米国におけるリスク情報の活用事例の中から特徴的なものを数点紹介する。...
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Examples of risk information utilization in the United States

NRRC (Nuclear Risk Research Center) is focusing on support of voluntary safety improvement activities of electric utilities. In this paper, several approaches to implement External Event PRA are described....
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Approach of NRRC for implementation of External Event PRA

For the quantitative evaluation of importance of maintenance and management to the piping in the turbine system and the feedwater system, an evaluation method of the piping failure frequency due to wall thinning, one of the major aging phenomena in the secondary and BOP systems, were developed. Based on the uncertainty of the thinning rate, initial thickness and material strength, frequency of the piping failure was evaluated probabilistically. As a trial evaluation, the difference of the failure frequency ...
英字タイトル:
Development of evaluation method of pipe failure frequency due to wall thinning

In the nuclear power plant under the severe accident, it is possible that the debris dust and the metallic powder are immixed in the coolant, and then the flow pattern can become the solid-liquid multiphase flow in the reactor coolant circulation system. In this study, the numerical analysis is conducted in order to evaluate the FAC profile in the piping under the solid-liquid multiphase flow. By using the FAC model, the mass transfer coefficient in the elbow was evaluated. The mass transfer coefficient bec...
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Piping System, Risk Management based on Wall Thinning Monitoring and Prediction (3) Evaluation of Wall Thinning Profile by Flow Accelerated Corrosion under Solid-Liquid Multiphase Flow

The water of Suppression pool at severe accident has become a hot, high chloride ion concentration and strong alkaline because of exhaust of the reactor heat, the melted cable, and pH controller. The equipment using the water has wetted part made stainless, therefore there is a possibility that SCC because of chloride ion occurs this wetted part. However, alkaline environment may reduce a possibility the SCC although poor knowledge. As such we examined the effect of structural material in a hot, high chlori...
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Effect assessment of structural material in a hot, high chloride ion concentration, and strong alkaline environment

Aging management technical evaluation (AMTE) is required for LWRs every 10 years at and after 30 years operation in Japan. Result of the AMTE is put into plan of a long-term maintenance program of each plant. Methods for implementation of aging management measures were set forth in “Code on Implementation and Review of Nuclear Power Plant Ageing Management Programs” of Atomic Energy Society of Japan. Technical basis of material aging evaluations in the standard are described in this paper....
英字タイトル:
Technical Basis of Material Aging Evaluation in the Aging Management Technical Evaluation