A method for constructing a trash rack in the intake open channel of a nuclear power plant

Abstract

The present invention discloses a method for constructing a trash rack in a nuclear power plant water intake open channel, which is characterized by including guide dikes on both sides of the water inlet. There is a trash rack structure in the middle of the guide dikes, which is mainly composed of a plurality of juxtaposed water intake culverts. There is an intertidal trash rack above the water intake culverts. A plurality of special trash rack cages are arranged in the water intake culverts. There is a movable gantry crane above the trash rack structure. The present invention can effectively solve the problems existing in the existing conventional trash rack schemes, increase the interception intensity, greatly reduce underwater operations and manpower use, improve the salvage and cleaning efficiency, and save project investment and operation and maintenance costs.

Description

Technical Field

[0001] The present invention relates to a method for constructing a trash rack in a nuclear power plant water intake open channel, belonging to the technical field of ensuring the cold source of a nuclear power plant. Background Art

[0002] A large amount of heat is generated during the operation of a nuclear power plant, and a reliable cold source must be available for cooling to ensure the safe and stable operation of the power plant. Taking seawater as the cold source, more than 60% of the heat generated during the operation of the unit is exported through the process of "pumping → heat exchange → discharging". Most nuclear power plants use open channels to take water. To ensure reliable water intake, most nuclear power plants are equipped with multiple filtering devices at the water intake open channel entrance or inside the channel, including trash racks, oil booms, coarse grids, trash net bags, coarse and fine grids, drum screens, and other devices. Although these measures have been taken, in recent years, due to the invasion of marine organisms or sundries into the open channel of the nuclear power plant and the excessive water level pressure difference on both sides of the drum screen, power reduction, shutdown, and reactor trip have occurred from time to time, seriously threatening the safe production of the nuclear power plant.

[0003] The intrusion of sundries into the water intake head is not obvious in the initial stage of the unit operation. However, with the increase in the number of operating units and the extension of the operation time, large-scale aggregation and intrusion of organisms or sundries into the water intake head occur from time to time, and the degree of transient impact on the unit caused is also becoming more and more serious. The number of shutdowns and reactor trips is also quite a lot. Some power plants are deeply affected by this, resulting in multiple unscheduled outages.

[0004] The commonly used trash racks have the following problems:

[0005] 1. The plane net has a large span, is prone to breakage under large stress, and is not easy to clean sundries, requiring diving operations;

[0006] 2. The trash net bag mainly collects suspended solids, and the effect of collecting floating objects is not ideal;

[0007] 3. The above-mentioned trash racks have relatively low strength and are vulnerable to typhoon effects, resulting in structural damage;

[0008] 4. It cannot be set close to the water intake pump house, and the effect of preventing the growth of marine organisms in the waters of the open channel is poor. Summary of the Invention

[0009] The technical problem solved by the present invention is: how to design a trash rack method that reduces pollution, protects the marine ecosystem, improves the salvage and cleaning efficiency, and saves project investment and operation and maintenance costs.

[0010] To solve the above technical problems, the technical solution of the present invention is to provide a method for constructing a trash rack structure in the intake channel of a nuclear power plant, which is characterized in that it includes guide dikes on both sides of the intake, and a trash rack structure is arranged in the middle of the guide dikes, mainly composed of a plurality of juxtaposed intake culverts. A tidal zone trash rack is arranged above the intake culverts, and a plurality of special trash rack cages are arranged in the intake culverts. A movable gantry crane is arranged above the trash rack structure.

[0011] Preferably, a marine organism release port is arranged at the connection between the left side of the intake channel and the guide dike. The right side of the intake channel is connected to the guide dike through a ship passage section. Gantry crane tracks facilitating the movement of the gantry crane are arranged on the front and back sides of the intake channel.

[0012] Preferably, the special trash rack cage is movably connected to the intake culvert.

[0013] Preferably, the special trash rack cage includes a frame. Removable mesh sheets are arranged on both sides of the frame. A plurality of lifting rings are arranged on the frame. The frame is welded by a plurality of stainless steel frames.

[0014] Features of the present invention:

[0015] 1. Diversion: By constructing porous intake culverts (single-hole net size is about 7 m × 5 m) in the open channel, the open channel is divided into multiple flow channels to reduce the possibility of the entire flow channel being blocked by the outbreak of marine organisms, thereby achieving the purpose of separate control. At the same time, three rows of trash rack cage inlets are arranged above the retention platform, and detachable trash rack mesh sheets are arranged at the openings. When the tide level is higher than the retention platform, the trash rack cage inlet can also become the water inlet of the culvert box, further reducing the possibility of the trash rack at the culvert box inlet being blocked..

[0016] 2. Interception and fishing: The combined use of the intake culverts, trash rack cages, and gantry crane can greatly improve the interception intensity and fishing efficiency; on the upstream side of the open channel, boats can be used for fishing. After entering the intake culvert, the trash rack cages can be used for collection and fishing; the trash rack cages can be set in various forms: trash rack cages with different pore sizes, trash rack cages with hooks, solid gates, etc. When in use, attention should be paid to observing the water level difference between the upstream and downstream of the interception cage to avoid excessive water level difference and causing damage to the cage;

[0017] 3. Retention: The interception of multiple rows of trash rack cages and the temporary storage function of the intake culverts can delay the invasion speed of marine organisms and reduce the risk of disaster caused by their concentrated outbreak. At the same time, other intake culverts can still continue to supply water;

[0018] 4. Cleaning: The elevation of the culvert box roof (retention platform) is set to the average tide level. Through the cooperation of the tidal zone trash rack and the retention platform, the tidal effect can be fully utilized to leave the disaster-causing marine organisms or sundries on the platform. When the tide ebbs, the retention platform is exposed above the water surface, facilitating personnel to clean the platform;

[0019] 5. Release: The marine organisms salvaged and collected can be released into the sea outside the open channel breakwater through the release port, which protects the marine ecosystem on the one hand and significantly reduces the amount of external transportation operations on the other hand;

[0020] 6. Emergency: The ship passage section adopts the form of a rubber dam or a liftable trash screen. When a ship passes through or in case of an emergency, the height of the dam or the trash screen can be lowered to realize the functions of ship passage and water discharge;

[0021] 7. Since the height of the water intake culvert is about 7 meters, in order to reduce the lifting height, the trash screen box can be set with two layers, each layer being about 3.5 meters high.

