3次元免震システムの研究開発; 1/2縮尺試験体による設計基準を上回る荷重領域を対象とした静的試験

Research and development of three-dimensional isolation system; Static loading test for beyond design basis conditions using half scale model

深沢 剛司*; 平山 智之*; 横井 忍*; 廣田 昭彦*; 杣木 孝裕*; 湯川 正貴*; 宮川 高行*; 内田 昌人*; 山本 智彦  ; 宮崎 真之; 渡壁 智祥; 岡村 茂樹; 藤田 聡*

Fukasawa, Tsuyoshi*; Hirayama, Tomoyuki*; Yokoi, Shinobu*; Hirota, Akihiko*; Somaki, Takahiro*; Yukawa, Masaki*; Miyagawa, Takayuki*; Uchita, Masato*; Yamamoto, Tomohiko; Miyazaki, Masashi; Watakabe, Tomoyoshi; Okamura, Shigeki; Fujita, Satoshi*

原子力発電施設の耐震性の向上を目的として、設計用基準地震動が見直されている。これによって、過去にも増して水平のみならず、上下方向の地震力の低減が機器の耐震性を確保するうえで重要となっている。著者らはこれまでに皿ばねユニットで構成される新たな3次元免震システムの開発を進めてきた。その設計成立性および耐性を検証するためには、本免震システムの荷重-変位関係の確認が必要となる。本論文では1/2縮尺試験体を対象に基準地震動およびこれを上回る荷重領域下で実施した静的試験で得られた結果を報告する。

The seismic integrity of sodium-cooled fast reactor (SFR) designs in nuclear power plants is of paramount importance. Based on the static loading test, this study investigates the force-displacement relationship and load transference in a three-dimensional seismic isolation system that is envisaged for use in reactor buildings. In SFR designs, the necessity for thin-walled structures to maintain high-temperature structure integrity can unintentionally compromise the seismic design. Consequently, addressing horizontal and vertical seismic forces become vital for ensuring seismic resilience. Currently, there are no specific codes or standards governing the integration of Three-dimensional seismic isolation systems into nuclear reactor buildings. However, current guidelines for the design of horizontal seismic isolation systems emphasize the necessity to clarify the force-displacement relationship and load transfer under conditions of superimposed horizontal and vertical loads. This study involves static loading tests performed on a half-scale specimen, which is subjected to horizontal and vertical loads exceeding the design basis ground motions for the SFR. The findings affirm that the system's horizontal supporting function maintains the segregation of horizontal and vertical load transference, even under seismic loads that exceed the design basis ground motions.