Thermal embrittlement of cast austenitic stainless steel components from the decommissioned advanced thermal prototype reactor Fugen has been characterized. Cast stainless steel materials were obtained from recirculation pump casing. The actual time at temperature for the materials was 138,000 h at 275 oC. The “Fugen” material show modest decrease in Charpy-impact properties and a small increase in micro-Vickers hardness in ferrite phase because of thermal aging at relatively low service temperatures. ...
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Research of Estimation Method of Thermal Aging Embrittlement on Cast Austenitic Stainless Steel

１．はじめに地震リスク情報の一つで、予想最大損失額を表す地震PML（Probable Maximum Loss）1)は、そもそも米国の保険情報の一つとして発展したが、わが国では証券化資産（オフィスビル、商業施設、賃貸マンション、ホテル、倉庫など）の地震リスク診断として一般化が進み、一定の市民権を得るに至っている。最近では、設計・計画時にPMLの下限値を指定することが、施工主の要求事項の一つに組み入れられるケースも増えている。一方、製造業の地震防災対策や事業継続計画（BCP；Business Conti......

One year has passed since Electronic Journal of Advanced Maintenance (EJAM) was started on the website of Japan Society of M aintenology (ISM) May 25“, 2009. “New Technology' (NT) is one of the EJAM categories, and introduces widely advanced techniqu es developed or modified for maintenance. Twenty-two NT articles have been introduced on EJAM website so far as of May 25t“, 2010. This report describes the concept of NT, general features of NT articles, actual performance and future wishes for NT....
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Current Status of EJAM ‘New Technology

It has been clarified that the fatigue life is reduced in the fatigue test of high-temperature and high-pressure water that simulates PWR reactor coolant environment compared to that in the tmosphere, and temperature, strain rate，etc. affect the decrease of fatigue life. In this study, the influence of crack growth behavior on fatigue life of SUS316 in simulated PWR reactor coolant environment of different temperature was investigated. Fatigue tests were conducted under different temperatures (325℃ and 200℃...
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Influence of Temperature on the Fatigue Crack Initiation and Growth in Reactor Coolant Environment

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 ...
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Influence of Temperature on the Fatigue Crack Initiation and Growth in Reactor Coolant Environment

Cumulative Usage Factor (CUF) is currently used for fatigue design and management to prevent fatigue failure. Fatigue damage is evaluated by CUF but CUF doesn’t show the real extent of fatigue damage and cannot be used for probabilistic index for risk assessment. Therefore, in order to clarify relation between CUF and damage state, the introduction of postulated crack growth curve (P-curve) of stainless steel was examined by Kamaya [1]. This curve was defined by single crack growth curve made from fati...
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Study on Fatigue Crack Growth Prediction Model of Carbon Steel based on Surface Observation of Fatigue Test Specimen

This study carried out uniaxial tension fatigue tests of Ti-6Al-4V focusing on sub-surface fractures in very high cycle regime. Crack growth properties in high vacuum were also investigated to simulate sub-surface crack propagation, which is kept away from atmosphere in principle. F racture surfaces were closely compared between the sub-surface crack and the crack propagated in vacuum. As a result, it was clarified that crack growth rate in vacuum was much lower than that in air, which corresponded to long...
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A Mechanism of Sub-Surface Crack Growth in Very High Cycle Fatigue

We have developed a new diagnostic technology for rotary mechanical systems by multiplex analysis of current signals of three-phase induction motors. Since the current signal is measured from the electric panel of the electric room, the state monitoring diagnosis of the rotary mechanical system such as the dangerous area can be done easily, safely and accurately. We also built a remote and on-line monitoring and diagnostic system with current signals using IoT and cloud. This diagnostic technology and its I...
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Introduction of Diagnosis Technique using current information and its IoT・Cloud efforts