A fuel assembly lower nozzle for balancing the flow of coolant at the core inlet

Abstract

The invention discloses a fuel assembly lower pipe seat for balancing flow rate of a coolant at a reactor core inlet, and relates to the design field of pressurized water nuclear reactors. The fuel assembly lower pipe seat for balancing flow rate of the coolant at the reactor core inlet disclosed by the invention comprises a lower grating, a supporting framework and a filtering structure, wherein the lower grating is located at the upper part of the supporting framework, the filtering structure is located at the upper part or the lower part of the lower grating, a guide pipe hole used for mounting a fuel assembly guide pipe, an instrument pipe hole used for mounting a fuel assembly instrument pipe and a water flow hole group used for flowing the coolant and re-distributing the flow rate are formed on the lower grating in a penetration manner; aiming at the phenomenon of non-uniform flow rate distribution on the contour section of the lower part area of the reactor core caused by jet flow of a large water flow hole in a lower plate of the reactor core, the structural design is optimized to obtain more uniform flow of the coolant at the lower part of the reactor core.

Description

technical field [0001] The invention relates to the design field of pressurized water nuclear reactors, in particular to a fuel assembly lower nozzle for balancing the coolant flow rate at the core inlet. Background technique [0002] The fuel assembly of pressurized water nuclear reactor is usually composed of several fuel rods, guide pipe parts, instrument pipe parts, grid, upper and lower pipe sockets, etc. Among them, the lower pipe socket is an important part of the fuel assembly skeleton and is one of the main bearing parts of the fuel assembly. First, its reliability directly affects the safety of fuel assemblies in operation, transportation and operation. At the same time, the lower nozzle is also an important interface part, and its structural design has a direct impact on the operational performance of the fuel assembly and the compatibility with the reactor internals. As the inlet of the core coolant, the hydraulic performance of the lower nozzle is also one of t...

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Problems solved by technology

[0004] The disadvantages of the above-mentioned two types of existing lower nozzle designs are: lack of optimal design for balanced flow distribution

In the existing design of the lower pipe seat, the grid plate of the lower pipe seat adopts the same hole pattern and evenly distributed flow holes. Under this design form, the flow distribution of the coolant is still not uniform when it passes through the lower pipe seat and then distributed, which is easy to produce Cross flow, increased risk of fuel rod vibration wear loss

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