Impact of structural aging on seismic risk assessment of reinforced concrete structures in nuclear power plants

Ellingwood, Bruce R.; Song, Jong‐Keol

doi:10.2172/219359

Cited by 11 publications

(4 citation statements)

References 18 publications

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“…Sources of uncertainty must be considered in risk‐informed decision making based on PRA (Ellingwood & Song, ). A probabilistic model provides the framework for analyzing the sources of uncertainties.…”

Section: Assessment Of Food Insecurity In Gilroy Camentioning

confidence: 99%

Understanding Community Resilience from a PRA Perspective Using Binary Decision Diagrams

2019

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Probabilistic risk assessment (PRA) is a useful tool to assess complex interconnected systems. This article leverages the capabilities of PRA tools developed for industrial and nuclear risk analysis in community resilience evaluations by modeling the food security of a community in terms of its built environment as an integrated system. To this end, we model the performance of Gilroy, CA, a moderate-size town, with regard to disruptions in its food supply caused by a severe earthquake. The food retailers of Gilroy, along with the electrical power network, water network elements, and bridges are considered as components of a system. Fault and event trees are constructed to model the requirements for continuous food supply to community residents and are analyzed efficiently using binary decision diagrams (BDDs). The study also identifies shortcomings in approximate classical system analysis methods in assessing community resilience. Importance factors are utilized to rank the importance of various factors to the overall risk of food insecurity. Finally, the study considers the impact of various sources of uncertainties in the hazard modeling and performance of infrastructure on food security measures. The methodology can be applicable for any existing critical infrastructure system and has potential extensions to other hazards.

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Section: Assessment Of Food Insecurity In Gilroy Camentioning

confidence: 99%

Understanding Community Resilience from a PRA Perspective Using Binary Decision Diagrams

2019

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“…1, a PWR that was widely reviewed in various independent risk studies. The core damage was represented by a simple Boolean expression in this study to assess the risk significance of the structural degradation of the reinforced concrete beams and shear walls [Zion, 1981;Ellingwood and Song, 1996]. It was concluded that aging of structural components that appear as singleton cutsets in the plant logic has a minimal impact on core damage frequency due to seismic events (less than a factor of 2).…”

Section: Literature Review For Dac Developmentmentioning

confidence: 99%

A Procedure for Determination of Degradation Acceptance Criteria for Structures and Passive Components in Nuclear Power Plants

Nie¹,

Braverman²,

Hofmayer³

et al. 2012

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The Korea Atomic Energy Research Institute (KAERI) has been collaborating with Brookhaven National Laboratory since 2007 to develop a realistic seismic risk evaluation system which includes the consideration of aging of structures and components in nuclear power plants (NPPs). This collaboration program aims at providing technical support to a five-year KAERI research project, which includes three specific areas that are essential to seismic probabilistic risk assessment: (1) probabilistic seismic hazard analysis, (2) seismic fragility analysis including the effects of aging, and (3) a plant seismic risk analysis. The understanding and assessment of age-related degradations of structures, systems, and components and their impact on plant safety is the major goal of this KAERI-BNL collaboration. Four annual reports have been published before this report as a result of the collaboration research: This report describes the research effort performed by BNL and KAERI for the Year 5 scope of work. The goal of this effort is to develop a procedure for determination of degradation acceptance criteria (DAC) for structures and passive components in nuclear power plants. This report covers the identification of an acceptable risk criterion, the development of a general procedure for three-tier DAC, determination of three-tier DAC for a condensate storage tank (CST), and insights on how to apply these DAC in inspection/maintenance planning. The development of DAC for the CST considers five degradation cases: (A) degraded stainless tank shell; (B) degraded anchor bolts; (C) anchorage concrete cracking; (D) a perfect correlation of the degradation scenarios A, B, and C; and (E) a non-perfect correlation of the three degradation scenarios. These degradation cases are the same as those considered in the seismic fragility analyses of the CST with degradations in the Year 3 and Year 4 studies. The effect of degradation on the fragility capacity as well as on the uncertainties was considered in the DAC development. A necessary and very important part of the Year 5 research is the probabilistic safety/risk analyses performed by KAERI to calculate the core damage frequencies (CDFs) for a range of fragility capacities of the CST, which correspond to the undegraded and various degraded conditions of the CST.This report also includes an extended summary of the seismic fragility analyses of the CST with age-related degradations and three additional seismic fragility analyses to facilitate the development of various DAC and discussions in this report.

