodiments, fins are provided outside the condensation section 4. In some embodiments, a chimney-shaped outer structure is provided outside the condensing section 4 to form a "chimney effect" at the condensing section 4 to increase the flow rate of the air. It is also conceivable that, in some embodiments, both fins and a chimney-shaped outer structure may be provided outside the condensation section 4 .

In some embodiments, the heat pipe heat exchanger may be installed according to the following steps, including: providing an evaporation section 1 to absorb heat from the spent fuel pool; providing a collecting section 8 and connecting one end of the evaporation section 1 to the collecting section 8; One end of the connecting pipe 2 is connected to the collecting section 8 ; one end of the condensing section 4 is connected to the other end of the connecting pipe 2 , and the other end of the condensing section 4 is connected to the evaporation section 1 through the return pipe 5 .

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Thus, provided that these modifications and variations of the present invention fall within the scope of the claims of the present invention and their technical equivalents, the present invention is also intended to include such modifications and variations.

Claims

A heat pipe heat exchanger, comprising:

an evaporation section configured to absorb heat from the spent fuel pool to evaporate the working medium;

a collection section, the collection section is connected with one end of the evaporation section;

a connecting pipe, one end of the connecting pipe is connected to the collecting section; and

The condensation section is configured to condense the evaporated working medium, one end of the condensation section is connected with the other end of the connecting pipe, and the other end of the condensation section is connected with the evaporation section through a return pipe.
The heat pipe heat exchanger according to claim 1, wherein the return pipe is connected to the evaporation section through the collecting section.
The heat pipe heat exchanger according to claim 1 or 2, wherein the diameter of the connecting pipe is larger than the diameter of the return pipe.
The heat pipe heat exchanger according to any one of claims 1 to 3, wherein the evaporation section is installed on the outer surface of the pool wall of the spent fuel pool.
The heat pipe heat exchanger according to any one of claims 1 to 4, wherein the evaporation section is integral with the pool wall of the spent fuel pool.
The heat pipe heat exchanger according to any one of claims 1 to 5, wherein the evaporation section is integral with the lattice in the spent fuel pool.
The heat pipe heat exchanger according to any one of claims 1 to 6, wherein the connecting pipe and the return pipe are arranged in the same pipe.
The heat pipe heat exchanger according to any one of claims 1 to 7, wherein the evaporation section adopts a modular structure design.
The heat pipe heat exchanger according to any one of claims 1 to 8, wherein the outside of the condensation section is provided with fins.
The heat pipe heat exchanger according to any one of claims 1 to 9, wherein a porous body is provided in the return pipe.
A method for installing a heat pipe heat exchanger, comprising the following steps:

Provide an evaporation section to absorb heat from the spent fuel pool;

providing a collection section and connecting one end of the evaporation section to the collection section;

connecting one end of the connecting pipe to the collection section; and

One end of the condensation section is connected to the other end of the connecting pipe, and the other end of the condensation section is connected to the evaporation section through a return pipe.