JPH0587962A - Off-shore nuclear power plant and construction, supporting and operation of power plant site and facility thereof - Google Patents

Abstract

PURPOSE:To enhance safety of a structure on which a power plant facility is constructed and to make plant maintenance works and the like easier, where a nuclear power plant is installed off-shore. CONSTITUTION:Most parts of this off-shore nuclear power plant 1 are submerged, and a nuclear power generation facility 3 is loaded in a semi-submerged floating structure 2 cross sectional area of which water surface penetrating parts is comparatively sampller than displacement thereof. The nuclear power plant and other off-shore facilities or in-land facilities are connected by a transmission line 21 so as to transmit the generated electricity from the nuclear power plant to the other off-shore facilities or the in-land facilities.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing, supporting, and operating a marine nuclear power generation facility, a power generation base, and a power generation facility.

[0002]

2. Description of the Related Art Known nuclear power plant facilities installed on land are inevitably subject to large impacts and stress during natural disasters such as earthquakes and typhoons, and must have sufficient strength and earthquake resistance to withstand these impacts and stresses. The cost is high because it is necessary. In addition, it is necessary to occupy a large area on land in order to reduce the damage caused by the leakage of radioactive materials in the event of an accident, and in addition to this, the consent of not only the direct landowner but also a wide range of residents in the surrounding area. Without it, construction is impossible, making new locations difficult.

Therefore, the idea of mounting a nuclear power generation facility on a structure constructed on the sea with few restrictions on location has been proposed and studied both in Japan and overseas, but many technical and economic problems have been realized. There is no such thing. The problematic points in this case are as follows. (1). Known offshore structures that have been considered for offshore nuclear power generation facilities are artificial islands constructed in shallow water,
It is either an artificial ground that makes a floating structure built elsewhere in the shallow sea, or a floating pier moored in the shallow sea or a ship-like structure, both of which are stationary structures. The artificial islands and artificial grounds of No.1 have the same impact and stress as the ground facilities during the earthquake, and in addition, the tsunami and typhoons during the earthquakes are considered to be larger than those of ordinary land facilities. In addition, due to the structure, the installation location is limited to a shallow water location and cannot be installed on the open ocean off the coast. The piers or ship-like floating structures in Figure 1 have much less impact and stress during an earthquake than land facilities, but they float on the water surface.
As shown in (A), it is difficult to install in the open ocean because the structure also sways as the sea surface rises and falls and is most susceptible to typhoons and tsunamis. If it is installed in an inner bay that is less affected by typhoons and tsunamis, the restrictions on location will not differ much from land facilities.

(2). To ensure safety, nuclear power generation facilities cannot be continuously operated unless they are thoroughly inspected and maintained regularly and spent fuel is replaced. These operations take at least several months, and it is inevitable to encounter typhoon and seasonal storms at sea during this period. With nuclear power generation equipment installed in stationary offshore facilities such as known proposals for offshore nuclear power generation equipment, it is technically difficult to perform inspection / maintenance and refueling on the sea while ensuring safety under stormy weather. It is difficult to secure safety.

[0005]

SUMMARY OF THE INVENTION Therefore, the present invention solves the above-mentioned conventional problems, improves the safety of the structure on which the nuclear power generation equipment is mounted, and facilitates maintenance work and the like. It is an object of the present invention to provide a method for constructing, supporting, and operating a marine nuclear power generation facility, a power generation base, and a power generation facility that can be carried out.

[0006]

In order to achieve the above object, most of the marine nuclear power generation equipment according to the present invention is underwater, and the cross-sectional area of the portion penetrating the water surface is small compared to the displacement. A nuclear power generator is installed in a floating structure, and this nuclear power generator is connected to another offshore facility or onshore facility with a transmission cable so that the power generated from the nuclear power generator can be sent to another offshore facility or onshore facility. ing.

