Experimental study on vertical component isolation system

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岡村 茂樹; 北村 誠司 ; 高橋 健司

Shigeki, Okamura; Kitamura, Seiji; Takahashi, Kenji

発電用新型炉に適用する3次元免震システムの開発を進めており、その一方策として、積層ゴムを用いた建屋水平免震に加えて、機器を上下方向に免震する装置を組み合わせる方式(機器上下免震システム)が考えられる。機器上下免震システムは、積層ゴムを用いた水平免震建屋を前提として、耐震上重要度の高い原子炉容器と一次系機器を共通床(コモンデッキ)で支持し、この床と基礎構造の間に上下方向の免震装置を設置し3次元免震を実現する。上下免震装置のばね要素には皿ばねを用い、皿ばねを直並列に重ねることにより所要の剛性とストロークをえ、減衰として鋼材ダンパを用いている。免震装置に過大な水平荷重を与えないように、水平荷重を支持するキーや支柱をコモンデッキとRV壁の間に配置する。機器上下免震システムの1/8縮尺モデルによる振動実験から、本システムの成立性の確認を行った。

In Japan, several kinds of three-dimensional seismic isolation system for next-generation nuclear power plant such as fast reactors have been studied in recent years. We proposed a structural concept of a vertical component isolation system, assuming a building adopting a horizontal base isolation system. In this concept, a reactor vessel and major primary components are suspended from a large common deck supported by isolation devices consisting of large coned disk springs. In order to verify the isolation performance of the vertical component isolation system, 1/8 series of shaking table tests using a scale model were conducted. The test model was composed of 4 vertical isolation devices, common deck and horizontal load suspension system which supports the horizontal load by the earthquake. For the design earthquake, the system smoothly operated, and sufficient isolation characteristics were shown. The examination on the horizontal load suspension system was carried out. The simulation analysis results matched well the test results, so the validity of the design technique was able to be verified. As the result, the prospect that the vertical isolation system applied to the FBR plant could technically realize was obtained.