[0022] The present invention can effectively solve the problems existing in the existing conventional trash interception schemes, increase the interception intensity, greatly reduce the underwater operations and the use of manpower, improve the salvage and cleaning efficiency, save the project investment and operation and maintenance costs, and at the same time have the function of releasing marine organisms. The main effects are as follows:

[0023] 1. Divide the large interception surface into several independent areas, reduce the height of the trash screen, reduce the load of the trash screen, and improve the safety of interception;

[0024] 2. The setting of the trash screen box improves the collection efficiency of marine organisms and sundries;

[0025] 3. The setting of the release port responds to the environmental protection requirements and at the same time reduces the amount of external transportation operations;

[0026] 4. The setting of the intertidal zone trash screen and the retention platform greatly reduces the underwater operation volume. Brief Description of the Drawings

[0027] Figure 1 is the top view of the present invention;

[0028] Figure 2 is the elevation view of the present invention;

[0029] Figure 3 is the cross-sectional view of the present invention;

[0030] Figure 4 is the structural schematic diagram of the special trash screen box of the present invention. Detailed Embodiments

[0031] To make the present invention more obvious and understandable, the preferred embodiments are described in detail below in conjunction with the accompanying drawings.

[0032] As Figures 1 to 4As shown, a method for constructing a pollution interception structure in the water intake open channel of a nuclear power plant is characterized by including diversion dikes on both sides of the water intake. There is a pollution interception structure 1 in the middle of the diversion dikes, which is mainly composed of a plurality of juxtaposed water intake culverts 2. There is an intertidal pollution interception net 4 above the pollution interception structure 1. A plurality of special pollution interception net boxes 3 are arranged in the water intake culverts 2. There is a movable gantry crane 5 above the pollution interception structure 1. There is a marine organism release port 6 at the connection between the left side of the pollution interception structure 1 and the diversion dike. The right side of the pollution interception structure 1 is connected to the diversion dike through a ship passage section 7. Gantry crane tracks 8 for facilitating the movement of the gantry crane 5 are arranged on the front and back sides of the pollution interception structure 1. The special pollution interception net box 3 is movably connected to the water intake culvert 2.

[0033] The special pollution interception net box 3 includes a frame 9. A detachable net piece 10 is provided at the top of the frame 9. Two lifting rings 11 are provided on the frame 9. The frame 9 is welded by a plurality of stainless steel frames 12. The special pollution interception net box 3 is composed of an "L"-shaped box body frame welded by steel sections and detachable net pieces fixed between the steel sections. The box body frame is welded by steel sections. To prevent seawater corrosion, the steel sections should preferably be made of stainless steel, and their type selection and spacing are determined according to the structural design. Small holes are opened on the steel sections to fix the detachable net pieces. The aperture and spacing of the small holes should be such that the net pieces can be tightly fixed without generating excessive gaps. The net pieces should be made of fine-mesh nets that are not attached by marine organisms, and the mesh size is determined according to the marine organisms to be intercepted. The pollution interception net box is fixed in the culvert through a gate slot provided on the side wall of the water intake culvert. The opening of the "L"-shaped box body faces the upstream side to collect disaster-causing organisms and sundries.

Claims

1. A trash rack structure device for the water intake open channel of a nuclear power plant, characterized in that, It includes guide dikes on both sides of the water inlet. There is a pollution interception structure (1) in the middle of the guide dikes, which is mainly composed of multiple parallel water intake culverts (2). There is an intertidal pollution interception net (4) above the water intake culvert (2). A plurality of special pollution interception net cages (3) are arranged in the water intake culvert (2). There is a movable gantry crane (5) above the pollution interception structure (1).

2. The trash rack structure device for water intake of a nuclear power plant according to claim 1, characterized in that, There is a marine organism release port (6) at the connection between the left side of the pollution interception structure (1) and the guide dike. There is an intertidal pollution interception net (4) above the water intake culvert (2). The elevation of the culvert top plate is set between the mean tide level and the low tide level to form a retention platform for facilitating the cleaning of intercepted objects. The right side of the pollution interception structure (1) is connected to the guide dike through a ship passage section (7). There are gantry crane tracks (8) facilitating the movement of the gantry crane (5) on the front and back sides of the pollution interception structure (1).

3. The anti-pollution structure device for the water intake open channel of a nuclear power plant according to claim 1, characterized in that The special pollution interception net cage (3) is movably connected to the water intake culvert (2).

4. The anti - pollution structure device for the intake open channel of a nuclear power plant according to claim 1, wherein, The special pollution interception net cage (3) includes a frame (9). Removable mesh sheets (10) are arranged on both sides of the frame (9). A plurality of lifting rings (11) are arranged on the frame (9). The frame (9) is welded by a plurality of stainless steel frames (12).

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