Ultrasonic decontamination auxiliary device for pressurized water reactor nuclear power plant pipeline hot spot and use method thereof

Abstract

This invention relates to the field of ultrasonic decontamination technology for hot spots in pressurized water reactor (PWR) nuclear power plant pipelines, specifically an auxiliary device and method for ultrasonic decontamination of hot spots in PWR nuclear power plant pipelines. This solution combines an electric heater with an ultrasonic transducer to directly heat the hot spots in the pipeline within a sealed cavity and generate ultrasonic vibrations, rapidly improving the decontamination effect. Localized heating avoids large-scale energy waste, and the compact modular design makes the device suitable for pipelines of different specifications, facilitating quick assembly and disassembly, reducing operational difficulty and time costs. Furthermore, the multi-layer sealing design of the sealing ring and sealing chamber, combined with the application of sealing silicone, ensures sealing performance under high temperature and pressure, preventing leakage of solution and heat. The ultrasonic transducer enhances the chemical decontamination process, especially for removing stubborn corrosives, ensuring thorough decontamination and reducing residual radioactive materials. These advantages give the device broad application value.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic decontamination technology for hot spots in pressurized water reactor nuclear power plant pipelines, and in particular to an auxiliary device and method for ultrasonic decontamination of hot spots in pressurized water reactor nuclear power plant pipelines. Background Technology

[0002] During the overhaul of pressurized water reactor nuclear power plant units, it is necessary to isolate radioactive hotspots in the systems and equipment in order to carry out maintenance work. If the presence of hotspots affects the maintenance work, appropriate radioactive decontamination work needs to be carried out. Chemical decontamination is one such method.

[0003] Chemical decontamination utilizes the dissolving and stripping properties of chemical reagents to remove radioactive corrosion products deposited inside pipelines. The decontaminants used in chemical decontamination have high temperature requirements, generally operating between 85℃ and 95℃. If the temperature is too low, it is difficult to achieve the desired decontamination effect, which will lead to excessively long decontamination cycles and affect the maintenance of other equipment. Furthermore, industrial practice has shown that ultrasound can assist in the chemical decontamination process of equipment.

[0004] In the chemical decontamination process at pipeline hotspots, small cleaning devices are typically used, equipped with cleaning tanks and heating units. However, due to the excessive heat dissipation caused by long temporary pipelines, it is difficult to reach the process temperature at the hotspots. Using external heating facilities to raise the pipeline temperature at the hotspots would significantly improve the chemical decontamination effect. Currently, there are no similar localized heating devices available. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention is proposed.

[0006] Therefore, the first objective of this invention is to provide an ultrasonic decontamination auxiliary device for hot spots in pressurized water reactor (PWR) nuclear power plant pipelines, which can solve the problem that it is difficult to reach the process temperature in the hot spots of the primary loop chemical decontamination pipelines of PWR nuclear power plants, resulting in unsatisfactory decontamination effects.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: an ultrasonic decontamination auxiliary device for hot spots in a pressurized water reactor nuclear power plant pipeline, comprising: a sealing mechanism including an axial sealing ring, an upper sealing chamber and a lower sealing chamber, wherein the upper sealing chamber and the lower sealing chamber cover the outside of the pipeline, the axial sealing ring is disposed on the inner and outer sides of the upper sealing chamber and the lower sealing chamber, and the upper part of the upper sealing chamber is in an open state; and a cleaning mechanism including a heating element and a vibrating element, wherein the heating element and the vibrating element are disposed below the lower sealing chamber.

[0008] As a preferred embodiment of the ultrasonic decontamination auxiliary device for hot spots in pressurized water reactor nuclear power plant pipelines according to the present invention, wherein: the upper sealing chamber and the lower sealing chamber each have a semi-circular opening on their left and right sides, and the opening matches the outer wall of the axial sealing ring.

[0009] As a preferred embodiment of the ultrasonic decontamination auxiliary device for hot spots in pressurized water reactor nuclear power plant pipelines according to the present invention, the axial sealing ring is divided into a first half-ring and a second half-ring. The first half-ring and the second half-ring are disposed outside the pipeline and fastened by a fixing structure to form a connection with the upper sealing chamber and the lower sealing chamber.

