確率論に基づく免震原子力施設の応答に関する研究,1; 積層ゴムの非線形性を考慮したモデリング

Study on seismic response of isolated nuclear power plant based on probabilistic assessment, 1; Modeling considering nonlinearity of rubber bearings

藤田 聡*; 皆川 佳祐*; 山口 彰*; 高田 孝*; 栗坂 健一 

Fujita, Satoshi*; Minagawa, Keisuke*; Yamaguchi, Akira*; Takata, Takashi*; Kurisaka, Kenichi

確率論的安全評価に使われる地震応答解析において想定を超える入力に対して応答を求める必要がある。免震システムに使われる積層ゴムが想定を超える入力を受けるとその復元力特性において非線形性が生じる。しかし、積層ゴムの非線形性を考慮した地震応答解析手法は未確立である。したがって、本研究ではPSAに基づく免震原子炉建屋の地震応答解析手法の開発を目的とする。本報では復元力における非線形性を考慮した積層ゴムモデルを作成して地震応答解析を行い、積層ゴムの非線形性が建屋応答に与える影響を検討した。その結果、水平方向では地震規模の増大に伴い最大応答加速度の増加傾向が顕著になり、上下方向では最大応答変位の増加傾向が顕著になることがわかった。

The response to the input more than assumption is requested in the seismic response analysis used for the Probabilistic Safety Assessment. Rubber bearings used as the isolation system cause nonlinearity in the restoring force when the input more than assumption is received. However, the seismic response analysis method for considering nonlinear of the rubber bearing has not been established. Therefore, this study aims at the development of the seismic response analysis method of an isolated nuclear power plant based on the probabilistic safety assessment. In this paper, isolated building model that the nonlinearity of the rubber bearing is considered is made, the seismic response analysis is done, and the influence that it gives respond was verified. As a result, in horizontal direction, it was confirmed that the increasing tendency of the response acceleration was remarkable because of the increase of the earthquake size. In vertical direction, it was confirmed that the increasing tendency of the response displacement was remarkable.