Fuel assembly and lower pipe base thereof

Abstract

The invention discloses a fuel assembly and a lower pipe base thereof. The lower pipe base comprises a connecting plate, a plurality of support legs and a support structure, wherein the plurality of support legs are connected below the connecting plate at intervals, and the support structure is connected below the connecting plate among the plurality of support legs. The support structure is arranged on the connecting plate, and the dimensional stability of the lower pipe base is improved while the stress of the lower pipe base is reduced and the fluid pressure loss coefficient in the area ofthe lower pipe base is reduced; space is reserved for improving the hydraulic performance by reducing the stress level of the connecting plate of the low pipe base, so that the flow field in the fuelrod bundle area above the lower pipe base is more uniform, and the flow-induced vibration level at low ends of fuel rods is favorably reduced.

Description

technical field [0001] The invention relates to the technical field of nuclear reactor fuel assemblies, in particular to a fuel assembly and its lower pipe seat. Background technique [0002] The existing lower nozzle base bears all the load of the fuel assembly, and transmits it to the connection plate through the joint of the guide tube, and then to the four support legs through the connection plate, and then to the lower core plate, resulting in large local stress at the connection plate, and the strength requirements high. [0003] In addition, in the existing lower nozzle base, after the fluid (coolant) enters the chamber of the lower nozzle base from the four injection holes of the lower core plate, the four fluids meet at the lower part of the lower nozzle base and undergo a sudden expansion and contraction process, which has a large fluid pressure loss coefficient. Contents of the invention [0004] The technical problem to be solved by the present invention is t...

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Problems solved by technology

[0002] The existing lower nozzle base bears all the load of the fuel assembly, and transmits it to the connection plate through the joint of the guide tube, and then to the four support legs through the connection plate, and then to the lower core plate, resulting in large local stress at the connection plate. high

[0003] In addition, in the existing lower nozzle base, after the fluid (coolant) enters the chamber of the lower nozzle base from the four injection holes of the lower core plate, the four fluids meet at the lower part of the lower nozzle base and undergo a sudden expansion and contraction process, which has a large fluid pressure loss coefficient

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