Bottom nozzle of nuclear reactor fuel assembly

Abstract

A bottom nozzle of a nuclear reactor fuel assembly comprises the following, interconnected coaxially: a support element, a diffuser and a hexagonal frame with ribs of variable height which are fastened in non-adjacent corners of the hexagonal frame with an offset from the plane of symmetry of the corners in such a manner that the end of one rib abuts the lateral surface of another rib. A profile of the ribs has a step on the lateral surface of the ribs and a tapering of the upper end of the ribs, the step serves for mounting the ring of an anti-debris filter, and the tapering for support in a support grid of a bundle of fuel elements. The tapering of the ribs can be in the form of teeth with flat tips. The technical result consists in increasing the reliability of a bottom nozzle and of a fuel assembly as a whole by reducing the hydraulic resistance of the bottom nozzle and the vibration loading of the fuel elements.

Description

technical field [0001] The present invention relates to nuclear technology, namely pressurized water nuclear power reactor fuel assemblies. Background technique [0002] In order to increase the reliability of the fuel assembly and its protection against damage by debris particles during operation, an anti-debris filter is installed in the tail end of the fuel assembly, which is placed between the tail ribs of the maximum passage section of the tail end , to reduce hydraulic resistance. Typically, modern anti-debris filters consist of a filter element and a rim through which the filter is attached to the tail end. [0003] Known is the tail end of the reactor fuel assembly No. 25 (Russian Federation Patent No. 2079170, date of publication May 10, 1997), equipped with fins, the end of which is connected to the bottom of the lower support grid between the rows of fuel element holes. The plane is connected; the disadvantage is that the holes through which the coolant passes t...

AI Technical Summary

Problems solved by technology

[0005] The disadvantage of the tail end of this fuel assembly is that when the anti-debris filter is installed, the passage section is reduced, and there is a shadow part of the coolant flow at the joint of the fins, and the connection between the ribs at the tail end and the outer edge of the anti-debris filter Turbulence in the flow of coolant, which leads to an increase in the coefficient of hydraulic drag, which leads to an increase in the vibration load on the fuel elements

Images