Helium leak detection on-line rapid calibration method for heat transfer tube of pressurized water reactor steam generator

Abstract

The invention belongs to the technical field of pressurized water reactor steam generator heat transfer tube helium leak detection, and particularly relates to a pressurized water reactor steam generator heat transfer tube helium leak detection online rapid calibration method. Developing a rapid calibration device and mounting and dismounting a rod; before checking is carried out, the quick calibration device is installed at one end in an evaporator water chamber through the installation and disassembly rod; a helium leak detection system is connected, and the crawler carrying the suction gun assembly is installed at the other end; when calibration is needed, the crawl device is controlled to crawl and move to the corresponding heat transfer pipe for calibration; and the inspection process is completed, calibration after implementation is carried out, and disassembly of the rapid calibration device is completed. According to the method, the defects of low efficiency, long time consumption, large personnel exposure dose, high labor intensity, damage risk caused by equipment disassembly and assembly and the like in an off-line calibration method for helium leak detection of the heat transfer tube of the nuclear reactor steam generator of the pressurized water reactor nuclear power plant are overcome, and data calibration required in the helium leak detection process of the heat transfer tube of the steam generator is met at the same time.

Description

Technical Field

[0001] The invention belongs to the technical field of helium leak detection for heat transfer tubes of steam generators for pressurized water reactors, and in particular relates to an online rapid calibration method for helium leak detection for heat transfer tubes of steam generators for pressurized water reactors. Background Art

[0002] The "Rules for In-Service Inspection of Mechanical Equipment in the Nuclear Island of Pressurized Water Reactor Nuclear Power Plants" (RSE-M) stipulate that steam generator heat transfer tubes must undergo a comprehensive helium test during the comprehensive in-service inspection to ensure safe and reliable operation of the nuclear power plant. During the helium leak testing of steam generator heat transfer tubes, the helium leak detection system must be calibrated before, after, and every four hours during the test to ensure the reliability of the helium leak detection data. The traditional calibration method is offline. This requires the crawler, sniffer assembly, and suction piping to be disassembled from the steam generator tube sheet and removed from the steam generator water chamber. The sniffer assembly and other components are then separated from the crawler and connected to a dedicated calibration tube equipped with a standard leak hole. Calibration is performed remotely using a PC to control the flow controller and helium mass spectrometer. After calibration, the sniffer assembly, crawler, and other components are reinstalled on the steam generator tube sheet, completing the calibration process. This entire calibration method is time-consuming and significantly impacts inspection efficiency. It also increases radiation exposure and labor intensity for operators, and there is a certain risk of damage during equipment disassembly and assembly. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for rapid online calibration of helium leak detection for heat transfer tubes of steam generators in pressurized water reactors (PWRs). The method solves the drawbacks of offline calibration methods for helium leak detection of heat transfer tubes of steam generators in nuclear reactors of PWR nuclear power plants, such as low efficiency, long time consumption, high radiation dose to personnel, high labor intensity, and risk of damage due to equipment disassembly, while meeting the data calibration requirements for implementing helium leak detection of heat transfer tubes of steam generators.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] The invention discloses an online rapid calibration device for helium leak detection of heat transfer tubes of steam generators of pressurized water reactors, comprising a calibration fixing head, an installation and removal rod, a flexible air pipe, and a standard leak hole. The calibration fixing head is arranged on the installation and removal rod, and the flexible air pipe is arranged next to the installation and removal rod, and the flexible air pipe is connected to the standard leak hole.

[0006] A rapid online calibration method for helium leak detection in heat transfer tubes of pressurized water reactor steam generators:

[0007] Step 1: Develop a quick calibration device and install a disassembly rod;

[0008] Step 2: Before the inspection is carried out, use the installation and removal rod to install the quick calibration device to one end of the evaporator water chamber;

[0009] Step 3: Connect the helium leak detection system and install the sniffer assembly on the other end of the crawler;

[0010] Step 4: When calibration is required, control the crawler to crawl to the corresponding heat transfer tube for calibration;

[0011] Step 5: Complete the inspection process, then perform post-implementation calibration and complete the disassembly of the rapid calibration device.

