KR20110115725A - Graphene/graphene oxide-dispersion coolants, using method of the same and nuclear corium cooling system using the same - Google Patents

Abstract

The present invention relates to a method of using a graphene / graphene-oxide dispersion coolant and a reactor core melt cooling system using the same. More particularly, the present invention relates to nanomaterials (graphene or graphene oxide) in cooling water in a reactor core melt cooling system. Reactor core melt cooling system and nanomaterials used to improve nuclear power safety by improving the cooling capacity by using this dispersed coolant for cooling to secure successful outer wall cooling capacity, thereby contributing to nuclear reactor safety during nuclear accident (Graphene or graphene-oxide).

Description

Graphene / Graphene Oxide-dispersion coolants, Using method of the same and Nuclear corium cooling system using the same}

The present invention relates to a method of using a graphene / graphene-oxide dispersion coolant and a reactor core melt cooling system using the same. More particularly, the present invention relates to nanomaterials (graphene or graphene oxide) in cooling water in a reactor core melt cooling system. By using this distributed coolant for cooling, the reactor core melt cooling system improves the cooling capacity to secure successful outer wall cooling capacity, and the nuclear reactor core melts are stored in the furnace during a serious accident, thereby contributing to securing nuclear safety.

Nuclear reactor accidents can cause serious damage to the core if various safety equipment designed according to the stability assessment malfunctions and reactor core cooling or reactivity control is not properly performed. The main phenomena of these serious accidents include the generation and explosion of hydrogen from fuel cladding, the melting of fuel and the behavior of molten fuel in reactor vessels, reactor vessel failure, steam explosions, direct heating of reactor containment buildings, and cores. Melt-concrete reactions and containment overpressure, especially those that directly affect the overall damage scale of a major accident are the breakdown of containment, which occurs mainly after the reactor vessel is broken. These phenomena of serious accidents are difficult to analyze or manage serious accidents because the development process is very uncertain and complicated.

In recent years, in the event of a serious accident, the reactor outer wall cooling technology, which prevents the reactor vessel from breaking by removing the decay heat generated from the core melt inside the reactor vessel by submerging the outer wall of the reactor, has emerged as a major technology to manage the serious accident of the reactor. As a result, many light water reactors abroad tend to reflect the design of the reactor outer wall cooling technology. For example, the reactor outer wall cooling method in the new water reactor AP1000 of the Westinghouse in the United States shown in FIG.

According to this method, in the event of a serious accident in which the core of the reactor is melted to produce the core melt 125, coolant is introduced into the reactor cavity 140 to supply the primary pipe from the bottom of the reactor cavity 140. 150) The outer wall of the reactor is flooded by filling the space to the junction with coolant. When the coolant is filled in the reactor cavity 140, the coolant inlet 134 of the lower portion of the heat shield 130 is opened by the pressure of the filled coolant, and the coolant flows into the heat shield 130, and the coolant flows into the heat shield 130. Is discharged back to the reactor cavity 140 through the coolant outlet 135 located above the heat shield 130 along the outer wall of the reactor vessel 120 by natural convection.

In other words, the coolant has a continuous natural circulation and cools the outer wall of the reactor in the order of the reactor cavity 140 → cooling water inlet 134 → inside the heat shield 130 → cooling water outlet 135 → reactor cavity 140. .

The reactor outer wall cooling method by the reactor cavity submersion is adopted and used as a method for cooling the outer wall of the reactor in most light water reactors as well as abroad.

However, in order to successfully preserve the core melt made of nuclear fuel in the reactor vessel (in the furnace) in the event of a major reactor accident, the thermal load applied to the bottom of the reactor vessel due to the decay heat of the melt pool made of the melt is the critical heat flux value during the reactor wall cooling. It should be smaller enough with (thermal) margin, but there was a problem that the water cooling water used in the existing outer wall cooling system had insufficient margin with the heat flux from the outer wall with respect to the heat removal capacity limit called the critical heat flux.

Accordingly, the present invention aims to improve the capability of the reactor outer wall cooling system. That is, since the success measure of the outer wall cooling is to secure a sufficient critical heat flux margin (for example, 50% or more), the present invention provides a reactor outer wall cooling system capable of achieving a critical heat flux improvement, and to provide a nanomaterial used therein. do.

The present invention relates to the use of nanomaterials dispersed in cooling water and used as a coolant, and provides a method of using nanomaterials to disperse the nanomaterial in cooling water and use it as a coolant in a reactor outer wall cooling system.

Here, the nano-material is characterized in that dispersed in a ratio of 10 ^-5 ~ 1% by volume relative to the total volume of the coolant.

In addition, the nanomaterial is characterized in that the graphene (graphene) or graphene oxide (graphene-oxide).

