JP2019035696A - Reactor core melt reception device and method of installing the same, heat-resistant component, and nuclear power facility - Google Patents

Abstract

To provide a reactor core melt reception device that can securely hold a reactor core melt, produced when an accident occurs, in a nuclear reactor container, and is easy to construct.SOLUTION: A reactor core melt reception device according to an embodiment is installed in a nuclear reactor container below a nuclear reactor pressure container, and receives a nuclear reactor melt produced if an accident occurs and a reactor core is molten. The reactor core melt reception device has: a plurality of sealed containers 41 arranged along a predetermined installation surface; a plurality of heat resistant members 47 housed in the sealed containers 41 respectively and fixed in the sealed containers 41; and particulate matter 50 which is charged in the respective sealed containers 41 and charged between the plurality of heat resistant members 47, and made of a heat-resistant material.SELECTED DRAWING: Figure 4

Description

  Embodiments of the present invention include a heat-resistant component, a core melt receiving device that receives a core melt generated when the core is melted in a nuclear accident, a method for installing the core melt receiving device, and a nuclear facility provided with the core melt receiving device About.

  In a water-cooled nuclear reactor, if the cooling water is lost due to the stoppage of water supply to the reactor pressure vessel or the breakage of piping connected to the reactor pressure vessel, the reactor water level falls and the core is exposed and cooled. May be insufficient. Assuming such a case, the reactor is automatically shut down in response to a water level lowering signal, and the core is submerged and cooled by injecting coolant using an emergency core cooling system (ECCS), and a core melting accident is performed. It is designed to prevent it.

  However, although the probability is very low, it can be assumed that the emergency core cooling device does not operate and water injection devices for other cores cannot be used. In such a case, the core is exposed due to a decrease in the reactor water level, and sufficient cooling is not performed, and the fuel rod temperature rises due to decay heat that continues to occur after the reactor shuts down, eventually leading to core melting. It is possible. When such a situation occurs, the hot core melt melts into the lower part of the reactor pressure vessel, and further melts through the reactor pressure vessel lower mirror and falls onto the floor in the reactor containment vessel. Can be considered.

  The core melt (melting core, debris) heats the concrete that is stretched between the reactor containment floor and the drain sump installed on the floor, and reacts with the concrete when the contact surface reaches a high temperature. A large amount of non-condensable gas such as is generated, and concrete is melted and eroded. The generated non-condensable gas increases the pressure in the containment vessel and may damage the containment vessel. Also, the containment vessel boundary may be damaged by melting and erosion of concrete. There is a possibility of reducing the structural strength. As a result, if the reaction between the core melt and concrete continues, the reactor containment vessel may be damaged, and the radioactive material in the reactor containment vessel may be released to the external environment.

  Also, if the core melt enters the drain sump normally located at the bottom of the reactor containment vessel, the area of the upper surface of the core melt is smaller than the volume of the core melt. Even if water is injected into the lower part of the core, the temperature of the core melt does not decrease, and erosion of the drain sump bottom may continue.

  In order to suppress the reaction between the core melt and the concrete, the core melt is cooled, and the temperature of the contact surface with the concrete at the bottom of the core melt is cooled to the erosion temperature or lower (1500 K or lower for general concrete). Or it is necessary to avoid direct contact between the core melt and concrete. For this reason, various countermeasures have been proposed in case the core melt falls. A typical one is called a core catcher, which is a facility that receives a fallen core melt with a heat-resistant material and cools the core melt in combination with water injection means.

  Even if cooling water is injected into the top surface of the core melt that has fallen onto the pedestal, which is the inner wall and floor of the reactor containment vessel, if the amount of heat removal at the bottom of the core melt is small, the temperature at the bottom of the core melt is caused by decay heat. May remain hot and may not be able to stop concrete erosion of the pedestal. Therefore, several methods of cooling the core melt from the bottom surface have been proposed. There is also a simple one called a corium shield in which only the heat-resistant material is laid on the storage container floor without using a cooling flow path. As for the laying method of the heat-resistant material, a coupling method using the engagement of grooves and protrusions has been proposed.