[0010] As a preferred embodiment of the ultrasonic decontamination auxiliary device for hot spots in pressurized water reactor nuclear power plant pipelines described in this invention, the lower part of the upper sealing chamber and the upper part of the lower sealing chamber are both provided with fastening bolt holes, and the sealing between the upper sealing chamber and the lower sealing chamber is achieved by fastening bolts.

[0011] In a preferred embodiment of the ultrasonic decontamination auxiliary device for hot spots in pressurized water reactor nuclear power plant pipelines described in this invention, the first half-ring and the second half-ring are located outside the upper sealing chamber and the lower sealing chamber, and are fastened by steel cable ties.

[0012] As a preferred embodiment of the ultrasonic decontamination auxiliary device for hot spots in pressurized water reactor nuclear power plant pipelines according to the present invention, the fixing structure includes a first sealing ring and a second sealing ring, the first sealing ring and the second sealing ring being located inside the upper sealing chamber and the lower sealing chamber, fitted onto the outer wall of the pipeline, and fastened with steel cable ties.

[0013] As a preferred embodiment of the ultrasonic decontamination auxiliary device for hot spots in pressurized water reactor nuclear power plant pipelines according to the present invention, wherein: one end of the axial sealing ring is machined with an external thread, and one end of the fixed structure is machined with an internal thread, which cooperates with the external thread of the axial sealing ring to clamp the two sides of the upper sealing chamber and the lower sealing chamber.

[0014] As a preferred embodiment of the ultrasonic decontamination auxiliary device for hot spots in pressurized water reactor nuclear power plant pipelines according to the present invention, the upper sealing chamber, the lower sealing chamber, the axial sealing ring, and the fixing structure are all made of stainless steel to ensure the rigidity of the materials; the heating element is an electric heater, and the vibrating element is an ultrasonic transducer.

[0015] Another objective of this invention is to provide a method for using an ultrasonic decontamination auxiliary device for hot spots in a pressurized water reactor nuclear power plant pipeline, comprising the following steps: installing the upper sealing chamber and the lower sealing chamber on both sides of the pipeline respectively, and tightly connecting the sealing chamber to the pipeline through the axial sealing ring and the fixing structure to ensure the formation of a closed cavity; injecting demineralized water into the cavity formed inside the upper sealing chamber and the lower sealing chamber; activating the heating element to control the temperature inside the cavity to reach a preset requirement; activating the vibration element to enhance the decontamination effect through ultrasonic vibration; and after the decontamination process is completed, stopping the heating and vibration, and removing the device.

[0016] In a preferred embodiment of the method of using the ultrasonic decontamination auxiliary device for hot spots in the pipeline of the pressurized water reactor nuclear power plant described in this invention, a 2% citric acid + 0.1% EDTA decontamination solution is injected into the pipeline at the same time as the device is started to chemically decontaminate the hot spots in the pipeline. The effects of the heating element and the vibrating element are used to enhance the decontamination effect inside the pipeline.

[0017] The beneficial effects of this invention are as follows: This solution combines an electric heater with an ultrasonic transducer to directly heat hot spots in the pipe within a sealed cavity and generate ultrasonic vibrations, which can rapidly improve the decontamination effect. Localized heating avoids large-scale energy waste, and the compact modular design makes the device suitable for pipes of different specifications, facilitating quick and easy assembly and disassembly, reducing operational difficulty and time costs. Furthermore, the multi-layer sealing design of the sealing ring and sealing chamber, combined with the application of sealing silicone, ensures sealing performance under high temperature and high pressure, preventing leakage of solution and heat. The ultrasonic transducer enhances the chemical decontamination process, especially for removing stubborn corrosives, ensuring thorough decontamination and reducing residual radioactive substances. These advantages give this device broad application value. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0019] Figure 1 This is a structural diagram of an ultrasonic decontamination auxiliary device for hot spots in pipelines of a pressurized water reactor nuclear power plant.

