Jet cleaning device for pressurized water reactor nuclear fuel assembly unloading

Abstract

The utility model provides a pressurized water reactor nuclear fuel assembly unloading jet cleaning device which comprises a telescopic mechanism, a refueling sleeve and a refueling fixing rod arranged in the refueling sleeve, one end of the refueling sleeve and one end of the refueling fixing rod are connected with the telescopic mechanism, the other end of the refueling fixing rod is connected with a nuclear fuel assembly, and a cleaning mechanism is installed on the refueling sleeve. In the translating process of the refueling sleeve and the process that the nuclear fuel assembly descends from the refueling sleeve, the nuclear fuel assembly is cleaned through a cleaning mechanism on the refueling sleeve, and boric acid concentration deposition and corrosion product deposition which are generated on the fuel assembly structure and the outer surface of a fuel rod cladding are removed through the pressure of high-pressure water; extra radioactive waste liquid is not generated in the cleaning process; radioactive substances of the fuel assembly are cleaned, so that the irradiation dose of a refueling operator is reduced; meanwhile, in the fuel loading and unloading operation process, the fuel assemblies are synchronously washed with high-pressure water, and the refueling nuclear overhaul period of a reactor is not affected.

Description

Technical Field

[0001] The utility model belongs to the technical field of radioactive decontamination of nuclear power units, and in particular relates to a pressurized water reactor nuclear fuel assembly unloading spray cleaning device. Background Art

[0002] Fuel assemblies from pressurized water reactor (PWR) nuclear power plants typically undergo three fuel cycles before being removed from the core and placed in a spent fuel pool until the spent fuel is reprocessed. Long-term exposure to radiation, high temperatures, and water chemistry in the core can lead to boric acid concentration, corrosion product deposition, and activation on the fuel assembly structure and the outer surface of the fuel rod cladding, adversely affecting reactor operation and refueling personnel.

[0003] First, the concentrated deposition of boric acid and corrosion products on the surface of nuclear fuel will affect the thermal conductivity of the fuel rod cladding, promote the formation of nuclear hot spots, and bring challenges to the integrity of the cladding; secondly, the concentrated deposition of boric acid and corrosion products will further increase the corrosion rate of the cladding; the deposition and activation of corrosion products will lead to an increase in the radioactive activity of the outer surface of the fuel assembly, causing the refueling operators to suffer more radiation doses during loading and unloading operations, which will have an adverse impact on radiation protection work.

[0004] Conventional external decontamination methods require moving irradiation equipment outside the reactor for decontamination, generating more radioactive waste liquids or gases, which require secondary treatment and increase treatment costs. Decontamination during nuclear power unit refueling overhauls can extend the overhaul period, indirectly affecting the unit's grid connection and resulting in significant economic losses. Utility Model Content

[0005] The purpose of the utility model is to provide a pressurized water reactor nuclear fuel assembly unloading spray cleaning device to overcome the problems of complex decontamination operation and long construction period of irradiation equipment in the prior art.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A pressurized water reactor nuclear fuel assembly unloading spray cleaning device includes a refueling fixing rod, one end of which is connected to a telescopic mechanism, and the other end is connected to the nuclear fuel assembly. A refueling sleeve is provided outside the refueling fixing rod, and a cleaning mechanism is installed on the refueling sleeve.

[0008] Furthermore, one end of the material changing sleeve is connected to the telescopic mechanism, and the other end is suspended in the air.

[0009] Furthermore, the telescopic mechanism adopts a material changing crane.

[0010] Furthermore, the cleaning mechanism includes a nozzle connected to a water pump, and the nozzle is arranged on the material changing sleeve.

[0011] Furthermore, the nozzle is connected to the water pump through a hard or soft pipe.

[0012] Furthermore, the nozzles are evenly arranged on the circumference of the lower portion of the inner wall of the material changing sleeve.

[0013] Furthermore, the suction end of the water pump is inserted into the refueling pool where the nuclear fuel assembly is located.

[0014] Furthermore, the nozzle is an umbrella-shaped nozzle.

[0015] Furthermore, the outlet pressure of the nozzle is greater than 5 MPa.

