JPS6145520Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a device for removing sludge from cleaning wastewater of a nuclear reactor.

Sludge lancing (hereinafter referred to as S/G sludge lancing) is a process in which high-pressure hydrazine liquid is sprayed onto the steam generator tube plate for the purpose of removing sludge on the steam generator tube plate before the start of operation of a nuclear power plant or during periodic inspections. Cleaning work is being carried out under the name .

FIG. 1 is a flow sheet showing the wastewater treatment mode of S/G sludge lancing currently being implemented.

In Fig. 1, hydrazine is pressurized by a high-pressure jet pump car 1 onto a tube plate B of a steam generator A.
100 ppm high-pressure hydrazine vehicle fluid 2 is spouted from the nozzle tip 8.

At that time, the sludge mixed with the sludge-containing discharge water 3 is transferred to the filter unit 4 (length:
Filtered water 9 is collected in a recirculation water tank 5, and filtered water is collected using a cotton filter (250mm in diameter and 65mm in outer diameter), containing 5 filters in 3 tiers (15 filters in total).
In order to facilitate the removal of sludge, a portion is returned to the inside of the steam generator as recirculated water 6 and poured into a rapid flow onto the tube sheet B, and the remainder is ionized as ion exchange water 10 (not shown) It is supplied to the exchange resin, cleaned, and then discharged to a designated location.

The 3μ filter made of cotton filled in the filter unit 4 is a high standard product for nuclear power use in order to guarantee strict regulatory values, and is therefore expensive. On the other hand, the filter used in filter unit 4 is
Core metal cylinder (length with perforated plate surface, 250
It is a bamboo ring-shaped material with a diameter of 65 mm (that is, a cylinder with a diameter of 25 mm), which is tightly wound with cotton cloth and cotton thread around the outer circumference of the cylinder (25 mm in diameter). It is sucked in from the outside and sludge is attached to the outer periphery. Since the filtered water 9 is of a type that passes through the inside of a metal cylinder, the amount of adhered sludge per filter is known.

However, the amount of waste is enormous compared to the amount of sludge because used sludge lancing filters are treated as radioactive waste and are subject to disposal in drums according to regulations.

Therefore, during cleaning work, the filters must be replaced and stored frequently, and four to six operators must be on hand at all times.

Considering that the Lansing construction itself is a major construction project that lasts 12 to 20 days (including equipment relocation), and that the current amount of work involves 500 to 800 filters, , some kind of countermeasures are becoming necessary. As described above, in the conventional method shown in Fig. 1, (1) too many filters are used;

(2) Labor costs are too high.

(3) The amount of waste is too large.

There are drawbacks such as.

The inventors conducted studies to solve the above-mentioned conventional drawbacks and obtained the following knowledge. In other words, the amount of sludge in the mixed water just before passing through the 3μ filter is
If some method could be used to reduce the current amount by half, then the amount of filter usage (and thus the amount of waste and personnel required to operate the filter) could be halved.

Therefore, the following studies were conducted regarding the characteristics of the removed sludge and the removal operation factors.

(1) Looking at the specific gravity of sludge, the composition of sludge is often about 80% iron and 15% copper. This means that precipitation is much easier than in the case of precipitate removal during general wastewater treatment.

(2) Sludge contains a large amount of iron, so we focused on the ferromagnetism of iron.

(3) By using filter cloth as the filter material, costs are reduced, and at the same time, the amount of waste is made as small as possible.

In order to eliminate the above-mentioned drawbacks, it was concluded that rough removal of relatively large particles of sludge is most effective.

The present invention has been made based on the above considerations. That is, the present invention has a sludge settler that is connected to a flow path of sludge-containing discharge water and that reduces the flow rate of the discharge water, and a magnetic field generator that is disposed at the bottom of the sludge settler, one end of which is the same. A wastewater discharge pipe in which a vertical pipe and an inclined pipe are connected to the upper part of the sludge settler, another magnetic field generating device disposed above the vertical pipe of the wastewater discharge pipe, and The device is characterized by having a striking mechanism that appropriately hits the vertical pipe wall, and a sludge discharge port provided at the lower end of the sludge settler, and its purpose is to discharge sludge with a simple device. The object of the present invention is to provide a device for removing sludge from wastewater that eliminates the above-mentioned drawbacks by rough removal.