[0012] Step 1 specifically includes:

[0013] Step 1.1: First, design the core rod of the calibration device according to the inner diameter of the heat transfer tube;

[0014] Step 1.2: The front section of the core rod is hollow, and a hole is opened on the side to connect to the hollow. The side is welded to the stainless steel tube. The tail of the stainless steel tube is equipped with a quick connector, which is connected to the flexible air pipe to form a gas path for the calibration process: standard leak hole - flexible air pipe - calibration device - heat transfer tube;

[0015] Step 1.3: O-rings, transfer rings, push rings, screws, and nuts are distributed around the core rod to form the expansion part of the calibration device;

[0016] Step 1.4: The lower part of the core rod is an inverted T-shaped structure, which is connected to the tail of the core rod;

[0017] Step 1.5: The installation and removal rod consists of a carbon fiber rod, an installation head, and a removal head. The installation head and removal head are located at both ends of the carbon fiber rod and fixed to the carbon fiber rod.

[0018] Step 1.6: Install the disassembly rod. The mounting head contains a hexagonal socket wrench that matches the hexagonal nut of the calibration device.

[0019] Step 1.7: The disassembly head of the disassembly rod has an L-shaped groove inside, which matches the inverted T-shaped structure of the calibration device. After installation, rotate it to hook the calibration device.

[0020] Step 1.3: Three O-rings, two transfer rings, one push ring, a screw and a nut are distributed around the outer periphery of the core rod, forming the expansion part of the calibration device.

[0021] Step 2 specifically includes:

[0022] Step 2.1: First, connect the flexible air tube to the quick connector of the calibration device;

[0023] Step 2.2: Place the calibration device nut inside the mounting head of the mounting and removal rod;

[0024] Step 2.3: Select an easily identifiable nozzle on the evaporator water chamber tube sheet. Align the guide head of the calibration device with the nozzle and push it inward to the bottom. Turn the installation and removal rod clockwise to tighten the nut. During the tightening process, the nut pushes the push ring forward, thereby compressing the O-ring to deform and expand. The friction of the O-ring supports the entire weight of the calibration device and prevents it from falling. At this time, withdraw the installation and removal rod.

[0025] Step 2.4: Verify the installation position of the calibration device and record the coordinates;

[0026] Step 2.5: Connect the other end of the flexible air tubing to the standard leak.

[0027] Step 3 specifically includes:

[0028] Step 3.1: First, connect the remote control computer, helium mass spectrometer, flow controller, crawler, sniffer assembly, corresponding gas lines, and communication lines according to the system connection requirements, and test whether the system connection is normal;

[0029] Step 3.2: After the system test is completed, check whether the connection between the suction gun assembly and the crawler is firm, and then install the crawler with the suction gun assembly at the other end of the evaporator water chamber.

[0030] Step 4 specifically includes:

[0031] Step 4.1: First, arrange personnel to open the standard leak valve;

[0032] Step 4.2: Calculate the coordinate position of the other end of the water chamber based on the coordinate position of the calibration device, ensuring that the two coordinate positions correspond to the same heat transfer tube;

[0033] Step 4.3: Use the remote computer to control the crawler to move the sniffer assembly to the corresponding coordinate position, ensuring that the sniffer port of the sniffer assembly is directly below the coordinate position;

[0034] Step 4.4: The operator controls the control system to lift the sniffer assembly to form a good seal between the sniffer assembly and the tube sheet. The operator remotely activates the flow control cabinet and the helium mass spectrometer to perform signal detection. If the signal display result corresponds to the calibration value of the calibrated leak, the sniffer calibration is qualified.

[0035] Step 4.5: After the system calibration is completed, arrange personnel to close the standard leak valve. The calibration process is completed and the crawler is controlled to move to the heat transfer tube to be inspected on the tube sheet to continue the inspection.

[0036] Step 5 specifically includes:

[0037] Step 5.1: After the inspection of a single evaporator is completed, repeat step 4 to complete the calibration after implementation;

[0038] Step 5.2: Align the hexagonal wrench inside the installation head of the installation and removal assembly with the nut, rotate the installation and removal assembly counterclockwise, and move the nut backward to gradually loosen the O-ring from its tightened state;

[0039] Step 5.3: After the nut is removed, the calibration device still cannot be removed due to a certain friction force. The disassembly head of the installation and disassembly rod needs to be aligned with the T-shaped structure of the calibration device and rotated to hook it. Then pull it back. The calibration device is pulled out of the heat transfer tube under the action of the pulling force, completing the disassembly.