In addition, the present invention, the reactor vessel 10; and a heat shield 20 surrounding the outer wall of the reactor vessel 10 at regular intervals; And a reactor cavity (30) having the heat shield (20) and the reactor vessel (10) therein, wherein the cooling material supplied to the system includes nanomaterials (51). It is to provide a cooling system of the outer wall of the reactor, characterized in that the dispersion is used as a coolant of the reactor outer wall cooling system.

Here, the reservoir 40 for storing the cooling water therein; and the nanomaterial dispersion tank 50 for storing the nanomaterial therein; And one end is connected to the reservoir 40 and the other end of the reactor cavity 30 Or a coolant injection pipe (60, 61) connected to a lower portion of the heat shield (20) to form a passage through which the coolant of the reservoir (40) is injected into the reactor cavity (30) or the heat shield (20); And, one end is in communication with the nanomaterial dispersion tank 50, the other end is in communication with the cooling water injection pipe 60 to form a passage for dispersing the nanomaterial 51 to the cooling water injection pipe 60 An injection pipe 70; and a cooling water injection valve 80 provided in the cooling water injection pipes 60 and 61 to control the flow of the cooling water injected into the reactor cavity 30 or the heat shield 20; 81); and, provided in the nanomaterial injection pipe 70, the cooling water injection Related nanomaterials injection valve 90 to regulate the flow of the nanomaterial 51 is distributed to 60; And at least one pump (100) provided on the cooling water supply system including the water reservoir (40) and the cooling water injection pipe (60, 61) to pump the cooling water. It is characterized in that the nanomaterial 51 is dispersed in the cooling water injected into 61) and used as a coolant of the reactor outer wall cooling system.

In addition, a reservoir 40 for storing the cooling water therein; and a nanomaterial dispersion tank 50 for storing the nanomaterial 51 therein; and one end connected to the reservoir 40 and the other end of the reactor cavity. 30 is connected to the lower portion of the heat shield 20 or the coolant injection pipe 60 to form a passage through which the coolant of the reservoir 40 is injected into the reactor cavity 30 or the heat shield 20. 61); And, one end is in communication with the nanomaterial dispersion tank 50, the other end is in communication with the interior of the heat shield 20, the passage for dispersing the nanomaterial 51 into the heat shield 20 Nano material injection pipe 71 to form a; and the coolant is provided in the cooling water injection pipe (60, 61), the cooling water for intermittent flow of the cooling water injected into the reactor cavity 30 or the heat shield 20 Injection valves 80 and 81; and provided in the nanomaterial injection pipe 71 to the heat shield 20. A nanomaterial injection valve 90 for intermittent flow of nanomaterials to be dispersed; And at least one pump (100) provided on the cooling water supply system including the water reservoir (40) and the cooling water injection pipe (60, 61) to pump the cooling water. 61) the nanomaterial 51 is dispersed in the cooling water circulated in the heat shield 20 and used as a coolant of the reactor outer wall cooling system.

In addition, the nanomaterial 51 is characterized in that dispersed in a ratio of 10 ^-5 ~ 1% by volume relative to the total coolant volume.

In addition, the nanomaterial 51 is characterized in that the graphene (graphene) or graphene oxide (graphene-oxide).

In addition, when the compressed gas 52 is injected into the nanomaterial dispersion tank 50 to open the nanomaterial injection valve 90, the nanomaterial 51 may be pushed to gas pressure.

In addition, the compressed gas 52 is characterized in that the N ₂ gas.

In addition, the other end of the nano-material injection pipe 71 is characterized in that the inclined outer wall of the reactor vessel 10 of the heat shield 20 is sprayed in a section larger than 70 ° and less than 90 °.

In addition, the other end of the nanomaterial injection pipe 71 is characterized in that it is installed so as to be perpendicular to the outer wall of the reactor vessel (10).

In addition, the other end of the nanomaterial injection pipe 71 is characterized in that the injection nozzle (Nozzle, 72) is provided.

In addition, the reservoir 40 is characterized in that the nuclear fuel reload tank (in-containment refueling water storage tank: IRWST) provided in the containment building (1).

By utilizing the present invention, it is possible to secure a successful outer wall cooling ability by improving the outer wall cooling capacity of the reactor (approximately 2.8 times increase the critical heat flux), so that the nuclear fuel core melt can be stored in the furnace in the event of a serious accident, thus greatly contributing to securing nuclear safety. Can be.

