Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities: Part 3 — Seismic Response of Crossover Piping for Seismic Isolation System

Abstract

This paper, which is part of the series entitled “Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities”, shows the linear seismic response of crossover piping installed in a seismically isolated plant. The crossover piping, supported by both isolated and non-isolated buildings, deforms with large relative displacement between the two buildings and the seismic response of the crossover piping is caused by two different seismic excitations from the buildings. A flexible and robust structure is needed for the high-pressure crossover piping. In this study, shaking tests on a 1/10 scale piping model and FEM analyses were performed to investigate the seismic response of the crossover piping which was excited and deformed by two different seismic motions under isolated and non-isolated conditions. Specifically, as linear response analysis of the crossover piping, modal time-history analysis and response spectrum analysis with multiple excitations were carried out and the applicability of the analyses was confirmed. Moreover, the seismic response of actual crossover piping was estimated and the feasibility was evaluated.

Seismic qualification of crossover piping systems on a sodium-cooled fast reactor with a seismic isolation system

“…With regard to the failure mode of the crossover piping, some studies were conducted to apply seismic isolation systems to LWRs as a part of a national Japanese project (Otani et al, 2014;Otoyo et al, 2014). These studies concluded that the failure mode of the crossover piping under seismic loads was low-cycle fatigue, similar to that of the piping of ordinary non-isolated plants, through a series of dynamic tests using a 1/10 scale model and analyses.…”