Hereinafter, one embodiment of the device of the present invention will be described in detail with reference to the accompanying drawings.

The apparatus for removing sludge from waste water according to one embodiment shown in FIG. A magnetic field generator 17 disposed at the lower part of the vessel 11, a wastewater discharge pipe 21 in which a vertical pipe 15 and an inclined pipe 20 are connected, one end of which communicates with the upper part of the sludge settler 11, and a vertical pipe 21 of the wastewater discharge pipe 21. Another magnetic field generating device 19 disposed at the upper part of the pipe 15, a striking mechanism 22 for appropriately hitting the wall of the vertical pipe 15 of the wastewater discharge pipe 21, and a sludge discharge port provided at the lower end of the sludge settler 11. 13.

The material of the sludge settler 11 is limited to non-magnetic material. Preferably, it is made of transparent rigid vinyl or copper. Further, the shape of the sludge settler 11 is detailed as follows. The main body has a cylindrical shape with a funnel-shaped cone attached to the upper and lower parts, and a discharge water inlet 23 is arranged at the center of the side surface of the body, and a discharge water outlet 12 is arranged at the apex of the upper funnel shape. It is set up. Sludge outlet 1
3 is attached directly below the lower funnel shape, and the sludge is discharged to the outside of the system via the valve 14.

The discharge water outlet 12 is then connected to a vertical pipe 15 (a transparent reinforced vinyl pipe with a spring). The vertical pipe 15 is provided with a vertical portion having a height of 2 to 4 m, and the tip thereof is connected to a gently curved inclined pipe 20, which is further connected to the inlet of the filter unit 4 shown in FIG. There is.

In the middle part of the vertical pipe 15, by electric current,
Coil 16 for forming a magnetic field with a width of about 1 m
is provided. Further, the coil 16 is structured to be movable up and down. Further, a coil 18 for forming a magnetic field by electric current is also provided on the entire surface below the discharge water inlet 23 at the lower part of the main body.

Furthermore, containers used for processing sludge discharged from the sludge discharge port 13 are shown in FIGS. 3 to 5.
As shown in the figure. In FIGS. 3 to 5, the sludge receptacle 24 is a cylindrical bucket-like vinyl container with many drainage holes provided on the side and bottom, and is placed in a drainage receptacle 25. ing.

Moreover, the main body upper funnel part is made in a shape that can be separated from the body part. The drain receptacle 25 is a vinyl container similar to a cylindrical bucket, and is provided with a tripod 26 and a valve 27 for draining standing water. The sludge filtration bag 28 is made into an elongated bag by sewing layers of cotton cloth together on a water-resistant net (Saran net, 60 mesh). The sludge filtration bag 28 (which has a slightly longer bag with approximately the same internal volume as the sludge receiver 24) is placed in the sludge receiver 24 and can be used with the upper end folded back to the outside. In some cases, the sludge discharge port 13 is directly connected to the lower end of the sludge discharge port 13 to prevent the sludge from scattering to the outside.

In this embodiment configured in this way, the sludge that has been transferred together with the discharge water 3 through the inlet pipe enters the sludge settler 11 and rapidly loses its flow velocity. It falls to the bottom of the sedimentator body. Furthermore, the sludge traveling straight collides with the cylindrical wall of the main body, loses its flow velocity, and at the same time coagulates to form large particles, which fall to the bottom according to Stokes' law. The sludge falling in this way is fixed by the magnetic field generated by the coil 18 at the lower part of the main body of the sludge settler 11. On the other hand, fine sludge that is not fixed by the magnetic field and tries to rise inside the vertical tube 15 is attracted to the wall of the vertical tube 15 by the magnetic field generated by the coil 16. Note that if there are too many particles rising inside the vertical tube 15, the position of the coil 16 is raised upward to an appropriate position. When the lancing stops (after 30 to 40 minutes of injection, it stops for about 15 minutes. Therefore, the flow of wastewater also stops), the operation moves on to take out the sludge. When the currents in the upper and lower coils 16 and 18 are cut off to eliminate the generation of upper and lower magnetic fields, the sludge accumulated in the lower part of the main body of the sludge settler 11 slides down the lower inclined surface of the main body toward the sludge discharge port 13. Further, the fine particles adsorbed on the wall of the vertical tube 15 aggregate and fall downward. At the same time, a hammer is applied to the wall of the vertical pipe 15 by a hammering mechanism 22 to help the sludge aggregate and fall.