1 is a configuration diagram of a reactor outer wall cooling system according to a first embodiment of the present invention,
2 is a configuration diagram of a reactor outer wall cooling system according to a second embodiment of the present invention,
3 is an enlarged view illustrating an enlarged portion 'A' of FIG. 2,
Figure 4 shows the test results carried out in the present invention, SEM image showing the appearance of the coating on the heater wire surface after each fluid boiled (left side × 100, right side × 10000, (a) water, (b) Al ₂ O ₃ nanomaterial dispersed fluid, (c) graphene dispersed fluid, (d) graphene-oxide dispersed fluid),
5 is a reference diagram for explaining the graphene used in the present invention,
6 is a view for explaining a reactor outer wall cooling method according to the prior art.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in this specification and claims should not be construed in a common or dictionary sense, and the inventors will be required to properly define the concepts of terms in order to best describe their invention. Based on the principle that it can, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various equivalents may be substituted for them at the time of the present application. It should be understood that there may be water and variations.

1 is a schematic diagram of a reactor outer wall cooling system according to a first embodiment of the present invention, Figure 2 is a schematic diagram of a reactor outer wall cooling system according to a second embodiment of the present invention, Figure 3 is' A 4 is an enlarged view illustrating the enlarged portion, and FIG. 4 shows the test results performed in the present invention, and SEM images showing the state in which the fluid is coated on the heater wire surface after boiling (left is × 100, right is × 10000) (a) water, (b) Al ₂ O ₃ nanomaterial dispersed fluid, (c) graphene dispersed fluid, (d) graphene-oxide dispersed fluid), and FIG. 5 is used in the present invention. Figure 6 is a reference for explaining the graphene, Figure 6 is a view for explaining a reactor outer wall cooling method according to the prior art.

First, the use of graphene (graphene) or graphene oxide (graphene-oxide) used in the present invention will be described.

The present invention relates to the use of nanomaterials dispersed in cooling water and used as a coolant, and provides a method of using nanomaterials to disperse the nanomaterial in cooling water and use it as a coolant in a reactor outer wall cooling system.

Here, the nanomaterial is characterized in that dispersed in a ratio of 10 ^-5 ~ 1% by volume relative to the total volume of the coolant, the nanomaterial is characterized in that the graphene (graphene) or graphene oxide (graphene-oxide).

Hereinafter, the cooling water generally refers to water used for cooling the reactor, and the coolant refers to the dispersion of nanomaterials in the water.

That is, the present invention uses a material in which nanomaterials are dispersed in cooling water (water) as a coolant used in a reactor outer wall cooling system.

Representative nanomaterials used in the practice of the present invention are graphene (graphene), graphene oxide (graphene-oxide), Al ₂ O _{3 is} also possible.

The graphene refers to a two-dimensional carbon allotrope made by forming carbon lattice structures in a honeycomb shape. Graphene is a compound word that combines graphite and suffix (-ene) to make organic compounds. Graphite, which is commonly used as a pencil core, is a multi-layered structure made by overlapping numerous graphenes.

That is, graphene is a monolayer composed of carbon atoms, and monolayer graphene dispersed in water is known to have a very high thermal conductivity of 5200 W / mK. Graphene-oxide is a compound of carbon, hydrogen, and oxygen. graphite) single layer structure.

That is, as shown in Figure 5, the graphene is a thin layer made of carbon atoms are a plurality of them are overlapping and connected by Van der waal's force (Van der waal's force) corresponds to graphite.

In the present invention, the graphene (graphene) or graphene oxide (graphene-oxide) is described in the function and action used as the coolant by dispersing in the cooling water.

First, critical heat flux (CHF) in boiling heat transfer refers to a thermal limit of a phenomenon in which a phase change occurs while a fluid or the like is boiling. For example, bubbles that occur on metal surfaces used to boil water. This rapidly decreases the heat transfer coefficient, resulting in local overheating of the thermal surface.

Therefore, in order to successfully preserve the core melt made of nuclear fuel in the reactor vessel (in the furnace) in the event of a major accident, the thermal load applied to the bottom of the reactor vessel due to the decay heat of the melt pool made of the melt is the critical heat flux value during the reactor wall cooling. It should be small with more (thermal) margin.

However, in the water cooling water used in the conventional reactor outer wall cooling system, there is a problem that there is not enough margin with the heat flux from the outer wall with respect to the heat removal capacity limit point called the critical heat flux. In the present invention, the outer wall cooling is performed to improve the outer wall cooling capacity. In order to secure sufficient critical heat flux margin (e.g., 50% or more) to achieve this successfully, i.e., to improve the critical heat flux.

Therefore, in the present invention, the function and action of the coolant dispersed in graphene (graphene), graphene oxide (graphene-oxide) or Al ₂ O ₃ in the cooling water (water) will be utilized in the reactor cooling system.

-Coolant performance verification test

In order to confirm the performance of the graphene (graphene), graphene oxide (graphene-oxide) or Al ₂ O ₃ coolant dispersion was carried out a test (modified Hummers method).

(1) test group and control group

In this test, (1) water, (2) Al ₂ O ₃ nanofluid, and (3) graphene nanofluid and (4) graphene-oxide nanofluid were prepared as test groups.

