KR102039681B1 - Performance evaluation test apparatus for spent nuclear fuel storage - Google Patents

Abstract

The performance tester of the spent fuel storage container includes a cask body, a lower support plate, a plurality of basket ducts, an electric heater, a heat pipe module, and a measuring instrument. The cask body is reduced to the same length / diameter ratio as the cask of the spent fuel reservoir. The plurality of basket ducts pass through the lower support plate and are aligned at a distance from each other inside the cask body. The electric heater is located inside each of the plurality of basket ducts. The heat pipe module includes a heat dissipation unit coupled to the upper end of the cask body, and a plurality of heat pipes for passing through each of the plurality of basket ducts and having an upper end coupled to the heat dissipation unit.

Description

Performance tester for spent fuel storage container {PERFORMANCE EVALUATION TEST APPARATUS FOR SPENT NUCLEAR FUEL STORAGE}

The present invention relates to a performance test apparatus of a spent fuel storage container capable of verifying the design of the spent fuel storage container and performing various performance experiments under various conditions.

Spent fuel is nuclear fuel that is drawn after being burned in a nuclear power plant and is transported to a reprocessing facility or storage after a certain cooling process. The high radioactivity and heat dissipation characteristics of spent fuel in this process necessitate a dedicated container specifically designed for safe transport or storage.

Typical spent nuclear fuel reservoirs include a sealed cylindrical cask and a basket assembly located within the cask. The basket assembly consists of a configuration in which a plurality of baskets containing the spent fuel assembly are arranged side by side in a horizontal or vertical direction.

Applicant has a cooling unit consisting of a heat pipe penetrating the inside of the basket and a metal cover for dissipating heat transferred through the heat pipe to the outside in Patent Application No. 2016-0151948 and Patent Application No. 2017-0026497 A spent fuel dry storage container has been proposed.

The spent fuel dry storage container proposed by the applicant has all the functions of the existing storage container and has improved cooling performance by the heat pipe and the metal cover. Therefore, it is possible to secure additional storage and transportation capacity while ensuring structural health as compared with existing storage containers that may be degraded by high temperature internal environment.

The present invention is a spent fuel storage container that can verify the design of the spent fuel storage container with a heat pipe, compare the performance with the existing storage container, and perform various performance experiments under various conditions according to the licensing requirements. To provide a performance tester of.

Performance test apparatus of the spent fuel storage container according to an embodiment of the present invention includes a cask body, a lower support plate, a plurality of basket ducts, an electric heater, a heat pipe module, and a measuring instrument. The cask body is reduced to the same length / diameter ratio as the cask of the spent fuel reservoir. The lower support plate is coupled to the bottom of the cask body. The plurality of basket ducts pass through the lower support plate and are aligned at a distance from each other inside the cask body. The electric heater is located inside each of the plurality of basket ducts. The heat pipe module includes a heat dissipation unit coupled to the upper end of the cask body, and a plurality of heat pipes for passing through each of the plurality of basket ducts and having an upper end coupled to the heat dissipation unit. The measuring device is installed in at least one of the cask body, the lower support plate, and the heat pipe module to measure temperature and pressure.

The plurality of basket ducts may include side grooves for installing an electric heater at the bottom, and may be arranged side by side in the horizontal and vertical directions of the ground at the same height.

Each of the plurality of basket ducts may be a rectangular tubular structure, four electric heaters may be located inside a corner of the basket duct, and the plurality of electric heaters may be held in a fixed position by the lower support plate. The entire length of the electric heater may be equal to the length of the basket duct, and a heating wire may be disposed in a portion of the electric heater corresponding to the inside of the cask body to form a heating unit.

The pipe for the heat pipe may be a tubular structure of which the bottom is closed and the top is open, and may penetrate the inner center of each of the plurality of basket ducts.

The heat dissipation part may include a metal pipe part consisting of a pipe structure having an open top and a bottom, a heat pipe connecting plate connected to the bottom of the metal pipe part and coupled to a plurality of heat pipes, and a transparent cover plate connected to the top of the metal pipe part. Can be.

