平成 19 年 7 月 19 日午前 10 時 13 分頃、新潟県中越沖においてマグニチュード 6.8 の地震が発生し、東京電力柏崎刈羽原子力発電所においては各号機で設計時の応答加速度を超える最大加速度を記録したが、耐震重要度 S クラス機器に損傷は確認されなかった。耐震重要度 B クラス機器については、一部機器に軽微な損傷が確認された。耐震重要度 C クラスの機器については、建屋間を接続する又は建屋外で変位が生じた地盤に設置された機器で影響が確認された。 損傷が確認された耐震重要度 C クラスの機器に共通する点は、地震により機器が設置されている地盤に変位が発生したことである。したがって、上位の耐震重要度機器への波及的影響防止の観点から、屋外に設置する耐震重要度の低い設備については、事後保全設備として管理できるが、設置状況に応じて地震による変位防止対策又は変位緩和対策を図ることが、設備保全上、最適な防護戦略と言える。...

At the Rokkasho Reprocessing Plant, we will continue our comprehensive and optimal maintenance management improvement activities referring to the concept of maintenance management conducted at the nuclear power plant (maintenance management regulations for nuclear power plants: JEAC 4209) It has been implemented. In this lecture, we will introduce the current status and future plans of maintenance management improvement at the Rokkasho Reprocessing Plant....
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Maintenance management improvement efforts at the Rokkasho Reprocessing Plant

Rokkasho Reprocessing Plant, the only commercial reprocessing facility in Japan, was applied for the approval of reprocessing business change to follow the new regulatory requirements on January 7, 2014. After several times of corrective applications, the end of the conformity review is nearing. In order to improve the safety of facilities, we are adding measures for earthquake, tornado, volcano, overflow, etc., as well as trying to strengthen measures for lightning strike, internal fires, external fires, e...
英字タイトル:
Summary of Conformity Review on New Regulatory Requirements for Rokkasho Reprocessing Plant

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...
英字タイトル:
Diversification of Seismic Design of Components of Nuclear Power Plants with Improvement of Static Seismic Coefficient considering Ductility Factor

This paper proposes new static seismic design methodology with newly defined DSC derived from elastic-plastic time historical seismic response analysis of the components and allowable ductility factor to prevent damage to components. The process of the seismic response analysis to obtain the ductility factor considering load-deflection characteristic of components, definition of the allowable ductility factor based on the actual experiences and the activities for a decision of Guidelines for Seismic Design...
英字タイトル:
Activities for a decision of Guidelines for Seismic Design with Static Seismic Coefficient considering Ductility Factor

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 response analysis to obtain the ductility factor considering load-deflection characteristic of components and definition of the allowable ductility factor based on the actual experiences are also described. Furthermore, trial analysis of the DSC for ac...
英字タイトル:
The seismic design example for the Specialized Safety Facility with Static Seismic Coefficient Procedure considering Ductility Factor

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

The Niigata-Nen Chuetsu-ONi EarthquaNe occurred in 2007 with a hypocenter very close to KashiwazaNi-Kariwa Nuclear Power Station of ToNyo Electric Power Company Holdings, Inc.. TEPCO’s subsequent plant investigation, earthquaNe response analysis using observation records and large-scale shaNing table tests have provided us valuable experiences, including the fact that safety related components were undamaged and non-safety-related components sustained only limited damage. The FuNushima Daiichi (1F) acc...
英字タイトル:
The knowledge got suffering situation of Nuclear Power Plants in 2007 Niigata-ken Chuetsu-Oki Earthquake and 2011 Great East Japan Earthquake

Spent fuel storage pools keep pool water by lining plate installed in inner surface. For the continuous maintenance method of those lining plate, the necessity occurs to quickly develop underwater repair welding technology. So, we are decided to develop new underwater welding method that is able to conquer those problems. In this paper, we report the concept of new welding method and results of confirmation examination for formation of new welding method by practical use conditions....
英字タイトル:
Development of High Reliable Welding Method with Underwater Laser Welding Technology for Stainless Steel Made Structures Installed in Underwater

The Niigata-Nen Chuetsu-ONi EarthquaNe (the NCO EarthquaNe) occurred in 2007 with a hypocenter very close to KashiwazaNi-Kariwa Nuclear Power Station. Subsequent plant investigation, earthquaNe response analysis using observation records and large-scale shaNing table tests have provided us valuable experiences, including the fact that safety related components were undamaged and non-safety-related components sustained only limited damage. In the FuNushima Daiichi / Daini Nuclear Power Stations affected by...
英字タイトル:
Application of “Defense in Depth” for seismic design of the components in the Nuclear Power Plant