Cold crucible device for nuclear waste solidification treatment

Abstract

The utility model belongs to the technical field of nuclear waste treatment, and particularly relates to a cold crucible device for nuclear waste solidification treatment, which comprises a crucible wall, a crucible cover, an upper water cooling ring, a lower water cooling ring, a water cooling chassis, a discharge port slide valve and an induction coil, the upper water-cooling ring and the lower water-cooling ring are arranged at the upper end and the lower end of the crucible wall respectively, the crucible cover is arranged above the crucible wall, the water-cooling base plate is arranged on the inner side below the crucible wall, and the induction coil is arranged on the outer side of the crucible wall; the crucible wall comprises a circle of stainless steel pipes arranged at intervals, the upper ends of the stainless steel pipes are communicated with the upper water-cooling ring, and the lower ends of the stainless steel pipes are connected with the lower water-cooling ring. According to the cold crucible, due to the fact that melt is cooled, solidified and shrunk, solidified solids obtained after the melt is cooled and a skull layer can move downwards along with the crucible lifting system by means of the gravity of the solidified solids and the skull layer, and after the crucible lifting system descends to a proper position, the solidified solids obtained after the melt is cooled and the skull layer can be completely moved out of the crucible base plate.

Description

TECHNICAL FIELD

[0001] The utility model belongs to nuclear waste treatment technical field, concretely relates to a cold crucible device for nuclear waste solidification treatment. BACKGROUND

[0002] Nuclear fuel will remain after the reaction radioactive waste, this radioactivity cannot be eliminated by physical or chemical methods, only can stop the decay of itself, and the half-life of these radionuclides often lasts for thousands of years or even hundreds of thousands of years. The present radioactive waste treatment mainly adopts solidification treatment, and then is transported to disposal site for deep burial treatment. Radioactive waste, especially high radioactive waste, needs to be solidified, and then properly handled, so that the environmental impact is reduced to the minimum.

[0003] The cold crucible induction furnace of the present electromagnetic induction cold crucible furnace process is a technology that uses the coil of high-frequency current to generate induced current on the surface of the melt to melt it. The crucible wall is a water-cooled sleeve, cooling water is introduced into the water-cooled sleeve, and a layer of solid glass condensate shell is formed on the inner side of the crucible wall due to the cooling effect. The glass solution is wrapped in the glass condensate shell to protect the furnace body from erosion, has a long service life, high working temperature, and can handle various nuclear waste, and has a large production capacity. The electromagnetic cold crucible smelting technology has the characteristics of high efficiency and low pollution, and has great advantages in smelting of high-temperature active metals and refractory materials. However, the water-cooled structure of the cold crucible used in the present electromagnetic cold crucible production consumes a large amount of heat of the system, which reduces the heating efficiency and increases the complexity of the overall structure. The structure of the crucible and the coil, the applied current load and other factors will affect the performance. SUMMARY

[0004] The utility model aims at providing a cold crucible device for nuclear waste solidification treatment to solve the problems in the above background technology.

[0005] To achieve the above-mentioned purpose, the following technical solutions are adopted in the present application:

[0006] A cold crucible device for nuclear waste solidification treatment, comprising a crucible wall, a crucible cover, an upper water-cooled ring, a lower water-cooled ring, a water-cooled bottom plate, a discharge port slide valve and an induction coil.

[0007] The upper water-cooled ring and the lower water-cooled ring are respectively arranged at the upper and lower ends of the crucible wall, the crucible cover is arranged above the crucible wall, the water-cooled bottom plate is arranged on the inner side below the crucible wall, a discharge port communicating with the inner cavity of the crucible wall is arranged on the water-cooled bottom plate, and the discharge port slide valve is slidably arranged on the lower surface of the water-cooled bottom plate; the induction coil is arranged on the outer side of the crucible wall.

[0008] The crucible wall comprises a circle of stainless steel pipes arranged in gaps, the upper end of the stainless steel pipe is communicated with the upper water cooling ring, and the lower end of the stainless steel pipe is connected with the lower water cooling ring.

[0009] The gap between the two adjacent stainless steel pipes is 1:5-30 of the outer diameter of the stainless steel pipe.

[0010] Further, the number of the stainless steel pipes is a multiple of 3.

[0011] Further, the gap between the two adjacent stainless steel pipes is 1:5-30 of the outer diameter of the stainless steel pipe.

