KR20150130600A - Drum for heat-drying radioactive liquid waste - Google Patents

Abstract

Disclosed is a drum for heating and drying radioactive concentrated liquid waste. The disclosed drum for heating and drying the radioactive concentrated liquid waste includes a plurality of inclination plates which are installed on the inner wall of the drum along a height direction and are downwardly inclined to drop a sludge rising by being carried over with steam by heating to the lower side of the drum as the drum for heating and drying the radioactive concentrated liquid waste.

Description

[0001] DRUM FOR HEAT-DRYING RADIOACTIVE LIQUID WASTE [0002]

An embodiment of the present invention relates to a drum for heating and drying a radioactive concentrated waste liquid. More specifically, the present invention relates to a drum for collecting radioactive liquid waste in a separate drum, indirectly heating the drum surface with a battery resistor, To a drum for heating and drying a radioactive concentrated waste solution so that the volume of the drum can be minimized.

Nuclear power plants generate solid, gas, and liquid radioactive waste during operation, and the radioactive waste generated is removed by using the treatment facilities according to the characteristics of each type, and then, in the case of solid, Exhaust to the middle, the liquid is discharged to the sea.

Among these processes, solid and liquid radioactive wastes that can not be processed technically by using the treatment facilities are temporarily stored in nuclear power plants, packed in radioactive waste drums, transported to waste storage and stored separately, and radioactive waste repository Upon completion, it will be transported to sea for permanent disposal (storage). Therefore, it can be economically and socially advantageous depending on how much the radioactive waste drum generated as a by-product of nuclear power generation is not generated or how much can be reduced by reducing the volume of generated radioactive waste.

In particular, in the case of liquid radioactive wastes, concentrated water concentrated in high concentration is drained during the operation of the liquid radioactive waste treatment facility, and the concentrated water is packed in a separate drum and transported to the waste reservoir. The amount of concentrated water drained The production amount of the radioactive waste drum becomes proportional.

Various methods have been proposed for concentrating and drying the radioactive waste solution. For example, Korean Patent Registration No. 10-1241126 discloses a method and apparatus for treating a radioactive waste liquid using mechanical vapor compression steam. The method comprises: 1) a step in which the concentrated water is heated in a heat exchanger (4) Temperature rise step; 2) During the circulation of the heated concentrated water into the concentrated water inflow end 11 located at the upper end of the waste liquid concentration and drying apparatus 1, the concentrated water is heated by the latent heat of the high-temperature high-pressure vapor of the high- A second heating step; 3) The concentrated water heated in step 2) flows into the first concentrated water flow end 13 and is heated by the latent heat of the high-temperature high-pressure steam circulating through the high-pressure steam inlet end 12 and the high- A third heating step; 4) a fourth step of heating step (4) in which the concentrated water heated in step 3) is heated by the latent heat of the high-temperature high-pressure steam circulating in the high-pressure steam flow end 14 while flowing into the second concentrated- ; 5) The concentrated water heated in the step 4) is injected into the drum 18 through the liquid dispensing end 17 as droplets, and the dissolved solid particles contained in the concentrated water are generated as dry powder; 6) the droplet is converted into low-pressure steam in the drum and flows into the low-pressure steam flow end 16 through the low-pressure steam passage 173 of the liquid distributing end; And 7) the low-pressure steam introduced into the low-pressure steam flow end is adiabatically compressed by the mechanical vapor recompression (MVR) pump 3 and re-introduced into the high-pressure steam inlet end 12 in a high- The radioactive waste liquid is treated.

Nuclear power plants use steam as a heating energy source, and in the case of Korean standard nuclear power plants, concentrated wastewater drying facilities. In the case of next generation improved nuclear power reactors, concentrated treatment wastewater treatment facilities are introduced, In recent years, there has been developed a radioactive concentrated waste liquid heat dryer capable of reducing the volume by indirectly heating a drum storing concentrated water with an electric resistor to evaporate the water inside the drum, It is in the process.

