JP2010101144A - Energy supply system reusing existing underground cavity - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an energy supply system reusing an existing underground cavity, which can be constructed at a low construction cost while ensuring the safety against earthquakes. <P>SOLUTION: In an existing underground cavity 1 having a vertical pit 2 formed by downward excavation from a ground surface 3, and a plurality of horizontal pit groups 4 extending horizontally while communicating with the vertical pit, a nuclear power plant that is an energy generation facility is provided in a horizontal pit group 4d provided in a position deeper than 50 meters below ground and on a bedrock, cooling water storage tanks 5 are provided in horizontal pit groups 4a and 4b in shallow positions, and drainage storage tanks 7 are provided in horizontal pit groups 4e and 4f in deep positions. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an energy supply system that reuses an existing underground cavity.

Patent Document 1 describes that a nuclear power generation system is provided in a basement of a city such as Tokyo. This patent document 1 discloses that, in the case of Tokyo, a subway or the like is installed as a place where a nuclear power generation system is installed, so that it is necessary to perform a deep underground installation of 50 m or deeper. Specifically, there is a single relatively strong (20kg / cm2) ground Dotan layer at a depth of 50m underground in Tokyo. A nuclear power generation system will be installed by digging a cavity.
JP 2003-270383 A

  However, such an underground nuclear power generation system has a problem that it takes a huge amount of money to construct an underground cavity. Geological survey (crustal survey) is necessary to establish a solid underground cavity. In particular, in the case of a nuclear power generation system, it is necessary to closely investigate whether or not there is a wide range of strong rocks to support the reactor pressure vessel. For this reason, since the survey range of such a geological survey has a wide depth to be surveyed and covers a wide range, the cost becomes very high.

  Furthermore, since the underground cavities necessary for the nuclear power generation system are very large, the amount of earth and sand excavated during construction is enormous. The cost of carrying out and disposal of this earth and sand will also be expensive.

  Also, it is virtually impossible to predict the impact of an earthquake on an underground cavity. That is, even if an underground cavity in which an underground nuclear power generation system is installed can be constructed, it is impossible to accurately predict how it will be affected unless an earthquake occurs around the underground cavity after the construction of the underground cavity. If sufficient seismic performance is not ensured, it is virtually impossible to construct a nuclear power system with the risk of radioactive contamination.

  Thus, even if the underground nuclear power generation system of Patent Document 1 is theoretically possible, it is extremely difficult to realize it because it is virtually impossible to predict the huge construction cost of underground cavities and the effects of earthquakes. It is.

  The present invention has been made in view of the above problems, and an object thereof is to provide an energy supply system that can be constructed at a low construction cost and that reuses an existing underground cavity that can ensure safety against an earthquake. .

  An energy supply system that reuses an existing underground cavity according to the present invention includes a vertical shaft that is formed by drilling downward from the ground surface, and a plurality of horizontal shaft groups that communicate with the vertical shaft and extend in the horizontal direction. In the existing underground cavities, the energy generating equipment is provided in the horizontal pit group provided on the bedrock and at a position deeper than 50 m underground.

  Furthermore, the energy supply system that reuses an existing underground cavity according to the present invention includes the other horizontal shaft group located at a shallower depth than the horizontal shaft group in which the energy generation facility is provided, in the energy generation facility. It is preferable that a cooling water storage tank for storing the cold water to be used is provided.

  Furthermore, in the energy supply system that reuses an existing underground cavity according to the present invention, the cooling water storage tank is provided in another horizontal shaft group located at a deeper depth than the horizontal shaft group in which the energy generation facility is provided. It is preferable that a waste water storage tank is provided for storing waste water that has become hot water supplied to the energy generation facility.

  Furthermore, in the energy supply system that reuses an existing underground cavity according to the present invention, the energy generation facility is preferably a nuclear power plant.

  Furthermore, in the energy supply system that reuses an existing underground cavity according to the present invention, the existing underground cavity is preferably an underground mine shaft of a coal mine that has become an abandoned mine.

  The present invention according to claim 1 is provided at a position deeper than 50 m underground, among the existing underground hollow horizontal shaft groups having a plurality of horizontal shaft groups communicating with the vertical shaft and extending in the horizontal direction. It is characterized by the installation of energy generation facilities in the horizontal pit group on the bedrock. By reusing the existing underground cavities, the underground conditions can be observed directly, and the underground geological conditions are ensured. Can know. Furthermore, by reusing the horizontal shaft, the construction cost can be greatly reduced, and at the same time, the remaining construction soil can be used for reclamation of the unused horizontal shaft.

