scholarly journals Seismic Probabilistic Risk Assessment of Nuclear Power Plants Using Response-Based Fragility Curves

2014 ◽  
Author(s):  
Ying-Hsiu Shen ◽  
Yin-Nan Huang ◽  
Ching-Ching Yu
Keyword(s):  
Risk Assessment ◽  
Boolean Algebra ◽  
Seismic Risk ◽  
Nuclear Power ◽  
Power Plants ◽  
Fragility Curves ◽  
Structural Response ◽  
Probabilistic Risk Assessment ◽  
Structural Components ◽  
Probabilistic Risk

Seismic probabilistic risk assessment (SPRA) has been widely used to compute the frequencies of core damage and release of radiation of a nuclear power plant (NPP). In 2011, Huang et al. (2011a, 2011b) published a SPRA methodology with the following characteristics different from the widely used Zion method: (a) seismic fragility curves are defined as a function of structural response parameters, such as floor spectral acceleration and story drift; (b) nonlinear response-history analysis is used to estimate statistical distributions of seismic demands for structural and non-structural components of NPPs; (c) Monte Carlo simulation is used to determine damage states of structural and non-structural components. In the study presented in this paper, the seismic risk of a sample NPP was evaluated using the methodology of Huang et al. (2011a, 2011b). The seismic risk was quantified using the annual frequency of unacceptable performance defined by a sample accident sequence for a sample NPP. The values of seismic risk computed using the methodology of Huang et al. (2011a, 2011b) and Boolean Algebra were compared to evaluate the accuracy and efficiency of the methodology of Huang et al. (2011a, 2011b). The two procedures generate similar risk values and the methodology of Huang et al. (2011a, 2011b) is more efficient than the procedure using Boolean Algebra.

Seismic Probabilistic Risk Assessment of Nuclear Power Plants: 10 CFR 50.69 Assumptions and Sources of Uncertainty

2018 ◽  
Author(s):  
Sara Lyons ◽  
Shilp Vasavada
Keyword(s):  
Risk Assessment ◽  
Seismic Risk ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Probabilistic Risk Assessment ◽  
Sources Of Uncertainty ◽  
Previously Treated ◽  
Risk Contribution ◽  
Probabilistic Risk

The U.S. Nuclear Regulatory Commission (NRC) promulgated Part 50.69 to Title 10 of the Code of Federal Regulations (CFR), “Risk-informed categorization and treatment of structures, systems and components for nuclear power reactors,” in November 2004 (hereafter referred to as 10 CFR 50.69). The rule provides a voluntary alternative to compliance with many regulations which require “special treatment,” or regulatory requirements which go beyond industrial controls, including: specific inspection, testing, qualification, and reporting requirements. The voluntary alternative includes a process for categorization of structures, systems, and components (SSCs) as having either low safety significance (LSS) or high safety significance (HSS). The categorization process can result in increased requirements for HSS SSCs which were previously treated as non-safety-related, and reduced requirements for LSS SSCs which were previously treated as safety-related. The categorization process includes plant-specific risk analyses which are used in combination with an integrated decision-making panel (IDP) to determine whether the SSC has a low or high safety significance. Seismic probabilistic risk assessment (SPRA) is one of the risk analyses options to account for the seismic risk contribution. Because the 10 CFR 50.69 rule has currently not been implemented widely, the significance of various SPRA assumptions and sources of uncertainty to the categorization process has had limited evaluation for a broad spectrum of U.S. nuclear power plants. This paper will assess the importance of certain aspects of the seismic risk contribution to the categorization process. NRC Standardized Plant Analysis Risk (SPAR) models will be used to perform sensitivity studies to quantify the impact of various assumptions and sources of uncertainty on the outcome of the categorization process.

A Review of Multi-Unit Nuclear Power Plant Probabilistic Risk Assessment Research

2018 ◽  
Author(s):  
Taotao Zhou ◽  
Mohammad Modarres ◽  
Enrique López Droguett
Keyword(s):  
Risk Assessment ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Reactor ◽  
Probabilistic Risk Assessment ◽  
Future Research ◽  
Risk Metric ◽  
A Site ◽  
Assessment Research ◽  
Probabilistic Risk

The events at the Fukushima nuclear power station drew attention to the need for consideration of risks from multiple nuclear reactor units co-located at a site. As a result, considerable international interests and research efforts have been dedicated to addressing the multi-unit risks over the past few years. This paper presents a review of the state-of-the-art multi-unit probabilistic risk assessment (MUPRA) of nuclear power plants. The concept of MUPRA is briefly presented and the relevant activities to address and develop methodologies are summarized including workshops, proceedings, projects and case studies. The paper presents different facets of MUPRA research, including multi-unit event, MUPRA modeling and site-based risk metric. The paper also identifies existing gaps and the need for future research.

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