The purpose of this study is to investigate environmental effects on SUS316 in different strain rate condition. The fatigue tests were conducted under different strain rate (0.4%/s and 0.004%/s) in simulated PWR environment with interrupting tests and the effect of strain rate on crack growth rate was evaluated by the observation of test specimen surface. From the results of investigation, the followings were confirmed; ・The effect of strain rate on crack growth rate is larger in 0.004%/s than 0.4%/s. ・The ...
英字タイトル:
Environmental effect of stainless steel in PWR environment. (Investigation of Crack initiation and growth behavior by Replica Observation)

Nuclear power plants (NPPs) are required to ensure safety in long term operation under aging degradation. The fatigue degradation is one of the major ageing phenomena and is evaluated to ensure safety by design fatigue curve obtained by the results of axial fatigue test. On the other hand, the stress that occurs in piping element such as elbow is not uniaxial but biaxial. For accurate evaluation of fatigue crack growth, it is required to confirm the effect of biaxial stress. In this study, membranous pressu...
英字タイトル:
Study on the Behavior of Fatigue Crack Growth of Austenitic Stainless Steel Piping under biaxial Stress

The fatigue tests were conducted under different temperature (325℃ and 200℃) in simulated PWR reactor coolant condition with interrupting tests and replica-observation. By observing fatigue crack on the specimen surface, the effect of temperature on crack initiation and growth were studied. From the results of the fatigue tests, the followings were confirmed; ・The number of cycles that fatigue cracks initiate is almost the same in different temperature. On the other hand, the number of cracks that initiate ...
英字タイトル:
Influence of Temperature on the Fatigue Crack Initiation and Growth in Reactor Coolant Environment