Japanese Patent No. 3150451

  By the way, in the system using the core catcher described above, in order to hold the core melt and to thermally protect the structure for holding the core, it is cooled by a system in which a heat-resistant material is spread and the outside is naturally circulated by cooling water. To do. Further, in the system in which the heat-resistant material is spread directly on the storage container floor surface, the concrete on the floor surface is thermally protected. The heat-resistant material in the core catcher mentioned above or the heat-resistant material laid on the containment vessel floor surface is displaced by an earthquake, mechanical impact due to dropping of the pressure vessel substructure, property change due to immersion in reactor water during normal operation, core melt There is a possibility of breakage or collapse due to factors such as short-term impingement at the time of fall, long-term thermal and chemical erosion of the core melt and heat-resistant material. Therefore, there is a possibility that the original function cannot be sufficiently exhibited when holding the core melt.

  The present embodiment is based on the above circumstances, and its purpose is to reduce the possibility of misalignment or breakage of the heat-resistant material, and to easily install the core-melt receiving device and its installation method, heat resistance It is to provide a nuclear facility equipped with parts and a core melt receiver.

  In order to solve the above problems, a core melt receiving apparatus according to the present embodiment is installed below the reactor pressure vessel in a reactor containment vessel that stores a reactor pressure vessel that accommodates the core, and an accident occurs. A core melt receiving device for receiving a core melt that is sometimes generated when the core is melted, comprising a plurality of sealed containers arranged along a predetermined installation surface, and a heat-resistant material filled in the sealed container And a granular material.

  Further, the nuclear facility according to the present embodiment includes a core, a reactor pressure vessel that accommodates the reactor core, a reactor containment vessel that stores the reactor pressure vessel, and the reactor pressure within the reactor containment vessel. A core melt receiving device installed below a vessel and receiving a core melt generated when the core melts in the event of an accident, the core melt receiving device being installed in a predetermined manner It has the some airtight container arranged along the surface, and the granular material which consists of a heat-resistant material with which the said airtight container was filled, It is characterized by the above-mentioned.

  Further, the core melt receiver installation method according to the present embodiment includes a core melt receiver that receives a core melt generated when the core is melted in the event of an accident, and has a reactor below the reactor pressure vessel that houses the core. A method of installing in a furnace containment vessel, a filling step of filling the airtight container with a granular material made of a heat-resistant material, a sealing step of sealing the airtight container after the filling step, and after the sealing step And a container installation step of arranging the plurality of sealed containers along a predetermined installation surface.

  Further, the heat-resistant component according to the present embodiment is a heat-resistant component that is arranged in a plurality along a predetermined installation surface, and includes a sealed container and a granular material made of a heat-resistant material filled in the sealed container. It is characterized by having.

  According to this embodiment, the possibility of deviation or breakage of the heat-resistant material is reduced, and the construction is easy.

1 is a schematic sectional elevation showing a configuration of a containment vessel according to a first embodiment. FIG. FIG. 2 is a schematic vertical sectional view showing the core catcher of FIG. 1 and its periphery in an enlarged manner. The perspective view which expands and shows a part of core melt receiving apparatus of FIG. The perspective view which shows the internal structure of one heat-resistant airtight container which comprises the core melt receiving apparatus of FIG. The perspective view which takes out and shows the bottom plate of the heat-resistant airtight container of FIG. The perspective view which takes out and shows one of the fixing tools of FIG. The flowchart which shows an example of the procedure of the installation method of the core melt receiving apparatus which concerns on 1st Embodiment. The typical elevation sectional view showing the core melt receiving device concerning a 2nd embodiment. The typical elevation sectional view showing the core melt receiving device concerning a 3rd embodiment. The typical elevation sectional view showing the internal structure of one heat-resistant airtight container of the core melt receiver concerning a 4th embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. Here, the same or similar parts are denoted by common reference numerals, and redundant description is omitted.