[0040] Step 1.4: The lower part of the core rod is an inverted T-shaped structure and is welded to the tail of the core rod.

[0041] Step 1.1: Calibrate the core rod to make it conical.

[0042] The beneficial effects achieved by the present invention are:

[0043] The present invention is applied to helium mass spectrometry leak detection of steam generator heat transfer tubes in nuclear reactors of pressurized water reactor nuclear power plants. The purpose is to calibrate the steam generator heat transfer tube helium leak detection system consisting of a helium mass spectrometry leak detector, a sniffer assembly, a flow control cabinet, a control system, and connecting pipelines, so as to ensure that the entire steam generator heat transfer tube helium leak detection system has sufficient sensitivity.

[0044] a) The helium leak test for a single steam generator heat transfer tube takes at least 36 hours to inspect. If the equipment is fault-free, calibration is required every 4 hours, for a total of at least 8 calibrations. A single offline calibration requires disassembly and assembly of the crawler and sniffer assembly, taking approximately 2 hours. A single online calibration only requires movement of the crawler, taking approximately 0.5 hours. A single calibration can save 1.5 hours, and a single steam generator heat transfer tube helium leak test can save at least 12 hours.

[0045] b) During offline calibration, the radiation dose for a single removal of equipment is approximately 50 μSv, and the radiation dose for a single installation of equipment is approximately 100 μSv. At least eight calibrations are required during the implementation process, with a total radiation dose of approximately 1200 μSv. Online calibration only requires one installation and one removal, with a total radiation dose of approximately 50 μSv. Implementing online calibration for helium leak detection on a single steam generator heat transfer tube can reduce the radiation dose to personnel by 1150 μSv.

[0046] c) Offline calibration requires two inspectors to work for 2 hours to disassemble and install equipment. They must wear lead and paper vests during the process. Installing and disassembling bulky equipment in a high-radiation environment is extremely demanding on the physical and mental abilities of the personnel. With the switch to online calibration, only one inspector is required to calibrate the leak switch in a low-dose area, significantly reducing the requirements for personnel quality.

[0047] d) During the helium leak test process, each offline calibration requires the installation and disassembly of the equipment, and each installation of the crawler requires insertion into a pipe hole. The center-to-center distance between the crawler's four claws is fixed. If inserted into the wrong pipe hole, the crawler may not be inserted into the hole, causing damage to the claws and the risk of the crawler falling. Online calibration only requires checking the installation before the test and disassembly after the test, eliminating the risk of damage and falling caused by frequent disassembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a schematic diagram of the online rapid calibration method for helium leak detection in the heat transfer tubes of a pressurized water reactor steam generator;

[0049] Figure 2 Schematic diagram of online calibration device;

[0050] Figure 3 This is the installation diagram of the online rapid calibration device;

[0051] Figure 4 This is a disassembly diagram of the online rapid calibration device;

[0052] In the figure: 1. Calibration fixing head; 2. Installation and removal rod; 3. Flexible air pipe; 4. Standard leak hole; 5. Evaporator tube sheet. DETAILED DESCRIPTION

[0053] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0054] This invention aims at the calibration characteristics of helium leak detection of steam generator heat transfer tubes, combines the structure of the inspection object, improves the calibration method, develops an online calibration device, and improves the offline calibration to online calibration:

[0055] The calibration device includes a calibration fixed head 1, an installation and removal rod 2, a flexible air tube 3, and a standard leak hole 4. The calibration fixed head 1 is set on the installation and removal rod 2, and the flexible air tube 3 is set next to the installation and removal rod 2. The flexible air tube 3 is connected to the standard leak hole 4.

