Composite type fuel assembly, nuclear reactor core and assembling method

Abstract

The invention discloses a composite type fuel assembly, a nuclear reactor core and an assembling method, wherein the composite type fuel assembly comprises a first fuel assembly, a second fuel assembly and a connecting mechanism for fixedly connecting the first fuel assembly and the second fuel assembly in an axial direction. The first fuel assembly and the second fuel assembly are fixedly connected through the connecting mechanism in the axial direction, so that the axial length of individual component of the first fuel assembly and the second fuel assembly can be effectively reduced so as toimprove the manufacturing feasibility and the safety of a reactor.

Description

technical field [0001] The invention relates to the field of nuclear power, in particular to a composite fuel assembly, a nuclear reactor core and an assembly method. Background technique [0002] In the field of nuclear power technology, fuel assemblies are the main components of nuclear reactor cores, and their safety and stability are very important. like figure 1 As shown, a conventional fuel assembly includes a rigid framework and fuel rods 2 . Wherein, the rigid frame includes a mixing grid 3 , an upper tube base 1 , a lower tube base 5 and a guide tube 4 . The mixing grid 3 is composed of regularly arranged cells for receiving and holding the fuel rods 2 . The guide tube 4 is longer than the fuel rod 2 , it protrudes from the end of the fuel rod 2 and is fixed on the upper tube base 1 and the lower tube base 5 . The lower tube base 5 is located at the lower part of the fuel assembly, and the lower tube base 5 has some supporting legs and a matching plate, and has ...

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Problems solved by technology

[0006] The length of a single fuel rod 2 is very long, and a lot of fuel pellets will be loaded in a fuel rod 2. During the entire fuel life, more fission gases will be released, causing the variation range of the internal pressure of the fuel rod 2 to be wider. large, which will bring challenges to the overall structural integrity design of the fuel rod 2

[0007] The length of a single fuel rod 2 is very long, so the cladding is very long, which will increase the difficulty of manufacturing the cladding; the long length of the fuel rod 2 will also increase the difficulty of the overall assembly and manufacture of the fuel rod 2

[0008] The length of a single fuel rod 2 is very long, which will cause difficulties in pulling the fuel rod 2 in the fuel assembly process, and the number of lattice layers that a single fuel rod 2 cladding will pass through will increase, especially the latest fuel assembly skeleton The fuel rod 2 part, which will increase the surface scratches of the fuel rod 2 cladding due to the rigid convex support of the grid spring, and then increase the production of zirconium chips, which will eventually affect the safety of the reactor.

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