[First Embodiment]
FIG. 1 is a schematic sectional elevation view showing the configuration of the nuclear facility according to the first embodiment. 2 is an enlarged schematic sectional view showing the core catcher of FIG. 1 and its periphery. FIG. 3 is an enlarged perspective view showing a part of the core melt receiver of FIG. FIG. 4 is a perspective view showing an internal structure of one heat-resistant airtight container constituting the core melt receiver of FIG. 5 is a perspective view showing the bottom plate of the heat-resistant airtight container of FIG. FIG. 6 is a perspective view showing one of the fixtures shown in FIG.

  A nuclear facility 100 shown in FIG. 1 is a boiling water nuclear facility, and a reactor pressure vessel 10 is disposed in a reactor containment vessel 12. A reactor core 11 is accommodated in the reactor pressure vessel 10. The internal space of the reactor containment vessel 12 includes a dry well 13 that accommodates the reactor pressure vessel 10 and a wet well 15 that accommodates the pressure suppression pool 14. The dry well 13 and the pressure suppression pool 14 communicate with each other through a vent pipe 16.

  The reactor pressure vessel 10 is supported by a cylindrical pedestal 17 made of concrete and having an open top. The bottom of the pedestal 17 is substantially circular and a concrete pedestal bottom 18 is formed. In the dry well 13, a space surrounded by the pedestal 17 and below the reactor pressure vessel 10 and above the pedestal bottom 18 is referred to as a pedestal space 19. A wet well 15 is formed around the pedestal 17.

  A part of the pedestal bottom 18 is dug to form a drain sump 20. However, the drain sump 20 is not shown in FIG. In the drain sump 20, a detector for detecting water leakage (not shown) is arranged.

  A core catcher 21 is disposed on the pedestal bottom 18. The core catcher 21 has a structure that can hold and cool the core melt falling through the bottom of the reactor pressure vessel 10 in the event of a core melting accident.

  In addition, although the drain sump 20 is often formed in the existing furnace as described above, it is conceivable to provide a structure having a water leakage detection function separately from the drain sump 20 when the core catcher 21 is installed. As an example of such a configuration, a detector may be installed on the core catcher 21, and a floor for collecting water leakage may be installed above the core catcher 21. When applying such a configuration, the drain sump 20 may be left alone or removed. Moreover, when installing the core catcher 21 at the time of plant construction, it is possible to provide the structure which has a water leak detection function different from the drain sump 20 mentioned above, without providing the drain sump 20. FIG.

  A water injection pipe 23 for supplying cooling water from the outside of the reactor containment vessel 12 to the upper side of the core catcher 21 in the event of an accident is provided, and a water injection valve 24 is provided in the pedestal space 19 in the middle of the water injection pipe 23.

  As shown in FIG. 2, the core catcher 21 includes a substantially circular horizontal support portion 30 that extends horizontally on the pedestal bottom portion 18, and a side wall portion 31 that extends upward along the periphery of the horizontal support portion 30. . Cooling water flow paths are formed between the horizontal support 30 and the pedestal bottom 18 and between the side wall 31 and the pedestal 17. The cooling water flow path is partitioned by the partition plate 60 and is configured to promote natural circulation. Although details are not shown in detail, the partition plate 60 is supported so as to keep an appropriate distance from the core catcher 21, the pedestal bottom 18 and the pedestal 17. In FIG. 2, the direction of the cooling water flow is indicated by an arrow A.

  Cooling water that has flowed into the pedestal space 19 through the water injection pipe 23 and the water injection valve 24 at the time of the reactor accident descends in the annular descending flow path 32 along the inner surface of the pedestal 17, and then the bottom centripetal flow along the pedestal bottom 18. It flows in the path 33 toward the center of the pedestal bottom 18. Thereafter, the cooling water rises in the central ascending flow path 34, flows in the centrifugal flow path 35 toward the radially outer side along the lower surface of the horizontal support portion 30, and then rises in an annular shape along the outer surface of the side wall portion 31. A part of the cooling water rising in the flow path 36 and flowing out from the outlet of the rise flow path 36 is again configured to flow into the down flow path 32 and part into the inside of the core melt receiver 40. .