[0056] a) Before the test begins, install the calibration device on the opposite steam generator water chamber tube sheet and mark the installation location. Lead the flexible air pipe connected to the calibration device to a low-radiation area outside the steam generator room, and connect the flexible air pipe to the standard leak hole in the low-radiation area;

[0057] b) Connect the lines and piping of the steam generator heat transfer tube helium leak detection system, connect the sniffer assembly to the crawler, and install the crawler on the steam generator tube sheet;

[0058] c) When calibration is required, the remote control personnel controls the crawler to move to the pipe hole corresponding to the installation position of the calibration device on the tube sheet, aligns the suction gun to be calibrated with the calibration pipe hole, and arranges personnel to open the standard leak valve;

[0059] d) The operator gives instructions through the control system to control the upward lifting of the suction gun assembly so that the suction gun assembly and the tube sheet form a good seal. Then start the flow control cabinet to extract the air in the steam generator heat transfer tube, and flow it to the helium mass spectrometer leak detector through the suction gun assembly-flow control cabinet. The helium mass spectrometer leak detector should be able to detect trace amounts of helium in the sampled air, and a corresponding signal should be displayed on the data acquisition software in the control system. If the signal display result can correspond to the calibration value of the calibrated leak (a certain error is allowed), it is considered that the calibration is qualified, the entire steam generator heat transfer tube helium leak detection system has sufficient sensitivity, and the calibration process is completed;

[0060] e) After the calibration is completed, the operator can control the crawler to return to the tube plate to continue the inspection of the heat transfer tube to be inspected.

[0061] Through the improvement, the inspection equipment does not need to be disassembled and assembled. When calibration is required, the crawler only needs to crawl to the corresponding pipe mouth for calibration. The calibration process is simple and efficient, and fast calibration is achieved.

[0062] The method comprises the following steps.

[0063] Step 1: Develop a quick calibration device and install a disassembly rod;

[0064] Step 2: Before the inspection is carried out, use the installation and removal rod to install the quick calibration device to one end of the evaporator water chamber;

[0065] Step 3: Connect the helium leak detection system and install the sniffer assembly on the other end of the crawler;

[0066] Step 4: When calibration is required, control the crawler to crawl to the corresponding heat transfer tube for calibration;

[0067] Step 5: Complete the inspection process, then perform post-implementation calibration and complete the disassembly of the calibration device.

[0068] The above step 1 specifically includes:

[0069] Step 1.1: First, design the calibration device core rod according to the inner diameter of the heat transfer tube. The head of the calibration core rod is conical and serves as a guide.

[0070] Step 1.2: The front section of the designed core rod is hollow, and a hole is opened on the side to connect to the hollow. The side is welded to the stainless steel tube. The tail of the stainless steel tube is equipped with a quick connector, which is connected to the flexible air pipe to form an air path for the calibration process: standard leak hole - flexible air pipe - calibration device - heat transfer tube;

[0071] Step 1.3: Three O-rings, two transfer rings, a push ring, a screw, and a nut are distributed around the outer periphery of the designed core rod to form the expansion part of the calibration device;

[0072] Step 1.4: The lower part of the core rod is designed to be an inverted T-shaped structure, which is welded to the tail of the core rod to facilitate hooking the calibration device and pulling it out as a whole;

[0073] Step 1.5: The developed mounting and disassembly rod consists of a carbon fiber rod, a mounting head, and a disassembly head. The mounting head and the disassembly head are distributed at both ends of the carbon fiber rod and fixed to the carbon fiber rod.

[0074] Step 1.6: The mounting head of the developed mounting and dismounting rod has a hexagonal socket wrench inside, which matches the hexagonal nut of the calibration device;

[0075] Step 1.7: The disassembly head of the developed mounting and disassembly rod has an L-shaped groove inside, which matches the inverted T-shaped structure of the calibration device. After installation, it can be rotated to hook the calibration device.

[0076] The above step 2 specifically includes:

[0077] Step 2.1: First, connect the flexible air tube to the quick connector of the calibration device;

[0078] Step 2.2: Place the calibration device nut inside the mounting head of the mounting and removal rod;

[0079] Step 2.3: Select an easily identifiable nozzle on the evaporator water chamber tube sheet, align the guide head of the calibration device with the nozzle and push it inward to the bottom. Turn the installation and removal rod clockwise to tighten the nut. During the tightening process, the nut pushes the push ring forward, thereby compressing the O-ring to deform and expand. The friction of the three O-rings can support the overall weight of the calibration device and prevent it from falling. At this time, the installation and removal rod can be withdrawn.