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“…This representation of the seismic fragility facilitates the development of an entire series of fragility curves for various levels of uncertainties. The seismic fragility analysis method based on this double lognormal model has been well studied and documented in the literature [e.g., Ellingwood, 1994, Ellingwood and Song, 1996, Kaplan, et al, 1989, Kennedy, et al, 1980, Kennedy and Ravindra, 1984.…”

Section: Overview Of Seismic Fragility Analysismentioning

confidence: 99%

“…Degradation of an SPC, often observed as loss of cross section or cracking, reduces the strength of the SPC and consequently causes the median fragility to decrease. However, the level of degradation may not affect the median fragility in a linear fashion, due to the dynamic nature of the seismic responses and also possibly the nonlinear behaviors of the SPC [Ellingwood and Song, 1996]. Since the degradation phenomena of SPCs have a significant amount of uncertainty and the knowledge for the development of the degradation models is not perfect, the uncertainty measures β R and β U increase as the SPCs age.…”

Section: Seismic Fragility Analysis Of Degraded Spcsmentioning

confidence: 99%

Seismic Fragility Analysis of a Condensate Storage Tank with Age-Related Degradations

Nie

Braverman

Hofmayer

et al. 2011

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The Korea Atomic Energy Research Institute (KAERI) is conducting a five-year research project to develop a realistic seismic risk evaluation system which includes the consideration of aging of structures and components in nuclear power plants (NPPs). The KAERI research project includes three specific areas that are essential to seismic probabilistic risk assessment (PRA): (1) probabilistic seismic hazard analysis, (2) seismic fragility analysis including the effects of aging, and (3) a plant seismic risk analysis. Since 2007, Brookhaven National Laboratory (BNL) has entered into a collaboration agreement with KAERI to support its development of seismic capability evaluation technology for degraded structures and components. The collaborative research effort is intended to continue over a five year period. The goal of this collaboration endeavor is to assist KAERI to develop seismic fragility analysis methods that consider the potential effects of age-related degradation of structures, systems, and components (SSCs). The research results of this multi-year collaboration will be utilized as input to seismic PRAs.In the Year 1 scope of work, BNL collected and reviewed degradation occurrences in US NPPs and identified important aging characteristics needed for the seismic capability evaluations. This information is presented in the Annual Report for the Year 1 Task, identified as BNL Report-81741-2008 and also designated as KAERI/RR-2931/2008. The report presents results of the statistical and trending analysis of this data and compares the results to prior aging studies. In addition, the report provides a description of U.S. current regulatory requirements, regulatory guidance documents, generic communications, industry standards and guidance, and past research related to aging degradation of SSCs.In the Year 2 scope of work, BNL carried out a research effort to identify and assess degradation models for the long-term behavior of dominant materials that are determined to be risk significant to NPPs. Multiple models have been identified for concrete, carbon and low-alloy steel, and stainless steel. These models are documented in the Annual Report for the Year 2 Task, identified as BNL Report-82249-2009 and also designated as KAERI/TR-3757/2009.In the Year 3 scope of work, BNL developed the seismic fragility capacities for a condensate storage tank with various degradation scenarios. The conservative deterministic failure margin (CDFM) method was utilized for the undegraded case and was modified to accommodate the degraded cases. A total of five seismic fragility analysis cases were considered: (1) undegraded case, (2) degraded stainless tank shell, (3) degraded anchor bolts, (4) anchorage concrete cracking, and (5) a perfect correlation of the three degradation scenarios. The design water level was used in these studies. The results and insights from these fragility analyses were described in the Annual Report for the Year 3 Task, identified as BNL-93771-2010 and also designated as KAERI/TR-4068/2010. This report des...

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Impact of structural aging on seismic risk assessment of reinforced concrete structures in nuclear power plants

Cited by 11 publications

References 18 publications

Understanding Community Resilience from a PRA Perspective Using Binary Decision Diagrams

Understanding Community Resilience from a PRA Perspective Using Binary Decision Diagrams

A Procedure for Determination of Degradation Acceptance Criteria for Structures and Passive Components in Nuclear Power Plants

Seismic Fragility Analysis of a Condensate Storage Tank with Age-Related Degradations

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