[0020] Figure 2 Diagram illustrating the steps for using an ultrasonic decontamination auxiliary device for hot spots in pressurized water reactor nuclear power plant piping. Detailed Implementation

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0022] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0023] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it an embodiment that is mutually exclusive, either alone or selectively, with other embodiments.

[0024] Example 1

[0025] Reference Figure 1 This is the first embodiment of the present invention. This embodiment provides an ultrasonic decontamination auxiliary device for hot spots in pipelines of a pressurized water reactor nuclear power plant, including a sealing mechanism 100, comprising an axial sealing ring 101, an upper sealing chamber 102, and a lower sealing chamber 103, the upper sealing chamber 102 and the lower sealing chamber 103 covering the outside of the pipeline, the axial sealing ring 101 being disposed on the inner and outer sides of the upper sealing chamber 102 and the lower sealing chamber 103, the upper part of the upper sealing chamber 102 being in an open state; and a cleaning mechanism 200, comprising a heating element 201 and a vibrating element 202, the heating element 201 and the vibrating element 202 being disposed below the lower sealing chamber 103.

[0026] The sealing mechanism 100 fixes the entire device to the outside of the pipeline through an axial sealing ring, an upper sealing chamber, and a lower sealing chamber, forming a closed cavity to prevent solution or gas leakage during the cleaning process. The axial sealing ring 101 provides additional sealing and support to ensure that the upper and lower sealing chambers are stable and do not fall off during operation. The opening design of the upper sealing chamber 102 facilitates installation and venting, while cooperating with the lower sealing chamber to form a sealed structure. The combination of the heating element 201 and the vibrating element 202 ensures the rise of the pipeline surface temperature, while enhancing the cleaning effect through vibration.

[0027] The tight fit between the axial sealing ring and the upper and lower sealing chambers not only achieves an external sealing effect but also enhances the stability of the equipment under high temperature and vibration conditions. This structural design not only enables the decontamination function but also improves the durability of the equipment in complex environments, preventing leakage of external solutions from the pipeline, thereby ensuring work efficiency and reducing the frequency of equipment maintenance.

[0028] Example 2

[0029] Reference Figure 1 This is the second embodiment of the present invention, which is based on the previous embodiment.

[0030] Specifically, the upper sealing chamber 102 and the lower sealing chamber 103 each have a semi-circular opening 106 on their left and right sides, and the opening 106 matches the outer wall of the axial sealing ring 101. This opening design allows the sealing chamber to be easily covered on the pipe, while matching the outer wall of the axial sealing ring, enhancing the sealing performance and reducing the difficulty of installation.

[0031] Specifically, the axial sealing ring 101 is divided into a first half-ring 101a and a second half-ring 101b. The first half-ring 101a and the second half-ring 101b are disposed outside the pipe and fastened by the fixing structure 104 to form a connection with the upper sealing chamber 102 and the lower sealing chamber 103.

[0032] The design of the two semi-rings makes it easy to wrap around the outside of the pipe during installation, and the fixing structure securely locks it in place to form a stable connection;

[0033] It is worth noting that the axial sealing ring 101 has a variety of different specifications. Each specification of the axial sealing ring 101 has the same outer diameter and different inner diameters to match pipes of different diameters, and the outer diameter is the same, which is sufficient.

[0034] Specifically, fastening bolt holes 105 are arranged at the lower part of the upper sealing chamber 102 and the upper part of the lower sealing chamber 103, and the sealing between the upper sealing chamber 102 and the lower sealing chamber 103 is achieved by fastening bolts 102a;

[0035] By fixing the upper and lower sealing chambers with bolts, the sealing performance of the device is further enhanced, while ensuring the stability of the cavity under heating and vibration.

[0036] Specifically, the first half-ring 101a and the second half-ring 101b are located outside the upper sealing chamber 102 and the lower sealing chamber 103, and are fastened by steel cable ties; the steel cable ties further ensure the fixation of the first half-ring and the second half-ring, and increase the overall stability and vibration resistance of the system.

