The purpose of this study is to investigate environmental effects on low cycle fatigue crack growth rate of SUS316 in different strain rate condition. The fatigue tests were conducted under different strain rate (0.4%/sec and 0.004%/sec) in simulated PWR environment with interrupting tests and the surface of specimens was observed. By the investigation of fatigue cracks growth, the effect of strain rate on crack growth rate was evaluated. From the results of tests, the followings were confirmed; ・Fatigu...
英字タイトル:
Influence of Strain Rate on Fatigue Crack Growth in SUS316 under Reactor Coolant Environment

JRR-3(Japan Research Reactor No.3) is a light water moderated and cooled, heavy water reflected, pool type research reactor with maximum thermal power of 20MW. The reactor is the first domes tic research reactor in Japan, and first criticality was attained in 1962. The large scale modification of the reactor was carried out for the year 1985-1990. As the modified JRR-3 has been operated for 18 years, it is necessary to be maintained for keeping the safe and stable operation. The review of maintenance activ...
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Maintenance activities of instrumentation control device at JRR-3

The maintenance evaluation for research reactors has been obligated in Japan from 2004 as for power reactors. JAEA (Japan A tomic Energy Agency) has started to evaluate the maintenance for own research reactors on 2004. In this paper, we report th e present status of the maintenance for JRR-3(Japanese Research Reactor No.3), as well as the linear evaluation methods use d. It is found that a series of preventing maintenance task on equipment and building of the reactor is properly performed....
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Assessment of Preventing Maintenance on Japanese Research Reactor JRR-3

To prevent degradation at Nuclear Power Plants (NPPs) by maintenance activity, fatigue evaluation should be improved to be more accurate. Studies of crack growth under equi-biaxial fatigue which is caused by thermal stress have been conducted for these purposes. Previous study shows that crack growth rate under equi-biaxial stress is faster than under uniaxial one. But the comparison is not quantitative. In this study, the difference of crack growth rate between equi-biaxial and uniaxial is confirmed q...
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Study on the Behavior of Fatigue Crack Growth of Austenitic Stainless Steel under Equi-biaxial Stress

Various activities were doing for the decommissioning of Fukushima Daiichi nuclear power station. In present, activities are limited by remote operation or short time manual operation, because these areas are still high radiation rate. In this situation, it is expected to reduce the radiation rate of these areas by the decontamination, shielding and removal radiation souses, et al. At the national project “Development of remote decontamination technology for reactor building”, we selected adoptable de...
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Development of Remote Dry-ice Blast Decontamination Vehicle for the lower part of the Reactor Building such as floor and wall

The research and education program “Advanced Research and Education Program for Nuclear Decommissioning (ARED)” is proceeded in Tokyo Tech with views to sustainable development of human resources having advanced knowledge and experiences concerning decommissioning engineering, and development of advanced technologies to resolve a number of complicated challenges. This paper reports about the present status of the development of human resources. ...
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Human resource development for the research and education program in Tokyo Tech

Non-destructive examination (NDE) methods for joint interfaces between different materials in high heat flux components of ITER divertor should be urgently developed to assure qualit y and reliability of joining techniques. This paper reports the present R&Ds status of NDE for ITER divertor and its outlook. The detection ability of joint defect by using ultrasonic wave and thermography NDE are examined in the joint interface between armor tiles and a cooling tubes of divertor mock-ups. The results of both ...
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Development of Non-destructive technique for ITER divertor high heat flux component

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℃...
英字タイトル:
Influence of Temperature on the Fatigue Crack Initiation and Growth in Reactor Coolant Environment

1.はじめに 現在、原子力発電所においては経年劣化による設備の 機能喪失を防ぐため保全活動が行われている。プラント 機器の保全において疲労の累積を予測し損傷の防止を図 ることは事故防止につながる重要な活動である。疲労累 積評価は単軸試験で得たデータを基にして作成された設 計疲労曲線を用いて行われている。設計疲労曲線による 評価はもともと機器の設計に用いる目的で作られている ため、運転中の機器の実際の疲労累積状態や余寿命の評 価が難しいという課題がある。 そこで、実機の疲労累積状態を仮想的なき裂の長さに 置......
英字タイトル:
Evaluation of Micro Fatigue Crack Growth under Equi-biaxial Stress by Membranous Pressure Fatigue Test