New fuel assembly and new control rod assembly inspection station for a marine nuclear power platform

Abstract

The application discloses a reactor new fuel assembly and new control rod assembly inspection platform suitable for a marine nuclear power platform, and belongs to the technical field of nuclear power platform equipment. The inspection platform comprises a support, three upper, middle and lower support frames, and three upper, middle and lower inspection platforms arranged on the three support frames respectively; a core upper grid plate simulation piece is welded on the upper inspection platform, and a core lower grid plate simulation piece is welded on the lower inspection platform; a control rod guide tube simulation piece and a support tube penetrate through the three upper, middle and lower inspection platforms respectively; a control rod simulation piece is welded with the support tube; a new fuel assembly size inspection gauge fixing bolt is welded and fixed on the lower inspection platform; and a new control rod assembly size inspection gauge fixing bolt is fixed on the lower inspection platform and used for fixing a new control rod assembly size inspection gauge. The inspection platform is used for checking new fuel assemblies and new control rod assemblies and measuring the pulling and inserting friction force of the new control rod assemblies during the refueling process of the marine nuclear power platform.

Description

Technical Field

[0001] This invention relates to an inspection apparatus for new fuel assemblies and new control rod assemblies, specifically an inspection stand for new fuel assemblies and new control rod assemblies for marine nuclear power platforms. Background Technology

[0002] After a certain period of operation, when the nuclear fuel on a marine nuclear power platform can no longer maintain a certain power output, refueling is necessary. To ensure that the dimensions, appearance, and positioning hook function of the new fuel assemblies meet the requirements of the refueling operation, and to measure the frictional force during the insertion and removal of the new control rod assemblies, effective new fuel inspection facilities must be designed to ensure that the new fuel assemblies meet the reactor design requirements during core assembly. As a welded steel floating platform carrying a nuclear power plant, a marine nuclear power platform is subjected to prolonged periods of heeling, rolling, pitching, and swaying in a marine environment. Furthermore, the usable space within the vessel is extremely limited, placing even higher demands on the design of new fuel assembly inspection facilities.

[0003] Onshore nuclear power plants have simple facilities for inspecting new fuel assemblies and control rod assemblies. Inspections can be completed simply by installing grippers and hooks for these assemblies within a compartment, followed by fuel loading. Onshore nuclear power plants are designed for inspecting new fuel assemblies and control rod assemblies on land in a static environment. However, existing inspection facilities are insufficient for inspecting new fuel assemblies and control rod assemblies on marine nuclear power platforms.

[0004] Meanwhile, relevant data shows that currently, no refueling is considered for marine nuclear power plants. All operations are carried out at marine nuclear power plant support bases or refueling docks. Therefore, it is not considered to conduct inspections of new fuel assemblies and new control rod assemblies in the marine environment. The inspection methods for new fuel assemblies and new control rod assemblies are the same as those for land-based commercial nuclear power plants, with fixed inspection facilities set up at the dock to inspect the new fuel assemblies.

[0005] As can be seen from the above, there are currently no examples of inspecting new fuel assemblies and new control rod assemblies under marine environmental conditions. Existing methods for inspecting new fuel assemblies and new control rod assemblies are not feasible due to environmental influences and space limitations, and the risk of safety accidents is too high. Therefore, a facility that can inspect new fuel assemblies and new control rod assemblies in a marine environment needs to be designed for marine nuclear power platforms. Summary of the Invention

[0006] In view of the current lack of relevant technologies and engineering applications, the purpose of this invention is to provide an inspection station for new fuel assemblies and new control rod assemblies in marine nuclear power platforms. This inspection station is used for the inspection of new fuel assemblies and new control rod assemblies during the refueling process of marine nuclear power platforms, enabling the inspection of new fuel assemblies and new control rod assemblies in a marine environment, ensuring that their size, appearance, etc. meet the requirements of core assembly, and guaranteeing the integrity of the positioning hook function of the new fuel assembly and the measurement of the insertion and withdrawal friction force of the new control rod assembly.

[0007] The technical solution adopted to achieve the purpose of this invention is a new fuel assembly and control rod assembly inspection station for marine nuclear power platforms, the inspection station comprising:

[0008] The inspection table support includes three supports: upper, middle, and lower. Each support has three inspection table surfaces: upper, middle, and lower. The middle inspection table surface has a through hole.

[0009] The core grating simulation component is a cylindrical structure welded to the upper inspection platform.