A plurality of through holes may be formed in the heat pipe connecting plate, a connector may be provided under each of the plurality of through holes, and an upper end of the plurality of heat pipe pipes may be assembled to the connector.

The plurality of heat pipe piping may function as a heat pipe evaporator for receiving a working fluid therein to transfer heat to the heat dissipation unit.

An apparatus for testing performance of spent fuel storage containers according to another embodiment of the present invention includes a cask body, a plurality of basket ducts, at least one electric heater, a heat dissipation unit, a plurality of heat pipes, and a measuring instrument. The plurality of basket ducts are located inside the cask body and at least one electric heater is located inside each of the plurality of basket ducts. The heat dissipation unit is coupled to the top of the cask body and has an inner space. The pipes for the plurality of heat pipes are formed of a pipe structure in which the lower end is closed and the upper end is open, penetrates through the inner center of each of the plurality of basket ducts, and the open upper end is coupled to the heat dissipation unit so as to communicate with the inner space of the heat dissipation unit. The measuring instrument is installed in the cask body and the heat dissipation unit to measure temperature and pressure. The performance test apparatus represents a spent fuel storage container equipped with a heat pipe when a plurality of heat pipes accommodate the working fluid, and the performance test apparatus heats when the plurality of heat pipes do not receive the working fluid. Represents a spent fuel storage container without a pipe.

The cask body may be reduced to the same length / diameter ratio as the cask of the spent fuel reservoir.

The heat dissipation unit may include a transparent cover plate so that the experimenter can observe the internal space. The heat dissipation part may further include a heat pipe connecting plate. The heat pipe connecting plate may include a plurality of through holes corresponding to the plurality of heat pipe pipes, and a plurality of connectors for coupling the plurality of heat pipe pipes.

The performance test apparatus of the present invention can simultaneously consider the convective heat transfer inside the sealed cask body and the radiant heat transfer due to the high temperature environment, and minimize the distortion effect due to the shape change by maintaining the same length / diameter ratio as the actual storage container. Can be. In addition, depending on whether or not to accommodate the working fluid of the heat pipe pipe can represent the performance of the storage containers of two different configurations (simulating).

1 is a perspective view of a performance test apparatus (hereinafter referred to as a "performance test apparatus" for convenience) of a spent fuel storage container according to an embodiment of the present invention.
2 is a cross-sectional view of the performance test apparatus shown in FIG.
3 is a cross-sectional view taken along the line III-III shown in FIG. 2.
4 is a cross-sectional view showing a plurality of baskets in the performance test apparatus shown in FIG.
FIG. 5 is a diagram illustrating a configuration of an electric heater and a heat flux distribution according to a length direction of the electric heater in the performance test apparatus illustrated in FIG. 2.
6 is a cross-sectional view showing a metal cover and a heat pipe in a spent fuel storage container.
FIG. 7 is an enlarged view of a portion A shown in FIG. 6.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

1 is a perspective view of a performance test apparatus (hereinafter referred to as a "performance test apparatus" for convenience) of a spent fuel storage container according to an embodiment of the present invention, Figure 2 is a cross-sectional view of the performance test apparatus shown in FIG. .

1 and 2, the performance test apparatus 100 according to the present embodiment is a reduced model of a spent fuel storage container (hereinafter, referred to as a 'storage container' for convenience), and is a storage container under various conditions according to a licensing requirement. It is a device to test the performance and verify the design. The performance test apparatus 100 includes a cask body 10, a lower support plate 20, a plurality of basket ducts 30, an electric heater 40, a heat pipe module 50, and a measuring device 60.

The cask body 10 is scaled down to have the same length / diameter (L / D) ratio as the cask of the storage container. For example, the cask body 10 may have a configuration in which both the length and the diameter of the cask of the storage container are reduced to 1/5, but the reduction ratio is not limited to this example. The cask body 10 may be made of the same material as the cask of the storage container, for example, a metal such as steel.

