Waste collection and filtration tanks

Abstract

The dirt collection and filtering tank relates to a device for filtering large volumes of liquids containing a lot of dirt, which can be used in particular in the nuclear industry, specifically in sump tanks in nuclear power plants (NPPs), for the purpose of filtering large volumes of cooling water in case of an accident. The garbage collecting and filtering tank includes an inlet hole in the lid, an outlet hole in which a filtering device is installed, a vertical shaft attached to the inlet hole and installed on the bottom of the tank, and a window for discharging liquid installed in the vertical shaft, the window being installed in the lower part of the vertical shaft and facing in the opposite direction to the filtering device, and the upper part of the vertical shaft is formed in the shape of a funnel. The garbage collecting and filtering tank can be used for filtering a large flow rate of liquid containing a large amount of garbage, especially in the safety system of a nuclear power plant.

Description

[Technical field]

[0001] The present invention relates to a device for filtering large volumes of liquid containing a lot of debris, which can be used in particular in the nuclear industry, specifically in sump tanks in Nuclear Power Plants (NPPs) for filtering large volumes of cooling water in the event of an accident. [Background technology]

[0002] A key problem during the operation of a nuclear power plant is filtering the coolant (usually water) that escapes from a damaged primary circuit pipeline in the event of an accident.

[0003] The use of coolant to cool the reactor core after an accident is just as important as it is during normal operation, as a lack of coolant could lead to a serious accident such as a core meltdown. For this reason, the coolant leaking from the damaged pipeline must be collected and sent to the Emergency Core Cooling System (ECCS) to further cool the reactor core.

[0004] At the same time, another problem is that in an accident involving the leakage of primary coolant, a large amount of debris will be generated in the containment vessel due to the destruction of structures and facilities.

[0005] The debris is mixed with a boric acid solution and used by the ECCS for long-term cooling of the reactor plant. The components of the debris can block the ECCS and reduce the cooling efficiency of the reactor unit. The main components of the debris are: Latent debris includes dust, dirt, clothing fibers, pieces of paper, plastic particles, rust, dried paint droplets, etc. This latent debris refers to debris generated during basic construction and repair work under the containment vessel and during the operation of the nuclear power plant. - Debris from destruction of insulation structure. - Debris caused by destruction of the coating. Chemical debris.

[0006] The coolant, which contains a large amount of debris, is collected in special sump tanks where it is purified by filters before being fed to the ECCS.

[0007] The problem is that a large amount of coolant containing a large amount of debris creates an obstruction at the inlet of the filter, significantly reducing or completely stopping the flow of coolant into the filter. This can result in a lack of coolant in the core, which can overheat and lead to a serious accident. For this reason, it is necessary to develop a tank to collect and filter the debris so that the debris does not clog the filter when the flow rate of the liquid carrying the large amount of debris is high.

[0008] A variety of technical solutions have been used to solve such problems.

[0009] A protective device for a sump tank with a filter module in an emergency cooling system of a water-cooled nuclear reactor is known (Patent of the Russian Federation No. 2686684, published on April 30, 2019, IPC: G21C 9 / 00).

[0010] The protection device includes a filter system installed in the upper receiving opening of a sump tank at the bottom of the reactor containment vessel, the sump tank being connected to the inlet of the pipeline of the emergency cooling system, the filter system being composed of a number of filter modules connected to a collector, which prevents the ingress of debris into the inlet of the pipeline of the emergency cooling system, each filter module having a slotted grid on the side and on the top and a filter element arranged in the grid, the filter element being made in the form of a filter pipe with a number of slots on the side, inside which pipe is arranged a distribution pipe with a number of holes, the diameter of the holes of which decreases continuously along the flow, and its internal cavity being connected to the collector.

[0011] This solution not only ensures a uniform flow over the filter surface and eliminates uneven clogging with debris, but also ensures a uniform flow along the surface of the filter element itself.

[0012] The drawback of this solution is that it does not ensure the safety of the filtration device in the case of high flow rates of liquids containing a large amount of debris that can clog the pores of the filter element.

[0013] The closest thing to the present invention is a catcher for collecting suspended particles (Inventor's Certificate SU 1733045, issued May 15, 1992, IPC: B01D 24 / 02).

[0014] This catcher is equipped with a sump tank with an inlet hole for contaminated water and an outlet hole for purified water, a two-stage filter including a first stage for coarse purification and a second stage made of mesh with a decreasing number of cells in the direction of the purified water outflow, and a pleated mesh installed between the mesh of the purification cells of the second stage.

[0015] In the sump tank, in order to improve the purification efficiency and the reliability of the catcher, the first stage purification element is a set of flat mesh elements connected in parallel, and each element has a vertical mesh containing the same cells as the first row of meshes of the second stage purification cells, which is installed symmetrically with respect to the axis of the element.