[0010] The core lower grating simulation component is welded onto the lower inspection platform.

[0011] The control rod guide tube simulation component is a circular tubular structure that runs through the upper, middle, and lower inspection platforms.

[0012] The support tube runs through the upper, middle and lower inspection surfaces;

[0013] A control rod simulator is welded to the support tube;

[0014] The new fuel assembly dimensional inspection gauge fixing bolt is a cylindrical structure that is welded and fixed to the lower inspection table surface to fix the new fuel assembly dimensional inspection gauge.

[0015] The new control rod assembly dimensional inspection gauge fixing pin is a cylindrical structure that is fixed on the lower inspection table and is used to fix the new control rod assembly dimensional inspection gauge.

[0016] Furthermore, the aforementioned inspection stand for new fuel assemblies and new control rod assemblies for marine nuclear power platforms is characterized in that: the inspection stand support inherently has new control rod assembly gripper hooks and new fuel assembly gripper hooks.

[0017] In the above technical solution, the size of the new fuel assembly size inspection gauge fixing pin is slightly smaller than the size of the fuel assembly, and the size of the new control rod assembly size inspection gauge fixing pin is slightly smaller than the design size of the new control rod.

[0018] In the above technical solution, the inspection table support is a frame structure composed of several transverse channel steels, longitudinal channel steels 14-2 and diagonal channel steels connected together.

[0019] In the above technical solution, the upper, middle and lower inspection platforms are three L-shaped supports, one side of the L-shaped support is fixedly connected to the support, and the other side forms a support platform.

[0020] In the above technical solution, the inspection table support is made of carbon steel, and the parts that come into contact with the fuel and control rods are made of stainless steel.

[0021] The present invention provides an inspection station for new fuel assemblies and new control rod assemblies for marine nuclear power platforms. This station enables the inspection of new fuel assemblies and new control rod assemblies in a swaying marine environment, ensuring that the size, appearance, and function of the new fuel assemblies and new control rod assemblies meet the reactor design requirements during core assembly. Furthermore, the station achieves functional centralization, reduces the number of devices, and is beneficial to improving the utilization rate of the internal space of the marine nuclear power platform. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the inspection station for the new fuel assembly and new control rod assembly of the present invention for marine nuclear power platforms.

[0023] Figure 2 This is an isometric view of the inspection table for the new fuel assembly and new control rod assembly of the present invention for marine nuclear power platforms.

[0024] Figure 3 This is a top view of the inspection stand for the new fuel assembly and new control rod assembly of the present invention for marine nuclear power platforms.

[0025] In the diagram: 1- Control rod guide tube simulation; 2- Core upper grid plate simulation; 3- Control rod simulation; 4- Support tube; 5- Inspection platform surface; 6- New control rod assembly gripper hook; 7- Inspection platform middle surface; 8- New fuel assembly gripper hook; 9- Inspection platform bottom surface; 10- Core lower grid plate simulation; 11- New fuel assembly dimensional inspection gauge I; 12- New fuel assembly dimensional inspection gauge II; 13- New control rod dimensional inspection gauge; 14- Inspection platform support (14-1- Transverse channel steel; 14-2- Longitudinal channel steel; 14-3- Diagonal channel steel); 15- New fuel assembly through hole; 16- New fuel assembly dimensional inspection gauge fixing bolt; 17- New control rod assembly dimensional inspection gauge fixing bolt. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0027] like Figure 1-3As shown, the inspection stand for new fuel assemblies and new control rod assemblies of the present invention for marine nuclear power platforms includes a control rod guide tube simulator 1, a core upper grid plate simulator 2, a control rod simulator 3, a support tube 4, a new control rod assembly gripper hook 6, a new fuel assembly gripper hook 8, a core lower grid plate simulator 10, a new fuel assembly size inspection gauge I 11, a new fuel assembly size inspection gauge II 12, a new control rod size inspection gauge 13, an inspection stand bracket 14, a new fuel assembly size inspection gauge fixing bolt 16, and a new control rod assembly size inspection gauge fixing bolt 17.

[0028] The inspection platform support 14 is a frame structure used for inspecting new fuel assemblies and control rod assemblies, as well as storing grippers, minimizing the space required for inspection and maximizing space utilization. The inspection platform support 14 is composed of several transverse channel steels 14-1, longitudinal channel steels 14-2, and diagonal channel steels 14-3, forming a frame structure to ensure stability. The inspection platform support 14 is made of carbon steel to ensure structural strength, while parts in contact with fuel and control rods are made of stainless steel to ensure material and environmental compatibility under operating and accident conditions, preventing contamination of fuel assemblies and control rod assemblies.