  A plurality of heat-resistant sealed containers (sealed containers) 41 constituting the core melt receiver 40 are laid along the upper surface of the horizontal support portion 30 and the inner surface (predetermined installation surface) of the side wall portion 31. Each of the heat-resistant airtight containers 41 is a heat-resistant component containing a heat-resistant material as will be described later. Each heat-resistant airtight container 41 is a substantially rectangular parallelepiped. However, since the upper surface of the horizontal support portion 30 is substantially circular as a whole, for example, as shown in FIG. 3, the upper surface shape of each heat-resistant sealed container 41 may be trapezoidal and arranged so as to be circular as a whole. FIG. 3 shows two rows of heat-resistant sealed containers 41 adjacent to each other arranged in the radial direction. In this case, for example, a regular polygonal column-shaped heat-resistant airtight container 41 (not shown) may be disposed at the center in the radial direction. As an example different from the arrangement shown in FIG. 3, a plurality of rectangular parallelepiped heat-resistant sealed containers 41 are arranged horizontally and vertically, and a triangular prism-shaped heat-resistant sealed container is arranged around the periphery, thereby forming a polygon that is nearly cylindrical as a whole. It may be columnar.

  As shown in FIG. 4, each heat-resistant airtight container 41 includes a container bottom plate 42 and a container cover 43 that covers the top of the container bottom plate 42 and is sealed in a watertight manner. However, FIG. 4 shows a state before the container cover 43 is attached, and the outer shape of the container cover 43 is indicated by a two-dot chain line. The constituent material of the heat-resistant sealed container 41 is preferably a high-melting-point heat-resistant material such as stainless steel or tungsten, and is inactive to the core melt (debris) components.

  One or a plurality of heat resistant members 47 (described as four in this embodiment) are arranged in each heat resistant sealed container 41, and each heat resistant member 47 is fixed on the container bottom plate 42 by a fixture 44. . As shown in FIG. 4, each heat-resistant member 47 has a rectangular parallelepiped shape, for example, and is made of a heat-resistant material such as zirconium oxide (zirconia) or aluminum oxide (alumina). A recess 45 into which the lower part of the heat-resistant member 47 is fitted is formed on the upper surface of the container bottom plate 42, and the heat-resistant member 47 is configured to be stably fixed. As shown in FIG. 6, the fixture 44 is attached so as to surround a side portion and an upper portion of the heat-resistant member 47, a bolt (not shown) is passed through the bolt hole 46, and a screw hole formed on the upper surface of the container bottom plate 42 ( It can be attached by tightening bolts (not shown).

  Between two adjacent heat-resistant members 47, a granular material 50 made of a heat-resistant material such as mortar is filled. In the example of FIG. 4, the powder body 50 is filled only in a part of the opposing portions of the two adjacent heat-resistant members 47, but all the gaps in the heat-resistant sealed container 41 are filled with the powder body 50. May be. The granular material 50 may be a commercially available mortar based on cement, or a powder containing zirconium oxide.

  In order to install a plurality of heat-resistant airtight containers 41 constituting the core melt receiver 40 side by side along the upper surface of the horizontal support portion 30 and the inner surface (predetermined installation surface) of the side wall portion 31, for example, anchor bolts (not shown) Can be used. That is, a plurality of anchor bolts are installed on the installation surface, a bolt hole (not shown) through which the anchor bolt penetrates is provided in the heat-resistant airtight container 41, and a nut (not shown) is tightened on the anchor bolt. 41 can be fixed. Moreover, you may couple | bond together the heat-resistant airtight container 41 which adjoins mutually by a coupling member (not shown).

  Since the heat-resistant airtight container 41 is watertight, when the cooling water falls on the core melt receiving device 40 due to an event that is not a severe accident such as leakage from a pipe connected to the reactor pressure vessel, the cooling water Can be prevented from entering the heat-resistant airtight container 41 and the internal heat-resistant member 47 and the like being deteriorated.

  Here, a method of installing the core melt receiver 40 of the present embodiment in the reactor containment vessel 12 will be described with reference to FIG. FIG. 7 is a flowchart showing an example of the procedure of the installation method of the core melt receiving apparatus according to the first embodiment.