[0012] Further, the height of the crucible wall is 1.3-1.5 of the diameter of the circumscribed circle formed by the circle of stainless steel pipes.

[0013] Further, the cross section of the induction coil is square.

[0014] Further, the distance between the lowermost turn of the induction coil and the upper surface of the water cooling disc is not less than 30 mm.

[0015] Further, the induction coil is divided into three equal sections along the axial direction of the crucible wall, which are the lower section induction coil, the middle section induction coil and the upper section induction coil, wherein the distance between the two adjacent turns of the lower section induction coil is equal to the distance between the two adjacent turns of the upper section induction coil, and is greater than the distance between the two adjacent turns of the middle section induction coil.

[0016] Further, a cooling water jacket is arranged in the slide valve of the discharge port, and a circle of cooling water pipes is welded on the inner surface of the crucible cover.

[0017] Further, a stirrer mounting hole, a temperature measuring instrument mounting hole, a charging port and a pressurized gas inlet are arranged on the crucible cover.

[0018] Compared with the prior art, the cold crucible device has the following advantages:

[0019] On the basis of the prior art, the ratio of the gap and the outer diameter of the circle of stainless steel pipes arranged on the side wall of the crucible is determined, so that the magnetic flux of the induction coil can pass through the crucible and the current at the center of the crucible is increased, and the heating efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a front view of the cold crucible device.

[0021] Figure 2 It is a plan view of the crucible wall.

[0022] Figure 3 It is a plan view of the water cooling disc.

[0023] Figure 4 is a front view of the water-cooled base plate.

[0024] Figure 5 is a side view of the water-cooled slide valve.

[0025] Figure 6 is a schematic view of the crucible cover.

[0026] Explanation of reference signs:

[0027] 1, crucible wall; 2, stainless steel pipe; 3, upper water-cooled ring; 4, crucible cover; 41, charging port; 42, temperature measuring instrument mounting hole; 43, stirrer mounting hole; 44, cooling water pipe; 45, pressurized gas inlet; 5, lower water-cooled ring; 6, water-cooled base plate; 61, discharge port; 62, preheating block; 63, upper plate; 64, side wall; 65, lower plate; 66, slide rail; 7, discharge port slide valve; 8, refractory layer; 9, induction coil. DETAILED DESCRIPTION

[0028] The technical scheme of the utility model will be described below in combination with the drawings. The following examples are only exemplary and can only be used to explain and illustrate the technical scheme of the utility model, but cannot be interpreted as a limitation of the technical scheme of the utility model.

[0029] As shown in Figures 1 to 6 , the application provides a cold crucible device for nuclear waste solidification treatment, which comprises a crucible wall 1, a crucible cover 4, an upper water-cooled ring 3, a lower water-cooled ring 5, a water-cooled base plate 6, a discharge port slide valve 7, and an induction coil 9. The cold crucible device of the application further comprises a device for providing cooling water and other components. These components are the same as the structure and connection relationship of the cold crucible of the prior art. The technical scheme actually only improves the corresponding part of the furnace body of the cold crucible, rather than designs a new cold crucible. Therefore, in the application, the necessary components of the cold crucible that are not mentioned are the same as those of the cold crucible of the prior art, and will not be described in detail one by one. Similarly, in the implementation of the cold crucible, it is necessary to provide high-frequency current. Therefore, the power supply for providing high-frequency current, the high-frequency component, or the corresponding control component are all prior art, and a person skilled in the art can obtain them by corresponding commercial procurement as needed.

[0030] As shown in Figure 1As shown, in the present application, the upper water cooling ring 3 and the lower water cooling ring 5 are respectively arranged at the upper and lower ends of the crucible wall 1, the crucible cover 4 is arranged above the crucible wall 1, the water cooling base 6 is arranged on the inner side below the crucible wall 1, the water cooling base 6 is provided with a discharge port 61 communicating with the inner cavity of the crucible wall, and the discharge port sliding valve 7 is slidingly arranged on the lower surface of the water cooling base 6; the induction coil 9 is arranged outside the crucible wall 1. The upper water cooling ring 3, the lower water cooling ring 5, the water cooling base 6 and the induction coil 9 mentioned herein are necessary components of the existing cold crucible, and in the present application, the upper water cooling ring, the lower water cooling ring and the water cooling base are only improved for the arrangement of the stainless steel pipe of the crucible wall, and the main structure is the same as the prior art.