The radioactive concentrated waste heat drier indirectly heats the lower side surface of the drum storing the concentrated water with the battery resistor to evaporate the moisture in the drum as much as possible so that only the dried sludge is left so that the effect of reducing the volume of the waste can be seen have. However, waste drums used in power plants use galvanized steel as their material, and the surface is painted with information necessary for warning and identification.

Since the radioactive waste drums used in nuclear power plants in Korea are very weak in external heat, if the surface of the drum is heated by the electric resistor, the surface of the drum surface is pressed, and the plating layer on the surface of the zinc- If ruptured, the water inside the drum will cause corrosion of the steel sheet. Therefore, the drums used in the radioactive concentrated waste heat drier which can indirectly heat the drum storing the concentrated water by indirectly heating the electric resistance by evaporating the water inside the drum can be used for the drum pressing phenomenon and the corrosion of the steel plate due to the plating layer rupture There is a problem that needs to be solved.

Korean Patent No. 10-1241126

Embodiments of the present invention provide a drum for heating and drying a radioactive concentrated waste solution capable of increasing the heat transfer area to increase the evaporation efficiency, allowing the dried sludge to fall smoothly toward the lower side of the drum, and improving the heat resistance and corrosion resistance .

A drum for heating and drying a radioactive concentrated waste solution according to an embodiment of the present invention is a drum for heating and drying a radioactive concentrated waste solution, which is installed along the height direction on the inner wall of the drum and coaxially raised together with water vapor by heating And a plurality of swash plates disposed downwardly inclined so that the sludge falls to the bottom of the drum.

Also, in the drum for heating and drying the radioactive concentrated waste solution according to the embodiment of the present invention, the material of the drum may be Cr-Ni-based stainless steel containing 18% Cr-8% Ni.

In the drum for heating and drying the radioactive concentrated waste solution according to the embodiment of the present invention, the average surface roughness Ra of the slope surface and the inner wall of the drum may be 0.64 탆 or less.

Further, in the drum for heating and drying the radioactive concentrated waste solution according to the embodiment of the present invention, the inclination angle of the swash plate may be 10 to 30 °.

In addition, in the drum for heating and drying the radioactive concentrated waste solution according to the embodiment of the present invention, the sludge can be accumulated up to 90% of the total volume of the drum.

According to the present invention, it is possible to prevent heat build-up on the surface of a conventional drum, rupture of a coating part and corrosion due to moisture, thereby imparting heat resistance and corrosion resistance, and also saving energy by increasing evaporation efficiency.

These drawings are for the purpose of describing an embodiment of the present invention, and therefore the technical idea of the present invention should not be construed as being limited to the accompanying drawings.
1 is a configuration diagram of a radioactive concentrated waste liquid heat dryer according to an embodiment of the present invention.
2 is an internal structural view of a drum for heating and drying a radioactive concentrated waste solution according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

It is to be noted that the drawings are for reference only for the purpose of clearly and concretely explaining the preferred embodiments of the present invention and technical ideas or features, and therefore may be different from actual product specifications.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. .

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

1 is a configuration diagram of a radioactive concentrated waste liquid heat dryer according to an embodiment of the present invention.

Referring to FIG. 1, a drum 1 for storing a radioactive waste liquid is indirectly heated by an electric resistor to evaporate moisture in a drum as much as possible, So that the volume of the waste can be reduced.

The radioactive concentrated waste liquid heat dryer 20 basically comprises a drum 1, electric resistance members 2 and 4 for heating the drum side surface, electric resistance members 3 for heating the drum, a drum mounting unit 5, A nozzle 6 and a water vapor discharge nozzle 7.

The radioactive concentrated waste liquid stored in the separate drum flows into the nozzle 6 through which the concentrated waste liquid flows, and when the pump reaches a certain level of the drum 1, the pump is stopped.

Then, the drum side heating electric resistors (2, 4) and the drum side heating electric resistor (3) are operated to indirectly heat the drum surface.

As a result, the inside of the drum is heated to the evaporation temperature of the fluid, and the water vapor evaporated when the evaporation temperature is reached is discharged to the steam discharge nozzle 7. The sludge component in the concentrated concentrated waste liquid flowing into the drum gradually becomes dry And is converted into sludge form.

