Method and system for measuring actual position deviation of nuclear power plant core fuel assembly

Abstract

The invention is suitable for the field of reactor core safety system of a nuclear power station, and discloses a measuring method and a system for actual-position deviation of a fuel assembly of a nuclear power station reactor core. The method comprises following steps of: moving an image acquisition device to a position above a target fuel assembly; acquiring the actual image position of the target fuel assembly by the image acquisition device; comparing the actual position of the target fuel assembly with a standard reference in an industrial machine; and calculating the difference between the actual coordinate and the standard reference by the industrial machine to obtain the deviation dimension. The system comprises the image acquisition device and the industrial machine. The measuring method and the system can measure the deviation between the actual position of a tube socket of the fuel assembly and a standard theoretical position accurately and efficiently, so as to discover abnormal situations and detect and examine timely during the abnormal situations, and therefore risks are effectively avoided and safety and reliability are high.

Description

technical field [0001] The invention belongs to the technical field of nuclear radiation safety and monitoring, and in particular relates to a method and system for measuring the actual position deviation of nuclear power plant core fuel assemblies. Background technique [0002] In the field of nuclear radiation safety and monitoring technology, the core is the key point of nuclear radiation safety and monitoring. , the fuel assembly will produce bending deformation. E.g: [0003] 1. The excessive pressing force of the compression spring of the fuel assembly is the main factor causing the bending of the fuel assembly; [0004] 2. Irradiation will reduce the stiffness of the fuel assembly. The lateral stiffness and axial stiffness of the fuel assembly at the end of its life are only about half of that of the fuel assembly at the beginning of its life, which is one of the factors causing the bending of the fuel assembly; [0005] 3. Irradiation growth and irradiation cre...

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Problems solved by technology

[0003] 1. The excessive compression force of the compression spring of the fuel assembly is the main factor causing the bending of the fuel assembly;

[0004] 2. Irradiation will reduce the stiffness of the fuel assembly. The lateral stiffness and axial stiffness of the fuel assembly at the end of its life are only about half of that of the fuel assembly at the beginning of its life, which is one of the factors causing the bending of the fuel assembly;

[0005] 3. Irradiation growth and irradiation creep of fuel assemblies can also lead to bending deformation of fuel assemblies;

[0006] 4. Due to the mechanical action between adjacent components, the amount of bending deformation of the fuel components in the core is different. Due to the constraints of space, the fuel components exert mutual force on the grid to cause the deformation of the fuel components

[0007] 5. During operation, differential radiation growth between the guide tubes of the fuel assembly, differential growth between the guide tubes and fuel rods due to thermal and neutron fluence gradients, and differential relaxation of the grid springs lead to bowing of the fuel assembly The phenomenon

[0008] 6. In addition, there are manufacturing errors in the fuel assembly process. The skeleton assembly of the grid and the fuel rod rods may cause assembly deformation, but this deformation is kept in a small range, and the bending deformation is on the order of 1mm

[0009] It can be seen from this that the fuel assembly is inevitably bent and deformed during use, resulting in the phenomenon of offset or twisting of the upper nozzle of the fuel assembly in the core. The actual position of the upper nozzle of the fuel assembly is consistent with the standard The theoretical position is different in the XY direction of the horizontal plane, resulting in a certain deviation between the actual position of the guide hole in the upper nozzle and the actual position of the guide pin in the upper member of the core. When the component is installed, it is difficult for the guide pin to be smoothly and accurately snapped into the guide hole in the upper tube seat of the fuel assembly, and interference occurs between the guide pin of the upper component and the guide hole in the upper tube seat of the fuel assembly, and this interference It is difficult to find when the superstructure is installed in place; during the lifting of the superstructure during the next refueling overhaul, it is possible to bring the jammed fuel assembly up, posing a great risk

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