RU118465U1 - TANK FOR RECEPTION AND TEMPORARY STORAGE OF LIQUID RADIOACTIVE WASTE AT A NUCLEAR POWER PLANT - Google Patents

Abstract

The proposal relates to the field of nuclear energy. The capacity includes a cylindrical body with a conical bottom. The conical bottom is made truncated, while in the upper and lower parts of it are installed one below the other two annular bubbler collectors with slotted holes with the possibility of supplying compressed air to them. Allowed to increase work efficiency. 3 ill.

Description

The utility model relates to the field of nuclear energy and can be used in nuclear power plants (hereinafter - NPPs) in the system of an intermediate node for storing liquid radioactive waste.

During the operation of nuclear power plants, radioactive substances are formed that are decontaminated in continuous and batch-type installations, which are placed in the building of the radioactive water treatment plant — in special water treatment.

Liquid radioactive waste (hereinafter - LRW) is treated to return decontaminated high purity water to the NPP cycle and to concentrate the radioactivity contained in the waste in the smallest residues that can be stored in the smallest containers.

Radioactive waters include: continuously cleaned purge water from reactors; leaks continuously cleaned periodically or periodically, drains, discharges after decontamination (floor drains), water emptying the reactor loops; continuously cleaned purge water of steam generators; Laundries and showers.

Along with radioactive isotopes, they contain products of corrosion and erosion, radioactive and non-radioactive contaminants, complexing substances, as well as detergents, oils, and lubricants.

Wastes of medium and low levels of activity are generated in such large quantities that it is almost impossible to create conditions for their storage.

Dumping into water bodies is permissible only if a tenfold dilution of radioactive water by non-radioactive wastewater is provided in the collector of this enterprise.

Due to these circumstances, it becomes necessary to provide for the construction of a complex of treatment facilities.

Liquid waste of high activity cannot be disposed of into the environment, but must be concentrated to the maximum possible level with subsequent long-term (eternal) burial in special tanks located in underground concrete chambers.

At nuclear power plants built in Russia and neighboring countries in the second half of the 20th century, LRW storage facilities were provided as part of special buildings.

As a rule, the accumulated LRW is temporarily stored in stainless steel tanks and for long-term storage should be processed into a form that allows their safe transportation and storage.

The most common and widely used industrial application for LRW processing is the method of concentrating them by evaporation in evaporators to a salinity of 50 ÷ 500 g / dm ³ .

The inventive utility model relates to containers for receiving and temporary storage of bottoms of evaporation plants and is intended for the reception of highly concentrated salt solutions or bottoms (homogeneous phase) obtained by processing the drain water of evaporation plants and the temporary content of LRW.

This tank provides protection against radiation and isolation of LRW for the subsequent extraction of LRW.

Known metal pre-stressed tank, including a bottom mounted on the base wall (see copyright certificate SU No. 1231188, Е04Н 7 / 04.1986).

Also known is a vertical cylindrical tank including a wall, a bottom (see copyright certificate SU No. 1231189, ЕНН 7/06, 1986).

The disadvantage of these devices is the implementation of the tank in the form of a cylinder with a flat bottom.

This implies the lack of visual monitoring of bottom leaks; the presence of stagnant zones in the cells of the tank, while mixing of LRW is not provided, which leads to the formation of salt deposits; complete emptying of the tank is excluded, repairs require a lot of labor, the tank is very metal-intensive, which leads to an increase in the load on the foundation.

Also known is a reservoir for storing, disposing of contaminated liquid (see patent RU No. 2095532, G21F 9/22, 1997).

The tank contains two containers, made coaxially, one inside the other, with a gap between the enclosing structures, and the contaminated liquid is poured into the internal container, and the space between the containers is filled with a liquid similar in physical and mechanical properties, but with a high degree of purification, while its upper level is or more contaminated fluid.

The disadvantages of this device are: large tank sizes; tank repair requires a lot of labor; leakage of radioactive water from a dirty cell can only be detected by contamination of the water of the clean cell, while the volume of LRW increases by the amount of liquid in the clean cell; the presence of stagnant zones of the bottom, which leads to the formation of salt deposits in the tank.

Also known is a container for storing liquid radioactive waste (see copyright certificate SU No. 1153720, G21F 9/22, 1999).

The tank contains a tank with a lid, a pipeline for supplying a radioactive medium in communication with the lower part of the tank, and pipes for supplying and discharging gas.

The disadvantages of this device are: the complexity of the manufacture of internals; the radioactive medium supply pipeline does not provide mixing of LRW in the tank; formation and compaction of salt deposits around the perimeter of the bottom of the tank.

