Parametric stress analyses for low-level liquid radwaste system piping of ITER subjected to seismic displacements

Abstract

The ITER project is aimed at demonstrating the feasibility of fusion as one of the possible energy options. A layout optimization is one of the design concerns for maintaining safety and reliability of the piping, because some piping penetrating the buildings is subjected to large seismic displacements. The objective of this study is to determine an optimum layout for the radioactive liquid transfer piping to withstand a given seismic displacements combined with internal pressure and thermal expansion. To do this, a series of finite element analyses were performed for various layouts. In addition, the feasibility for utilizing the double-walled structure was investigated. Analysis result shows that effects of the internal pressure and thermal expansion on the total stress are very small compared to that of the seismic displacements. Also, the stress as well as the deformation of the double-walled piping is larger than that of the single-walled piping although the difference is not big. Based on this result, an optimum configuration, a spiral along with U shape, is suggested.