In particular, the drum 1 for heating and drying the radioactive concentrated waste solution according to the embodiment of the present invention has a structure in which the heat transfer area is increased to increase the evaporation efficiency, and the dried sludge can be smoothly dropped to the lower side of the drum.

To this end, the drum 1 for heating and drying the radioactive concentrated waste solution according to the embodiment of the present invention is provided with a swash plate 8.

The swash plate 8 is arranged on the inner wall of the drum 1 along the height direction, and is attached with a downward inclination. As a result, the sludge that has been raised in the radial direction together with water vapor by heating may fall to the bottom of the drum.

That is, the swash plate 8 functions to prevent the steam flow so that the evaporated steam can stay in the drum even a little longer, so that the heat transfer can be maximized. At the same time, the steam that is evaporated comes into direct contact with the swash plate 8 As a result, the fibrous sludge contained in the water vapor, which carries over the water, is adhered to the surface of the swash plate 8 due to moisture, and the adhered sludge forms a sludge layer and falls downward in the drum.

 At this time, the inclination angle of the swash plate 8 is preferably in the range of 10 to 30 °, which is preferable for guiding the fixed sludge to fall down smoothly. When the inclination angle is less than 10 °, the retention time of steam can be increased. However, it is ineffective to obtain a driving force capable of dropping the dried sludge adhered to the surface to the lower side of the drum. On the other hand, It is easy to obtain the driving force that allows the dried sludge to fall downward in the drum lower direction, but it is inefficient to increase the residence time of steam.

In the embodiment of the present invention, the average surface roughness Ra of the surface of the swash plate 8 and the inner wall of the drum 1 is preferably not more than 0.64 占 퐉. The drying sludge that has lost moisture is not fixed to the surface of the swash plate 8 and the inner surface of the drum 1 by polishing the surface of the swash plate 8 and the inner wall of the drum 1 with the average surface roughness Ra, It is possible to more smoothly fall downward.

The drum 1 may be made of Cr-Ni-based stainless steel containing 18% Cr-8% Ni in order to improve the heat resistance. By using such a material, it is possible to solve the pressing phenomenon of the drum surface which occurs when the conventional radioactive waste drum is used as it is.

It is preferable that the drying sludge 9 accumulated in the drum 1 according to the embodiment of the present invention is limited to the uppermost inclined plate 8. [ That is, the sludge is accumulated up to 90% of the total volume of the drum. This is to ensure the expansion space of the water vapor evaporated in the drying sludge accumulated just before the upper swash plate 8, and more optimally, at least 10% of the total internal volume of the drum.

The drum 1 of the embodiment of the present invention can reduce the volume of the dried sludge to 100: 20 by volume of the radioactive concentrated waste solution, and can save energy by increasing durability and evaporation efficiency.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, And it goes without saying that the invention belongs to the scope of the invention.

1: Drums
2: Electric resistor for drum side heating
3: Electric resistance heater for heating drum
4: Electric resistor for drum side heating
5: Drum mounting part
6: High concentration waste fluid inflow nozzle
7: Water vapor discharge nozzle
8: Swash plate
9: Dry sludge
10: Water vapor flow

Claims (5)

A drum for heating and drying a radioactive concentrated waste solution,
And a plurality of swash plates installed along the height direction on the inner wall of the drum and arranged to be inclined downward so that the sludge which has been raised in the radial direction together with water vapor by heating is dropped to the bottom of the drum. The drum according to claim 1, wherein the material of the drum
Ni-based stainless steel containing 18% Cr-8% Ni. The drum for heating and drying a radioactive concentrated waste solution according to claim 1, wherein the average surface roughness Ra of the slope surface and the inner wall of the drum is 0.64 μm or less. The drum of claim 1, wherein the inclined plate has an inclination angle of 10 to 30 degrees. The drum of claim 1, wherein the sludge accumulates up to 90% of the total volume of the drum.

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