A tubular positioning grid for double-sided cooling of fuel rods in pressurized water reactors

Abstract

The invention discloses a tubular positioning grid frame for double-sided cooling of fuel rods in a pressurized water reactor. The positioning grid frame is formed by welding quasi-square grid units. The convex surface of the center is in contact with the outer circle of the fuel rod to form support and positioning for the fuel rod, and the grid unit is stamped or drawn from a circular tube. The invention provides a tubular positioning grid for double-sided cooling of fuel rods of a pressurized water reactor, which has simple structure, low manufacturing process technical difficulty, better economy and better safety, and is easy to install.

Description

technical field [0001] The invention relates to the technical field of nuclear reactor engineering, in particular to a tubular positioning grid for cooling fuel rods on both sides of a pressurized water reactor. Background technique [0002] During the operation of a nuclear power plant reactor, the performance of nuclear fuel is one of the important factors affecting the safety and economy of the reactor. Fuel temperature is an important reference index when considering power density, safety margin, unloaded fuel consumption and power generation cost. In order to reduce the breakage rate of fuel elements and increase the service life of components, people are constantly improving the quality of fuel and cladding materials, such as using new zirconium alloys, large grain pellets, etc. However, the less recognized benefits of increased power density can greatly improve the economics of nuclear power plants. Usually, the nuclear fuel is designed to be cylindrical, with a dia...

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Problems solved by technology

[0006] In U.S. Patent Publication No. US2010 / 0027734A1, a spacer grid for fuel rods is disclosed. It solves the problem of supporting and positioning the annular fuel rods of the pressurized water reactor, but the structure of the positioning grid is complicated and the manufacturing process is difficult. Under the influence of long-term scouring, it is easy to cause relaxation, reduce the elastic support capacity, and cause the instability of fuel rods

Moreover, the manufacturing process of this strip is complicated, the manufacturing time is long, and the installation is complicated.

[0007] At present, there are related documents in the prior art that disclose the positioning grid of the reactor. For example, Chinese patent specifications CN86102224A, CN87100909A, CN1140885A, CN1820326A and other patent documents disclose the positioning grid. The plate-like material of the belt is assembled in a criss-cross manner, and the manufacturing of the positioning grid is troublesome, and it is designed and used for the fuel assembly of the existing nuclear power plant

The support and positioning of fuel rods in nuclear reactors is the core of the safe operation of the reactor. For this reason, new solutions must be sought to improve the support and positioning of fuel rods in annular fuel assemblies, but so far no reference materials have clearly pointed out the direction of solving the problem

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