[0037] Specifically, the fixing structure 104 includes a first sealing ring 104a and a second sealing ring 104b. The first sealing ring 104a and the second sealing ring 104b are located inside the upper sealing chamber 102 and the lower sealing chamber 103, are fitted on the outer wall of the pipe, and are fastened by steel cable ties.

[0038] The design of two sealing rings ensures the sealing performance between the device and the pipeline, further preventing leakage. Through the tight cooperation between the sealing rings and the steel cable ties, not only is efficient sealing performance achieved, but the vibration resistance of the equipment is also enhanced, enabling the device to remain sealed and leak-free during ultrasonic vibration. At the same time, it reduces the loss of heat and cleaning solution, and improves the working stability of the device.

[0039] Specifically, one end of the axial sealing ring 101 is machined with an external thread 101c, and one end of the fixing structure 104 is machined with an internal thread 104c, which cooperates with the external thread of the axial sealing ring 101 to clamp the two sides of the upper sealing chamber 102 and the lower sealing chamber 103.

[0040] The design of external and internal threads enhances the fixing force between the sealing chambers, further improving the stability and resistance to external forces of the sealing chambers; the axial sealing ring 101 and the fixing structure 104 seal the left and right sides of the upper sealing chamber 102 and the lower sealing chamber 103 with the gaps in the pipe.

[0041] Specifically, the upper sealing chamber 102, the lower sealing chamber 103, the axial sealing ring 101, and the fixing structure 104 are all made of stainless steel to ensure the rigidity of the materials; the heating element 201 is an electric heater, and the vibrating element 202 is an ultrasonic transducer.

[0042] The use of stainless steel ensures the rigidity and durability of the device under high temperature and high pressure conditions; the synergistic operation of the electric heater and ultrasonic transducer in high-temperature environments enhances the thoroughness of the internal decontamination process. This design accelerates the removal of corrosion products and reduces decontamination time through vibration-assisted heating.

[0043] Example 3

[0044] Reference Figure 2 This is the third embodiment of the present invention. This embodiment provides a method for using an ultrasonic decontamination auxiliary device for hot spots in a pressurized water reactor nuclear power plant pipeline, including the following steps: installing an upper sealing chamber 102 and a lower sealing chamber 103 on both sides of the pipeline respectively, and tightly connecting the sealing chambers to the pipeline through an axial sealing ring 101 and a fixing structure 104 to ensure the formation of a closed cavity; injecting demineralized water into the cavity formed inside the upper sealing chamber 102 and the lower sealing chamber 103; activating the heating element 201 to control the temperature inside the cavity to reach the preset requirements; activating the vibration element 202 to enhance the decontamination effect through ultrasonic vibration; after the decontamination process is completed, stopping the heating and vibration, and removing the device.

[0045] Specifically, at the same time the device is started, a 2% citric acid + 0.1% EDTA cleaning solution is injected into the pipeline to chemically clean the hot spots inside the pipeline. The heating element 201 and the vibrating element 202 are used to enhance the cleaning effect inside the pipeline.

[0046] In use, first install the axial sealing ring 101. Before installing the axial sealing ring 101, apply sealing silicone to the pipe surface. After the axial sealing ring 101 is fixed to the pipe, use steel cable ties to tighten the two halves of the axial sealing ring 101. Then, fix the upper sealing chamber 102 and the lower sealing chamber 103 to the axial sealing ring 101 using fastening bolts 102a. Apply sealing silicone to the contact parts of the axial sealing ring 101 with the upper sealing chamber 102 and the lower sealing chamber 103. Next, combine the first sealing ring 104a and the second sealing ring 104b, fit them onto the outer wall of the pipe, and tighten them with steel cable ties. Finally, engage them with the external threads of the axial sealing ring 101 to clamp the two sides of the upper sealing chamber 102 and the lower sealing chamber 103. Apply sealing silicone to the contact parts of the axial sealing ring 101 with the sides of the upper sealing chamber 102 and the lower sealing chamber 103. After the device is installed, inject demineralized water into the chambers formed inside the upper sealing chamber 102 and the lower sealing chamber 103. A temporary chemical decontamination system is used to inject a 2% citric acid + 0.1% EDTA decontamination solution into the pipeline to chemically decontaminate hot spots inside the pipeline. The electric heater and ultrasonic transducer at the bottom of the lower sealing chamber 103 are then activated to bring the temperature of the demineralized water injected into the chamber formed inside the upper sealing chamber 102 and the lower sealing chamber 103 to 90°C.