[0016] Furthermore, the axis of the refueling sleeve coincides with the axis of the refueling fixing rod and the axis of the nuclear fuel assembly.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects:

[0018] The utility model provides a pressurized water reactor nuclear fuel assembly unloading spray cleaning device, comprising a telescopic mechanism, a refueling sleeve and one end of a refueling fixing rod arranged in the refueling sleeve are both connected to the telescopic mechanism, the other end of the refueling fixing rod is connected to the nuclear fuel assembly, and the cleaning mechanism is installed on the refueling sleeve. During the translation process of the refueling sleeve and the descending process of the nuclear fuel assembly from the refueling sleeve, the cleaning mechanism on the refueling sleeve realizes the cleaning of the nuclear fuel assembly, and utilizes the pressure of high-pressure water to remove boric acid concentrated deposits and corrosion product deposits generated on the fuel assembly structure and the outer surface of the fuel rod cladding; the cleaning process does not generate additional radioactive waste liquid; the radioactive substances of the fuel assembly are cleaned away, thereby reducing the radiation dose of the refueling operator; and simultaneously, during the process of fuel loading and unloading operations, the fuel assembly is synchronously flushed with high-pressure water, without affecting the refueling nuclear overhaul period of the reactor.

[0019] Preferably, the suction end of the water pump of the refreshing mechanism is inserted into the refueling water pool where the nuclear fuel assembly is located to absorb the coolant, thereby realizing water circulation in the system.

[0020] Preferably, the nozzle adopts an umbrella-shaped nozzle, which can effectively increase the flushing area.

[0021] Preferably, the outlet pressure of the nozzle is not less than 5 MPa, ensuring the high-pressure water flushing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The utility model is a structural diagram of a pressurized water reactor nuclear fuel assembly unloading spray cleaning device in an embodiment.

[0023] In the figure, 1. Refueling pool; 2. Refueling crane; 3. Refueling sleeve; 4. Pressure vessel; 5. Nozzle; 6. Refueling fixing rod; 7. Nuclear fuel assembly; 8. Water pump. DETAILED DESCRIPTION

[0024] In order to help those skilled in the art better understand the present invention, the following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0025] Example 1

[0026] In one embodiment of the present invention, a pressurized water reactor nuclear fuel assembly unloading spray cleaning device is provided, such as Figure 1 As shown, it includes a refueling fixing rod 6, a telescopic mechanism, a refueling sleeve 3 and a cleaning mechanism, wherein the refueling sleeve 3 and one end of the refueling sleeve 3 are both connected to the telescopic mechanism, the refueling sleeve 3 has openings at both ends, the refueling fixing rod 6 is arranged in the refueling sleeve 3, and the other end of the refueling fixing rod 6 is used to connect the nuclear fuel assembly 7, and the cleaning mechanism is installed on the refueling sleeve 3. When the telescopic mechanism lifts or lowers the refueling fixing rod 6, it is used to clean the nuclear fuel assembly 7.

[0027] Specifically, the nuclear fuel assembly 7 is placed in the pressure vessel 4, and the pressure vessel 4 is placed in the refueling pool 1, and there is a coolant in the refueling pool 1;

[0028] The telescopic mechanism uses a material change crane 2, which can drive the material change fixed rod 6 to move up and down;

[0029] The cleaning mechanism includes a nozzle 5 and a water pump 8 connected to the nozzle 5 through a hard or soft pipe, wherein the nozzle 5 is evenly arranged on the circumference of the lower part of the inner wall of the refueling sleeve 3 and is connected to the output end of the water pump 8. The suction end of the water pump 8 is inserted into the refueling water pool 1 where the nuclear fuel assembly 7 is located, and coolant is drawn therefrom to clean the nuclear fuel assembly 7.

[0030] Example 2

[0031] In another embodiment of the present invention, a pressurized water reactor nuclear fuel assembly unloading spray cleaning device is provided, comprising a refueling pool 1, a refueling crane 2, a refueling sleeve 3, a pressure vessel 4, a nozzle 5, a refueling fixing rod 6, a nuclear fuel assembly 7, and a water pump 8;

[0032] In this embodiment, there are a refueling crane 2, a refueling sleeve 3, a nozzle 5, and a water pump 8; a plurality of high-pressure water nozzles 5 are provided on the inner wall of the refueling sleeve 3 along the circumference and at different heights; the upper end of the refueling fixing rod 6 is connected to the refueling crane 2, and the lower end of the refueling fixing rod 6 is inserted into the refueling sleeve 3 and then connected to the nuclear fuel assembly 7; the nozzle 5 is connected to the water pump 8 through a pipeline, and the suction end of the water pump 8 is inserted into the refueling pool 1 to absorb the coolant in the pool 1.

[0033] The nozzles 5 are evenly arranged around the circumference of the refueling sleeve 3 , and perform high-pressure water flushing on the nuclear fuel assembly 7 during the process of the nuclear fuel assembly 7 being lifted and lowered by the refueling crane 2 .