[0031] In the present application, the key is to improve the crucible wall 1, because the electromagnetic cold crucible for glass solidification is mainly used for nuclear waste solidification, especially high radioactive waste, which contains a large amount of radioactive and corrosive substances. Therefore, 316L stainless steel pipe is used as the main material of the cold crucible, and the inner diameter and height of the stainless steel pipe 2 are set according to the needs, which are not limited here. This can be illustrated by example, but it is by no means that the device of the present application can only be applied to this size device. For example, if the height of the prepared cold crucible is 500 mm, a stainless steel pipe with an outer diameter of 16 mm is selected to surround it, the wall thickness of each stainless steel pipe 2 is 2.5 mm, and the gap between adjacent two stainless steel pipes is 2 mm. This embodiment illustrates that there are 60 stainless steel pipes in one circle, which is not a limitation of the present application. This is an example for illustration. In actual design, other number of stainless steel pipes can be selected according to the needs. The key of the present application is that the number of stainless steel pipes 2 is a multiple of 3. The reason for such a number requirement is to facilitate the design of cooling water to ensure the stability of the hardness of the glass solid shell. Of course, if the temperature cooling can be guaranteed, other number of stainless steel pipes can also be used without any problem.

[0032] The upper water cooling ring 3 of the present application is divided into ten partitions on average, each group of six stainless steel pipes, three stainless steel pipes for water inlet and three stainless steel pipes for water outlet. The lower water cooling ring is divided into 20 petals, every 3 water cooling steel pipes are a petal, and the 3 stainless steel pipes in each petal are connected for water inlet, and the adjacent 3 stainless steel pipes are connected for water outlet.

[0033] A refractory material layer 8 is arranged in the gap of one circle of stainless steel pipes and on the inner and outer sides to surround the stainless steel pipes 2. The refractory material of the present application is inorganic material without affecting the electromagnetic field, and the refractory material of the present application can withstand a pressure of 3 MPa.

[0034] Generally, the thicker the wall thickness of the crucible wall 1, the greater the magnetic field shielding, the greater the gap between the two adjacent stainless steel tubes, the better the magnetic permeability, but the larger the gap, the lower the overall strength of the crucible, and the larger the gap, the higher the possibility of material leakage, therefore, the applicant has obtained a gap between the two adjacent stainless steel tubes and the outer diameter of the stainless steel tube by research, the ratio is 1:5-30, preferably 1:5-15, which can balance the strength of the crucible, the possibility of leakage and the magnetic permeability. And the ratio of the height of the crucible wall 1 to the diameter of the circumscribed circle formed by the stainless steel tube is between 1.3-1.5, which can achieve the best effect.

[0035] In this application, the water-cooled base 6 is composed of an upper plate 63, a lower plate 65 and a side wall 64, and the water-cooled base 6 is in close contact with the inner wall of the crucible.

[0036] In this application, a discharge port 61 is provided on the water-cooled base 6, which communicates with the inner cavity of the crucible wall, and the discharge port 61 is a bullet-shaped opening composed of a triangular opening and a rectangular opening. A preheating block 62 for heating is provided on the discharge port side of the upper surface of the water-cooled base, which can heat and melt the nearby glass shell when needed by a separate electric heating component, so as to facilitate the flow of glass solution from the discharge port. Opposite slide rails 66 are provided on the lower surface of the water-cooled base and the two sides of the discharge port, and a discharge port slide valve 7 slides in the slide rails 66 to close or open the discharge port. The slide rail structure of the present application is the conventional slide rail structure.

[0037] In this application, a cooling water jacket is provided in the discharge port slide valve 7 to ensure the service life of the discharge port slide valve, as shown in detail in Figure 5 .

