Development of systems reliability analysis code SECOM-2 for seismic PSA

Oikawa, Tetsukuni; Masaaki, Kondo; Mizuno, Yoshinobu; Watanabe, Yuichi; Fukuoka, Hiroshi; Muramatsu, Ken

doi:10.1016/s0951-8320(98)00025-8

Cited by 19 publications

(7 citation statements)

References 12 publications

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“…40 The Seismic Core Melt Frequency Evaluation Code version 2 (SECOM2), which can be applied to DQFM, was also developed by JAERI. 41 Multiunit PRA was conducted using SECOM2 for two boiling-water reactors (BWRs). The result indicated that the frequency at which the two units simultaneously suffered core damage was 2.3 times higher than that when no correlation was considered.…”

Section: Correlation Of Ssc Damage In Seismic Pramentioning

confidence: 99%

Quantification of risk dilution induced by correlation parameters in dynamic probabilistic risk assessment of nuclear power plants

Kubo

Tanaka

Ishikawa

2023

Proceedings of the Institution of Mechanical Engineers, Part O:

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Nuclear power plants are critical infrastructures that produce electricity. However, accidents in nuclear power plants can cause considerable consequences such as the release of radioactive materials. Therefore, appropriately managing their risk is necessary. Various nuclear regulatory agencies employ probabilistic risk assessment (PRA) to effectively evaluate risks in nuclear power plants. Dynamic PRA has gained popularity because it allows for more realistic assessment by reducing the assumptions and engineering judgments related to time-dependent failure probability and/or human-action reliability in the conventional PRA methodology. However, removing all assumptions and engineering judgments is difficult; thus, the risk analyst, for example, the regulator, must understand their effects on the assessment results. This study focuses on “risk dilution,” which emerges from the assumptions about uncertainty. Dynamic PRA of a station blackout sequence in a boiling-water reactor was performed using the dynamic PRA tool, namely, Risk Assessment with Plant Interactive Dynamics (RAPID) and the severe-accident code Thermal–Hydraulic Analysis of Loss of Coolant, Emergency Core Cooling, and Severe Core Damage version 2 (THALES2), which altered the correlation parameters among the uncertainties of the events that occurred in sequence. The results demonstrated that the conditional core-damage probability and mean value of the core-damage time varied from 0.27 to 0.47 and from 7.1 to 8.7 h, respectively. When the dynamic PRA results are used for risk-informed decision making, the decision maker should adequately consider the effect of risk dilution.

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Section: Correlation Of Ssc Damage In Seismic Pramentioning

confidence: 99%

Quantification of risk dilution induced by correlation parameters in dynamic probabilistic risk assessment of nuclear power plants

Kubo

Tanaka

Ishikawa

2023

Proceedings of the Institution of Mechanical Engineers, Part O:

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“…In this case, MCS represents a minimal set of components whose simultaneous failure results in a system failure, while MPS is a minimal set of components whose simultaneous work ensures that the system works properly. Methodologies of fault trees and two terminal networks are used to analyze different types of systems, such as the ones in nuclear power plants, [8][9][10][11] aviation systems, [12][13][14] distribution systems 15 and others. [16][17][18] Special algorithms for reliability analysis of systems with a huge number of MCSs or MPSs are considered in the second group of articles.…”

Section: Introductionmentioning

confidence: 99%

Analysis of minimal cut and path sets based on direct partial Boolean derivatives

Levashenko

Zaitseva

2015

Proceedings of the Institution of Mechanical Engineers, Part O:

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Principal steps in reliability engineering include estimation of system reliability and identification and quantification of situations which cause a system failure. There are several techniques that can be used to solve these tasks. Some of them are based on minimal cut (path) sets, which represent minimal sets of basic events, whose simultaneous occurrence leads to a failure (repair) of the system. In this article, applications of minimal cut (path) sets in reliability analysis are summarized, and their connection with direct partial Boolean derivatives is studied. In reliability analysis, direct partial Boolean derivatives identify situations in which a failure (repair) of one system component results in a system failure (repair). Therefore, they reveal the influence of one system component on the whole system. However, minimal cut (path) sets define the influence of a simultaneous failure (repair) of a group of system components on the system activity. Therefore, there should be some correlation between direct partial Boolean derivatives and minimal cut (path) sets. This correlation is studied in this article, and as a result, new algorithms for identification of minimal cut (path) sets are proposed based on this correlation.

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“…From this point of view, seismic PSA has been conducted. For example, seismic PSA has been conducted in JAEA for a hypothetical BWR plant 9 and an evaluation code system SECOM2 (Seismic Core Melt frequency Evaluation Code, version 2) was developed [10][11] for this purpose. In addition, a part of the SECOM2 code system was available to the public as the SECOM2-DQFM (Direct Quantification of Fault tree using Monte Carlo simulation) code 12 .…”

Section: Introductionmentioning

confidence: 99%

Effect of Analytical Methodology for Assessment on Seismically Induced Core Damage

Uchiyama¹,

Kawaguchi²,

Wakabayashi

2011

JPES

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The purpose of this study is to investigate the effects of the difference between analytical methodologies for seismic probabilistic safety assessment (PSA), especially the difference in the probability of system failures and core damage sequences. We selected two methods, upper bound approximation (UBA) using minimal cut sets and direct quantification using Monte Carlo simulation (DQFM) for comparison. The former is often used in PSA for both internal and external event. The latter is developed in Japan Atomic Energy Agency (JAEA) as a part of SECOM2, a system reliability analysis code for seismic PSA, and expanded to divide the core damage state into different core damage sequences. The result showed that there is a significant difference between UBA method and DQFM method.

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Development of systems reliability analysis code SECOM-2 for seismic PSA

Cited by 19 publications

References 12 publications

Quantification of risk dilution induced by correlation parameters in dynamic probabilistic risk assessment of nuclear power plants

Quantification of risk dilution induced by correlation parameters in dynamic probabilistic risk assessment of nuclear power plants

Analysis of minimal cut and path sets based on direct partial Boolean derivatives

Effect of Analytical Methodology for Assessment on Seismically Induced Core Damage

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