  The present invention according to claim 2 includes a cooling water storage tank for storing cold water used in the energy generating facility in another horizontal shaft group located at a shallower depth than the horizontal shaft group in which the energy generating facility is provided. Since it is provided, cooling water can be supplied to the energy generation facility by dropping water even in an emergency.

  According to the third aspect of the present invention, the drainage that has become hot water supplied from the cooling water storage tank to the energy generating facility to another horizontal shaft group located at a deeper depth than the horizontal shaft group in which the energy generating facility is provided. Since the waste water storage tank for storing the waste water is provided, the waste water of the energy generating equipment can be accommodated by the falling water even when the equipment such as a pump for sending the waste water to the ground has a failure.

  According to the fourth aspect of the present invention, since the energy generating facility is a nuclear power plant, radioactivity can be prevented from diffusing into the atmosphere in an emergency.

  Since the present invention according to claim 5 is an underground mine shaft of a coal mine in which an existing underground cavity is abandoned, an energy generation facility can be constructed at a low depth in the sedimentary layer at a low cost.

  Hereinafter, an embodiment of an energy supply system that reuses an existing underground cavity according to the present invention will be described with reference to FIGS. 1 to 6. The energy supply system that reuses an existing underground cavity according to the present embodiment includes a vertical shaft 2 that is formed by excavating downward from the ground surface 3, and a plurality of horizontal channels that communicate with the vertical shaft 2 and extend in the horizontal direction. In the existing underground cavity 1 having the mine group 4, a nuclear power generation system which is an energy generating facility in the horizontal mine group 4d provided on the bedrock and provided at a position deeper than the underground 50m in the horizontal mine group 4 6 is provided.

  FIG. 1 is a vertical sectional view of an existing underground cavity 1. This existing underground cavity 1 is an underground mine shaft of an abandoned coal mine, and is formed by drilling downward from the surface 3 of the coal mine, and a vertical shaft 2 that communicates with the vertical shaft 2 and extends in the horizontal direction. It consists of a plurality of horizontal pit groups 4.

  In general, as shown in FIG. 1, the crustal structure of a domestic coal mine has a sedimentary layer in which a coal layer B exists at the top and a rock layer A exists below the coal layer B. Then, the horizontal shaft group 4 is excavated along the upper surface of the bedrock layer A, and coal of the coal layer B is collected. Moreover, since this bedrock layer A has a property which does not allow water to pass through easily, while coal bed B has a property which can easily pass water, it has abundant water amount in the upper part of the bedrock layer A in which this horizontal shaft group 4 is located. There are often groundwater veins. In addition, in FIG. 1, since drawing becomes complicated about sedimentary layers other than the bedrock layer A and the coal layer B, illustration is abbreviate | omitted. Reference numeral 3 denotes the ground surface.

  The vertical shaft 2 includes not only one extending in the vertical direction as shown in FIG. 1 but also one extending obliquely downward called a tilt shaft. The vertical shaft 2 is a shaft larger than the horizontal shafts constituting the horizontal shaft group 4, and an elevator for carrying in / out, a drain pipe, a blower pipe, a power transmission line and the like are left unattended.

  The plurality of horizontal shaft groups 4 are illustrated as horizontal shaft groups 4a to 4f. Each horizontal shaft group 4 exists between the bedrock A and the coal bed B, respectively, and spreads in a mesh shape as shown in FIG.

  Next, the structure of the energy supply system that reuses the existing underground cavity 1 of this embodiment will be described.

  As shown in FIGS. 3 and 4, a nuclear power plant that is an energy generating facility is provided in an internal space 6 c of a storage dome 6 that is constructed by expanding a horizontal shaft constituting the horizontal shaft group 4 d. This horizontal shaft group 4d is provided at a depth of 50 m or more from the ground surface. Some coal mines in Japan extend up to about 1000 m underground, and it is preferable that such coal mines are provided at a depth of several hundred meters. By providing a nuclear power plant at such a deep depth, radioactivity can be prevented from directly diffusing into the atmosphere even in an emergency.

  The storage dome 6 is composed of a half dome portion 6a made of a concrete outer shell having a thickness of 1 m or more, and a foundation portion 6b provided in the rock layer A located below the horizontal shaft group 4d. The foundation portion 6b is constructed by placing concrete on the trace of the rock layer A excavated in a concave shape. In the plurality of storage domes 6 in this embodiment, a nuclear reactor containment vessel, a power generation facility, a condensate facility, and the like (not shown) are stored.

  The other side shaft groups 4a and 4b located at a shallower depth than the side shaft group 4d in which the nuclear power plant is provided store cold water used in the condensing equipment, the emergency core cooling device, etc. of the nuclear power plant. A cooling water storage tank 5 is provided. As shown in FIGS. 3 and 5, the cooling water storage tank 5 is constructed of a concrete outer shell by expanding a horizontal shaft.