[0034] Example 3

[0035] In another embodiment of the present invention, a pressurized water reactor nuclear fuel assembly unloading spray cleaning device is provided, such as Figure 1 As shown, it includes a refueling fixing rod 6, a telescopic mechanism, a refueling sleeve 3 and a cleaning mechanism, wherein the refueling sleeve 3 and one end of the refueling sleeve 3 are both connected to the telescopic mechanism, the refueling sleeve 3 has openings at both ends, the refueling fixing rod 6 is arranged in the refueling sleeve 3, and the other end of the refueling fixing rod 6 is used to connect the nuclear fuel assembly 7, and the cleaning mechanism is installed on the refueling sleeve 3. When the telescopic mechanism lifts or lowers the refueling fixing rod 6, it is used to clean the nuclear fuel assembly 7.

[0036] Specifically, the nuclear fuel assembly 7 is placed in the pressure vessel 4, and the pressure vessel 4 is placed in the refueling pool 1, and there is a coolant in the refueling pool 1;

[0037] The telescopic mechanism uses a material change crane 2, which can drive the material change fixed rod 6 to move up and down;

[0038] The cleaning mechanism includes a nozzle 5 and a water pump 8 connected to the nozzle 5 through a hard or soft pipe, wherein the nozzle 5 is evenly arranged on the circumference of the lower part of the inner wall of the refueling sleeve 3 and is connected to the output end of the water pump 8. The suction end of the water pump 8 is inserted into the refueling water pool 1 where the nuclear fuel assembly 7 is located, and coolant is drawn therefrom to clean the nuclear fuel assembly 7.

[0039] The nozzle 5 is an umbrella-shaped nozzle to increase the flushing area.

[0040] Example 4

[0041] In another embodiment of the present invention, a pressurized water reactor nuclear fuel assembly unloading spray cleaning device is provided, such as Figure 1As shown, it includes a refueling fixing rod 6, a telescopic mechanism, a refueling sleeve 3 and a cleaning mechanism, wherein the refueling sleeve 3 and one end of the refueling sleeve 3 are both connected to the telescopic mechanism, the refueling sleeve 3 has openings at both ends, the refueling fixing rod 6 is arranged in the refueling sleeve 3, and the other end of the refueling fixing rod 6 is used to connect the nuclear fuel assembly 7, and the cleaning mechanism is installed on the refueling sleeve 3. When the telescopic mechanism lifts or lowers the refueling fixing rod 6, it is used to clean the nuclear fuel assembly 7.

[0042] Specifically, the nuclear fuel assembly 7 is placed in the pressure vessel 4, and the pressure vessel 4 is placed in the refueling pool 1, and there is a coolant in the refueling pool 1;

[0043] The telescopic mechanism uses a material change crane 2, which can drive the material change fixed rod 6 to move up and down;

[0044] The cleaning mechanism includes a nozzle 5 and a water pump 8 connected to the nozzle 5 via a hard or soft pipe. The nozzles 5 are evenly arranged on the circumference of the lower inner wall of the refueling sleeve 3 and connected to the output end of the water pump 8. The suction end of the water pump 8 is inserted into the refueling pool 1 where the nuclear fuel assembly 7 is located, and draws coolant from the pool to clean the nuclear fuel assembly 7.

[0045] The nozzle 5 is an umbrella-shaped nozzle to increase the flushing area; the outlet pressure of the nozzle 5 should not be less than 5 MPa to ensure the high-pressure water flushing effect; the distance between the nuclear fuel assembly 7 and the nozzle (5) is less than or equal to 20 mm.

[0046] Example 5

[0047] In another embodiment of the present invention, a pressurized water reactor nuclear fuel assembly unloading spray cleaning device is provided, such as Figure 1 As shown, it includes a refueling fixing rod 6, a telescopic mechanism, a refueling sleeve 3 and a cleaning mechanism, wherein the refueling sleeve 3 and one end of the refueling sleeve 3 are both connected to the telescopic mechanism, the refueling sleeve 3 has openings at both ends, the refueling fixing rod 6 is arranged in the refueling sleeve 3, and the other end of the refueling fixing rod 6 is used to connect the nuclear fuel assembly 7, and the cleaning mechanism is installed on the refueling sleeve 3. When the telescopic mechanism lifts or lowers the refueling fixing rod 6, it is used to clean the nuclear fuel assembly 7.

[0048] Specifically, the nuclear fuel assembly 7 is placed in the pressure vessel 4, and the pressure vessel 4 is placed in the refueling pool 1, and there is a coolant in the refueling pool 1;

[0049] The telescopic mechanism uses a material change crane 2, which can drive the material change fixed rod 6 to move up and down;

[0050] The cleaning mechanism includes a nozzle 5 and a water pump 8 connected to the nozzle 5 via a hard or soft pipe. The nozzles 5 are evenly arranged on the circumference of the lower inner wall of the refueling sleeve 3 and connected to the output end of the water pump 8. The suction end of the water pump 8 is inserted into the refueling pool 1 where the nuclear fuel assembly 7 is located, and draws coolant from the pool to clean the nuclear fuel assembly 7.