[0080] Step 2.4: Verify the installation position of the calibration device and record the coordinates;

[0081] Step 2.5: Connect the other end of the flexible air tube to the standard leak hole;

[0082] The above step 3 specifically includes:

[0083] Step 3.1: First, connect the remote control computer, helium mass spectrometer, flow controller, crawler, sniffer assembly, corresponding gas lines, communication lines, etc. according to the system connection requirements, and test whether the system connection is normal;

[0084] Step 3.2: After the system test is completed, check whether the connection between the suction gun assembly and the crawler is firm, and then install the crawler with the suction gun assembly at the other end of the evaporator water chamber.

[0085] The above step 4 specifically includes:

[0086] Step 4.1: First, arrange personnel to open the standard leak valve;

[0087] Step 4.2: Calculate the coordinate position of the other end of the water chamber based on the coordinate position of the calibration device, ensuring that the two coordinate positions correspond to the same heat transfer tube;

[0088] Step 4.3: Use the remote computer to control the crawler to move the sniffer assembly to the corresponding coordinate position, ensuring that the sniffer port of the sniffer assembly is directly below the coordinate position;

[0089] Step 4.4: The operator controls the control system to lift the sniffer assembly to form a good seal between the sniffer assembly and the tube sheet. The flow control cabinet and helium mass spectrometer are remotely activated to perform signal detection. If the signal display result corresponds to the calibration value of the calibrated leak, the sniffer calibration is qualified.

[0090] Step 4.5: After the system calibration is completed, arrange personnel to close the standard leak valve. The calibration process is completed and the crawler is controlled to move to the heat transfer tube to be inspected on the tube sheet to continue the inspection.

[0091] The above step 5 specifically includes:

[0092] Step 5.1: After the inspection of a single evaporator is completed, repeat the above step 4 to complete the calibration after implementation;

[0093] Step 5.2: Align the hexagonal wrench inside the installation head of the installation and removal assembly with the nut, rotate the installation and removal assembly counterclockwise, and move the nut backward to gradually loosen the O-ring from its tightened state;

[0094] Step 5.3: After the nut is removed, the calibration device still cannot be removed due to a certain friction force. The disassembly head of the installation and disassembly rod needs to be aligned with the T-shaped structure of the calibration device and rotated to hook it. Then pull it back. The calibration device is pulled out of the heat transfer tube under the action of the pulling force, completing the disassembly.

Claims

1. An online rapid calibration device for helium leak detection in heat transfer tubes of pressurized water reactor steam generators, characterized by: It includes a calibration fixed head, an installation and disassembly rod, a flexible air pipe, and a standard leak hole. The calibration fixed head is arranged on the installation and disassembly rod, and the flexible air pipe is arranged beside the installation and disassembly rod. The flexible air pipe is connected to the standard leak hole.

2. A method for rapid online calibration of helium leak detection in heat transfer tubes of pressurized water reactor steam generators, characterized by: Step 1: Develop a quick calibration device and install a disassembly rod; Step 2: Before the inspection is carried out, use the installation and removal rod to install the quick calibration device to one end of the evaporator water chamber; Step 3: Connect the helium leak detection system and install the sniffer assembly on the other end of the crawler; Step 4: When calibration is required, control the crawler to crawl to the corresponding heat transfer tube for calibration; Step 5: Complete the inspection process, then perform post-implementation calibration and complete the disassembly of the rapid calibration device.

3. The method for online rapid calibration of helium leak detection for heat transfer tubes of a pressurized water reactor steam generator according to claim 2, characterized in that: Step 1 specifically includes: Step 1.1: First, design the core rod of the calibration device according to the inner diameter of the heat transfer tube; Step 1.2: The front section of the core rod is hollow, and a hole is opened on the side to connect to the hollow. The side is welded to the stainless steel tube. The tail of the stainless steel tube is equipped with a quick connector, which is connected to the flexible air pipe to form a gas path for the calibration process: standard leak hole - flexible air pipe - calibration device - heat transfer tube; Step 1.3: O-rings, transfer rings, push rings, screws, and nuts are distributed around the core rod to form the expansion part of the calibration device; Step 1.4: The lower part of the core rod is an inverted T-shaped structure, which is connected to the tail of the core rod; Step 1.5: The installation and removal rod consists of a carbon fiber rod, an installation head, and a removal head. The installation head and removal head are located at both ends of the carbon fiber rod and fixed to the carbon fiber rod. Step 1.6: Install the disassembly rod. The mounting head has a hexagonal socket wrench inside, which matches the hexagonal nut of the calibration device. Step 1.7: The disassembly head of the disassembly rod has an L-shaped groove inside, which matches the inverted T-shaped structure of the calibration device. After installation, rotate it to hook the calibration device.