The Al ₂ O ₃ nanofluid is obtained by dispersing alumina nanoparticles in water. The alumina nanoparticles are smaller than 100 nm and have thermal conductivity of 490 W / mK. Further, Al ₂ O ₃ is used in a dispersion of 0.001V% (0.001% by volume) of the total nanofluid.

The graphene and graphene-oxide nanofluids are prepared from graphite. The size of the graphite powder particles is smaller than 45 μm, and the thermal conductivity corresponds to 5200 W / mK. Furthermore, graphene and graphene-oxide are each dispersed at a ratio of 0.001V% of the total nanofluid.

(2) test method

In this test, a heater wire (nickel-chromium) is installed in a rectangular container, and the control or test group is placed inside the container, and then the heater wire is heated while being connected to an electric device to boil the control or test group. The critical heat flux values (CHF values, q ") of the fluids (1) to (4) are calculated by the following equations (1) and (2).

식 (1)

Formula (1)

식 (2)

Formula (2)

(Where R _w = resistance of heater wire, V = measured voltage, I = measured current, R _s = system resistance excluding heater wire resistance, D = diameter of heater wire, L = length of heater wire)

(3) test result

The critical heat flux values calculated in the above (2) are shown in [Table 1].

As shown in Table 1, the critical heat flux (CHF) of distilled water is 950 kW / m ² , Al ₂ O ₃ nanofluid is 2400 kW / m ² , graphene nanofluid is 1750 kW / m ² , and graphene. -The oxide nanofluid was measured at 2650kW / m ² , and it can be seen that the critical heat flux (CHF) of the graphene-oxide nanofluid was the largest.

Furthermore, in FIG. 4, SEM images showing the appearance of the coating on the heater wire surface after boiling each fluid (× 100 on the left, × 10000 on the right, (a) water, (b) Al ₂ O ₃ nanomaterial dispersed Fluid, (c) graphene-dispersed fluid, and (d) graphene-oxide-dispersed fluid), Al ₂ O ₃ nanomaterials and graphene-based materials do not adhere to the heater wire surface. I can see what happens.

And, as shown in Figure 4 it can be seen that the coating of the graphene-based material has a regular porous structure.

Applying these test results to the reactor wall cooling system in which the present invention is utilized, carbon-based graphene and graphene oxides are dispersed in water so that when the heat of collapse of the molten pool is applied to the bottom of the reactor vessel, the heat flux is increased from the outer wall. Water causes boiling, and when such boiling occurs, graphene-based materials dispersed in the water are coated with the outer wall of the reactor. This coating has a regular porous structure as shown in Figure 4, the boiling heat and heat dissipation efficiency due to the high thermal conductivity (5200w / mK) of the graphene and the porous structure is greatly increased, so that the critical heat flux value uses water as the cooling water. It is about 2.8 times higher than that.

In other words, the use of coolant dispersed in water as a coolant in the reactor outer wall cooling system, the critical heat flux value becomes much larger, and the outer wall cooling capacity is secured. This can greatly contribute to securing nuclear safety.

Furthermore, it is determined that the thermal conductivity does not critically affect the critical heat flux (CHF) value. That is, the thermal conductivity of the Al ₂ O ₃ nanomaterial dispersed fluid was about 10 times lower than that of the graphene dispersed fluid, but the CHF value was reversed, whereas the graphene was dispersed in the Al ₂ O ₃ nanomaterial dispersed fluid. Because it came out bigger than the fluid.

-System using coolant with dispersed nano materials as coolant

An embodiment of a reactor outer wall cooling system using a coolant in which any one of graphene, graphene oxide, and Al ₂ O ₃ is dispersed in water will be described.

The present invention includes a reactor vessel (10); and a heat shield (20) surrounding the outer wall of the reactor vessel (10) at regular intervals; And a reactor cavity (30) having the heat shield (20) and the reactor vessel (10) therein, wherein the cooling material supplied to the system includes nanomaterials (51). It is to provide a cooling system of the outer wall of the reactor, characterized in that the dispersion is used as a coolant of the reactor outer wall cooling system.

In other words, regardless of the configuration of the entire system, the system using the graphene or graphene-oxide-dispersed water as the coolant may correspond to the present invention by utilizing the results of the above test.

Furthermore, the present invention will be described with reference to specific examples.

(1) First embodiment

1 is a block diagram of a reactor outer wall cooling system according to a first embodiment of the present invention.