[0051] The nozzle 5 is an umbrella-shaped nozzle to increase the flushing area; the outlet pressure of the nozzle 5 should not be less than 5 MPa to ensure the high-pressure water flushing effect; the distance between the nuclear fuel assembly 7 and the nozzle (5) is less than or equal to 20 mm;

[0052] The axis of the refueling sleeve 3 coincides with the axis of the refueling fixing rod 6 and the axis of the nuclear fuel assembly 7 .

[0053] Working process

[0054] The refueling crane 2 and the refueling fixing rod 6 are used to lift the nuclear fuel assembly 7 from the pressure vessel 4 into the refueling sleeve 3. During the lifting process, the water pump 8 pumps water to the nozzle 5, and the high-pressure water sprayed from the nozzle 5 is used to high-pressure water flush the nuclear fuel assembly. When the nuclear fuel assembly 7 is lowered from the refueling sleeve 3 to the storage position within the reactor, the water pump 8 is restarted, and the high-pressure water sprayed from the nozzle 5 is used to high-pressure water flush the nuclear fuel assembly.

[0055] It should be noted that the present invention utilizes the refueling crane 2 and the refueling fixing rod 6 to lift the nuclear fuel assembly 7 from the unpressurized vessel 4 into the refueling sleeve 3. During the translation process of the refueling sleeve 3 and the descent of the nuclear fuel assembly 7 from the refueling sleeve 3, the water pump 8 is utilized to draw water from the refueling pool 1 and inject high-pressure water into the nozzle 5. The pressure of the high-pressure water is utilized to remove the boric acid concentrated deposits and corrosion product deposits generated on the outer surface of the fuel assembly structure and the fuel rod cladding. The cleaning process does not generate additional radioactive waste liquid. The radioactive substances in the fuel assembly are cleaned away, thereby reducing the radiation dose of the refueling operators. At the same time, during the fuel loading and unloading operation, the nuclear fuel assembly 7 is simultaneously flushed with high-pressure water, which does not affect the refueling nuclear overhaul period of the reactor.

[0056] The above is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited to this. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed in the present invention should be covered by the protection scope of the present invention.

Claims

1. A pressurized water reactor nuclear fuel assembly unloading spray cleaning device, characterized in that: It comprises a refueling fixing rod (6), one end of which is connected to a telescopic mechanism, and the other end of which is connected to a nuclear fuel assembly (7); a refueling sleeve (3) is provided outside the refueling fixing rod (6), and a cleaning mechanism is installed on the refueling sleeve (3).

2. A pressurized water reactor nuclear fuel assembly unloading spray cleaning device according to claim 1, characterized in that: One end of the material changing sleeve (3) is connected to the telescopic mechanism, and the other end is suspended in the air.

3. A pressurized water reactor nuclear fuel assembly unloading spray cleaning device according to claim 1 or 2, characterized in that: The telescopic mechanism adopts a material changing crane (2).

4. The pressurized water reactor nuclear fuel assembly unloading spray cleaning device according to claim 1, characterized in that: The cleaning mechanism comprises a nozzle (5), the nozzle (5) is connected to a water pump (8), and the nozzle (5) is arranged on the material changing sleeve (3).

5. The pressurized water reactor nuclear fuel assembly unloading spray cleaning device according to claim 4, characterized in that: The nozzle (5) is connected to the water pump (8) via a hard or soft pipe.

6. The pressurized water reactor nuclear fuel assembly unloading spray cleaning device according to claim 4, characterized in that: The nozzles (5) are evenly arranged in the circumferential direction of the lower portion of the inner wall of the material changing sleeve (3).

7. The pressurized water reactor nuclear fuel assembly unloading spray cleaning device according to claim 4, characterized in that: The suction end of the water pump (8) is inserted into the refueling pool (1) where the nuclear fuel assembly (7) is located.

8. The pressurized water reactor nuclear fuel assembly unloading spray cleaning device according to claim 4, characterized in that: The nozzle (5) is an umbrella-shaped nozzle.

9. The pressurized water reactor nuclear fuel assembly unloading spray cleaning device according to claim 4, characterized in that: The outlet pressure of the nozzle (5) is greater than 5 MPa.

10. The pressurized water reactor nuclear fuel assembly unloading spray cleaning device according to claim 1, characterized in that: The axis of the refueling sleeve (3) coincides with the axis of the refueling fixing rod (6) and the axis of the nuclear fuel assembly (7).

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