Evaluation procedure of earthquake resistant safety tolerance accompanied with elapsed change of apparatus piping system

For a piping model introduced a defect formation into the piping through elapsed degradation, four points supported flexural and vibration tests were conducted to elucidate differences of fracture states due to degraded shapes, changes in response to earthquake in piping system due to presence or absence of degraded portion, and so forth. As a result, by element test simulated with elapsed degraded shapes formation in actual plant, fractured shapes against each degraded shapes could be confirmed. And, as a result of comparison with evaluation for the obtained experimental results due to stress reference at actual cross section, an evaluation that the moment forming leakage at the piping was in dangerous side was obtained. (G.K.)