[0029] In this embodiment, three transverse channel steels 14-1 form three supports: upper, middle and lower. Each support is provided with a tabletop 5, a middle tabletop 7 and a bottom tabletop 9. All three tabletops are L-shaped structures. One side of the L-shaped structure is connected to the transverse channel steel 14-1 by bolts, and the other side provides support.

[0030] The control rod guide tube simulator 1 is a circular tube structure that runs through three surfaces of the inspection table: the top surface 5, the middle surface 7, and the bottom surface 9. It is used to measure the friction force during the insertion and removal of a new control rod. During inspection, the new control rod assembly gripper is connected to a crane via a force gauge. The crane moves the new control rod assembly directly above the control rod guide tube simulator 1 using the gripper, slowly inserts it, and then pulls it out. The force gauge measures the friction force during insertion and removal of the new control rod assembly, thus measuring the insertion and removal friction force. The outer diameter of the control rod guide tube simulator 1 matches the maximum outer diameter of the new control rod assembly and meets the insertion depth requirements. This ensures that the new control rod assembly can be inserted into and removed from the simulator during inspection. It can also be used to measure the friction force during insertion and removal of the new control rod assembly, thus achieving the measurement of the insertion and removal friction force.

[0031] The upper core grid plate simulation component 2 is a circular tube structure, welded onto the inspection platform surface 5. The lower core grid plate simulation component 10 is welded onto the bottom platform surface 9 of the inspection platform. A through hole 15 is opened on the middle platform surface of the inspection platform to ensure the insertion of new fuel assemblies for checking the positioning hook function of new fuel assemblies.

[0032] The control rod simulator 3 passes through and is stored on the support tube 4. During inspection, the control rod simulator 3 is inserted into the control rod guide tube of the new fuel assembly. The insertion process should be smooth and unobstructed. Then, the control rod simulator is pulled out smoothly and unobstructed. The size of the control rod simulator matches the size of the new control rod to ensure that the new control rod can be inserted into and pulled out of the new control rod guide tube, thus realizing the insertion and removal test of the new control rod guide tube.

[0033] The new control rod assembly gripper hook 6 and the new fuel assembly gripper hook 8 are bolted to the transverse channel steel 14-1. To increase space utilization and avoid interference, the new control rod assembly gripper hook 6 and the new fuel assembly gripper hook 8 can be installed on different support transverse channel steels 14-1 and staggered longitudinally. The grippers are stored on the hooks and secured with straps to meet the safe storage requirements of marine environments.

[0034] The new fuel assembly dimensional inspection gauge fixing pin 16 is welded to the bottom surface 9 of the inspection table. It is a cylindrical structure, slightly smaller than the new fuel assembly, and is used to fix the new fuel assembly dimensional inspection gauges I11 and II12. The inner diameter of the new fuel assembly dimensional inspection gauge I11 matches the outer diameter of the upper connector of the new fuel assembly, and the inner diameter of the new fuel assembly dimensional inspection gauge II12 matches the outer diameter of the component box, ensuring that the new fuel assembly can pass smoothly through the gauges and achieve dimensional inspection of the new fuel assembly.

[0035] The new control rod assembly dimensional inspection gauge fixing pin 17 is welded to the bottom surface 9 of the inspection table. It has a cylindrical structure and its size is slightly smaller than the design size of the new control rod. It is used to fix the new control rod assembly dimensional inspection gauge 13. The inner diameter of the new control rod assembly dimensional inspection gauge 13 matches the maximum outer diameter of the new control rod, ensuring that the new control rod can pass through smoothly, realizing the dimensional inspection and appearance inspection of the control rod assembly.

