A device and method for loading and unloading plugs and filling lead

Abstract

The present invention belongs to the technical field of dry storage of spent fuel from heavy water reactors, and specifically relates to a device and method for filling lead into a loading and unloading plug. The device comprises a loading and unloading plug, a lead filling funnel, a boiler, an inlet valve, a water trough, an electronic scale, a drain valve, and a heating tape. The loading and unloading plug is placed on the water trough, with a pouring hole formed on the top of the loading and unloading plug. The side of the loading and unloading plug is wrapped with a heating tape. The entire water trough is placed on the electronic scale. The top of the water trough is provided with an inlet valve connected to a pipeline, and the bottom of the water trough is connected to a drain valve via a pipeline. The lead filling funnel and boiler are located outside the water trough. The beneficial effect is that the top of the loading and unloading plug has four evenly distributed pouring holes along the circumference. The lead filling device, combined with the sequential pouring and water trough filling and draining methods, produces a "rock spray"-like liquid lead during the pouring process, maximally removing all gases from the lead solution, ensuring the final density and compactness, and effectively reducing deformation of the shielding plug caused by metal shrinkage in the loading and unloading plug. The lead filling quality fully meets technical requirements.

Description

Technical Field

[0001] The invention belongs to the technical field of dry storage of spent fuel of heavy water reactors, and particularly relates to a device and method for loading and unloading plugs and filling lead. Background Art

[0002] Heavy water reactor loading and unloading plugs are used to shield radioactivity when spent fuel is dry-stored in the storage area for fuel loading, ensuring that workers are protected from accidental doses of radiation. However, the loading and unloading plugs require a certain amount of lead to be filled into the chamber to meet the above requirements. Therefore, a set of lead-filling processes and methods for loading and unloading plugs need to be developed to ensure that the shielding effect of the loading and unloading plugs meets the requirements, and at the same time, it can be promoted and applied to similar industries.

[0003] The use of existing technology may cause the compressed air to be unable to be eliminated due to the gradual narrowing of the space inside the loading and unloading plug, thereby affecting the radiation shielding effect of the loading and unloading plug; the poor density of the lead layer after casting and the metal shrinkage cause the loading and unloading plug to deform, which will affect the precise assembly of the loading and unloading plug. Summary of the Invention

[0004] The purpose of the present invention is to provide a lead-filling device and method for a loading and unloading plug. When dry storage of spent fuel and loading of spent fuel are carried out in a storage area, the loading and unloading plug plays a role in shielding radioactive rays, ensuring that workers are protected from the risk of accidental dose exposure and effectively protecting the safety of the workers.

[0005] The technical solution of the present invention is as follows: a loading and unloading plug lead filling device, including a loading and unloading plug, a lead filling funnel, a boiler, a water inlet valve, a water tank, an electronic scale, a drain valve and a heating belt, the loading and unloading plug is placed on the water tank, a pouring hole is opened on the top of the loading and unloading plug, a heating belt is wrapped around the side of the loading and unloading plug, the water tank is placed on the electronic scale as a whole, a water inlet valve connected to a pipeline is provided on the upper part of the water tank, the bottom of the water tank is connected to the drain valve through a pipeline, and the lead filling funnel and the boiler are located outside the water tank.

[0006] The water tank is a square structure.

[0007] The loading and unloading plug is a hollow frustum-shaped structure.

[0008] The top of the loading and unloading plug is provided with four evenly distributed casting holes along the circumferential direction.

[0009] The pouring holes are respectively a first pouring hole, a second pouring hole, a third pouring hole and a fourth pouring hole.

[0010] A method for loading and unloading a plug and filling it with lead, comprising the following steps:

[0011] Step 1: Place the sink on the electronic scale;

[0012] Step 2: Place the processed loading and unloading plug on the sink;

[0013] Step 3: Apply infrared heating tape to the plug sleeve during installation and removal;

[0014] Step 4: Open the water inlet valve. When the water level reaches two-thirds of the tank, open the drain valve.

[0015] Step 5: Record the weight displayed on the electronic scale;

[0016] Step 6: Place the cleaned lead ingots into the furnace, start heating the furnace, and stir the lead liquid slowly and evenly in this state;

[0017] Step 7: Move the boiler to the top of the loading and unloading plug, and install the lead funnel to the first pouring hole, the second pouring hole, the third pouring hole, and the fourth pouring hole in sequence;

[0018] Step 8: Start the heating belt to tilt the boiler;

[0019] Step 9: Pour lead into the loading and unloading plug. When the electronic scale shows that the weight reaches 98% of the theoretical value of lead filling, it is confirmed that the lead filled meets the requirements;

[0020] Step 10: After the weight reaches the requirement, turn off the heating belt;

[0021] Step 11: Open the inlet and outlet valves for 3 hours and then close them to confirm that the loading and unloading plugs have cooled down and the deformation meets the requirements;

[0022] Step 12: Cover the four pouring holes of the loading and unloading plug with corresponding blind plates and weld and polish them.