According to a first embodiment of the present invention, a reactor vessel (10); and a heat shield (20) surrounding the outer wall of the reactor vessel (10) at regular intervals; And a reactor cavity (30) having the heat shield (20) and the reactor vessel (10) therein, comprising: a reservoir (40) for storing cooling water therein; and , Nanomaterial dispersion tank 50 for storing the nanomaterial therein; and one end is connected to the reservoir 40 and the other end is connected to the lower portion of the reactor cavity 30 or the heat shield 20, the reservoir Cooling water injection pipes (60, 61) for forming a passage in which the coolant of the 40 is injected into the reactor cavity (30) or the heat shield 20; and one end is in communication with the nanomaterial dispersion tank (50) And the other end is in communication with the coolant injection pipe 60 to form a passage for dispersing the nanomaterial 51 into the coolant injection pipe 60; and a nanomaterial injection pipe 70; and the coolant injection pipe 60 61, the reactor cavity 30 or the heat shield 20 Cooling water injection valves (80,81) for intermittent flow of the cooling water injected into; and the nanomaterial 51 provided in the nanomaterial injection pipe (70), dispersed in the cooling water injection pipe (60) A nano material injection valve 90 for intermittent; And at least one pump (100) provided on the cooling water supply system including the water reservoir (40) and the cooling water injection pipe (60, 61) to pump the cooling water. 61) provides a cooling system of the outer wall of the reactor, characterized in that the nanomaterial 51 is dispersed in the cooling water injected into the reactor to be used as a coolant of the reactor outer wall cooling system.

Reactor outer wall cooling system according to this embodiment is a system for cooling the reactor outer wall of the APR1400, a new domestic light water reactor, as shown in Figure 1, the reservoir 40, the cooling water injection pipe (60, 61), nanomaterial dispersion It comprises a tank 50, nanomaterial injection pipe 70 and the cooling water pump (100).

The reservoir 40 stores coolant (water) for cooling the outer wall of the reactor vessel 10 during a major accident in which the core is melted, and a nuclear fuel reload tank (in-containment) provided inside the containment building (1). The refueling water storage tank (IRWST) can be used as a reservoir 40 to form a cooling system using existing equipment without additional reservoir equipment.

One end of the cooling water injection pipe (60, 61) is connected to the reservoir 40 and the other end is connected to the lower portion of the reactor cavity (30) or the lower portion of the heat shield (20).

That is, the first cooling water injection pipe 60 is connected to the lower portion of the reactor cavity 30 to fill the reactor cavity 30, and then coolant flows into the heat shield 20 to naturally circulate due to natural convection. Will be

In order to compensate for this disadvantage, in the present invention, the second cooling water injection pipe 61 is directly connected to the lower portion of the heat shield 20 so that the reactor outer wall can be quickly cooled. In this method, since the cooling water is forcibly injected before the natural convection occurs, the cooling water must be continuously forced until the reactor cavity 30 is completely filled. Furthermore, it is possible to utilize the case where the coolant is continuously injected without forcing the reactor cavity 30, that is, without using any natural convection.

The cooling water pump 100 is provided on the path of the cooling water injection pipes 60 and 61 to forcibly pump the cooling water stored in the reservoir 40 to supply the cooling water.

The nanomaterial dispersion tank 50 stores a nanomaterial 51 dispersed in a cooling water (water) for cooling the outer wall of the reactor vessel 10 during a major accident in which the core is melted. Graphene, graphene-oxide, and Al ₂ O ₃ .

Further, the nanomaterial 51 is preferably dispersed in a ratio of 10 ^-5 to 1% by volume relative to the total coolant volume.

In addition, when the compressed gas 52 is injected into the nanomaterial dispersion tank 50 to open the nanomaterial injection valve 90, the nanomaterial 51 is pushed to the gas pressure by cooling water (water). ), But is not limited thereto, and any method may be used. In the present invention, the compressed gas 52 uses N ₂ gas, but is not limited thereto, and various other gases may be used.

One end of the nanomaterial injection pipe 70 communicates with the nanomaterial dispersion tank 50 and the other end communicates with the cooling water injection pipe 60 to disperse the nanomaterial 51 into the cooling water injection pipe 60. To form a passageway.

As such, the reservoir 40, the coolant injection pipes 60 and 61, the coolant pump 100, the nanomaterial dispersion tank 50 and the nanomaterial injection pipe 70 are inside the reactor cavity 30 and the heat shield 20. By forming a supply system for supplying a coolant which is a coolant (water) in which the nanomaterials 51 are dispersed, and causes a serious accident in which the core is melted to form the core melt 11, Cooling water is supplied through the cooling water injection pipe 60, and the coolant injection pipe 60 includes a coolant formed by dispersing the nanomaterial 51 through the nanomaterial injection pipe 70, such as the reactor cavity 30 or the heat shield 20. ), And the coolant is circulated between the heat shield 20 and the reactor vessel 10 by natural convection (or forced pumping), so that the nanomaterial 51 is coated on the outer wall of the reactor cavity 30 so that the critical heat flux Cooling the core melt 11 while acting as an enhancement mechanism. It becomes.

