JPH0353196A - Atomic power generation system and its constructing method - Google Patents

Abstract

PURPOSE:To construct a system under the ground by providing a nuclear reactor installed in a concrete wall below an underground dam, evaporative cooling towers one of which is connected to cooling water of the nuclear reactor and the other of which is connected to a pipe through which water stored in the underground dam is led in, etc. CONSTITUTION:A pipe is perpendicularly driven into the ground and cement or the like is charged through this pipe to fill up gaps of a water-permeable layer 1, thereby constructing a stop wall 5. A metallic storage vessel 10 is installed in a concrete shielding body, and a nuclear reactor 8 where an uranium oxide reacts to generate heat is installed in the vessel 10. The nuclear reactor 8 is provided with a circulation entrance 12 is primary cooling water, which cools the heat generated by nuclear reaction, and an exit 14 through which primary cooling water evaporated by the heat is discharged from the nuclear reactor 8. An evaporative cooling tower 20 has an air discharge port 22 in the upper part and has an air inlet port 24 in the side face part, and a pipe in which primary cooling water passes is coiled in this tower. A sprinkler 30 to sprinkle water led from the stop wall 5 through a pipe 26 and a tank 28 is installed on the tower. A large-sized fan 32 which sucks air from on the ground and discharges vapor is installed in the vicinity of the air inlet port 24.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a nuclear power generation system using an underground dam constructed underground. Geological strata include impermeable and permeable layers, and these impermeable and permeable layers often form faults, resulting in a number of geological structures (groundwater basins) that purify groundwater. Therefore, 40% of the water that falls on the ground goes underground; this water soaks into the permeable layer, collects on the impermeable layer, and flows down to the sea. However, underground water does not flow freely, but as mentioned above, many faults are formed in the strata, so it is blocked by the faults and flows along the fault lines. The porosity of a permeable layer is usually 20-45%, and the permeable layer has the potential to store a large amount of water (10-20% of the volume of the stratum). Recently, an underground dam was built in Okinawa in 1979, with a cut-off wall 500 m long and 16.5 m high near the outlet of the groundwater basin to store 700,000 tons of water. Underground dams are being built one after another.