Further, the offshore nuclear power plant according to the present invention collects and transforms electric power and transmits power to the onshore facility, and also monitors and controls the entire base, manages operations, and rests and operates and maintains maintenance staff. Install one or more core facilities on the continental shelf to serve all or part of the functions such as storage of materials, and moor the above-mentioned maritime nuclear power generation facilities around this core facility. The nuclear power generation facility and the core facility are connected by a transmission cable so that the generated power can be sent from the nuclear power generation device of the nuclear power generation facility to the core facility. Further, the offshore nuclear power plant according to the present invention is, in the above-mentioned offshore nuclear power plant, connected to a core facility of the offshore nuclear power plant by a power transmission cable, receives electric power transmitted from the core facility, and receives a demand area. Power transmission / reception facility for transmitting power to the power station, and equipment / materials necessary for the operation / maintenance of the offshore nuclear power station, and the arrival / departure / berthing facility of ships, etc. for transporting and contacting or guarding the materials and personnel to the power station. Is located on the nearest coast.

Further, the method for constructing / supporting / operating a marine nuclear power generation facility according to the present invention is a method for constructing / supporting a marine nuclear power plant in the marine nuclear power generation base or outside the base on a sea / shore. We will build equipment, towing, mooring and connecting to the offshore nuclear power plant to operate it,
Construction and support facilities for power generation facilities that have passed a certain period of time are towed, and maintenance work such as inspection, repair, and fuel replacement is performed.
It is returned to the power generation base and put into operation.

[0009]

Most of the semi-submersible floating structures used in offshore nuclear power generation facilities are as described in the specification of the patent right acquired by the inventor himself (see Japanese Patent Publication No. 50-12675). Even if a storm or tsunami is encountered on the open ocean, if the cross section of the part that penetrates the water surface is smaller than the drainage and the natural period of rolling is 40 seconds or more, As shown in B), there is almost no shaking and there is no danger of receiving a large stress or impact, so the safety of the structure itself is extremely high. In addition, since the power generator installed in this structure does not need to consider acceleration, impact, inclination, and shaking, there are few design restrictions and it can be economically constructed. By the way, from the characteristics of this type of floating structure, when the required outer diameter size and drainage are calculated, the scale is suitable for mounting a large capacity nuclear power generator set.

The current 1000 MW class nuclear power plant installed on land has a total weight of 40 to 100,000 tons, most of which is shielding concrete and its basic structure. Since the semi-submersible floating structure has a thick concrete outer shell and there are no inhabitants in the surrounding area, the necessary shielding can be seen in the example of nuclear power generation equipment used to propel ships. It is thought that it can be simplified compared to the nuclear power plant installed on land. The net weight of the reactor body, power generator and peripheral equipment excluding the shield is less than 20,000 tons in the case of a boiling water nuclear power plant.

According to the observation data, the natural period of the waves generated in the open sea hardly exceeds 20 seconds. For safety, if the natural period of rolling of a semi-submersible floating structure is set to 40 seconds, the floating structure itself must be larger than a certain limit for this purpose. The mechanical characteristics of the semi-submersible floating structure will be described with reference to FIG. In this type of floating structure, the center of buoyancy (metacenter) does not move horizontally due to the tilting of the structure like normal floating structures such as ships, and thus no restoring force is generated. , The restoring force to the inclination of the structure is generated because the center of gravity G is below the center B of the buoyancy. The natural period of rolling of a floating structure of this type can be calculated by the following formula when the slope is small and water resistance is ignored.

## EQU1 ## Ts = 2π / √g · K / √h g is the acceleration of gravity, K is the radius of rotation of the structure, and h is the vertical distance between the center of buoyancy (metacenter) and the center of gravity of the entire structure. .. The restoring force to the inclination of this structure is the vertical distance h
Since it is proportional to, it cannot be made too small for safety. Therefore, in order to increase the natural period Ts, it is necessary to increase the turning radius K. Since K is approximately proportional to the external dimensions of the structure, in order to make the natural period 40 seconds or more,
There is a minimum outside dimension.