A cooling water injection valve 81 is provided at an outlet side of the cooling water pump 100 in the path of the cooling water injection pipes 60 and 61 to control the flow of the cooling water supplied through the cooling water injection pipes 60 and 61, and the water tank 40 Cooling water injection valve 80 is also provided at the outlet side of the c) to intercept the flow of cooling water supplied to the cooling water injection pipe (60, 61) from the reservoir (40).

In addition, a nano material injection valve 90 is provided in the path of the nano material injection pipe 70 to intercept the flow of the nano material 51 dispersed through the nano material injection pipe 70.

In addition, as shown in FIG. 3, the domestic new water reactor APR1400 has a plurality of furnace measuring tubes 12 installed at the lower portion of the reactor vessel 10 to vertically penetrate the center of the bottom surface of the heat shield 20. Since the second coolant injection pipe 61 is connected to the lower portion of the heat shield 20, the second coolant injection pipe 61 branches a plurality of second coolant injection pipes 61 so as to extend outside of the shielding body 20. It is preferable that one end is disposed along the bottom circumference of the heat shield 20 to avoid interference with the furnace measuring tube 12 so as to vertically penetrate the bottom of the heat shield 20 upwards.

(2) Second Embodiment

2 and 3 show the configuration of the reactor outer wall cooling system according to a second embodiment of the present invention.

According to a second embodiment of the present invention, a reactor vessel (10); and a heat shield (20) surrounding the outer wall of the reactor vessel (10) at regular intervals; And a reactor cavity (30) having the heat shield (20) and the reactor vessel (10) therein, comprising: a reservoir (40) for storing cooling water therein; and A nano material dispersion tank 50 storing the nano material 51 therein; and one end connected to the reservoir 40 and the other end connected to a lower portion of the reactor cavity 30 or the heat shield 20. Cooling water injection pipes 60 and 61 forming a passage through which the coolant of the reservoir 40 is injected into the reactor cavity 30 or the heat shield 20; and one end of the nanomaterial dispersion tank 50. And a nanomaterial injection pipe 71 communicating with the inside of the heat shield 20 to form a passage for dispersing the nanomaterial 51 into the heat shield 20. Cooling water injection pipe (60, 61) is provided, the reactor cavity 30 or the heat shield 20 Cooling water injection valves (80,81) to regulate the flow of the cooling water injected into the interior; and, provided in the nanomaterial injection pipe 71, the nano to control the flow of nanomaterials dispersed in the heat shield 20 Material injection valve 90; And at least one pump (100) provided on the cooling water supply system including the water reservoir (40) and the cooling water injection pipe (60, 61) to pump the cooling water. 61) provides a cooling system of the outer wall of the reactor, characterized in that the nano-material 51 is dispersed in the cooling water circulated in the heat shield 20 to be used as a coolant of the reactor outer wall cooling system.

Reactor outer wall cooling system according to this embodiment is a system for cooling the reactor outer wall of the APR1400, a new domestic light water reactor, as shown in Figure 2, the reservoir 40, the cooling water injection pipe (60, 61), nanomaterial dispersion It comprises a tank 50, nanomaterial injection pipe 71 and the cooling water pump 100.

Compared with the first embodiment, the second embodiment has a difference in that the nanomaterial injection pipe 71 is directly connected to the inside of the heat shield 20 without being connected to the cooling water injection pipes 60 and 61. The remaining components and operations are the same, so I will focus on the differences.

One end of the nanomaterial injection pipe 71 is in communication with the nanomaterial dispersion tank 50, and the other end thereof is in communication with the inside of the heat shield 20 so that the nanomaterial 51 into the heat shield 20. Form a passageway to disperse. That is, in the second embodiment, a method of dispersing the nanomaterial 51 directly in the cooling water (water) circulating inside the heat shield 20 is used.

Here, the other end of the nano-material injection pipe 71 is installed through the heat shield 20, the outer wall slope of the lower portion of the reactor vessel 10 is installed so as to be sprayed in a section larger than 70 ° and less than 90 ° Preferably, the other end of the nanomaterial injection pipe (71) is preferably installed to be perpendicular to the outer wall of the reactor vessel (10).

The lower portion of the reactor vessel 10 is generally hemispherical, and considering the reactor vessel 10 as a cross section as shown in FIG. 3, the inclination of each point of the lower outer wall of the reactor vessel 10 is distributed at 0 to 90 °. . The inclination of the lowest end of the reactor vessel 10 is 0 degrees, and the inclination of the top of the semicircle corresponds to 90 degrees. Among these, the part with the highest heat flow rate (heat load) at the time of accident is the part of the lower part of the reactor vessel 10 whose inclination of the outer wall is 70 to 90 °, so that the nanomaterial 51 is preferably injected into this part. The other end of the 71 is preferably injected perpendicular to the outer wall of the reactor vessel 10 so that the nanomaterial 51 is easily coated on the outer wall of the reactor vessel 10.

