報告書番号

U90045

タイトル（和文）

風化軟質岩盤上の原子炉建屋の地震応答特性

タイトル（英文）

RESPONSE CHARACTERISTICS OF REACTOR BUILDINGON WEATHERED SOFT ROCK GROUND

概要 （図表や脚注は「報告書全文」に掲載しております）

本研究は建屋地震入力および建屋－地盤間の相互作用特性に着目して建屋応答の面からみた風化軟質岩盤上の原子力発電所の耐震安定性について検討を行ったものである。ＰＷＲ建屋およびＢＷＲ建屋に対して，根入れ深さをパラメータとした解析を行った結果，建屋応答せん断応力は在来立地形式である岩着の場合を上回る場合があるものの，根入れを考慮した場合には許容値以下となっており，また，機器応答については，ほとんどのケースで岩着の場合の床応答スペクトル値を下回り，機器応答の面からも風化軟質岩盤上での原子力発電所立地の成立性が確認された。

概要 （英文）

THIS STUDY INVESTIGATED THE SEIMIC STABILITYOF NUCLEAR POWER PLANTSON WEATHERED SOFT ROCK GROUND WITH A FOCUS ON THE SEISMIC RESPONSE OF THE REACTOR BUILDING. HERE,SOFT ROCK GROUND REFERS TO WEATHERED SOFT ROCK WITH A THICKNESS OF SEVERAL TENS OF METERS OVERLYING HARD BEDROCK. UNDER THESE CONDITIONS,TWO SUBJECTS ARISE REGARDING ESTIMATION OF THE SEISMIC RESPONSE OF THE REACTOR BUILDING. ESTIMATION OF THE SEISMIC RESPONSE OF THE SURFACE GROUNDAND ESTIMATION OF THE SOIL-STRUCTURE INTERACTION CHARACTERISTICS FOR THE EMBEDDED STRUCTURE ONLAYERD GROUND WITH A LOW IMPEDANCE RADIO BETWEEN THE SURFACE GROUND AND UNDERLYING FOUNDATION. SEISMIC RESPONSE ANALYSES WERE CONDUCTED AND THE FOLLOWING WAS CLARIFIED. (1) ONE-DIMENSIONAL RESPONSE ANALYSES OF WEATHERED SOFT ROCK GROUND OVERLYING HARD BEDROCK WERE CONDUCTED WITH THETHICKNESS,SHEAR-WAVE VELOCITY AND NONLINEAR CHARACTERISTICS OF THE SURFACE -LAYER MATERIAL AS PARAMETERS. THE RESPONCE ACCELERATION PROVED TOBE LARGER THAN THE CASE FOR UNIFORM HARD BEDROCK. (2) A SIMPLIFIED S/R(SWAY AND ROCKING) MODEL,WHICH CONSIDERS THE SOIL-STRUCTURE INTERACTION FOR THE EMBEDDED STRUCTURE ON THE LAYERED GROUND,IS PROPOSED,AND ITS APPLICABILITY IS PROVED BY COMPARING THE RESULTS WITH THE EXACT MODEL.(3) USING THE OBSERVED WAVE (E+F WAVE) ,WHICH IS ESTIMATED TO BE THE SUM OF THE IMPINGING WAVE AND THE REFLECTING WAVE,THE ACCELERATION RESPONSE OF THE REACTOR BUILDING PROVED TO BE SMALLER THAN FOR THE HARD-ROCKSITE WHEN THE EFFECT OF EMBEDMENT IS TAKEN INTO ACCOUNT. THE SEISMIC STABILITY OF A NUCLEAR REACTOR ON SOFT ROCK GROUND IS SHOWN FROM THE OTHER RESPONSE QUANTITIES SUCH AS THE SHEAR STRESS OF THE STRUCTURAL MEMBER AND THE ACCELERATION RESPONSE SPECTRUM.

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