The cask body 10 may have a cylindrical shape with the top and bottom open, and the lower support plate 20 is coupled to the bottom of the cask body 10. The first flange 11 may be located along the lower circumference of the cask body 10, and the edges of the first flange 11 and the lower support plate 20 may be integrally coupled by a fastening means such as a bolt. have. The coupling structure of the cask body 10 and the lower support plate 20 is not limited to the illustrated example.

The plurality of basket ducts 30 is a model of the basket of the storage container, and is vertically positioned at a distance from each other in the cask body 10. The plurality of basket ducts 30 may pass through the lower support plate 20 and may be fixed to the lower support plate 20.

3 is a cross-sectional view taken along the line III-III shown in FIG. 2, and FIG. 4 is a cross-sectional view showing a plurality of baskets in the performance test apparatus shown in FIG.

2 to 4, the basket duct 30 is a long rectangular tube structure in the vertical direction (z direction), and along the horizontal direction (x direction) and vertical direction (y direction) of the ground at the same height. Arranged side by side. The upper end of the basket duct 30 may be positioned below the upper end of the cask body 10, and the lower end of the basket duct 30 may be positioned below the lower support plate 20.

Side grooves 31 for installing the electric heater may be formed at the bottom of the basket duct 30. The plurality of basket ducts 30 may be arranged approximately cross-shaped when viewed from above (see FIG. 3), and the through portions for installing the meter out of the plurality of basket ducts 30 from the lower support plate 20 ( 21 may be located.

2 and 3, the electric heater 40 is positioned inside each of the plurality of basket ducts 30. The electric heater 40 is a heating element for implementing a heat state of the storage container, and has a temperature control function. Four electrical heaters 40 per basket duct 30 may be located inside a corner of the basket duct 30. The plurality of basket ducts 30 and the plurality of electric heaters 40 maintain a fixed position by the lower support plate 20.

FIG. 5 is a diagram illustrating a configuration of an electric heater and a heat flux distribution according to a length direction of the electric heater in the performance test apparatus illustrated in FIG. 2.

3 and 5, a terminal 41 for receiving power is positioned at the lower end of the electric heater 40. The total length L of the electric heater 40 may be equal to the length of the basket duct 30, and a heating wire is disposed at a portion of the electric heater 40 corresponding to the inside of the cask body 10 so that the heating part 42 is disposed. ) Can be configured.

The heat flux distribution of the heating part 42 includes a first part A10 in which the heat flux gradually rises along the longitudinal direction from one end of the heating part 42, a second part A20 in which the heat flux maintains a maximum value, and , A pattern including the third portion A30 in which the heat flux gradually decreases. Most of the heating portions 42 belong to the second portion A20.

Referring back to FIGS. 1 to 3, the heat pipe module 50 passes through each of the heat dissipation unit 51 coupled to the upper end of the cask body 10 and the plurality of basket ducts 30, respectively. It includes a pipe for the heat pipe (55) coupled to. The heat pipe piping 55 is a reduced model of the heat pipe evaporation part of the storage container, and the heat dissipation part 51 is a reduced model of the metal cover (heat pipe heat dissipating part) of the storage container.

6 is a cross-sectional view illustrating a metal cover and a heat pipe in a storage container, and FIG. 7 is an enlarged view of a portion A of FIG. 6. 6 and 7, the heat pipe heat dissipation unit 71 is coupled to an upper end of a cask (not shown) in the storage container, and the heat pipe evaporation unit 72 is a plurality of baskets (not shown), respectively. While passing through the upper end is coupled to the heat pipe heat dissipation unit (71).