Also known is a tank containing a vertical cylindrical tank with a conical bottom, a system for supplying and discharging water and removing contaminants (see patent RU No. 2182508, B01D 21/02, 2002).

Inside the tank there is a pipe for supplying water, a tray for collecting purified water and a nozzle in the form of a spiral plate mounted on the pipe for supplying water, the outer edge of which is attached to the wall of the container with the formation of a gap. The inner edge of the spiral plate is rigidly attached to the outer surface of the pipe, a slit hole is made along the entire height of the pipe, and a plug is installed in the lower part of the pipe.

The disadvantage of this device is that the inlet pipe of the suction line is mounted to the lower part of the tank, which makes it impossible to carry out repair work on valves and pipelines without emptying the tank.

The closest in technical essence to the claimed solution is a container for the collection and temporary storage of liquid radioactive waste, made in the form of a vertical cylinder with a conical bottom and with systems for supplying and discharging media (see V. M. Sedov et al., “Chemical technology of coolants nuclear power plants ”, Moscow, Energoatomizdat, 1985, pp. 287-288).

The disadvantages of this device is the low efficiency of its work and the increased metal consumption of the structure.

The technical result of the proposed solution is to increase the efficiency of the device.

To achieve the specified technical result, in the tank for collecting and temporary storage of liquid radioactive waste at a nuclear power plant, including a cylindrical body with a conical bottom, according to the proposal, the conical bottom is made truncated, while in the upper and lower parts there are two annular bubble collectors installed one below the other with slotted holes with the possibility of supplying compressed air to them.

The essence of the proposal is illustrated by drawings, where figure 1 shows a longitudinal section of a General view of the tank; figure 2 shows a cross section of a container aa; figure 3 presents a section BB of the bubbler collector.

It should be noted that the drawings show only those details that are necessary for understanding the essence of the proposal, and the accompanying equipment, well known to specialists in this field, is not presented in the drawings.

The device is a container 1 for collecting and temporary storage of LRW with a cylindrical body and with a conical bottom 2 made of stainless steel (figure 1).

In this case, the conical bottom 2 is made with a truncated platform 3, which is located in the lower part of the conical bottom 2 and along the central axis of the device.

On a truncated platform 3 of the conical bottom 2, a lower annular bubbler collector 4 is installed inside the housing. The lower collector 4 is designed to prevent the formation of salt deposits.

In the upper part of the conical bottom 2 is located the upper annular bubbler collector 5. The upper collector 5 is designed for efficient mixing of the medium.

The collectors 4, 5 are made of stainless steel pipes with holes in the form of slots that are evenly spaced along the plane and oriented towards the truncated area 3 (FIGS. 2, 3). At the same time, pipelines 6 for supplying compressed air are connected to the collectors 4, 5.

For transportation of LRW from tank 1, it is equipped with an unloading pipeline 7, which is lowered to the truncated site 3 and brought to the middle part of the shell of the tank 1.

To increase radiation safety, the tank 1 is equipped with a water lock 8 located in the upper part of the cylindrical body.

The device operates as follows.

Highly concentrated salt solutions obtained during the processing of floor drain water in evaporation plants enter tank 1 for receiving and temporary storage of LRW. The volume of the CWF tank provides the necessary technological exposure of LRW prior to their processing and (or) decay of short-lived radionuclides.

Highly concentrated salt solutions are subject to a change in the state of aggregation, including the formation of sediments and deposits. The separation of the precipitate in the tank 1 occurs by sedimentation. At the same time, the sediment remains in the conical bottom 2, and the decantate is returned through the discharge line 7 into the technological cycle of processing the drain water.

To exclude the formation of salt deposits in the conical bottom 2 on a truncated platform 3, compressed air is piped to the lower annular bubble collector 4. When compressed air is supplied, the salt deposits are eroded and mixed.

For uniform mixing and averaging of the solution in the tank, compressed air is supplied to the upper bubbler collector 5.

The inventive utility model made it possible to combine in one technical solution the functions of the reception and temporary storage of highly concentrated salt solutions with a given concentration, to prevent the formation of salt deposits at the bottom of the tank, to make it possible to carry out repair work on the discharge pipeline and valves without the condition of the tank being completely empty.

Claims (1)

A container for receiving and temporarily storing liquid radioactive waste at a nuclear power plant, including a cylindrical body with a conical bottom, characterized in that the conical bottom is truncated, while in the upper and lower parts there are two annular bubbler collectors with slotted openings underneath with the possibility of supply of compressed air to them.