[0038] The crucible cover 4 of the present application is used to prevent material volatilization and install part of auxiliary devices, at least a stirrer mounting hole 43, a temperature measuring instrument mounting hole 42, a feeding port 41 and a pressurized gas inlet 45 are provided on the crucible cover 4, and a circle of cooling water pipes 44 are welded on the inner surface of the crucible cover to cool the crucible cover. A stirrer is installed through the stirrer mounting hole, the stirrer of the present application is prior art, and those skilled in the art can obtain it through commercial channels according to needs. A temperature measuring instrument is installed through the temperature measuring instrument mounting hole, similarly, the temperature measuring instrument is prior art, and those skilled in the art can obtain it through commercial channels according to needs; similarly, the feeding port is connected with the feeding device of the prior art. The improvement of the present application is to provide a pressurized gas inlet on the crucible cover, during the heating process, inert gas or inert gas mixed with oxygen, or other designed gas can be introduced according to needs, the pressure is within the safe bearing range of refractory materials, on the one hand, it can improve the stirring effect, on the other hand, it can improve the material flow rate of the discharge port during discharging.

[0039] The induction coil 9 of the application is arranged outside the crucible and surrounds the crucible wall 1, and the purpose is to change the output of the high-frequency generator into a changing magnetic field, the magnetic flux passes through the crucible and generates eddy current in the material in the crucible, the cross section of the induction coil of the application is square, and the distance between the lowest turn of the induction coil and the upper surface of the water-cooled bottom plate is not less than 30mm.

[0040] In the application, the induction coil is divided into three equal sections along the axial direction of the crucible wall, which are the lower induction coil, the middle induction coil and the upper induction coil, wherein the distance between the two adjacent turns of the lower induction coil is equal to the distance between the two adjacent turns of the upper induction coil, and is greater than the distance between the two adjacent turns of the middle induction coil. The design of such an induction coil is to improve the uniformity of the magnetic field distribution in the crucible.

[0041] Finally, it should be pointed out that the above examples are only used to illustrate the technical solutions of the application, and not to limit them; although the application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. A cold crucible device for solidification treatment of nuclear waste, characterized in that: It includes crucible wall, crucible cover, upper water cooling ring, lower water cooling ring, water cooling chassis, discharge port slide valve and induction coil; The upper water-cooling ring and the lower water-cooling ring are respectively arranged at the upper and lower ends of the crucible wall, the crucible cover is arranged above the crucible wall, the water-cooling base is arranged on the inner side of the lower part of the crucible wall, and a discharge port communicating with the inner cavity of the crucible wall is provided on the water-cooling base, and the discharge port slide valve is slidably arranged on the lower surface of the water-cooling base; the induction coil is arranged on the outer side of the crucible wall; The crucible wall includes a circle of stainless steel tubes with gaps, the upper end of the stainless steel tubes is connected to the upper water cooling ring, and the lower end of the stainless steel tubes is connected to the lower water cooling ring; The ratio of the gap between two adjacent stainless steel pipes to the outer diameter of the stainless steel pipe is 1:5-30.

2. The cold crucible device for solidification treatment of nuclear waste according to claim 1, characterized in that: The number of stainless steel pipes is a multiple of 3.

3. The cold crucible device for nuclear waste solidification treatment according to claim 1, characterized in that: Refractory materials are arranged in the gaps and on both inner and outer sides of a circle of stainless steel pipes to form a refractory material layer, which surrounds the stainless steel pipes.

4. The cold crucible device for solidification treatment of nuclear waste according to claim 1, characterized in that: The ratio of the height of the crucible wall to the diameter of the circumscribed circle formed by a circle of stainless steel tubes is between 1.3 and 1.

5.

5. The cold crucible device for solidification treatment of nuclear waste according to claim 1, characterized in that: The cross section of the induction coil is square.

6. The cold crucible device for solidification treatment of nuclear waste according to claim 5, characterized in that: The distance between the lowest turn of the induction coil and the upper surface of the water-cooled chassis shall not be less than 30 mm.

7. The cold crucible device for solidification treatment of nuclear waste according to claim 5, characterized in that: The induction coil is divided into three equal sections along the axial direction of the crucible wall, namely, a lower induction coil, a middle induction coil, and an upper induction coil. The spacing between two adjacent turns of the lower induction coil is equal to the spacing between two adjacent turns of the upper induction coil, and is greater than the spacing between two adjacent turns of the middle induction coil.

8. The cold crucible device for solidification treatment of nuclear waste according to claim 1, characterized in that: A cooling water jacket is provided in the discharge port slide valve, and a circle of cooling water pipe is welded on the inner surface of the crucible cover.

9. The cold crucible device for solidification treatment of nuclear waste according to claim 1, characterized in that: The crucible cover is provided with a stirrer mounting hole, a thermometer mounting hole, a feeding port and a pressurized gas inlet.

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