Development of Resilience Evaluation Method for Nuclear Power Plant
Preface
After Fukushima Daiichi nuclear power plant accident, the capability accident management (AM) to recover the important safety functions as soon and high as possible was recognized as the important assessment for safety of nuclear power plants (NPPs).
The AM capability of nuclear power plants to recover their safety function should be assessed considering the time-change of situation based on the accident scenario. It is important to evaluate the safety function can be recovered or not to the necessary minimum state before a deadline finally leading to a severe accident.
“Resilience” means a capability to recover or restore to original state. We will think that the “Resilience” for NPP is the capability of AM to recover lost safety function such as the decompressing function or the core cooling function, and so on.
These 4 series papers introduce “the Resilience Index” that the Maintenance Index Working Group of Japanese Society of Maintenance has developed for NPPs’ AM capability assessment concerning especially each topic;
Basic Concept of Resilience Index
Reliability Assessment of Degradation of Static equipment
Test Evaluation of Resilience Index for PWR
System safety of operating NPPs
This new index will be useful to evaluate the impact of maintenance activity and to suggest improvements of maintenance protocols in order to increase of system safety.
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 analys
We have developed a new index called Resilience index, which evaluate the dynamic stability 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 Resilience index successfully visualize the management capability, and therefore, resilience capability of a nuclear power plant.
We have developed a new index called Resilience index, which evaluate the dynamic stability 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 Resilience index successfully visualize the management capability, and therefore, resilience capability of a nuclear power plant.
The total system design on Nuclear Plant ensures “Nuclear safety” with making practically achievable efforts to prevent and mitigate nuclear and radiological accidents. The performance based system design with “Defence in depth (D-I-D)” has been laid out as the key means in “preventing accidents”, “controlling escalation to serious consequences”, and “preventing harmful consequences to the public”. D-I-D is extended to the management of severe accidents, and is an approach intended to provide protection against the development of a wide variety of events by means of redundant, diverse and independent protective barriers. It is crucial to maintain plant integrity with mass quantity of radioactive material present in reactor core, against potential consequences (risk) on people and the environment caused by external hazards, particularly, earthquake and tsunami. The fundamental approach on D-I-D is to address uncertainties by means of successive measures, so that if one measure fails, other, or subsequent measure will be available to ensure safety. Risk analysis should be conducted to validate and enhance reliability of the defence
EJAM Vol.8 p.23-42 Academic Articles Special Issue on "Development of Resilience Evaluation Method for Nuclear Power Plan by Maintenance Index Subcommittee"
Measures for Tsunami Striking Nuclear Power Station in Japan
Planning and Consideration on SFR R&D Activities in China
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