The heat pipe is composed of a heat pipe heat dissipation part 71 serving as a cover and a heat pipe evaporation part 72 inserted into the basket, and the inside of the heat pipe maintains a vacuum condition. The heat pipe heat dissipation unit 71 is formed of a hollow metal container, and the heat pipe evaporation unit 72 is a tubular structure in which the lower end is closed and the upper end is opened, and the open upper end is an internal space of the heat pipe heat dissipation unit 71. It is coupled to the heat pipe heat dissipation portion 71 so as to communicate with. Water is accommodated in the heat pipe evaporator 72 as a working fluid.

The working fluid of the heat pipe evaporator 72 absorbs the residual heat of nuclear fuel contained in the basket and is heated, and the heated working fluid is phase-changed into steam and rises upward (see arrow B in FIG. 7). The working fluid in the vapor state is discharged into the internal space of the heat pipe heat dissipation unit 71 to transfer heat to the heat pipe heat dissipation unit 71. The heat pipe heat dissipation unit 71 emits heat to the outside air, and the working fluid is condensed by heat dissipation of the heat pipe heat dissipation unit 71.

The condensed working fluid is again lowered by gravity to be recovered to the heat pipe evaporator 72 (see arrow C in FIG. 7), and the remaining heat of the nuclear fuel is absorbed and cooled by repeating the aforementioned cycle. At this time, the hollow heat pipe heat dissipation unit 71 realizes an excellent heat dissipation effect because the surface area in contact with the outside air is very large, and can effectively remove the residual heat of the nuclear fuel.

Meanwhile, the heat pipe evaporator 72 of the actual storage container may be manufactured in a double pipe structure that separates a flow path of the working fluid in the liquid state and the working fluid in the vapor state. Shown schematically as (72).

Referring again to FIGS. 1 to 3, the pipe 55 for the heat pipe is a pipe structure in which a lower end is blocked and an upper end is opened, and passes through an inner center of each of the plurality of basket ducts 30. The length of the heat pipe tubing 55 may be equal to the length of the cask body 10. The upper end of the heat pipe pipe 55 is coupled to the heat dissipation unit 51, and the lower end of the heat pipe pipe 55 may be positioned at the same height as the lower end of the cask body 10.

The heat dissipation unit 51 is a hollow container structure made of metal in whole or in part, and is coupled to the upper end of the cask body 10 to seal the inside of the cask body 10 together with the lower support plate 20. The heat dissipation part 51 is a metal pipe part 52 formed of a pipe structure having an open top and a bottom, a heat pipe connecting plate 53 connected to the bottom of the metal pipe part 52, and connected to an upper end of the metal pipe part 52. The transparent cover plate 54 may be included.

The metal pipe part 52 is made of a metal such as a metal cover of a storage container, and functions to radiate heat by transferring heat received through the heat pipe pipe 55 to the outside air.

A plurality of through holes 531 corresponding to the plurality of heat pipe pipes 55 may be disposed in the heat pipe connecting plate 53, and a connector 56 may be provided under each of the through holes 531. The upper end of the heat pipe pipe 55 is assembled to the connector 56 and mechanically coupled to the heat dissipation unit 51, and the inside of the heat pipe pipe 55 by the connector 56 and the through hole 531. The space may communicate with the internal space of the heat dissipation unit 51.

The transparent cover plate 54 may be made of a transparent plastic plate such as acrylic or polycarbonate, and the experimenter may observe the inside of the heat dissipation unit 51 by the transparent cover plate 54. Since the inside of the heat dissipation unit 51 is a space in which the vaporized working fluid is radiated and the condensed working fluid is recovered to the heat pipe pipe 55 again, the experimenter circulates the working fluid through the transparent cover plate 54. Can be observed visually (by eye or directly using a high speed camera or video camera).

On the other hand, the heat dissipation unit 51 may include a cover plate made of a metal material such as a metal tube instead of the transparent cover plate 54. In this case, the experimenter can not observe the circulating process of the working fluid, but since the heat dissipation unit 51 is configured as close as possible to the metal cover of the storage container, the function of the actual metal cover can be almost identical.