That is, as can be seen from the enlarged view of the portion B of FIG. 3, as indicated by the third tangent line L3 of point c of the outer wall of the reactor vessel 10, the slope of the point c is 0 ° and the second tangent line of the b point ( As can be seen in L2), the inclination of point b corresponds to 90 °, and the inclination of the outer wall of the reactor vessel 10 may be distributed from 0 ° to 90 °.

Further, since the inclination of the outer wall of the reactor vessel 10 at point a is 70 °, and the inclination of the outer wall of the reactor vessel 10 at point b corresponds to 90 °, the portion having the highest heat flow rate (heat load) at the point of accident is the reactor vessel ( Since the inclination of the outer wall of the lower part of 10) is 70 to 90 °, it is preferable to inject the nanomaterial 51 to this part.

In addition, the other end of the nanomaterial injection pipe 71 is preferably provided with a nozzle (Nozzle, 72).

As such, the reservoir 40, the coolant injection pipes 60 and 61, the coolant pump 100, the nanomaterial dispersion tank 50 and the nanomaterial injection pipe 71 are inside the reactor cavity 30 and the heat shield 20. Forming a supply system for supplying a coolant in which the nanomaterials 51 are dispersed into the heat shield 20 to the coolant (water) passing through the core, a core accident occurs in which the core melts to form the core melt 11. When the cooling water of the reservoir 40 is supplied through the coolant injection pipe 60, the coolant formed by directly dispersing the nanomaterial 51 through the nanomaterial injection pipe 71 into the heat shield 20 is heat. The core is allowed to circulate between the shield 20 and the reactor vessel 10 by natural convection (or forced pumping) so that the nanomaterial 51 is coated on the outer wall of the reactor cavity 30 to act as a critical heat flux enhancement mechanism. The melt 11 is cooled.

In the event of a serious accident that the core melts in the reactor, the core melt composed of nuclear fuel and structures is relocated to the lower part of the reactor vessel to form a core melt pool, and the reactor vessel is damaged through high temperature and chemical reactions due to the heat of collapse of the core melt. This can expose a large amount of radioactive material out of the reactor vessel.

In order to prevent such an accident, the reactor outer wall cooling system according to the second embodiment of the present invention (in the case of the first embodiment, only the location where the nanomaterial 51 is supplied is different, the same is the same) is operated to operate the reactor. A method of cooling the outer wall of the battery will be described in detail with reference to FIGS. 2 and 3.

When a serious accident is detected, the cooling water injection valves 80 and 81 are all opened and the cooling water pump 100 is operated to cool the cooling water (water) stored in the water tank 40 to the reactor cavity 30 or the heat shield 20. It is supplied to the inside of the, the heat shield 20 and the coolant (dispersed) in the cooling water (water) circulated between the reactor vessel 10 to the coolant (S1) to be circulated (S1).

If the coolant is continuously supplied to the inside of the heat shield 20 through the coolant inlet 23 provided in the lower portion of the heat shield 20 in the step S1, the supplied coolant passes through the inside of the heat shield 20 nano The material 51 is coated on the outer wall of the reactor vessel 10 and cooled while acting as a critical heat flux enhancing mechanism, and then to the reactor cavity 30 through a cooling water outlet 22 provided on top of the heat shield 20. After exiting and going down, the coolant is returned to the coolant inlet 23 again to repeat the same cycle (S2).

When the coolant injected into the heat shield 20 through the steps S1 and S2 sufficiently cools the outer wall of the reactor vessel 10 to a stable state, the operation of the coolant pump 100 is stopped and the coolant injection valve ( 80, 81) and the nanomaterial injection valve 90 is closed to stop the cooling (S3).

As described above, although the present invention has been described by way of limited embodiments and drawings, the present invention is not limited thereto and is intended by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalents of the claims to be described.

10: reactor vessel
20: heat shield
30: reactor cavity
40: reservoir
50: Nano Material Dispersion Tank
60,61: 1st, 2nd cooling water injection pipe
70: nano material injection piping
80,81: Cooling water injection valve
90: nano material injection valve
100: pump
110: steam generator

Claims (14)

