Low pressure drop lower nozzle, fuel assembly lower assembly and fuel assembly

Abstract

The invention discloses a low-pressure-drop lower pipe seat, a fuel assembly lower assembly and a fuel assembly. The sealed skirt-edge type lower pipe seat comprises a connection plate, a plurality of supporting legs and skirt edges, wherein the supporting legs are connected under the connection plate at intervals; the skirt edges are connected below the connection plate and between the adjacent supporting legs; the skirt edges and the supporting legs jointly surround the lower part of the periphery of the connection plate. According to the low-pressure-drop lower pipe seat provided by the invention, the skirt edges are sealed under the connection plate, so that while the pressure loss coefficient of the lower pipe seat is reduced, higher strength is realized, and the dimensional stability of the lower pipe seat is improved. In the fuel assembly, a more uniform lower pipe seat outlet flow field is provided, so that a flow field of a fuel bundle area above the lower pipe seat is more uniform, the flow-induced vibration level of the lower end of a fuel rod is favorably reduced, and the pressure loss coefficient of the lower pipe seat is reduced.

Description

Technical field [0001] The present invention relates to the technical field of nuclear reactors, in particular to a low-pressure drop down tube seat, a fuel assembly lower assembly using the down tube seat, and a fuel assembly. Background technique [0002] At present, the internal components of commercial PWR reactors are designed in four types: Westinghouse, Siemens, Combustion Engineering, and Bavi, each type of fuel assembly lower support member (lower core plate) is different. To match these four types of internal components, there are also four types of fuel assembly lower pipe sockets. [0003] The lower tube seat of the existing Westinghouse type pressurized water reactor fuel assembly is a connecting plate (also called a matching plate, support plate, adapter plate) with a bench structure with four supporting legs, and a partial skirt between the two supporting legs to improve strength. The lower part of the skirt leaves a channel between the two supporting legs for flui...

AI Technical Summary

Problems solved by technology

The existing lower nozzle of this kind will experience a sudden expansion and contraction process after the fluid (coolant) enters the lower nozzle chamber from the injection hole of the lower core plate, and has a large fluid pressure loss coefficient

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