The second flange 12 may be located along the top circumference of the cask body 10, and the third flange 521 may be located along the bottom circumference of the metal tube 52. The edge of the second flange 12 and the heat pipe connecting plate 53 and the third flange 521 may be integrally coupled by a fastening means such as a bolt.

In addition, a fourth flange 522 may be located along the upper circumference of the metal pipe portion 52, and the edge of the transparent cover plate 54 and the fourth flange 522 are integrally coupled by a fastening means such as a bolt. Can be. The fastening structure of the heat radiating part 51 and the cask main body 10 is not limited to the illustration of illustration.

The pipe for the heat pipe 55 may or may not receive the working fluid. In the former case, the performance test apparatus 100 may represent a storage container having a heat pipe. In the latter case, since the pipe 55 for the heat pipe without the working fluid cannot function as the heat pipe evaporator, the performance test apparatus 100 may represent a conventional storage container having no heat pipe.

The measuring device 60 may be installed in each of the cask body 10, the lower support plate 20, and the heat pipe module 50, and measures at least one of their temperature and pressure in real time during the experiment. The measuring device 60 may be provided in plural along the longitudinal direction and the circumferential direction of the cask body 10, and the transparent cover plate 54 of the penetrating portion 21 and the heat dissipating portion 51 of the lower support plate 20. Can be installed on

1 to 3, for convenience, a plurality of measuring devices 60 installed in the cask body 10, a penetrating portion 21 installed on the lower support plate 20 for installing the measuring device, and a transparent cover plate 54 for installing the measuring device. Measurement port 57 is shown. Meter 60 may include a thermocouple as a temperature detector. In FIG. 2, reference numeral 13 denotes a through hole of the cask body 10 for installing the measuring device 60.

The performance test apparatus 100 having the above-described configuration is disposed at a place or facility maintaining a predetermined test temperature according to the test conditions given in consideration of the actual storage container operation, and the cask main body 10 and the plurality of basket ducts. (30) After filling with an inert gas such as helium and sealed, and operating the electric heater 40 to respond to the heat generated from the nuclear fuel to perform thermal stability tests and evaluation under conditions similar to the actual.

The heating temperature of the electric heater 40 can be set in various ways according to the experimental conditions, and the plurality of measuring devices 60 measures the temperature and pressure of the cask body 10 and the heat pipe module 50 in real time during the experiment. do. Therefore, the performance test apparatus 100 can easily perform various performance tests, such as the integrity evaluation of the storage container.

The performance test apparatus 100 of the present embodiment can simultaneously consider the convective heat transfer inside the sealed cask body 10 and the radiant heat transfer due to the high temperature environment, and maintain the same length / diameter ratio as the actual storage container to change the shape. The distortion effect can be minimized. In addition, the performance of the storage pipes representing the two different configurations (simulating) can be tested depending on whether or not the working pipe accommodates the heat pipe (55).

That is, when the working fluid is accommodated in the heat pipe pipe 55, the heat pipe pipe 55 performs the same heat transfer function as the heat pipe evaporator, and the heat dissipation unit 51 is transferred from the heat pipe pipe 55. The received fluid is transferred to the outside air to condense the working fluid. In this case, the performance test apparatus 100 may represent a storage container having a heat pipe (for convenience, referred to as a 'first storage container') and test its performance.

On the other hand, since the heat pipe pipe 55 without the working fluid cannot function as the heat pipe evaporator, in this case, the performance test apparatus 100 is referred to as a conventional storage container without a heat pipe (for convenience, referred to as a 'second storage container'). ) Can be used to test its performance. In addition, the performance of the first storage container and the second storage container may be compared and evaluated using one performance test apparatus 100.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the range of.