[0023] In step 6, the furnace temperature is raised at a rate of about 50°C / second, and the temperature is raised to 450°C and then kept warm.

[0024] The beneficial effects of the present invention are as follows: the device and method have been demonstrated many times, and so far, 100,000 spent fuel rod bundles have been assembled, with the workers receiving zero doses of radiation, excellent shielding effect, and satisfactory use results. Four evenly distributed pouring holes are opened on the top of the loading and unloading plug along the circumference. In conjunction with the use of a lead pouring device, sequential pouring, and water tank filling and drainage methods, during the pouring process, the liquid lead produces a "rock spray" (similar to the arc shape produced by the bursting of bubbles in magma), maximally excluding all gases in the lead water, ensuring the density and compactness of the final state, and effectively reducing the deformation of the shielding plug caused by the metal shrinkage of the loading and unloading plug. The quality of the lead pouring fully meets the technical requirements. It can be seen that the present invention solves the problems of poor lead layer density and plug deformation caused by metal shrinkage in the prior art, thereby improving the shielding effect and installation accuracy of the loading and unloading plug. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of a plug-filling and lead-loading device provided by the present invention.

[0026] In the figure: 1 loading and unloading plug, 2 first pouring hole, 3 second pouring hole, 4 third pouring hole, 5 fourth pouring hole, 6 lead pouring funnel, 7 boiler, 8 water inlet valve, 9 water tank, 10 electronic scale, 11 drain valve, 12 heating belt. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] like Figure 1 As shown, a loading and unloading plug lead filling device includes a loading and unloading plug 1, a lead filling funnel 6, a boiler 7, an inlet valve 8, a water tank 9, an electronic scale 10, a drain valve 11 and a heating belt 12. The water tank 9 is a square structure, on which a hollow frustum-shaped loading and unloading plug 1 is placed. Four evenly distributed pouring holes are opened along the circumferential direction on the top of the loading and unloading plug 1, namely the first pouring hole 2, the second pouring hole 3, the third pouring hole 4 and the fourth pouring hole 5. A heating belt 12 is wrapped around the side of the loading and unloading plug 1. The water tank 9 is placed on the electronic scale 10 as a whole. A water inlet valve 8 connected to the pipeline is provided on the upper part of the water tank 9. The bottom of the water tank is connected to the drain valve 11 through a pipeline. The lead filling funnel 6 and the boiler 7 are located outside the water tank.

[0029] The use process of the present invention is as follows:

[0030] A water tank 9 is placed on an electronic scale 10. The processed loading and unloading plug 1 is placed in the water tank 9. The water tank inlet valve 8 is opened. When the water level reaches two-thirds of the water tank 9, the outlet valve 11 is opened to ensure that the water level in the water tank remains constant. A corresponding heating belt 12 is placed on the loading and unloading plug 1 to ensure that the lead poured in successively can dissolve and solidify together. At the same time, the water level remains constant to ensure that the loading and unloading plug does not deform. At the same time, an electronic scale records the current weight, and the weight is continuously monitored afterwards to ensure that the amount of lead poured into the loading and unloading plug reaches 98% of the theoretical value.

[0031] Place the water tank 9 on the electronic scale 10; place the processed loading and unloading plug 1 on the water tank 9; and put an infrared heating belt 12 on the loading and unloading plug 1;

[0032] Open the water inlet valve 8. When the water level reaches two-thirds of the liquid level of the water tank 9, open the drain valve 11; record the weight displayed on the electronic scale 10; load the cleaned lead ingots into the furnace 7, start heating the furnace at a rate of about 50°C / second, and start keeping the temperature at 450°C. In this state, the lead liquid is stirred slowly and evenly to achieve the purpose of degassing and deslagging; use the factory crane to move the boiler 7 above the loading and unloading plug, and install the lead filling funnel 6 into the pouring hole in sequence; start the heating belt 12, and operate the boiler 7 handle in sequence to tilt the boiler 7; pour lead into the loading and unloading plug 1. When the weight displayed on the electronic scale (excluding gross weight) reaches 98% of the theoretical value of lead filling, it is confirmed that the lead poured meets the requirement; after the above weight meets the requirement, turn off the heating belt; the inlet and drain valves are opened for 3 hours and then closed to confirm that the loading and unloading plug has cooled to the required position and the deformation meets the minimum water requirement; cover the four pouring holes of the loading and unloading plug with corresponding blind plates and weld and polish them.