  First, a plurality of heat-resistant members 47 are accommodated in each of the plurality of heat-resistant sealed containers 41, and are fixed in the heat-resistant sealed containers 41 by the fixtures 44 (heat-resistant member fixing step S1). However, at this time, the container cover 43 is removed, and the heat-resistant sealed container 41 is not sealed.

  Next, the granular material 50 made of a heat-resistant material is filled in a gap between the plurality of heat-resistant members 47 in the heat-resistant sealed container 41 or a gap between the heat-resistant sealed container 41 and the heat-resistant member 47 (filling step S2).

  Next, the container cover 43 of the heat-resistant sealed container 41 is placed on the container bottom plate 42, and the container cover 43 and the container bottom plate 42 are joined in a watertight manner by welding or the like (sealing step S3).

  The above steps S1 to S3 can be performed outside the reactor containment vessel 12.

  Next, the sealed heat-resistant airtight container 41 is carried into the reactor containment vessel 12 (carrying-in step S4).

  Next, the heat-resistant airtight containers 41 carried into the reactor containment vessel 12 are arranged along the upper surface of the horizontal support portion 30 and the inner surface (predetermined installation surface) of the side wall portion 31 (container installation step S5).

  According to this embodiment, since the heat-resistant member 47 is housed and fixed in the heat-resistant airtight container 41, for example, a mechanical impact caused by dropping of the pressure vessel lower structure, immersion of heat-resistant material by reactor water during normal operation, The shift of heat-resistant materials due to an earthquake can be prevented.

  Further, by using a high melting point debris component and an inert material for the heat-resistant airtight container 41, short-term impingement when the core melt is dropped can be prevented. By using a heat-resistant material such as zirconium oxide as the material of the heat-resistant member 47, long-term erosion due to the core melt can be suppressed. By filling the heat-resistant member 47 with the granular material 50 made of a heat-resistant material, the granular material 50 is hardly melted even in a high temperature state, and the elongation due to the thermal expansion of the heat-resistant member 47 can be absorbed. Damage to the heat-resistant member 47 can be prevented. As a result, the influence of the cause of the positional shift, breakage, and collapse of the heat-resistant member 47 can be minimized, and the original function of the heat-resistant member 47 can be brought out.

  From the viewpoint of the time during which the core catcher 21 can hold the core melt, and from the viewpoint of heat exchange between the core melt and the cooling water via the core melt receiver 40, the volume in the heat-resistant sealed container 41 is set to the heat-resistant member 47. It is preferable to fill the powder body 50 in all the gaps. More specifically, since the core melt can be held for a longer time as the mass of the heat-resistant material in the heat-resistant sealed container 41 is larger, it is desirable that the ratio of the heat-resistant material member 47 is higher. Moreover, since the process time, such as filling and filling rate management, becomes longer as the proportion of the powder particles 50 is larger, it is desirable that the proportion of the heat-resistant material 47 is larger from the viewpoint of manufacturability. Therefore, the larger the heat-resistant member 47 is, the more preferable, on the premise that a sufficient gap is secured to absorb the thermal expansion of the heat-resistant member 47 and the workability of attaching the fixing tool 44 after the heat-resistant material 47 is installed. . In addition, from the viewpoint of increasing the mass of the heat-resistant material in the heat-resistant airtight container 41 and improving the efficiency of heat exchange, it is desirable to fill the gaps with the powder 50 instead of spaces.

  On the other hand, in order to absorb the elongation due to the thermal expansion of the heat-resistant material in the heat-resistant airtight container 41, the gap is not completely filled with the powder 50, but a certain space is secured, or the filling rate of the powder 50 is It is made to become below predetermined.

  Furthermore, according to the present embodiment, since a plurality of heat-resistant members 47 are housed and fixed in each heat-resistant sealed container 41, a plurality of heat-resistant sealed containers 41 are disposed outside the reactor containment vessel 12. The heat-resistant member 47 is housed and fixed, and each heat-resistant sealed container 41 is sealed and then loaded into the reactor containment vessel 12 so that these heat-resistant sealed containers 41 can be installed. And the installation work in the reactor containment vessel 12 can be efficiently advanced.

