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Ōsaka, Japan

Horikawa Y.,Nuclear Engineering Ltd | Uragami M.,Kansai Electric Power Co. | Waki T.,Kansai Electric Power Co.
International Congress on Advances in Nuclear Power Plants, ICAPP 2013: Nuclear Power - A Safe and Sustainable Choice for Green Future, Held with the 28th KAIF/KNS Annual Conference | Year: 2013

The dominant radioactive solid wastes generated from nuclear power plants in Japan have been disposed of at the low-level waste disposal facility. These wastes contain two kinds of waste packages; homogenous wastes that liquid concentrates are solidified with cement or asphalt in drums, and solidified dry active wastes that non-combustible wastes are embedded with mortal in drums. Incinerator ashes which are produced by incineration of combustible wastes such as paper, clothes, etc. are placed in drums. Spent liquid filters and spent air filters are placed in drums or containers. These drums are stored in the on-site storage facilities. Replaced steam generators and other large-volume solid wastes are placed in depository. Replaced control rods, channel boxes, etc. are stored in spent fuel pools and spent ion exchange resins are stored in tanks. These wastes should be conditioned and treated in compliance with the technical standards for Safety Verification of Radioactive Waste Package for disposal. In this paper the pre-disposal treatment of radioactive wastes generated from nuclear power plants is discussed. Source

Narumiya Y.,Kansai Electric Power Co. | Kuramoto T.,Nuclear Engineering Ltd
International Conference on Nuclear Engineering, Proceedings, ICONE | Year: 2012

The safety of NPPs has to be maintained in any condition which has to be considered. Rational criteria are especially needed for adequate classification of external hazards. Characteristics of external hazards, e.g. Tsunami, Earthquake, Land slide etc, are changed by features of the site. It is necessary to make a rational and clear process of classification to appropriate method of risk assessment. This study treated of various external hazards included natural phenomena and man-made events. Much disaster information was gathered from historical documents these one thousand and five hundred years (1). Published standards of US and IAEA were referred. This study provided some viewpoints for classification, e.g. hazard frequency, range of impact, basic design, and difficulty of accident management etc. The classification included several paths; a full-scope PRA, a hazard analysis, or a comparison between an impact of the hazard and the design condition against it. Copyright © 2012 by ASME. Source

Chigusa N.,Kansai Electric Power Co. | Narumiya Y.,Kansai Electric Power Co. | Kuramoto T.,Nuclear Engineering Ltd
International Topical Meeting on Probabilistic Safety Assessment and Analysis 2011, PSA 2011 | Year: 2011

This paper discusses the development of the quantitative method to evaluate the reliability for the maintenance plan with respect to the risk impact both for Core Damage Frequency and Plant Trip Frequency. The quantitative approach includes the considerations for the effect of the Condition Based Maintenance (CBM) changing in addition to the Time Based Maintenance (TBM), and the reliability for the maintenance plan is evaluated using the actual plant-specific maintenance information collected in the plant. In this study, overhaul and surveillance test for the components are considered as TBM. The objective components should include "Prevention System (PS)" in addition to "Mitigation System (MS)". Therefore, in this quantitative reliability evaluation, it is necessary to cover both PS and MS, and the Plant Trip Frequency in addition to Core Damage Frequency should be introduced as the risk index. The conventional PSA method is enough to confirm the plant overall risk level and the risk profile, however, this quantitative approach should have the extended method such as extension of the objective component sphere and detailed analysis for the component failure data. In this paper, the developed method to evaluate the reliability for the maintenance plan using the risk information is described. And, the tested evaluation to confirm the effectiveness of this quantitative method is also described. And furthermore, the requirements for the plant-specific maintenance information to be used in this quantitative method are described. Source

Tatsumi M.,Nuclear Engineering Ltd | Chiba G.,Hokkaido University
Journal of Nuclear Science and Technology | Year: 2014

As the basis and fundamentals of nuclear technology, reactor physics has an important role to play; recent requirements for reliability and accountability to realize a higher level of safety have been encouraging researchers and engineers to study and develop more advanced and sophisticated numerical methods and calculation codes. Many of the outstanding research and developments are presented in scientific journals, including the Journal of Nuclear Science and Technology. Some topics have been covered in this summary from the latest activities in the field of reactor physics. © 2014 Atomic Energy Society of Japan. Source

Nuclear Engineering Ltd. | Date: 2008-11-06

Eddy current sensors.

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