Passive Systems Reliability

Application of MELCOR Simulations for PCCS Case Study

Ilkka Männistö, Ilkka Karanta

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

Abstract

Increasing use of passive safety systems also increases the need for advanced methods of analyzing their reliability. Passive components work in a variety of ways. IAEA classifies these components and systems based on the level of passivity they exhibit. Reliability analysis of passive components relying mostly on physical phenomena require a combination of physics modeling and probabilistic methods. Challenges are to identify the mechanisms that can degrade or otherwise affect the systems stated safety function and the sources of uncertainty. Sources of uncertainty can be the geometric properties and layout of the system, material properties, design parameters and phenomenological analysis. A pilot case study of simulating a passive containment cooling system (PCCS) using MELCOR is applied within a simplified passive systems reliability framework. The aim of the framework is to explicitly state the interactions and information flow between deterministic physics modeling and probabilistic risk assessments, and the uncertainties related to them. The framework includes identification of main hazards, main sources of uncertainty both in the input data and the models, propagation of the uncertainties in physical models and finally the inclusion of the reliability assessment into the probabilistic risk analysis (PRA) model. The framework is partly based on a case study on a passive containment cooling system performed for this project. This paper includes the main results and lessons learned from the case study.
Original languageEnglish
Title of host publicationProceedings of the 11th International Probabilistic Safety Assessment and Management Conference & The Annual European Safety and Reliability Conference
Subtitle of host publicationPSAM11 ESREL 2012
Pages2778-2785
Volume4
Publication statusPublished - 2012
MoE publication typeA4 Article in a conference publication
Event11th International Probabilistic Safety Assessment and Management Conference and The Annual European Safety and Reliability Conference, PSAM11 & ESREL 2012 - Helsinki, Finland
Duration: 25 Jun 201229 Jun 2012

Conference

Conference11th International Probabilistic Safety Assessment and Management Conference and The Annual European Safety and Reliability Conference, PSAM11 & ESREL 2012
CountryFinland
CityHelsinki
Period25/06/1229/06/12

Fingerprint

Cooling systems
Security systems
Physics
Risk analysis
Reliability analysis
Risk assessment
Materials properties
Hazards
Uncertainty

Keywords

  • probabilistic risk analysis (PRA)
  • passive systems
  • passive containment cooling system (PCCS)

Cite this

Männistö, I., & Karanta, I. (2012). Passive Systems Reliability: Application of MELCOR Simulations for PCCS Case Study. In Proceedings of the 11th International Probabilistic Safety Assessment and Management Conference & The Annual European Safety and Reliability Conference: PSAM11 ESREL 2012 (Vol. 4, pp. 2778-2785)
Männistö, Ilkka ; Karanta, Ilkka. / Passive Systems Reliability : Application of MELCOR Simulations for PCCS Case Study. Proceedings of the 11th International Probabilistic Safety Assessment and Management Conference & The Annual European Safety and Reliability Conference: PSAM11 ESREL 2012. Vol. 4 2012. pp. 2778-2785
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abstract = "Increasing use of passive safety systems also increases the need for advanced methods of analyzing their reliability. Passive components work in a variety of ways. IAEA classifies these components and systems based on the level of passivity they exhibit. Reliability analysis of passive components relying mostly on physical phenomena require a combination of physics modeling and probabilistic methods. Challenges are to identify the mechanisms that can degrade or otherwise affect the systems stated safety function and the sources of uncertainty. Sources of uncertainty can be the geometric properties and layout of the system, material properties, design parameters and phenomenological analysis. A pilot case study of simulating a passive containment cooling system (PCCS) using MELCOR is applied within a simplified passive systems reliability framework. The aim of the framework is to explicitly state the interactions and information flow between deterministic physics modeling and probabilistic risk assessments, and the uncertainties related to them. The framework includes identification of main hazards, main sources of uncertainty both in the input data and the models, propagation of the uncertainties in physical models and finally the inclusion of the reliability assessment into the probabilistic risk analysis (PRA) model. The framework is partly based on a case study on a passive containment cooling system performed for this project. This paper includes the main results and lessons learned from the case study.",
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Männistö, I & Karanta, I 2012, Passive Systems Reliability: Application of MELCOR Simulations for PCCS Case Study. in Proceedings of the 11th International Probabilistic Safety Assessment and Management Conference & The Annual European Safety and Reliability Conference: PSAM11 ESREL 2012. vol. 4, pp. 2778-2785, 11th International Probabilistic Safety Assessment and Management Conference and The Annual European Safety and Reliability Conference, PSAM11 & ESREL 2012, Helsinki, Finland, 25/06/12.

Passive Systems Reliability : Application of MELCOR Simulations for PCCS Case Study. / Männistö, Ilkka; Karanta, Ilkka.

Proceedings of the 11th International Probabilistic Safety Assessment and Management Conference & The Annual European Safety and Reliability Conference: PSAM11 ESREL 2012. Vol. 4 2012. p. 2778-2785.

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

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Männistö I, Karanta I. Passive Systems Reliability: Application of MELCOR Simulations for PCCS Case Study. In Proceedings of the 11th International Probabilistic Safety Assessment and Management Conference & The Annual European Safety and Reliability Conference: PSAM11 ESREL 2012. Vol. 4. 2012. p. 2778-2785