As described above, if the vertical distance h is made too small, the restoring force against the inclination becomes small and a safety problem occurs. Therefore, the practical K / h is 10 or less for a small-scale structure,
It is said to be 20 or less for a rather large structure. Therefore, the minimum turning radius K for the natural period of 40 seconds or more is 1
It will be 9.88m (about 20m). The minimum dimensions of isotropic (filled) structures of various shapes with the radius of gyration described above are shown in Table 1 on the next page.

[Table 1] Volume Sphere 62.9m (diameter) 130.1 thousand m ² Cylinder 52.1m (diameter) 110.9 d: h = 1: 1 Cylinder 60.1m (diameter) 56.9 d: h = 3: 1 Cube 48.7m (side length) ) 115.4 Rectangular parallelepiped 64.1m (side length b) 198.8 a: b: c = 1: 2: 3 Although the above dimensions are the dimensions of an isotropic object, the actual structure is hollow, so the same radius of gyration is used. In order to hold, the external dimensions and volume are slightly larger than the above values. Therefore, a floating structure with sufficient drainage capacity to mount a nuclear power plant with a net weight of about 20,000 tons together with a shield of several times that weight, on the other hand, satisfies the condition of a natural period of 40 seconds or more. It can be seen that it has a sufficient outer size. Therefore, it is clear that it is mechanically sufficiently feasible to mount a complete nuclear power generator on a semi-submersible floating structure and install it in the open ocean where the wind and waves are rough.

[0013] Since detailed inspection and maintenance and fuel exchange, which are inevitable for the continuous operation of the nuclear power generation facility, are towed to a dedicated support facility having sufficient facilities and carried out inside the facility, the known offshore structure is known. Of the nuclear power plant installed on the object,
Difficulty associated with operations such as inspection / maintenance and refueling at sea can be avoided. Even if it takes a few days to tow to the support facility, the operation of the entire system will not be affected so much, so there is a high degree of freedom in the location of the support base. Since only the reactors that have been shut down are handled within the support base, it is far less dangerous than the operating nuclear power plant itself and highly socially acceptable. Therefore, choose an area with less risk of earthquakes,
It is also possible to be located in an inner bay where there is little risk of typhoons and tsunamis.

As described above, the system in which the movable power generation facility is constructed in a dedicated support facility, moored in the open sea to operate, and towed again to the support facility for inspection / maintenance and fuel exchange, is safe. Although there is a big advantage in terms of ease of location, it is necessary to lay a cable that transports a large electric power of 1000 MW class from the open ocean to the coast, and to safely and reliably connect towed power generation equipment at sea. In addition, since the amount of electric power that is transported is extremely large, it is important from an economic standpoint to minimize transmission loss, and for that reason, cutting-edge power transmission technologies such as ultra-high voltage DC transmission and the use of low-temperature superconductors are required. Use is desirable.

On the other hand, when the output form of each power generation facility is a normal high-voltage AC output, design / construction, operation / maintenance are easy, and economical construction / operation is possible. Therefore, a core facility that converts the current form suitable for long-distance power transmission to the coast is installed in the base where the power generation equipment is moored and placed, and each power generation equipment is short If the power transmission is done, the whole system has less technical difficulty and can be constructed and operated economically. In addition to the monitoring and control and operation management of the entire base, it is indispensable to carry out inspection and maintenance for various power generators. For this purpose, it is necessary for the personnel to stay at the marine facilities at all times and to have equipment for inspection / maintenance and living facilities and materials / fuels necessary for operation / maintenance / living. Technically, it is possible to provide storage of maintenance materials and a facility for living and resting of operating personnel for each power generation facility, but when looking at the entire base, the facilities overlap,
The work content of the operation and maintenance personnel of each power generation facility will be complicated and diversified, requiring a large number of personnel and increasing operating costs. In addition, each power generation facility is large and complicated, increasing the chances of trouble and increasing the cost.