  In the above description, the expression “heat resistance” includes high strength at high temperature, high melting point, and low reactivity with high temperature core melt.

  In the core catcher 21 shown in FIG. 1 and FIG. 2, the horizontal support portion 30 is assumed to spread horizontally, but as a modification, the horizontal support portion 30 has a bowl shape with a low center and a high peripheral portion ( (Mortar shape). With such a shape, further promotion of the natural circulation of cooling water is expected.

  Moreover, the heat-resistant airtight container 41 and the heat-resistant member 47 can take various shapes according to the shape of the installation surface. In particular, when laying on the bottom or wall of a pedestal space where an existing structure exists, or depending on the shape and structure of the core catcher 21, it is desirable to have a complicated shape in consideration of interference with other structures. Cases are also conceivable. In such a case, the heat-resistant airtight container 41 made of metal and easy to process is formed into a complicated shape, and the heat-resistant member 47 such as a rectangular parallelepiped is disposed inside and filled with the powder body 50. Manufacturability is improved compared to forming in a complicated shape.

[Second Embodiment]
FIG. 8 is a schematic vertical sectional view showing a core melt receiving apparatus according to the second embodiment. In this embodiment, the core catcher 21 (FIG. 1, FIG. 2) is not installed in the reactor containment vessel 12, and a plurality of heat-resistant airtight containers 41 constituting the core melt receiver 40 are provided on the bottom of the pedestal bottom 18. It is spread along the upper surface and the inner surface (predetermined installation surface) of the pedestal 17. Other configurations are the same as those of the first embodiment. Here, the drain sump 20 (FIG. 1) is not shown.

  In this embodiment, when the core catcher is not installed in the reactor containment vessel 12, it is possible to avoid the core melt from coming into direct contact with the upper surface of the concrete pedestal bottom 18 or the inner surface of the pedestal 17. Other operations and effects are the same as those of the first embodiment.

[Third Embodiment]
FIG. 9 is a schematic vertical sectional view showing a core melt receiving device according to a third embodiment. This embodiment is a modification of the second embodiment, and a gap 53 is formed between a plurality of heat-resistant sealed containers 41. Other configurations are the same as those of the second embodiment.

  In this embodiment, when the heat-resistant airtight container 41 is thermally expanded, the heat-resistant airtight containers 41 can be prevented from interfering with each other and being damaged.

  In the example shown in FIG. 9, a gap 53 is formed in the vicinity of the joint between the inner surface of the pedestal 17 and the upper surface of the pedestal bottom portion 18, but the inner surface of the pedestal 17 or the upper surface of the pedestal bottom portion 18 is also located at other positions. By forming a gap between the heat-resistant airtight containers 41 or between the heat-resistant airtight containers 41 adjacent to each other, damage to the heat-resistant airtight containers 41 and the like due to thermal expansion of the heat-resistant airtight containers 41 and the like can be avoided.

  In the above description, in the third embodiment, as a modification of the second embodiment, the heat-resistant sealed container 41 is arranged along the inner surface of the pedestal 17 and the upper surface of the pedestal bottom portion 18. As a modification of this embodiment, as in the first embodiment, when the heat-resistant sealed containers 41 are arranged along the upper surface of the horizontal support portion 30 of the core catcher 21 and the inner surface of the side wall portion 31 (see FIG. 2), A similar effect can be obtained by forming a gap between the sealed containers 41 or between the heat-resistant sealed container 41 and the upper surface of the horizontal support portion 30 or the inner surface of the side wall portion 31.

[Fourth Embodiment]
FIG. 10 is a schematic vertical sectional view showing the internal structure of one heat-resistant airtight container of the core melt receiver according to the fourth embodiment.

  In this embodiment, the plurality of heat-resistant members 47 housed in the heat-resistant sealed container 41 are two layers of an upper layer heat-resistant member (first heat-resistant member) 47a and a lower layer heat-resistant member (second heat-resistant member) 47b. .