4. The method for online rapid calibration of helium leak detection for heat transfer tubes of a pressurized water reactor steam generator according to claim 3, characterized in that: Step 1.3: Three O-rings, two transfer rings, one push ring, a screw and a nut are distributed around the outer periphery of the core rod, forming the expansion part of the calibration device.

5. The method for online rapid calibration of helium leak detection for heat transfer tubes of a pressurized water reactor steam generator according to claim 3, characterized in that: Step 2 specifically includes: Step 2.1: First, connect the flexible air tube to the quick connector of the calibration device; Step 2.2: Place the calibration device nut inside the mounting head of the mounting and removal rod; Step 2.3: Select an easily identifiable nozzle on the evaporator water chamber tube sheet. Align the guide head of the calibration device with the nozzle and push it inward to the bottom. Turn the installation and removal rod clockwise to tighten the nut. During the tightening process, the nut pushes the push ring forward, thereby compressing the O-ring to deform and expand. The friction of the O-ring supports the entire weight of the calibration device and prevents it from falling. At this time, withdraw the installation and removal rod. Step 2.4: Verify the installation position of the calibration device and record the coordinates; Step 2.5: Connect the other end of the flexible air tubing to the standard leak.

6. The method for online rapid calibration of helium leak detection for heat transfer tubes of a pressurized water reactor steam generator according to claim 5, characterized in that: Step 3 specifically includes: Step 3.1: First, connect the remote control computer, helium mass spectrometer, flow controller, crawler, sniffer assembly, corresponding gas lines, and communication lines according to the system connection requirements, and test whether the system connection is normal; Step 3.2: After the system test is completed, check whether the connection between the suction gun assembly and the crawler is firm, and then install the crawler with the suction gun assembly at the other end of the evaporator water chamber.

7. The method for online rapid calibration of helium leak detection for heat transfer tubes of a pressurized water reactor steam generator according to claim 6, characterized in that: Step 4 specifically includes: Step 4.1: First, arrange personnel to open the standard leak valve; Step 4.2: Calculate the coordinate position of the other end of the water chamber based on the coordinate position of the calibration device, ensuring that the two coordinate positions correspond to the same heat transfer tube; Step 4.3: Use the remote computer to control the crawler to move the sniffer assembly to the corresponding coordinate position, ensuring that the sniffer port of the sniffer assembly is directly below the coordinate position; Step 4.4: The operator controls the control system to lift the sniffer assembly to form a good seal between the sniffer assembly and the tube sheet. The operator remotely activates the flow control cabinet and the helium mass spectrometer to perform signal detection. If the signal display result corresponds to the calibration value of the calibrated leak, the sniffer calibration is qualified. Step 4.5: After the system calibration is completed, arrange personnel to close the standard leak valve. The calibration process is completed and the crawler is controlled to move to the heat transfer tube to be inspected on the tube sheet to continue the inspection.

8. The method for online rapid calibration of helium leak detection for heat transfer tubes of a pressurized water reactor steam generator according to claim 7, characterized in that: Step 5 specifically includes: Step 5.1: After the inspection of a single evaporator is completed, repeat step 4 to complete the calibration after implementation; Step 5.2: Align the hexagonal wrench inside the installation head of the installation and removal assembly with the nut, rotate the installation and removal assembly counterclockwise, and move the nut backward to gradually loosen the O-ring from its tightened state; Step 5.3: After the nut is removed, the calibration device still cannot be removed due to a certain friction force. The disassembly head of the installation and disassembly rod needs to be aligned with the T-shaped structure of the calibration device and rotated to hook it. Then pull it back. The calibration device is pulled out of the heat transfer tube under the action of the pulling force, completing the disassembly.

9. The method for online rapid calibration of helium leak detection for heat transfer tubes of a pressurized water reactor steam generator according to claim 3, characterized in that: Step 1.4: The lower part of the core rod is an inverted T-shaped structure and is welded to the tail of the core rod.

10. The method for online rapid calibration of helium leak detection for heat transfer tubes of a pressurized water reactor steam generator according to claim 3, characterized in that: Step 1.1: Calibrate the core rod to make it conical.

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