Title:
Seismic Fragility Analysis of Nuclear Reactor Concrete Containment Considering Alkali-Silica Reaction
Author(s):
Chanyoung Kim
Publication:
Web Session
Volume:
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
10/23/2022
Abstract:
This study aims to investigate the seismic fragility of nuclear concrete containments subjected to the material degradation due to alkali silica reaction (ASR). Current guidelines for the seismic probability risk assessment of nuclear power plants suggest that the time-dependent change and degradation of material properties should be taken into account for the seismic fragility analysis. However, further studies need to develop the methodology to estimate the effects of material degradation on the seismic capacity of concrete containments and their uncertainties. Recently, the ASR damage was observed in nuclear power plants with a long operation period and thus is gaining more attention. In this study, the material deterioration due to ASR in concrete is simulated using the open-source software Open sees, and the seismic fragility analysis is conducted considering nonlinear time-history behavior. The numerical model implements the distribution of multi-directional ASR expansions using a weight function assigning a higher strain rate to unconfined directions. The distribution of the ASR expansions in each case is validated with the results reported in the literature from accelerated ASR experiments. The maximum drift at the cycle shown the maximum shear force is selected as the damage index for the limit state from the seismic analysis results. From the seismic fragility analysis, the median acceleration capacity of the case-study concrete containment turns out to decrease by 5.4% due to the ASR damage.