In Japanese regulatory guide for seismic design of nuclear power plants, the combination of the design by the dynamic response analysis with design basis earthquake and the design by the design basis seismic static coefficient (DSC) is required. This paper proposes new static seismic design methodology with newly defined DSC derived from elastic-plastic time historical seismic response analysis of components and allowable ductility factor to prevent damage to components. The process of the seismic re...
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Diversification of Seismic Design of Components of Nuclear Power Plants with Improvement of Static Seismic Coefficient considering Ductility Factor

By using the FCVS technology, we had started to develop a high decontamination air cleaning system to remove multi-nuclides for radiation protection to conduct decommissioning the Fukushima NPP (Fig. 17). Development of high efficiency multi-nuclide aerosol filters for radiation protection during a process of cutting core debris at Hokkaido University. A plasma cutter, laser cutter, wire cutter, drilling machine, etc., will be used and will generate aerosols. Therefore, the air cleaning system should be...
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Development of a high efficiency multi-nuclide aerosol filters for radiation protection during a process of cutting core debris (1) Plan of this project

By using the FCVS technology, we had started to develop a high decontamination air cleaning system to remove multi-nuclides for radiation protection to conduct decommissioning the Fukushima NPP. High efficiency multi-nuclide aerosol filters for radiation protection during a process of cutting core debris has been developing at Hokkaido University. A plasma cutter, laser cutter, wire cutter, drilling machine, etc., will be used and will generate aerosols. Therefore, the air cleaning system should be neede...
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Development of a high efficiency multi-nuclide aerosol filters for radiation protection during a process of cutting core debris (2) Measurement of DF for Metal Fiber Filter

The Atomic Energy Society of Japan(AESJ) established an Investigation Committee on Development of Activity and Risk Evaluation Method for Faults by Engineering Approach. The Committee utilizes the most advanced scientific and rational judgement, and continuous discussions and efforts in the global field, in order to collect and organize these knowledges and reflect the global standards and nuclear regulations, such as risk evaluation method for the faults displacement and prevention of severe accidents, ...
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Risk Evaluation Method for Faults Displacement by Engineering Approach (1)The Outline on the Report of the Committee of AESJ and Application Concept of Margin Analysis Utilizing Accident Sequences

Studies have been carried out about fault displacements under the facilities as external hazard、 and risk evaluation method for influence on facilities by fault displacements using engineering approach、 _accident management” for domestic nuclear facilities. In this paper it shows the scenario of accident results in fault displacements directly under the nuclear power station causes loss of safety of the plant、 and shows risk evaluation method measures for the image of quantitative effect of risk reducti...
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Risk Evaluation Method for Fault Displacements by Engineering Approach (5)Measures for Risk Reduction by Accident Management

Japan, as a frequent earthquake country, has a responsibility to resolve efficient measures to enhance nuclear safety, to continue utilizing the nuclear power, based on the risks and importance levels in the scientific and rational manner. In his paper describes how to evaluate the risk of faults movement by engineering approach. An open fruitful discussion by experts in the various areas of earthquake, geology, geotechnical, civil, and a seismic design as well as other stakeholders such as academia prof...
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Risk Evaluation Method for Faults by Engineering Approach (1) Nuclear safety for accident scenario and measures for fault movement

Although Kashiwazaki-Kariwa Nuclear Power Station was affected by Chuetsu-Oki Earthquake, the important components in the reactor building were hardly damaged, and fundamental nuclear safety was ensured. However, as the mass communication media reported the pictures o f the black smoke of fire accident of the transformer, sloshing of the pool, etc. without declaration of “Safety“ by the Central Government or sufficient explanation, the habitants on the site and the Japan's people were put into anxiety and ...
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Necessity of Radiation Education Suggested from Press Report during Earthquake Damage ofKashiwazaki-Kariwa Nuclear Power Station

The tsunami generated by Great East Japan Earthquake caused the severe accident to the BWR plant of the Fukushima Dai-ichi Nuclear Power Station. This work considered how safety m easures with the re-operation application of the nuclear power plant contributed to the co re damage risk reduction caused by the tsunami using probabilistic risk assessment (PRA)....
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Examination of the safety measures in the nuclear power plant by tsunami level 1PRA

The high level maintenance technology has become necessary to increase a capacity factor of nuclear power plants. In a nuclear power plant, There are various kinds of troubles concer ning with pipes. One of them is a small leak from a small hole by liquid drop impingement erosion (LDIE). Even such a small leak, it was sometimes a cause of the plant trip and an eco nomical losses about 200M$ during several month outage, by operating a 1000MWe fossil power plant. We conducted a LDIE test by using a test spec...
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Pipe Wall wastage by Liquid Droplet Erosion and It's Countermeasure

Evaluation of wastage speed for nuclear power plant maintains plant reliability and power up rating is important. There are two main cause of wastage flow accelerated corrosion (FAC) and mechanical erosion. This study is to develop evaluating the wastage speed by liquid droplet impingement erosion (LDIE). LDIE oft en occurs at downstream of corner of pipe or orifice. In this study, the liquid drop impinging tests were conducted with the test pieces mounted on a high speed rotating disk that cross thin wate...
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Study on pipe wastage mechanism by Liquid Droplet Impingement Erosion