Flexible tube sheet structure for nuclear power plant steam generator

Abstract

The invention relates to a flexible tube sheet structure for a nuclear power plant steam generator. The flexible tube sheet structure comprises a thermal expansion buffer section and a flexible tube sheet; the two ends of the flexible tube sheet are connected with the thermal expansion buffer section through a transition section; the thermal expansion buffer section is in a barrel shape in the whole and is composed of an inner barrel, an outer barrel and a connection flange, wherein the inner barrel and the outer barrel are different in thickness, a cavity serving as a fluid dead zone is formed between the inner barrel and the outer barrel, the two ends of the connection flange are welded to one end of the inner barrel and one end of the outer barrel, the other end of the inner barrel is welded to the end of the transition section, and the side wall of the other end of the outer barrel is welded to a steam generator barrel body; the flexible tube sheet and the transition section are subjected to primary forging forming, the transition section is a circular-arc-shaped rotation body, and heat exchange tube holes are uniformly and densely distributed in the flexible tube sheet; and the flexible tube sheet, the transition section and the inner barrel of the thermal expansion buffer section are equal in effective thickness. Through the flexible tube sheet structure, the thickness ofa tube sheet can be decreased, thermal stress of the two sides of the tube sheet is decreased, in addition, the tube sheet has certain flexibility, and the thermal expansion difference between the heat exchange tube and the steam generator barrel body can be decreased to a certain extent.

Description

technical field

[0001] The invention relates to the technical field of nuclear power plant evaporators, in particular to a flexible tube sheet structure for a nuclear power plant steam generator. Background technique

[0002] The main form of steam generators in the nuclear power industry is the shell-and-tube steam generator, and the tube sheet of the steam generator is one of the important parts of the steam generator. The working conditions of steam generators in nuclear power plants are harsh. The design temperature of the steam outlet tube sheet can be as high as 660°C, and the design pressure can be as high as 18MPa. It must withstand high pressure, high temperature and medium erosion. Traditionally designed rigid tube sheets need to increase the thickness of the tube sheet to withstand higher pressure loads. On the other hand, the tube sheet needs to be as thin as possible to reduce the influence of temperature difference and thermal stress. It is difficult to achieve...

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