  As described above, in the upper part of the bedrock layer A, there are many cases where underground water veins having abundant water amount exist. Therefore, it is preferable to store such groundwater in the cooling water storage tank 5. This groundwater can be taken from a horizontal shaft group in which the cooling water storage tank 5 is not provided, such as the horizontal shaft group 4c. In addition, when the amount of groundwater in the groundwater vein is small, it is also possible to store fresh water or seawater taken from the river, lake, pond, ocean, etc. around the existing underground cavity 1 in the cooling water storage tank 5. In this case, water is taken in through a water intake pipe (not shown) provided in the vertical shaft 2.

  In this embodiment, the cooling water storage tank 5 extends the horizontal shafts of the horizontal shaft groups 4a and 4b and is provided with a concrete outer shell. A cooling water storage tank can be formed by partitioning with a plurality of waterproof walls without providing a shell. Furthermore, in the case of a horizontal shaft group with a large amount of groundwater ejection, the entire horizontal shaft group can be submerged and used as a cooling water storage tank. In this case, it is only necessary to partition the periphery of the vertical shaft with a waterproof wall.

  In the other side shaft groups 4e and 4f located at a deeper depth than the side shaft group 4d in which the nuclear power plant is provided, waste water that is supplied from the cooling water storage tank 5 to the nuclear power plant and becomes hot water is stored. A drainage storage tank 7 is provided.

  A nuclear power plant uses a power generation turbine for any type of reactor, such as a boiling water reactor (BWR), a pressurized water reactor (PWR), a graphite-decelerated boiling light water pressure tube reactor (RBMK), etc. The rotating steam must be cooled by condensate equipment.

  Cooling by this condensing equipment is performed by using cooling water. However, when the cooling water supply is stopped, the reactor cannot be controlled, and in the worst case, it causes melting of the core. In general nuclear power plants, seawater, lake water, river water, and the like, which are cooling water, are supplied to the condensing facility by an electric pump, but this electric pump stops when a power failure occurs. For this reason, in the event of a power failure, the operation of the electric pump is ensured by a backup emergency power generation system (mostly a diesel generator) so that the supply of cooling water does not stop.

  However, there is a problem that it becomes impossible to supply cooling water to the condensing facility when a power failure occurs due to an earthquake or the like and even the emergency power generation system or the electric pump breaks down.

  In the present embodiment, the other horizontal shaft groups 4a and 4b located at a shallower depth than the horizontal shaft group 4d in which the nuclear power plant is provided are used in the condensing equipment of the nuclear power plant, the emergency core cooling device, and the like. A cooling water storage tank 5 for storing cold water is provided, and this cooling water is supplied by dropping into a condensing facility of a nuclear power plant even when an electric pump is not used. The amount of falling water is adjusted by a valve that can be operated electrically or manually.

  During normal operation, the cooling water used by the condensate equipment arranged in the horizontal shaft group 4d becomes warm drainage and is sent to the ground. This hot waste water is preferably used as an energy source. For example, it is used for various purposes such as a heat source in a factory, cooling and heating of buildings and general houses, and heating of a greenhouse, and the water temperature is lowered. And the cooled water is returned to the cooling water storage tank 5 of the horizontal shaft groups 4a and 4b again as cooling water.

  During an emergency operation such as a power failure, the cooling water used by the condensate equipment of the horizontal shaft group 4d becomes warm water, and the drainage storage of the horizontal shaft groups 4e and 4f located at a deeper depth than the horizontal shaft group 4d by falling. It flows into the tank 7. For this reason, it is preferable that each tank capacity of the cooling water storage tank 5 and the waste water storage tank 7 has a tank capacity capable of storing all the cooling water and waste water necessary until the reactor is stopped. By providing the cooling water storage tank 5 and the drainage storage tank 7 as described above, the nuclear reactor can be safely stopped even when the emergency power generation system or the electric pump is disabled.

  Next, the construction method of the energy supply system which reused the existing underground cavity of this embodiment is demonstrated.

  The coal mine that has become an abandoned mine that is an existing underground cavity 1 is generally poured into the abandoned mine, and the underground mine is submerged. This is to prevent ground subsidence due to collapse of the underground tunnel due to water pressure.

  First, the water filling the underground mine of the horizontal mine group 4a closest to the ground surface is drained, and the mine is investigated. Investigate the location of the falling ground, and if there is a falling ground, perform repair work to ensure a safe state.

