RF tags that are implemented RFID technology as tag has been used in various fields. Tags have been developed, such as resistance to chemic als and high temperature resistant RF tags are also used in specialized fields. The RF tag apply to the existing nuclear field, had been co ncerned about the effects of radiation to the RF tags. Now, since the RF tag with a goal to develop radiation-proof, we have examined, such as applying for maintenance of nuclear facilities under radiation environment. We report t...
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Application to the conservation of RF tags in the radiation environment

The application status of risk information in the area of operation and maintenance at US and European nuclear power plants has been reviewe d. In the US, risk-informed activities have become ingrained in nuclear power plant operation and maintenance over the past 15 years, provid ing both safety and operational benefits. In addition to the many US plants, Risk-Informed inservice inspection (RI-ISI) and On-Line Mainten ance have been utilized in many of the European nuclear power plants, especially at the ...
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Risk and Maintenance : Application to Nuclear Power Plants in Foreign Countries

This study focuses on the nuclear power plant capacity factor and safety regulation in two cases; first, long-term trend of capacity factor and evolution of safety regulation in the U. S as well as comparison with Japanese regulation, second, short-term fluctuation of capacity factor and the regulatory actions in late 1990’s in the U. S., to find regulatory impact on capacity factor. Some factors requisite for effective regulation are identified from these case studies....
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Case Study of Regulatory Impact on Nuclear Power Plant Capacity Factor

Technical codes and standards on natural phenomena, in particular, earthquake and tsunami for nuclear power plants in the other developed countries including IAEA safety standards were investigated. Then, the results were compared wi th the corresponding Japanese technical codes and standards. As a result, it was found that: (1) technical codes and standards on natural phenomena, especially those for earthquakes and tsunami/flooding in those foreign countries and their requirements are all included in the ...
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Investigative study on the technical code requirements of natural eventshazards for nuclear power plants

Residual stress by welding would be one of the most significant factors in evaluating failure probabilities of PLR piping since the SCC growth behavior is strongly affected by residual stress distribution. The residual stress distribution is well known to ch ange caused by varying of welding conditions such as groove shape, electrical voltage and current, inter-pass temperature, etc. Therefore, to evaluate the scatter of welding condition and their influence on residual stress is important to assess the st...
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Probabilistic Structural Integrity Assessment of Reactor Coolant Pressure Boundary Piping-1- The Scatter of Welding Conditions and Welding Residual Stress -

Stress corrosion cracking (SCC) in primary loop recirculation piping made of austenitic stainless steel has been observed near welding joints. The SCC grows near the welding zone mainly due to high tensile residual stress by welding as well as the other contributing f actors of material and environment. The residual stress analysis due to welding of austenitic stainless piping is important and has been already conducted by many researchers. In present work, the effect of scatters of welding conditions such...
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Probabilistic Structural Integrity Assessment of Reactor Coolant Pressure Boundary Piping-2- Residual Stress Analyses of the Effect of Scatter of Welding Conditions -

A probabilistic fracture mechanics (PFM) analysis code PASCAL-SP, which evaluates failure probabilities at welded joints in piping where being susceptible to stress corrosion cracking (SCC), h as been developed. This code is based on Monte Carlo simulation technique and Japanese code related to the SCC evaluation. Uncertainties and scatters of welding residual stress distribution we re modeled using database obtained from parametric FEM analyses. Sensitivity analyses concerning uncertainties and scatters o...
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Probabilistic Structural Integrity Assessment of Reactor Coolant Pressure Boundary Piping-3 - Probabilistic Fracture Mechanics Analyses Concerning Welding Residual Stress Distribution -

The nuclear reactor regulation law was amended three years ago (2012). In this amendment, the operation period of the commercial nuclear power plants in Japan was limited to 40 years. This limit may produce various problems in plant life management. So this paper proposes several recommendations for improvement. ...
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Recommendations related to the Problem of Limiting the Life of Japanese Nuclear Plants to 40 Years

１．欧州ストレステストの実施欧州理事会（年4回開催されるEU（欧州連合）の首脳会議）は2011 年3 月の福島事故後、以下の決定を行った。・ EU における全原子力発電所の安全性を、包括的で透明性のあるリスク及び安全評価（ストレステスト）としてレビューすること。・ 欧州原子力安全規制者グループ（ENSREG）及び欧州委員会（EC）は、ストレステストの範囲や様式を作成すること。・ 独立した国別の規制機関及びピアレビューにより評価を行うこと。・ 結果や講じるべき対策についてEC 及びENSREG 内で共有......

AI application examples in the field of nuclear power maintenance in the United States (US) and Europe were investigated from publicly available information. Various tools and software utilizing digital technology such as IoT and AI are being developed by manufacturers and IT vendors, and their application has begun in some nuclear power stations in Europe and the US. AI technology is being applied to power generation, transmission and distribution facilities including nuclear power plants in the US and Eur...
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Application of AI technology in the Maintenance at Western Nuclear Power Plants