[0047] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for using an ultrasonic decontamination auxiliary device for hot spots in pipelines of a pressurized water reactor nuclear power plant, comprising the ultrasonic decontamination auxiliary device for hot spots in pipelines of a pressurized water reactor nuclear power plant, characterized in that, The ultrasonic decontamination auxiliary device for hot spots in the pressurized water reactor nuclear power plant pipeline includes... The sealing mechanism (100) includes an axial sealing ring (101), an upper sealing chamber (102), and a lower sealing chamber (103). The upper sealing chamber (102) and the lower sealing chamber (103) cover the outside of the pipe. The axial sealing ring (101) is disposed on the inner and outer sides of the upper sealing chamber (102) and the lower sealing chamber (103). The upper part of the upper sealing chamber (102) is in an open state. The cleaning mechanism (200) includes a heating element (201) and a vibrating element (202), which are disposed below the lower sealing chamber (103); The upper sealing chamber (102) and the lower sealing chamber (103) each have a semi-circular opening (106) on their left and right sides, and the opening (106) matches the outer wall of the axial sealing ring (101); The axial sealing ring (101) is divided into a first half-ring (101a) and a second half-ring (101b). The first half-ring (101a) and the second half-ring (101b) are disposed outside the pipe and fastened by a fixing structure (104) to form a connection with the upper sealing chamber (102) and the lower sealing chamber (103). The lower part of the upper sealing chamber (102) and the upper part of the lower sealing chamber (103) are both provided with fastening bolt holes (105), and the sealing between the upper sealing chamber (102) and the lower sealing chamber (103) is achieved by fastening bolts (102a); The first half-ring (101a) and the second half-ring (101b) are located outside the upper sealing chamber (102) and the lower sealing chamber (103) and are fastened by steel cable ties; The fixing structure (104) includes a first sealing ring (104a) and a second sealing ring (104b). The first sealing ring (104a) and the second sealing ring (104b) are located inside the upper sealing chamber (102) and the lower sealing chamber (103), are fitted on the outer wall of the pipe, and are fastened by steel cable ties. One end of the axial sealing ring (101) is machined with an external thread (101c), and one end of the fixing structure (104) is machined with an internal thread (104c), which cooperates with the external thread of the axial sealing ring (101) to clamp the two sides of the upper sealing chamber (102) and the lower sealing chamber (103). The upper sealing chamber (102) and the lower sealing chamber (103) are respectively installed on both sides of the pipeline. The sealing chambers are tightly connected to the pipeline by the axial sealing ring (101) and the fixing structure (104) to ensure that a closed cavity is formed. Demineralized water is injected into the cavity formed inside the upper sealing chamber (102) and the lower sealing chamber (103); The heating element (201) is activated to control the temperature inside the cavity to reach the preset requirement; Activate the vibrating element (202) to enhance the cleaning effect through ultrasonic vibration; After the decontamination process is complete, stop heating and vibration, and remove the device.

2. The method of using the ultrasonic decontamination auxiliary device for hot spots in pressurized water reactor nuclear power plant pipelines as described in claim 1, characterized in that: At the same time as the device is started, a 2% citric acid + 0.1% EDTA cleaning solution is injected into the pipeline to chemically clean the hot spots inside the pipeline. The heating element (201) and the vibrating element (202) are used to enhance the cleaning effect inside the pipeline.

3. The method of using the ultrasonic decontamination auxiliary device for hot spots in pressurized water reactor nuclear power plant pipelines as described in claim 2, characterized in that: The upper sealing chamber (102), the lower sealing chamber (103), the axial sealing ring (101), and the fixing structure (104) are all made of stainless steel to ensure the rigidity of the materials; The heating element (201) is an electric heater, and the vibrating element (202) is an ultrasonic transducer.

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