These dams are mainly intended for drinking water or irrigation water, but in the case of Kabashima Dam, the amount of water that can be taken in a day is about 250 m', which is one-fourtieth of the total water storage capacity. Conventional technology Until now, nuclear power generation systems in Japan had a BER (boiling water type) or PWR (pressurized wood type) concentrator with a
There are systems installed and used on the ground that use highly enriched uranium oxide as fuel to produce high-temperature steam, and use the steam to turn a generator turbine. In general, nuclear power generation consumes 1.5 million Kw of energy to obtain an output of 500,000 Kw, 500,000 Kw is converted into electrical energy, and the rest becomes thermal energy. The primary cooling water is used as a moderator for the neutrons generated by the reactor, and at the same time, by circulating the cooling water within the reactor, it plays the role of transporting the heat generated within the reactor core to the outside. The design is such that the heated primary cooling water is cooled and returned to the core by exchanging heat with the seawater of the secondary cooling water through a condenser. The seawater used for this secondary cooling water is 180,000m"/b for a power generation type with an output of 500,000Kw, which is equivalent to 4.32 million mA 7 days per day. The temperature of water is usually raised by about 7°C before it is discharged into the sea. Therefore, the energy taken by seawater is as follows: Q+ "432X 10"X 7 cal/day - 1
460,000 K/sec Problems to be Solved by the Invention However, in the case of such conventional nuclear power generation systems, seawater is used as secondary cooling water, but the amount discharged is extremely large; Because it was not designed to be released far offshore, the ocean warms and red tides occur. Problems such as abnormal occurrence of jellyfish are occurring. Seawater used as secondary cooling water has the problem of being susceptible to corrosion of water intakes, condensers, pipes, etc. because it contains a large amount of salt. Nuclear power plants are installed in locations where earthquakes are unlikely to occur, but because they are installed on the ground, they also have the disadvantage that in the event of an earthquake, the nuclear reactor is susceptible to distortion. ing. In terms of location conditions for power plants, the closer they are to urban centers where there is a lot of power demand, the better, but nuclear power plants are generally located far from areas of power demand, so they have the disadvantage of poor energy efficiency. There is also. Furthermore, seawater is used as secondary cooling water, but at a rate of 20% per second.
For example, the energy E+ consumed when pumping water at a height of 10 m above sea level to a nuclear reactor at a height of 10 m above sea level is El −
200X 9. 8X 10G = 18,000K%#, which has the disadvantage of low nuclear power generation efficiency and the difficulty of installing it in areas with large tidal differences in seawater. Therefore, in view of the shortcomings of the conventional technology, the present invention is to provide an underground nuclear power generation system that is not easily affected by earthquakes, does not require the use of seawater, and can be installed relatively close to the city center. Purpose. Means for Solving the Problems: An underground dam is formed by providing a cut-off wall in an underground water basin; a nuclear reactor is installed in a concrete wall on the bedrock below the underground dam; It consists of an evaporative cooling tower connected to the primary cooling water of the furnace, and the other connected to a pipe that draws water stored in the underground dam, and the steam outlet and air intake of the cooling tower are connected to each other through a chimney. This objective will be achieved through a nuclear power generation system connected to the ground. The above nuclear power generation system is constructed using the method shown below. Search for the desired underground water basin through geological surveys. A cutoff wall of a predetermined height and length is installed approximately perpendicular to the fault by injecting concrete or water glass (sodium silicate) near the outlet of the groundwater basin. A nuclear reactor is installed on the bedrock below the underground dam, and the reactor is covered with a concrete shielding wall. An evaporative cooling tower is installed next to the reactor, and the evaporator of the cooling tower is communicated with the ground through a chimney, and the air intake of the cooling tower is communicated with the ground through the chimney. Furthermore, the primary cooling water of the reactor is guided to the cooling tower, and the water from the underground dam is also guided to the cooling tower. The structure is designed so that all of the dam water used for cooling evaporates without returning to the ground. The amount of water stored in the underground dam is adjusted to the output of nuclear power generation, but in the case of an evaporative cooling tower system, the amount of water stored in the underground dam is 2.016 m"/
h is required, which is equivalent to 48.h per day. Since it requires 384 - of water, the total water storage amount is 500 in 100 @ conversion.
Build more than 10,000ml. Function The present invention will be explained in detail below according to embodiments shown in the drawings. Figure 1 is a schematic cross-sectional view of the strata surface, which mainly consists of a permeable layer 1 and an impermeable layer 2, and these layers 1 and 2 are connected to a discontinuity line 3,
A fault is formed in the part indicated by 4. Water accumulates in this permeable layer 1 and flows along the impermeable layer 2 as a groundwater basin. Therefore, as shown in Figures 1 and 2, a cutoff wall 5 is provided above the impermeable layer and approximately perpendicular to the discontinuity line of the fault. This water stop wall 5 is made by driving a pipe perpendicularly into the ground and passing it through the pipe using cement milk made by dissolving cement in water, cement milk mixed with clay, or water glass (
It is created by injecting materials such as sodium silicate to fill the gaps in the permeable layer. Reference numeral 6 denotes a concrete shield for biological shielding of the nuclear reactor, which is provided on the bedrock 7 below the water stop wall 5. Inside the concrete shield 6, there is a metal containment vessel 10.
A nuclear reactor 8 is installed inside the containment vessel 10 to react with uranium oxide and generate heat. The reactor 8 is provided with a primary cooling water circulation inlet 12 for cooling the heat generated by the nuclear reaction, and an outlet 14 for discharging the primary cooling water vaporized by the heat from the reactor 8. , the reactor 8 is controlled so that it does not become abnormally hot. The steam discharged from the exhaust port 14 of the nuclear reactor 8 is led to the power generation turbine 16 via pipe means, where power generation is performed by driving the turbine 16.
After being discharged from the reactor B, it is condensed in the evaporative cooling tower 20 and returned from gas to liquid, and then returned to the reactor B via the water supply pump 18 and the purification device 19. Since this primary cooling water is exposed to radioactivity within the reactor 8, it is configured to circulate within a closed circuit. The evaporative cooling tower 20 has an exhaust port 2 at the top as shown in FIG.
2. A pipe consisting of a heat conduction pipe having an intake port 24 on the side surface and through which primary cooling water passes is wound in a coil shape, and above it there are pipes from the water stop wall 5 to the pipe 26 and the tank 28.
Sprinkler 3 for sprinkling water guided through