[0036] The usage process of the inspection station for the new fuel assembly and control rod assembly of the present invention for marine nuclear power platforms is as follows:

[0037] During the inspection of new fuel and control rods under marine environmental conditions, the new fuel assembly is first hoisted above the new fuel assembly dimensional inspection gauge using a crane connected to the new fuel assembly gripper. Operators then pass the new fuel assembly dimensional inspection gauges I11 and II12 through the new fuel assembly to perform dimensional inspection. After the dimensional inspection is completed, the new fuel assembly is passed through the core upper grating plate simulator 2, the new fuel assembly through-hole 15, and the core lower grating plate simulator 10 using the crane, and fixed on the new fuel assembly inspection platform. The new fuel assembly gripper is used to press down on the guide tube component of the new fuel assembly to check whether the positioning hook boss retracts smoothly and completely into the lower connector. After removing the force from the guide tube component, the positioning hook boss is checked to ensure it extends smoothly out of the lower connector, and the lower end of the new fuel assembly is positioned, thus completing the positioning hook function check. The control rod simulator 3 is then inserted into the control rod guide tube of the fuel assembly using the crane, ensuring a smooth and unobstructed insertion process. The control rod simulator 3 is then pulled out smoothly and unobstructed, completing the control rod guide tube component insertion and removal test. Finally, the new control rod assembly is inspected. A crane is used to connect the new control rod assembly gripper, and the new control rod assembly is hoisted above the new control rod dimensional inspection gauge 13. The operator holds the new control rod dimensional inspection gauge 13 through the new control rod assembly to check its dimensions. Next, the insertion and withdrawal friction of the new control rod assembly is measured. The new control rod assembly is connected to the crane via a force gauge. The crane uses the new control rod assembly gripper to move the new control rod assembly directly above the control rod guide tube simulator 1, slowly inserting and then withdrawing it. The force gauge is used to measure the friction force during insertion and withdrawal of the control rod assembly into and out of the simulator, thus achieving the measurement of the control rod insertion and withdrawal friction. After all components are inspected, the new fuel assembly gripper and the new control rod assembly gripper are respectively secured to the new fuel assembly gripper hook 8 and the new control rod assembly hook 6 for storage.

[0038] The design of the inspection table structure and the equipment of the present invention ensure safe and reliable inspection of new fuel assemblies and new control rod assemblies under inclined and swaying environmental conditions.

Claims

1. A new fuel assembly and control rod assembly inspection stand for marine nuclear power platforms, characterized in that, include: The inspection table support (14) includes three supports: upper, middle and lower. Each support is provided with three inspection table surfaces (5, 7, 9) respectively; the middle inspection table surface has a through hole (15); The core upper grid plate simulation component (2) is a cylindrical structure welded to the upper inspection platform. The core lower grating simulation component (10) is welded onto the lower inspection platform (9). The control rod guide tube simulation component (1) is a circular tube structure that runs through the upper, middle and lower inspection surfaces; The support tube (4) runs through the upper, middle and lower inspection surfaces; The control rod simulation component (3) is welded to the support tube (4); The new fuel assembly dimension inspection gauge fixing bolt (16) is a cylindrical structure, welded and fixed on the lower inspection table (9), and is used to fix the new fuel assembly dimension inspection gauge (11, 12); The new control rod assembly dimension inspection gauge fixing pin (17) is a cylindrical structure, fixed on the lower inspection table (9), and is used to fix the new control rod assembly dimension inspection gauge (13).

2. The inspection station for new fuel assemblies and new control rod assemblies for marine nuclear power platforms according to claim 1, characterized in that: The inspection table support has a new control rod assembly gripper hook (6) and a new fuel assembly gripper hook (8).

3. The inspection station for new fuel assemblies and new control rod assemblies for marine nuclear power platforms according to claim 1, characterized in that: The size of the new fuel assembly size inspection gauge fixing pin (16) is slightly smaller than the size of the fuel assembly, and the size of the new control rod assembly size inspection gauge fixing pin (17) is slightly smaller than the design size of the new control rod.

4. The inspection station for new fuel assemblies and new control rod assemblies for marine nuclear power platforms according to claim 1, characterized in that: The inspection table support (14) is a frame structure composed of several transverse channel steels (14-1), longitudinal channel steels (14-2), and diagonal channel steels (14-3).

5. The inspection station for new fuel assemblies and new control rod assemblies for marine nuclear power platforms according to claim 1, characterized in that: The upper, middle, and lower inspection platforms (5, 7, 9) are three L-shaped supports, one side of which is fixedly connected to the support, and the other side forms a support platform.

6. The inspection station for new fuel assemblies and new control rod assemblies for marine nuclear power platforms according to any one of claims 1-5, characterized in that: The inspection table support is made of carbon steel, while the parts that come into contact with the fuel and control rods are made of stainless steel.

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