  The upper heat resistant member 47a is made of a material having higher heat resistance than the lower heat resistant member 47b. For example, the upper heat-resistant member 47a is made of zirconium oxide, and the lower heat-resistant member 47b is made of aluminum oxide. When the core melt falls from above into the core melt receiver, the upper heat-resistant member 47a is exposed to a higher temperature than the lower heat-resistant member 47b, and there is a high possibility that a reaction with debris components will occur. In this embodiment, the upper heat-resistant member 47a is made of a material having higher heat resistance and lower reactivity with the debris component than the lower heat-resistant member 47b, so that the damage to the upper heat-resistant member 47a can be suppressed. it can. Further, by not using an expensive material having high heat resistance such as zirconium oxide for the lower layer heat resistant member 47b, the overall cost can be suppressed.

  In this embodiment, the horizontal position of the joint between the upper heat-resistant members 47a and the joint between the lower heat-resistant members 47b are shifted. As a result, even if the core melt enters from the upper side of the heat-resistant airtight container 41 in the event of an accident, even if the powder 50 between the upper heat-resistant members 47a melts and the core melt falls, the core melts. The fall of the object is prevented by the lower layer heat-resistant member 47b. Thereby, the fall of the core melt can be prevented.

  In the fourth embodiment, the configuration other than the internal structure of the heat-resistant sealed container 41 is the same as that of any of the first to third embodiments.

  In the above description, assuming that the core melt falls from above with respect to the heat-resistant sealed container 41, the case where the upper part of the heat-resistant sealed container 41 is exposed to a higher temperature than the lower part has been described. However, in the heat-resistant sealed container 41 disposed on the inner surface of the pedestal 17 or the inner surface of the side wall portion 31 of the core catcher 21, the inner side close to the core melt is exposed to a higher temperature in the event of an accident. Therefore, in that case, the inner side close to the core melt corresponds to the upper heat-resistant member (first heat-resistant member) 47a in the above description, and the outer side far from the core melt corresponds to the lower heat-resistant member (second heat-resistant member in the above description). ) 47b.

  In the above description, the horizontal position of the joint between the upper heat-resistant members 47a and the joint between the lower heat-resistant members 47b is shifted, but the inner surface of the pedestal 17 or the inner surface of the side wall 31 of the core catcher 21 Considering the heat-resistant airtight container 41 to be arranged, the joint between the first heat-resistant members 47a and the joint between the second heat-resistant members 47b do not overlap each other when viewed from the core melt at the time of the accident. That's fine.

[Other Embodiments]
As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  For example, in the first embodiment, if the required performance can be satisfied for the core melt holding and the heat exchange between the core melt and the cooling water via the core melt receiving device 40, the heat resistant sealed container 41 can be used. The structure filled with the granular material 50 without providing the heat-resistant member 47 may be sufficient. Even with such a configuration, it is possible to reduce the possibility of breakage of heat-resistant materials due to earthquakes, mechanical shocks, etc., deterioration due to water, and the like, and it is easy to perform construction on the installation surface.

DESCRIPTION OF SYMBOLS 10 ... Reactor pressure vessel, 11 ... Core, 12 ... Reactor containment vessel, 13 ... Dry well, 14 ... Pressure suppression pool, 15 ... Wet well, 16 ... Vent pipe, 17 ... Pedestal, 18 ... Bottom of pedestal, 19 ... Pedestal space, 20 ... Drain sump, 21 ... Core catcher, 23 ... Water injection piping, 24 ... Water injection valve, 30 ... Horizontal support, 31 ... Side wall, 32 ... Down flow path, 33 ... Bottom centripetal flow path, 34 ... Center rise Flow path, 35 ... Centrifugal flow path, 36 ... Ascending flow path, 40 ... Core melt receiving device, 41 ... Heat-resistant sealed container (sealed container), 42 ... Container bottom plate, 43 ... Container cover, 44 ... Fixing tool, 45 ... 46, Bolt hole, 47 ... Heat resistant member, 47a ... Upper layer heat resistant member (first heat resistant member), 47b ... Lower layer heat resistant member (second heat resistant member), 50 Granules, 53 ... gap, 60 ... partition plate, 100 ... nuclear facilities