Once the sludge has settled in the sludge discharge port 13, the valve 14 is opened all at once.

Next, the sludge mixed water is stored in the sludge receiver 24. Since the water in the sludge accumulates in the drainage receiver 25, it is extracted as appropriate. Such sludge discharge processing is repeated, and when the sludge has accumulated in the sludge receiver 24 for about eight minutes, the sludge receiver 24 is taken out and another sludge receiver is installed in the drainage receiver 25. When the sludge in the sludge receiver 25 is completely dry, remove the sludge from the sludge filter bag 2.
8, tie the neck with a string and discard. On the other hand, the water extracted from the drainage receiver 25 and stored therein is led into the filter unit 4 and subjected to the above-described treatment.

According to the device of the present invention described above, the following effects can be achieved.

(1) The amount of sludge at the filter inlet can be reliably reduced simply by passing it through the sludge settler.

(2) Sludge removal operation is easy.

(3) The sludge removal operation is extremely simple and can reliably handle wastewater treatment that involves intermittent and sudden changes in water volume associated with lancing.

Further, by applying the present invention to conventional S/G sludge lancing, the following effects can be obtained.

(1) The amount of filter media used is extremely small, making it ideal for nuclear power plant wastewater treatment, where radioactive waste must be packed in drums.

(2) The number of filters used is extremely reduced,
Therefore, the number of operating personnel is extremely reduced, so the cost is extremely low.

(3) Sludge filter media uses only cotton material, so the cost is very low.

(4) Since the capacity of the removal equipment is close to the capacity of the removed sludge, the amount of waste will be extremely small.

The present invention can be applied not only to a device for removing sludge from cleaning wastewater of a nuclear reactor, but also to a device for removing sludge from wastewater that generally contains a large amount of fine iron powder.

[Brief explanation of drawings]

Figure 1 is a flow sheet showing the wastewater treatment mode of S/G sludge lancing currently in use, Figure 2 is a diagram showing an outline of one embodiment of the device of the present invention, and Figures 3 to 5 are in accordance with the present invention. FIG. 2 is a schematic illustration of one embodiment of a container used when using the invented device. A...Steam generator, B...Tube plate, 1...High pressure jet pump car, 2...High pressure hydrazine liquid, 3...
...Discharge water, 4...Filter unit, 5...Recirculating water tank, 6...Recirculating water, 7...Discharge water receiving tank, 8...Nozzle tip, 9...Filtered water, 10
... Water for ion exchange treatment, 11 ... Sludge settler, 12 ... Discharge water outlet, 13 ... Sludge discharge port, 14 ... Valve, 15 ... Vertical pipe, 16 ...
... Coil, 17 ... Magnetic field generator, 18 ... Coil, 19 ... Other magnetic field generator, 20 ... Inclined pipe, 21 ... Drain discharge pipe, 22 ... Beating mechanism, 2
3...Effluent inlet, 24...Sludge receiver,
25...Drained water receiver, 26...Tripod, 27...Valve for draining standing water, 28...Sludge filtration bag.

Claims (1)

[Scope of utility model registration request] A sludge settler that is connected to the flow path of the sludge-containing discharge water and that reduces the flow rate of the discharge water; a magnetic field generator disposed at the bottom of the sludge settler; A drainage discharge pipe in which a vertical pipe and an inclined pipe are connected to each other in communication with the upper part, another magnetic field generating device disposed above the vertical pipe of the drainage discharge pipe, and the vertical pipe wall of the drainage discharge pipe. 1. A device for removing sludge from wastewater, comprising: a striking mechanism for applying appropriate blows to the sludge; and a sludge discharge port provided at the lower end of the sludge settler.