[0033] A method for loading and unloading a plug and filling it with lead, comprising the following steps:

[0034] Step 1: Place the water tank 9 on the electronic scale 10;

[0035] Step 2: Place the processed loading and unloading plug 1 on the water tank 9;

[0036] Step 3: Put the infrared heating belt 12 on the loading and unloading plug 1;

[0037] Step 4: Open the water inlet valve 8. When the water level reaches two-thirds of the level of the water tank 9, open the drain valve 11.

[0038] Step 5: Record the weight displayed on the electronic scale 10;

[0039] Step 6: Load the cleaned lead ingots into the melting furnace 7 and start heating the furnace at a rate of about 50°C / second until it reaches 450°C and then start keeping the temperature. In this state, the lead liquid is stirred at a constant speed and slowly to achieve the purpose of degassing and deslagging.

[0040] Step 7: Use the factory crane to move the boiler 7 to the top of the loading and unloading plug, and install the lead pouring funnel 6 to the first pouring hole 2, the second pouring hole 3, the third pouring hole 4 and the fourth pouring hole 5 in sequence;

[0041] Step 8: Start the heating belt 12 and operate the handles of the boiler 7 in sequence to tilt the boiler 7;

[0042] Step 9: Pour lead into the loading and unloading plug 1. When the weight displayed on the electronic scale (excluding the gross weight) reaches 98% of the theoretical value of lead filling, it is confirmed that the lead filled meets the requirements;

[0043] Step 10: After the above weight reaches the requirement, turn off the heating belt;

[0044] Step 11: Open the inlet and outlet valves for 3 hours and then close them to confirm that the loading and unloading plugs have cooled down to the point where the deformation meets the requirements;

[0045] Step 12: Cover the four pouring holes of the loading and unloading plug with corresponding blind plates and weld and polish them.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that modifications to the technical solutions described in the aforementioned embodiments, or equivalent replacement of some or all of the technical features therein, do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for loading and unloading plugs and filling lead, characterized in that: The utility model comprises a loading and unloading plug, a lead filling funnel, a boiler, a water inlet valve, a water tank, an electronic scale, a drain valve and a heating belt. The loading and unloading plug is placed on the water tank, a pouring hole is opened on the top of the loading and unloading plug, a heating belt is wrapped around the side of the loading and unloading plug, and the entire water tank is placed on the electronic scale. The upper part of the water tank is provided with a water inlet valve connected to a pipeline, and the bottom of the water tank is connected to a drain valve through a pipeline. The lead filling funnel and the boiler are located outside the water tank. The loading and unloading plug is a hollow truncated cone structure; The top of the loading and unloading plug is provided with four evenly distributed pouring holes along the circumferential direction; The pouring holes are respectively a first pouring hole, a second pouring hole, a third pouring hole and a fourth pouring hole.

2. A plug-filling device for loading and unloading lead according to claim 1, characterized in that: The water tank is a square structure.

3. A method for filling lead in a plug by using the device according to claim 1, characterized in that: The steps include: Step 1: Place the sink on the electronic scale; Step 2: Place the processed loading and unloading plug on the sink; Step 3: Apply infrared heating tape to the plug sleeve during installation and removal; Step 4: Open the water inlet valve. When the water level reaches two-thirds of the tank, open the drain valve. Step 5: Record the weight displayed on the electronic scale; Step 6: Place the cleaned lead ingots into the furnace, start heating the furnace, and stir the lead liquid slowly and evenly in this state; Step 7: Move the boiler to the top of the loading and unloading plug, and install the lead funnel to the first pouring hole, the second pouring hole, the third pouring hole, and the fourth pouring hole in sequence; Step 8: Start the heating belt to tilt the boiler; Step 9: Pour lead into the loading and unloading plug. When the electronic scale shows that the weight reaches 98% of the theoretical value of lead filling, it is confirmed that the lead filled meets the requirements; Step 10: After the weight reaches the requirement, turn off the heating belt; Step 11: Open the inlet and outlet valves for 3 hours and then close them to confirm that the loading and unloading plugs have cooled down and the deformation meets the requirements; Step 12: Cover the four pouring holes of the loading and unloading plug with corresponding blind plates and weld and polish them.

4. A method for filling a plug with lead according to claim 3, characterized in that: In step 6, the furnace is heated at a rate of 50°C / second until the temperature reaches 450°C and then kept warm.

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