We have developed a new index called Resilience index, which evaluate the reliability of system safety of nuclear power plant under severe accident by considering the capability to recover from the situation the system safety function was lost. In this paper, a detailed evaluation procedure for the Resilience index was described. System safety of a PWR plant under severe accident was then assessed according to the Resilience index concept to discuss applicability of the index. We found that the Resilie...
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Fundamental Study on Applicability of Resilience Index for System Safety Assessment

In this research, a new index “The Resilience Index” was proposed to evaluate the capability of nuclear power plant to recover from the situation of safety function lost. Three elements assumed to evaluate the resilience index are the achievement rate, necessary time, and probability of success of each accident management activity. The resilience index is expected to visualize the improvement of safety of each nuclear power plant against severe accidents. ...
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Development of Resilience Evaluation Method for Nuclear Power Plant (Part 1: Proposal of Resilience Index for Assessment of Safety of Nuclear Power Plant under Severe Accident)

We have developed a new index, called the resilience index, that evaluates the dynamic stability of the system safety of a nuclear power plant during a severe accident by considering the ability to recover system safety functions that have become lost in the situation. In this paper, a detailed evaluation procedure for the resilience index is described. The system safety of a PWR plant during a severe accident is then assessed according to the resilience index in order to discuss the applicability of ...
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Development of Resilience Evaluation Method for Nuclear Power Plants (Part 3: Study on Evaluation Method and Applicability of Resilience Index)

We have developed a new index, called the resilience index, that evaluates the dynamic stability of the system safety of a nuclear power plant during a severe accident by considering the ability to recover system safety functions that have become lost in the situation. In this paper, a detailed evaluation procedure for the resilience index is described. The system safety of a PWR plant during a severe accident is then assessed according to the resilience index in order to discuss the applicability of ...
英字タイトル:
Development of Resilience Evaluation Method for Nuclear Power Plants (Part 3: Study on Evaluation Method and Applicability of Resilience Index)

In this research, a new index “The Resilience Index” was proposed to evaluate the capability of nuclear power plant to recover from the situation of safety function lost. Three elements assumed to evaluate the resilience index are the achievement rate, necessary time, and probability of success of each accident management activity. The resilience index is expected to visualize the improvement of safety of each nuclear power plant against severe accidents. ...
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Development of Resilience Evaluation Method for Nuclear Power Plant (Part.1: Proposal of Resilience Index for Assessment of Safety of Nuclear Power Plant under Severe Accident)

Based on the fact that Hamaoka Nuclear Power Station is located in the hypocenter area of the Nankai Trough giant earthquake, we have voluntarily made efforts to improve safety, such as seismic margin improvement work, even before the occurrence of the Tohoku-Pacific Ocean Earthquake. Furthermore, after the Fukushima Daiichi accident, we have voluntarily continued risk reduction activities such as tsunami countermeasures and severe accident countermeasures. This time, we will introduce the outline of the sa...
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Safety measures of Hamaoka Nuclear Power Station

Two magnetic methods are proposed for the evaluation of initial degradations of type 304 stainless steel in stress corrosion cracking (SCC). The first one is the measurement of the distribution of chromium depletion by means of a magnetic force microscope (MEM). MEM observations are performed for some samples sensitized in various conditions, and the obtained results coincide with the expected ones from the chromium behavior. Moreover, the phase distributions in the solution-annealed and sensitized states a...
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Evaluation of Initial Degradation in Stress Corrosion Cracking by Magnetic Methods

Particularly, Since the on Fukushima the system Dai-ichi safety assessment accident, the of importance plants in operation, of “system the safety” various has degradation been recognized. aspects with transiti on of time ha been emphasized. Accordingly, functional degradation will be the assessment target, reliability and assessment the changes will in the be made safety on codes the consolidation and the concept of of important safety will functions be dealt under with; a where, system, the not on individ...
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Lessons & Learns from Fukushima Daiichi Accident and New Concept of System Safety on Nuclear Power Plants

Guided wave has been applied to a wide variety of non-destructive testing for a plate, bar and pipe, among others. In this study, we propose a wireless sensing system for the guided wave testing in structural components. The three-dimensional motion of the structural component can be visualized using the measured guided waves at a fixed position, which are individually excited at various positions. This method is based on the elastodynamic reciprocity theorem. Here, the validity of the visualization met...
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Visualization of Guided Wave Excited with Hammer and Identification of Propagation Mode

Since the Fukushima Dai-ichi accident, the importance of “system safety'' has been recognized anew. Particularly, system safety assessment of plants in operation from the various degradation perspectives, specifically, transition of time is very important. Accordingly, functional degradation will be the assessment target of degradation, and the changes in the safety standards and the concept of safety will be dealt with; where, the reliability assessment will be made on the consolidation of important func...
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Study of System Safety Evaluation on LTO of National Project - Functional Degradation and System Safety Assessment of Nuclear Plants in Operation