To prevent degradation at Nuclear Power Plants (NPPs) by maintenance activity, fatigue evaluation should be improved to be more accurate. Studies of crack growth under equi-biaxial fatigue which is caused by thermal stress have been conducted for these purposes. Previous study shows that crack growth rate under equi-biaxial stress is faster than under uniaxial one. But the comparison is not quantitative. In this study, the difference of crack growth rate between equi-biaxial and uniaxial is confirmed q...
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Study on the Behavior of Fatigue Crack Growth of Austenitic Stainless Steel under Equi-biaxial Stress

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

１．はじめに 事故時における原子力発電所の安全確保上重要なのは、一時的に喪失した安全機能をアクシデントマネジメント(AM)によりいかに早く必要なレベルまで回復できるかにある。そこで、原子力発電所の事故時における安全機能の信頼度を経年変化と保全の効果を取り入れて簡易かつ定量的に評価するため「レジリエンス指標」が提案され、その策定手法の開発が進められている。[1] 本研究では、レジリエンス指標を活用するため、低サイクル疲労による構造物損傷確率モデルを作成し、静的劣化要因に対する機器信頼性評価への適用性について......
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Study on Reliability Analysis for Degradation of Static Components in the Application 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)

In August 2004, a pipe rupture accident occurred at The Kansai Electric Power Company Mihama Unit3. Japan Society of Mechanical Engineers (JSME) recognized that it was an urgent problem to settle the rules on Pipe Wall Thinning Management by Fluid Flow. JSME enacted “rules on Pipe Wall Thinning“ that stipulates the basic requirements of pipe wall thinning management, considering from these situations. In 2006 , JSME enacted the “rules on Pipe Wall Thinning Management for PWR Power Plants” (JSME S NG1-2006...
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Analysis of Data on Pipe Wall Thinning Phenomena by Fluid FlowIn Pressurized Water Reactor Plant

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)

The resilience index has been proposed to evaluate the capability for recovering safety performance of systems subjected severe accident for nuclear power plants. In this study, a failure probability assessment model was developed for the resilience evaluation of static components in nuclear power plants. This model took into consideration the effect of material degradation caused by low-cycle fatigue. Crack initiation due to fatigue damage was assumed and its depth was determined from the magnitude of f...
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Development of Evaluation Method for Resilience Index in Nuclear Power Plant (Part 2: Development of Reliability Assessment Model Considering Degradation of Static Components)

Resilience index is proposed to be applied to evaluate the capability to recover safety performance of systems under severe accident of nuclear power plant. This study developed the failure probability model of equipment by low-cycle fatigue and applied the model to the reliability analysis for degradation of static components in resilience index, ...
英字タイトル:
Development of Resilience Evaluation Method for Nuclear Power Plant (Part 2: Study on Reliability Analytical Method for Degradation of Static Components)