Furthermore, a large fan 32 is installed near the intake port 24 to suck in air from the ground and discharge steam toward the ground. This evaporative cooling tower 20 attempts to absorb the energy of primary cooling water using the latent heat of vaporization of water, and can absorb a large amount of energy with a small amount of secondary cooling water. 34 is a chimney connected to the exhaust port of the evaporative cooling tower 20 for discharging steam to the ground, and 36 is a chimney connected to the intake port 24. The diameters of these chimneys are determined in relation to the output of the reactor 8, the amount of cooling water, and the amount of air blown, and a relatively large diameter is preferable. In Fig. 3, 38 is a bar flow pipe for discharging overflow water generated by the difference between the amount of water gushing out into the underground dam installed above the water stop wall 5 and the amount of water absorbed from the underground dam. , and the Saiichi bar flow pipe is 3
A hydroelectric turbine 40 installed at a height of 0 to 50 m is rotated to generate electricity by a generator 41. The water used for power generation is discharged into a second underground dam, which is stopped by a water-stop wall 42 installed in an underground water basin below the underground dam. The water from the second underground dam is configured to be pumped to the first underground dam via a pump 43. Pumping is performed using surplus electricity from nuclear power generation late at night. This is to compensate by pumping up water when the amount of water stored in the first subsurface dam decreases so much that it no longer meets the requirements for secondary cooling. The intake pipe 26 and the bar flow pipe 38 for the secondary cooling water have their mouths provided in a water intake well 44 dug near the cutoff wall 5 of the underground dam above. In this embodiment, the second subterranean dam is installed underground, but the structure is not limited to this, and the overflow water may be forcibly discharged into the groundwater vein in the permeable layer. It's okay. 39 is underground 1.0 to store spent fuel.
This is a storage space installed at a distance of 00m or more. By the way, with an evaporative cooling tower, the amount of secondary cooling water required for nuclear power generation with a world power of 500,000 K is 33. 6m' required, equivalent to 48. 384m". Therefore, assuming that there is no energy loss, the amount of heat Q taken away when water at 15°C evaporates is as follows per day. Q. -85°CX 48. 384rn"XIO"+53
9X 4g. 384+11"X10"-3. 02
X 10' cal/day - 1,460,000 kcal/sec The blown air is further heated and absorbs thermal energy. Evaporative cooling towers cool by evaporating 30% of the secondary cooling water. 70% is used as liquid for cooling.Therefore, the amount of power generated by underground nuclear power generation can be calculated from the relationship between the total amount of underground water storage, the amount of water that gushes out, and the amount of water used, but for safety reasons, the total amount of water storage is often considered. It is better to set it to
Table 1 shows the relationship between the amount of secondary cooling water required by the evaporative cooling tower and the total amount of water stored in the groundwater dam.
As shown in 2. Table 2 Required water storage amount is calculated as 100 times the daily water intake amount. When the power output of nuclear power generation is 500,000 Kw, the amount of water that normally gushes out of an underground dam in a day is 96.768 m'', and if this surplus water is used for hydroelectric power generation, the theoretical amount of hydroelectric power generation Q is , Q = 9.8X 0.56m"/sX 40m (Head) = 219Kw Tortt.
In this embodiment, water overflowing from a groundwater dam is configured to be used for hydroelectric power generation, but the present invention is not limited to this.
Groundwater may be pumped up and used as irrigation water for plants above ground, and the plants may be used as a barometer for measuring conditions such as acid rain. Effects As explained above, the nuclear power generation system according to the present invention is configured to take in the necessary amount of groundwater, which is abundant underground, by forming an underground dam, or to generate electricity. It can be installed anywhere that has an underground water basin, and it is energy efficient because there is no need to pump up groundwater. Since the nuclear power generation system is configured to be installed underground, the effects of earthquake S waves (transverse waves) are significantly attenuated compared to conventional equipment installed above ground, making it much better in earthquake resistance. Furthermore, since the reactor is installed several tens of meters underground, even if radioactivity is generated from the reactor in the event of an abnormality, the concrete and non-permeable layers in the geological formations will shield living organisms, ensuring safety. Excellent in Also, unlike the conventional method, the secondary cooling water is not seawater but underground water, which makes the vibrator and other equipment less likely to corrode and has excellent durability. In addition to using the water that springs up underground without running out of water, the system also prevents the water used for cooling from returning to the groundwater vein, so the groundwater will not be contaminated.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view showing the relationship between permeable layers and non-permeable layers in the geological formations, Figure 2 is a cross-sectional view of a groundwater dam installed underground, and Figure 3 is a schematic cross-sectional view of a system showing an embodiment of the present invention. This is a diagram. Construction... Permeable layer 2... Non-permeable layer 3, 4.
... Fault 5 ... Water stop wall 6 ... Shielding body
8...Reactor lO...Metallic containment vessel
l2...Circulation inlet 14...Outlet 16
...Power generation turbine l8...Water pump 1
9... Purifier 20... Evaporative cooling W 22
...Exhaust port 24...Intake port 26...
Pipe 28...Tank 30...Sprinkler 32...Large fan 34.36...
・Chimney 38...Overflow life 39...Storage, 140...Hydroelectric power generation turbine 43...Is 42...Water stop wall 44...Water intake well

Claims (2)

[Claims] (1) An underground dam formed by installing a water stop wall in an underground water basin, a nuclear reactor installed within a concrete wall on bedrock below the underground dam, and a primary cooling water for the reactor inside. It consists of an evaporative cooling tower to which a water conveying pipe is installed and a pipe for drawing water stored in the underground dam is connected, and the steam outlet and air intake of the cooling tower are each communicated with the ground through a chimney. nuclear power generation system. (2) A construction method for an underground nuclear power generation system consisting of the following steps. a) Searching for a groundwater basin with the desired amount of water storage through geological survey; b) Installing concrete or water glass near the outlet of the groundwater basin.
c) Forming a subterranean dam by installing a cutoff wall of a predetermined height and length approximately perpendicular to the fault by injecting sodium silicate, etc.; installing a reactor and covering the reactor with a concrete shield; d) installing an evaporative cooling tower next to the reactor, communicating the evaporation port of the cooling tower with the ground via a chimney; a step of communicating the air intake of the cooling tower with the ground via a chimney; e) a step of further guiding the primary cooling water of the reactor to the cooling tower and also guiding water from the underground dam to the cooling tower;