Claims (15)

A core melt receiving device installed below the reactor pressure vessel in the reactor containment vessel for storing the reactor pressure vessel containing the core and receiving the core melt generated when the core melts in the event of an accident. There,
A plurality of sealed containers arranged along a predetermined installation surface;
A granular material made of a heat-resistant material filled in the sealed container;
A core melt receiver. The heat-resistant member accommodated in each of the sealed containers and further fixed in the sealed container is further provided, wherein the granular material is filled in a gap between the sealed container and the heat-resistant member. The core melt receiver as described.   The core melt receiving apparatus according to claim 2, wherein the installation surface is a floor surface in the reactor containment vessel.   The said installation surface is located above the floor surface in the said reactor containment vessel, The cooling water flow path through which a cooling water distribute | circulates between the said installation surface and the said floor surface is formed. 2. The core melt receiving apparatus according to 2.   5. A gap for absorbing thermal expansion of the sealed container is formed between the sealed containers or between the sealed container and the installation surface. The core melt receiver according to any one of the preceding claims.   The heat-resistant member housed in at least one of the plurality of closed containers is compared with the first heat-resistant member and the first heat-resistant member disposed on the side relatively close to the core melt at the time of an accident. And a second heat-resistant member disposed on the side farther from the core melt at the time of an accident, wherein the heat-resistant temperature of the first heat-resistant member is higher than the heat-resistant temperature of the second heat-resistant member, The core melt receiving device according to any one of claims 2 to 5. A plurality of first heat-resistant members, wherein the heat-resistant member housed in at least one of the plurality of closed containers is disposed on a side relatively close to the core melt at the time of an accident, and the first heat-resistant member A plurality of second heat-resistant members disposed on the side farther from the core melt at the time of an accident than
The gap between the plurality of first heat-resistant members and the gap between the plurality of second heat-resistant members are in positions where they do not overlap when viewed from the core melt at the time of an accident. Item 7. The core melt receiver according to any one of Items 6 to 7.   The core melt receiving apparatus according to any one of claims 2 to 7, wherein a heat resistant temperature of the heat resistant member is equal to or higher than a heat resistant temperature of the granular material and the sealed container.   The core melt receiving device according to any one of claims 2 to 8, wherein the heat-resistant member contains zirconia.   The core melt receiving apparatus according to any one of claims 2 to 9, wherein the sealed container is made of a metal material.   11. The apparatus according to claim 2, further comprising a fixture that is disposed inside at least one of the plurality of sealed containers and fixes the plurality of heat-resistant members to the sealed container. The core melt receiving apparatus described in 1.   The recess into which at least one of the heat-resistant members is fitted is formed at the bottom of at least one sealed container of the plurality of sealed containers. The core melt receiving apparatus described in 1. The reactor core,
A reactor pressure vessel containing the core;
A reactor containment vessel for housing the reactor pressure vessel;
A core melt receiving device that is installed below the reactor pressure vessel in the reactor containment vessel and receives a core melt generated when the core is melted in the event of an accident;
A nuclear facility equipped with
The core melt receiver is
A plurality of sealed containers arranged along a predetermined installation surface;
A granular material made of a heat-resistant material filled in the sealed container;
A nuclear facility characterized by comprising: A method of installing a core melt receiving device for receiving a core melt generated when a core is melted at the time of an accident in a reactor containment vessel below a reactor pressure vessel containing the core,
A filling step of filling a plurality of hermetic containers with a granular material made of a heat-resistant material;
A sealing step of sealing the plurality of sealed containers after the filling step;
A container installation step of arranging the plurality of sealed containers along a predetermined installation surface after the sealing step;
A method for installing a core melt receiving apparatus, comprising: A heat-resistant component that is arranged in a plurality along a predetermined installation surface,
A sealed container;
A granular material made of a heat-resistant material filled in the sealed container;
Heat-resistant parts characterized by comprising

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