報告書番号

N08003

タイトル（和文）

2007年新潟県中越沖地震を踏まえた原子力発電所における埋設消火配管の継手性能評価

タイトル（英文）

Performance Evaluation on Jointed Fire Pipes Buried Underground in A Nuclear Power Plant as A Lesson Learned from The 2007 Niigata-ken Chuetsu-oki Earthquake

概要 （図表や脚注は「報告書全文」に掲載しております）

本報告は、原子力発電所における埋設消火配管の継手性能について、4点曲げ載荷実験と有限要素解析、弾性床上のはり理論に基づき検討したものである。対象とした継手は、溶接継手、フランジ継手、ねじ継手、カップリング継手である。4点曲げ載荷実験の結果、溶接継手やフランジ継手は機械式継手の一つであるカップリング継手に比べて5倍の最大曲げ耐力を有していることが示された。また、4点曲げ載荷実験と溶接継手を対象とした有限要素解析から、送水機能喪失の目安となる各継手の内圧の保持限界状態を明らかにした。さらに、弾性床上のはり理論を用いて各継手が内圧保持限界にいたる地盤変位を算出し、その結果、溶接継手はカップリング継手やねじ継手に比べて5倍程度の地盤変位吸収能力を有していることが明らかとなった。

概要 （英文）

The present study discusses strength and capacity to accommodate ground displacement of jointed fire pipes. For this purpose, a bending test, a finite element analysis and an elastic beam theory analysis were conducted. The bending experiments were conducted for four types of actually used joints, namely a welded joint, a flange joint, a screw joint and a coupling joint. The relationships between the bending moment and the rotation angle at the joint were investigated based on the experimental results. As a result, the welded joint and the flange joint had a significant load capacity if compared with the couple joint. The ratio of the load capacity of the coupled joint to the welded joint was about five times. Furthermore, the bending moment and the rotation angle were identified when the inner pressure of water became the atmospheric pressure based on the bending experiment. In addition, the limit state of the welded joint was determined based on the finite element analysis result. Finally, capacities to accommodate ground displacement for respective joint were estimated based on the elastic beam theory. Consequently, the displacement capacity of the welded joint was more than about five times that of the coupling and screw joints.

報告者

キーワード