100: performance test apparatus 10: cask body
20: lower support plate 30: basket duct
40: electric heater 50: heat pipe module
51: heat radiating portion 52: metal tube portion
53: heat pipe connecting plate 54: transparent cover plate
55: pipe for heat pipe 60: measuring instrument
71: heat pipe heat dissipation unit 72: heat pipe evaporation unit

Claims (12)

A cask body that is reduced to the same length / diameter ratio as the cask of the nuclear fuel storage container after use, and whose bottom is coupled to the lower support plate;
A plurality of basket ducts penetrating the lower support plate, aligned at a distance from each other in the cask body, and having an electric heater positioned therein;
And a heat dissipation unit coupled to an upper end of the cask body, and a plurality of heat pipes for passing through each of the plurality of basket ducts and having an upper end coupled to the heat dissipation unit. A heat pipe module in which internal spaces of a pipe for pipes pass through each other; And
A measuring device installed in at least one of the cask body, the lower support plate, and the heat pipe module to measure temperature and pressure;
Performance testing device of the spent fuel storage container comprising a. The method of claim 1,
The plurality of basket duct includes a side groove for installing an electric heater at the bottom, and the performance test apparatus of the spent fuel storage container arranged side by side along the horizontal and vertical direction of the ground at the same height. The method of claim 2,
Each of the plurality of basket ducts is a rectangular tube structure, four electric heaters are located inside a corner of the basket duct, and the plurality of electric heaters are used fuel storage container to maintain a fixed position by the lower support plate Performance testing equipment. The method of claim 3,
The overall length of the electric heater is the same as the length of the basket duct, the heating device is disposed in the portion corresponding to the inside of the cask body of the electric heater is a performance test device of the spent nuclear fuel storage container constituting the heating unit. The method of claim 1,
The pipe for the heat pipe is a pipe structure, the lower end is closed and the upper end is open, the performance test apparatus of the spent fuel storage container passing through the inner center of each of the plurality of basket ducts. The method of claim 5,
The heat dissipation unit,
A metal pipe part consisting of a pipe structure having an upper end and an lower end;
A heat pipe connecting plate connected to a lower end of the metal pipe part and coupled to the plurality of heat pipe pipes; And
Transparent cover plate connected to the top of the metal tube
Performance testing device of the spent fuel storage container comprising a. The method of claim 6,
A plurality of through holes are formed in the heat pipe connecting plate, and a connector is provided under each of the plurality of through holes, and the performance of the spent fuel storage container in which upper ends of the plurality of heat pipe pipes are assembled to the connector. Experiment apparatus. The method of claim 5,
The plurality of heat pipes for the performance test apparatus of the spent nuclear fuel storage container that serves as a heat pipe evaporation unit for receiving the working fluid therein to transfer heat to the heat dissipation unit. In the performance test apparatus of the spent fuel storage container,
Cask body;
A plurality of basket ducts located inside the cask body;
At least one electric heater located inside each of the plurality of basket ducts;
A heat dissipation unit coupled to an upper end of the cask body and having an inner space;
A plurality of heat pipes coupled to the heat dissipation unit is formed of a tubular structure of the lower end is closed and the top is open, penetrates the inner center of each of the plurality of basket ducts, and the open upper end is in communication with the internal space of the heat dissipation unit pipe; And
Is installed in the cask body and the heat dissipation unit includes a measuring instrument for measuring the temperature and pressure,
The performance test apparatus represents a spent fuel storage container provided with a heat pipe when the plurality of heat pipe pipes accommodates a working fluid, and the performance when the plurality of heat pipe pipes do not receive a working fluid. The experimental apparatus is a performance experimental apparatus of a spent fuel storage container representing a spent fuel storage container without a heat pipe. The method of claim 9,
The cask body is a performance test apparatus of the spent fuel storage container that is reduced to the same length / diameter ratio of the cask of the spent fuel storage container. The method of claim 9,
The heat dissipation unit is a performance test apparatus of the spent nuclear fuel storage container including a transparent cover plate for the experimenter to observe the inner space. The method of claim 11,
The heat dissipation unit further includes a heat pipe connecting plate,
And the heat pipe connecting plate includes a plurality of through holes corresponding to the plurality of heat pipe pipes, and a plurality of connectors for coupling the plurality of heat pipe pipes.

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