Therefore, there is a great merit that the facilities for responding to these needs of individual power generation facilities are collectively concentrated in a permanent core facility. This system is a facility that receives and connects power transmission cables from each power generation facility to a power station on the sea, and a substation / transmission facility that receives the power generated by each power generation facility and converts it into a current form suitable for long-distance transportation. , Equipment necessary for monitoring, controlling and managing the entire power generation base,
Stores equipment and energy for maintenance required for each power generation facility
Supply facilities, residential facilities for operation and maintenance staff to stay and rest, power transmission and reception on the coast, permanent connection with power generation facilities, departure / arrival of ships, mooring facilities, etc. By providing a core facility and arranging and mooring each power generation facility around this, various needs and problems caused by mooring and operating a movable power generation facility on the sea are advantageously solved.

The receiving and transmitting facilities on the nearest coast and the depot, as well as the departure and arrival and berthing facilities for vessels for replenishment and communication, are all ordinary facilities, and are planned not to handle radioactive materials at all.
Since it can be operated, there are no technical or social problems.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 3 is a vertical sectional front view showing a marine nuclear power plant according to an embodiment of the present invention, and FIG. 4 is a transverse plan view thereof.
Reference numeral 1 is an offshore nuclear power generation facility, which is a semi-submersible floating structure 2 and various nuclear power generators 3 such as a nuclear reactor mounted therein.
It consists of The structure 2 has a cross section as shown in FIG. 2 when cut along the line AA in FIG. 4 is structure 1
The pressure-resistant outer wall of 5 penetrates the water surface and partially exposes it on the water surface.
A part that stabilizes the relative position of the water surface by increasing and decreasing buoyancy depending on the level of the water surface, 6 a ballast tank, 7 a reactor room, 8 an auxiliary equipment room around the reactor, 9 a turbine and a generator room , 10 is a condenser and pump room, 11 is a room for operation and control system, 12 is a control and living area, 13 is a hatch for outfitting, 14 is a contact deck for normal times, and 15 is a surface for emergency. Connecting deck, 16 is a mooring line. Further, C is the position of the water surface in normal times, D is the position of the water surface when preparing for stormy weather, and E is the water surface position when performing work such as outfitting, towing, mooring, etc. It is easy, but has a great restoring force to the inclination. The water surface position is adjusted by pouring and draining the ballast tank 6.

FIG. 5 shows a schematic diagram in which the nuclear power generation facility 1 is moored around the core facility 20 and is connected to the core facility 20 by a transmission cable 21 to form a maritime nuclear power generation base 22. In this example, in addition to collecting and transforming electricity and transmitting it to land, all or part of the functions such as monitoring and control of the entire base, operation management, stay rest of operation management personnel, storage of materials for operation maintenance, etc. One core facility 20 to be used for
Anchor moored on a continental shelf of about 0 m via a mooring line 25 connected to an anchor 23 provided on the seabed, and a plurality of power generation facilities 1 similarly provided on the seabed around this core facility 20.
Moored via mooring lines 27 connected to 26. The core facility 20 is constructed based on a semi-submersible floating structure similar to the power generation facility 1. The electric power generated by each power generation facility 1 is sent to the core facility 20 by the cable 21.
28 is a large-capacity transmission cable that sends electric power from the core facility 20 to the onshore facility. In this example, the number of core facilities 20 is one, but needless to say, it may be more than one.