[0016] The last mesh cell of the first stage has a larger cell than the last mesh cell of the second stage, and the catcher is provided with a vertical shaft installed at the bottom of the sump tank coaxially with the inlet hole and having a cross-sectional area greater than the cross-sectional area of ​​the inlet hole, a window is provided in the wall of the shaft near the ceiling of the sump tank, and the lower part of the shaft communicates with each mesh element of the first stage.

[0017] This solution increases the efficiency of the catcher and its reliability of operation, but it has the drawback that it does not ensure safe operation of the filter in the case of high flows of liquids with a large amount of dirt. [Prior art documents] [Patent documents]

[0018] [Patent Document 1] Russian Patent No. 2686684 [Patent Document 2] USSR Inventor's Certificate No. 1733045 Summary of the Invention [Problem to be solved by the invention]

[0019] The object of the present invention is to develop a dirt collection and filtering tank capable of reliable operation under high flow rates of liquids containing large amounts of dirt.

[0020] The technical achievement is to increase the safety of operation of waste collection and filtering tanks in the case of high flow rates of liquids containing large amounts of waste. [Means for solving the problem]

[0021] This technical result is achieved by the following features:

[0022] That is, the waste collection and filtration tank comprises an inlet hole provided in a lid, an outlet hole in which a filtration device is installed, a vertical shaft attached to the inlet hole and installed on the bottom of the tank, and a window for discharging liquid provided in the vertical shaft, the window being provided at the bottom of the vertical shaft and facing in the opposite direction to the filtration device.

[0023] The upper part of the vertical shaft is preferably funnel shaped.

[0024] The walls of the vertical shaft are preferably provided with vertical ribs.

[0025] The walls of the funnel are preferably provided with horizontal ribs.

[0026] Above the funnel it is advisable to install a guard. [Brief description of the drawings]

[0027] [Figure 1] FIG. 1 is a cross-sectional view of a waste collection and filtering tank with a vertical shaft in a preferred embodiment. [Diagram 2] FIG. 2 is a side cross-sectional view of a dirt collection and filtering tank in a preferred embodiment. [Diagram 3] FIG. 2 is a top cross-sectional view of a dirt collection and filtering tank according to a preferred embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] A vertical shaft 4 is attached to an entrance hole provided in a lid 1 of the waste collection and filtering tank, and the lower part of the vertical shaft 4 is attached to a bottom 2 of the waste collection and filtering tank.

[0029] In a preferred embodiment, a funnel 3 is provided at the top of a vertical shaft 4, the funnel 3 having vertical ribs 5 and horizontal ribs 6 formed therein.

[0030] At the bottom of the vertical shaft 4 there is a window 8 facing away from the filtration device 9 .

[0031] The debris contained in the liquid flow is primarily collected in a debris settling zone 10 .

[0032] In a preferred embodiment, the funnel 3 is provided with a guard 7 .

[0033] In a preferred embodiment, the dirt collection and filtering tank operates as follows.

[0034] When a large volume of liquid containing a large amount of garbage flows from the lid 1 of the garbage collection and filtering tank through the funnel 3 into the vertical shaft 4, a liquid flow is formed and at the same time, some of the kinetic energy is lost due to braking by the vertical ribs 5 and horizontal ribs 6 on the funnel 3 and the vertical shaft 4. The guard 7 prevents especially large pieces of garbage from entering the tank.

[0035] The liquid flow falling from height then hits the bottom of the vertical shaft 4, thereby losing further kinetic energy, and then passes through the window 8 into the main space of the tank and is directed away from the filter 9, thereby losing further kinetic energy on its way to the filter 9. As a result, the refuse is deposited and collected in the refuse settling zone 10, located as far away as possible from the filter 9, thereby preventing clogging of the filter 9.

[0036] This allows for unhindered operation and improves safety.

[0037] Dirt collection and filtering tanks can be used for filtering large volumes of liquids containing large amounts of dirt, especially in the safety systems of nuclear power plants.

Claims

1. A waste collection and filtering tank, comprising: An inlet hole provided in the lid; an outlet hole in which a filtration device is installed; a vertical shaft attached to the inlet hole and located on the bottom of the tank; a window in the vertical shaft for discharging liquid; Equipped with A waste collection and filtering tank, characterized in that the window is provided at the bottom of the vertical shaft and faces away from the filtering device.

2. The top of the vertical shaft is formed in the shape of a funnel 2. A refuse collection and filtering tank according to claim 1.

3. The walls of the vertical shaft are provided with vertical ribs 2. A refuse collection and filtering tank according to claim 1.

4. The funnel wall is provided with horizontal ribs 3. A refuse collection and filtering tank according to claim 2.

5. A guard is provided above the funnel.

3. A refuse collection and filtering tank according to claim 2.

Images