  After securing the safe state of the horizontal shaft group 4a, the water filling the underground mine of the horizontal shaft group 4b is drained, and the same investigation and repair work as the horizontal shaft group 4a is performed. Similarly, drainage, investigation, and repair work are performed on the horizontal shaft groups 4c to 4f in order from the surface closest to the ground surface, and the safe state of each horizontal shaft group 4 is ensured.

  In the present embodiment, by using the existing underground cavity 1, it is possible to greatly reduce the cost of investigation such as trial digging and to know the specific state of the geology because the state of each horizontal shaft group 4 can be visually observed. it can. Furthermore, since coal mines that have become abandoned mines have been in operation for a long time, they have been affected by many earthquakes. For this reason, safety against these earthquakes can be inferred from the state of the existing underground cavity 1. It is impossible to know the effects of such past earthquakes directly from the state of the existing underground cavity 1 by conventional geological surveys.

  When it is determined that the safety of the existing underground cavity 1 is ensured and there is no problem with the effects of an earthquake or the like, construction of an energy supply system that reuses the existing underground cavity is started.

  First, the old equipment such as the loading / unloading elevator of the vertical shaft 2 described above is removed, and equipment (not shown) such as a loading / unloading elevator is newly installed inside the vertical shaft 2. Moreover, the vertical shaft 2 is provided with a plurality of closed doors 21 that prevent radioactivity from diffusing into the atmosphere in an emergency. Next, the cold water storage tank 5 is constructed in the horizontal shaft groups 4a and 4b, the storage dome 6 of the nuclear power plant is constructed in the horizontal shaft group 4d, and the drainage storage tank 7 is constructed in the horizontal shaft groups 4e and 4f. Construction of these underground facilities can reduce the amount of construction waste soil by widening existing tunnels. Furthermore, by using it for the reclamation of the tunnels (for example, the horizontal shaft group 4c) that do not use the construction waste soil, it is possible to reduce the labor to carry out to the ground and the disposal cost of the construction waste soil. This construction waste soil is used for reclamation of a horizontal shaft group that does not need to be provided with facilities, such as the horizontal shaft group 4c, thereby preventing the horizontal shaft group from falling and treating the construction waste soil. Can do.

  In addition, the cold water storage tank 5, the storage dome 6, the drainage storage tank 7, etc. are concrete buildings, and the concrete used as the raw material is mixed with lime ash generated after coal erasure to produce concrete. Performance can be improved. This lime ash is generated when refining coal, and is piled up in large quantities around the mined coal mine as waste. Therefore, by using this lime ash as a concrete material, two advantages of processing this lime ash and obtaining a concrete material can be obtained.

1 is a vertical sectional view of an existing underground cavity 1 provided with an energy supply system that reuses an existing underground cavity according to an embodiment of the present invention. It is a horizontal sectional view of the horizontal shaft group 4 of the existing underground cavity 1 shown in FIG. 1 is a vertical sectional view of an existing underground cavity 1 showing a state in which an energy supply system that reuses an existing underground cavity according to an embodiment of the present invention is provided. It is a horizontal sectional view of 4 d of horizontal shaft groups of the existing underground cavity 1 shown in FIG. It is a horizontal sectional view of the horizontal shaft group 4a of the existing underground cavity 1 shown in FIG. It is a horizontal sectional view of the horizontal shaft group 4e of the existing underground cavity 1 shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Existing underground cavity 2 Vertical shaft 21 Closure door 3 Ground surface 4, 4a, 4b, 4c, 4d, 4e, 4f Horizontal shaft group 5 Cooling water storage tank 6 Storage dome 6a Half dome part 6b Base part 6c Internal space 7 Drainage storage Tank A Rock bed B Coal bed

Claims (5)

A shaft formed by drilling downward from the ground surface;
In the existing underground cavity having a plurality of horizontal shaft groups communicating with the vertical shaft and extending in the horizontal direction,
Energy supply that reuses existing underground cavities, characterized in that energy generating equipment is provided in the horizontal pit group provided on the bedrock and at a position deeper than 50m underground in the horizontal pit group system. The other horizontal shaft group located at a shallower depth than the horizontal shaft group provided with the energy generation facility is provided with a cooling water storage tank for storing cold water used in the energy generation facility. The energy supply system which reused the existing underground cavity of claim | item 1. In the other side shaft group located at a deeper depth than the side shaft group in which the energy generation facility is provided, the waste water that has become hot water supplied from the cooling water storage tank to the energy generation facility is stored. The energy supply system which reused the existing underground cavity of Claim 1 provided with the waste water storage tank. 2. The energy supply system that reuses an existing underground cavity according to claim 1, wherein the energy generation facility is a nuclear power plant. 2. The energy supply system that reuses an existing underground cavity according to claim 1, wherein the existing underground cavity is an underground mine of a coal mine that has become an abandoned mine.

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