[0020]

According to the invention of claim 1, which is constructed as described above, and is not easily affected by a natural disaster such as an earthquake, a tsunami, a typhoon, a volcanic eruption, etc., the safety of the facility is high and the residents in the vicinity Because it can be constructed and installed on the open ocean where there is no land, it has significantly higher social acceptance than a nuclear power plant installed on land.
Moreover, even if there is a trouble, there is no inhabitant in the vicinity, and the released substance is diffused and diluted by the time it reaches the region where the inhabitant lives, so there is little risk of heavy contamination. Furthermore, because it is installed in the open ocean, it is less affected by hot drainage. Furthermore, the inside of the semi-submersible floating structure is
Since it is a very quiet space with almost no vibrations, shocks, accelerations, and inclinations, the nuclear power generation equipment equipped with a nuclear power generation device here has a lower expected value of seismic resistance, shaking, and shock unlike ordinary land-based nuclear power generation equipment. It can be designed and is therefore a very economical facility.

According to the invention of claim 2, one power generation facility can be added one by one in response to an increase in electric power demand and an alternative demand of an aged power plant, but since advance acquisition of a site for future expansion is unnecessary, The flexibility of the system is high because planning and construction can be started with the final scale undetermined. In addition to this, the invention of claim 3 can efficiently transmit and receive electric power from the core facility to the onshore facility.

According to the invention of claim 4, the construction and support of the nuclear power generation facility can be carried out at a suitable place, and the aged power generation facility can be moved to easily perform the decommissioning of the decommissioning. You will be able to make a variety of technical choices.

[Brief description of drawings]

FIG. 1 is a schematic view showing a state of being affected by a typhoon or a tsunami, where (A) shows a known floating structure and (B) shows a floating structure of the present invention.

FIG. 2 is a vertical sectional side view for explaining the mechanical characteristics of the floating structure of the present invention.

FIG. 3 is a vertical sectional front view showing a marine nuclear power generation facility according to an embodiment of the present invention.

4 is a cross-sectional plan view of FIG.

FIG. 5 is a schematic view showing a state in which a nuclear power generation facility is moored around a core facility to form a maritime nuclear power generation base.

[Explanation of symbols]

 1 Offshore nuclear power generation facility 2 Semi-submersible floating structure 3 Nuclear power generation device 20 Core facility 21,28 Transmission cable 22 Maritime nuclear power station 23,26 Anchor 25,27 Mooring line

Claims (4)

[Claims] 1. A nuclear power generator is installed in a semi-submersible levitation structure which is mostly in water and whose cross-sectional area that penetrates the water surface is smaller than the amount of drainage. An offshore nuclear power generation facility characterized in that the facility or the onshore facility is connected by a transmission cable so that the power generated from the nuclear power generator can be sent to another offshore facility or the onshore facility. 2. The function of collecting and transforming electric power and transmitting power to the onshore facility, and also monitoring and controlling the entire base, operation and management, rest of staff for operation management, storage of materials for operation and maintenance, etc. One or a plurality of core facilities to be used for a part of the facilities are installed on the continental shelf, and the core facilities are provided around the core facility.
A plurality of offshore nuclear power generation facilities described above are moored, and these nuclear power generation facilities and the core facility are connected by a transmission cable so that power generated from the nuclear power generation device of the nuclear power generation facility can be transmitted to the core facility. Offshore nuclear power station. 3. A power transmission / reception facility, which is connected to a core facility of a marine nuclear power station by a power transmission cable, receives power transmitted from the core facility and transmits the power to a demand location, and operation / maintenance of the marine nuclear power station. The offshore nuclear power plant according to claim 2, wherein a departure / arrival / berthing facility for ships or the like for storing necessary equipment / materials for transporting / contacting or guarding the materials / personnel to the power plant is provided on the nearest coast. .. 4. The offshore nuclear power generation facility according to claim 2 is constructed, or the offshore nuclear power generation facility according to claim 1 is constructed within a construction / support facility installed on the sea or outside the station, and towed to the offshore nuclear power generation base.・ Moored and connected to operate the power generation facility, build the power generation facility after a certain period of time, tow it to a support facility, perform maintenance work such as inspection, repair, fuel exchange, etc., and return to the power generation base to operate again A method for constructing, supporting, and operating a marine nuclear power generation facility characterized by the above.