Development of computer program for APR1400 SG U-tube layout and tube-sheet dia. determination for triangular U-tube pattern

摘要

NPP Steam Generators consists of thousands of litotes that are installed on tube-sheet. Due to the massive number of U-tubes, it is not usual to determine the design parameters of individual U-tubes such as the height and radius of rounds and location on tube-sheet. This paper presents design process of how to determine the coordinate, height of U-tube and the diameter of tube-sheet and described the algorithm. The input parameter consists of total heat transfer area, the average height of u-tubes, the pitch between U-tubes and the predetermined number of U-tubes. The results are the individual U-tube coordinates, the straight section length of vertical and horizontal section of U-tube, and the enveloping radius of tube-sheet that can accommodate all required U-tubes to be installed, and the maximum diameter of tube-sheet. This will in turn determine the inner diameter of SG shell and height. The overall size of SG can then be determined. The algorithm developed in this study can be used for the optimization of SG design.