The present invention relates to the use of nanomaterials dispersed in cooling water and used as a coolant.
A method of using nanomaterials, wherein the nanomaterials are dispersed in cooling water and used as a coolant in a reactor wall cooling system. The method of claim 1,
The nanomaterial is a method of using a nanomaterial, characterized in that dispersed in a ratio of 10 ^-5 ~ 1% by volume relative to the total volume of the coolant. The method according to claim 1 or 2,
The nanomaterial is a graphene (graphene) or graphene oxide (graphene-oxide) method of using a nanomaterial, characterized in that. A reactor vessel (10); and a heat shield (20) surrounding the outer wall of the reactor vessel (10) at regular intervals; And a reactor cavity (30) having the heat shield (20) and the reactor vessel (10) therein, wherein the reactor outer wall cooling system comprises:
A nuclear reactor outer wall cooling system, characterized in that for dispersing nanomaterials (51) in the cooling water supplied to the system as a coolant of the reactor outer wall cooling system. The method of claim 4, wherein
Reservoir 40 for storing the cooling water therein;
Nanomaterial dispersion tank 50 for storing the nanomaterial therein;
One end is connected to the reservoir 40 and the other end is connected to the lower portion of the reactor cavity 30 or the heat shield 20, so that the coolant in the reservoir 40 is the reactor cavity 30 or the heat shield 20. Cooling water injection pipe (60, 61) to form a passage that is injected into the interior of the;
One end is in communication with the nanomaterial dispersion tank 50, the other end is in communication with the cooling water injection pipe 60 to form a passage for dispersing the nanomaterial 51 into the cooling water injection pipe 60. 70;
Cooling water injection valves (80,81) provided in the cooling water injection pipes (60, 61) to control the flow of cooling water injected into the reactor cavity (30) or the heat shield (20);
A nanomaterial injection valve (90) provided in the nanomaterial injection pipe (70) to control the flow of the nanomaterial (51) dispersed in the cooling water injection pipe (60); And
And at least one pump (100) provided on the cooling water supply system including the reservoir (40) and the cooling water injection pipe (60, 61) to pump the cooling water.
Reactor outer wall cooling system, characterized in that for dispersing the nano-material (51) in the cooling water injected into the cooling water injection pipe (60, 61) as a coolant of the reactor outer wall cooling system. The method of claim 4, wherein
Reservoir 40 for storing the cooling water therein;
Nanomaterial dispersion tank 50 for storing the nanomaterial 51 therein;
One end is connected to the reservoir 40 and the other end is connected to the lower portion of the reactor cavity 30 or the heat shield 20, so that the coolant in the reservoir 40 is the reactor cavity 30 or the heat shield 20. Cooling water injection pipe (60, 61) to form a passage that is injected into the interior of the;
One end is in communication with the nanomaterial dispersion tank 50, the other end is in communication with the interior of the heat shield 20 to form a passage for dispersing the nanomaterial 51 into the inside of the heat shield 20 Injection pipe 71;
Cooling water injection valves (80,81) provided in the cooling water injection pipes (60, 61) to control the flow of cooling water injected into the reactor cavity (30) or the heat shield (20);
A nanomaterial injection valve (90) provided in the nanomaterial injection pipe (71) to control a flow of nanomaterials dispersed in the heat shield (20); And
And at least one pump (100) provided on the cooling water supply system including the reservoir (40) and the cooling water injection pipe (60, 61) to pump the cooling water.
Reactor outer wall cooling system, characterized in that the injection of the cooling water injection pipes (60, 61) and the nano material 51 in the cooling water circulating inside the heat shield 20 to be used as a coolant of the reactor outer wall cooling system . The method according to any one of claims 4 to 6,
The nanomaterial (51) is a cooling system of the outer wall of the reactor, characterized in that dispersed in a ratio of 10 ^-5 ~ 1% by volume relative to the total coolant volume. The method of claim 7, wherein
The nanomaterial (51) is a cooling system of the reactor outer wall, characterized in that the graphene (graphene) or graphene oxide (graphene-oxide). The method according to claim 5 or 6,
When the compressed gas (52) is injected into the nanomaterial dispersion tank (50) to open the nanomaterial injection valve (90) to push the nanomaterial (51) with gas pressure, the cooling system of the reactor outer wall. 10. The method of claim 9,
Cooling system of the reactor outer wall, characterized in that the compressed gas (52) is N ₂ gas. The method of claim 6,
The other end of the nanomaterial injection pipe 71 is installed so that the inclination of the outer wall of the reactor vessel 10 of the heat shield 20 is sprayed in a section larger than 70 ° and less than 90 °, the cooling of the outer wall of the reactor system. The method of claim 11,
The other end of the nanomaterial injection pipe (71) is installed so as to be perpendicular to the outer wall of the reactor vessel (10) cooling system of the outer wall of the reactor. The method according to any one of claims 6, 11 and 12,
Cooling system of the outer wall of the reactor, characterized in that the injection nozzle (Nozzle, 72) is provided at the other end of the nanomaterial injection pipe (71). The method according to claim 5 or 6,
The reservoir 40 is an in-containment refueling water storage tank (IRWST) provided in the containment building (1), the cooling system of the outer wall of the reactor.

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