PSAM 16 - Paper Overview

PSAM 16 Conference Paper Overview

Welcome to the PSAM 16 Conference paper and speaker overview page.

Lead Author: César Queral Co-author(s): Sergio Courtin, sergio.courtin@upm.es Rafael Iglesias Marcos Cabezas Alberto Garcia-Herranz Julia Herrero-Otero Enrique Meléndez, ema@csn.es Rafael Mendizábal, rmsanz@csn.es Miguel Sánchez-Perea, msp@csn.es

On the use of SPAR-CSN models for identifying DEC-A sequences. First ideas.
The Fukushima accident has brought, among others, an increment and improvement of the safety requirements for the nuclear power plants. One important requirement established in many countries is that the so-called Design Extension Conditions (DEC) need to be fully considered in the assessment of current and new advanced nuclear power plants. This safety improvement of NPPs focuses on the conditions of multiple failures of the safety system, included in the currently available guidances widely in the world (e.g., as proposed by IAEA SSR 2/1). The associated applications and practices begin to emerge, given that the topic of DEC is being advanced rapidly both nationally and internationally. Nevertheless, these practices are still not comprehensive, in particular, regarding the interface with the plant design basis, its role in the Defence-in-Depth, selection of requirements, impact on operating limits and conditions and/or selection of DEC sequences to be included in the analyses. As for the selection of DEC sequences, most if not all, the current practices/guidances indicate that ”the selection of events to be analysed shall be justified on the basis of deterministic and probabilistic arguments and of engineering judgement” and that “the selection process shall take into account all those events or combinations of events that cannot be considered extremely unlikely with a high degree of confidence and that might give rise to accident conditions more severe than those considered in design basis accidents”. Thus, there is a broad claim for the use of the PSA models as a tool for the DEC identification process. The Spanish Regulatory Body (CSN), in collaboration with the Universidad Politécnica de Madrid (UPM), has been assembling its own generic standardized model (SPAR-CSN) for 3-loop PWR-WEC designs for different purposes and uses. The present paper aims at enlarging the scope of initially foreseen applications to the goal of designing a suitable PSA-based methodology for DEC sequences. The paper will show the first ideas and provisions foreseen with this aim. Key Words: Design Extension Conditions (DEC), PSA, Standardized PSA models, DEC-A selection, mPSA based

On the use of SPAR-CSN models for identifying DEC-A sequences. First ideas.

The Fukushima accident has brought, among others, an increment and improvement of the safety requirements for the nuclear power plants. One important requirement established in many countries is that the so-called Design Extension Conditions (DEC) need to be fully considered in the assessment of current and new advanced nuclear power plants. This safety improvement of NPPs focuses on the conditions of multiple failures of the safety system, included in the currently available guidances widely in the world (e.g., as proposed by IAEA SSR 2/1). The associated applications and practices begin to emerge, given that the topic of DEC is being advanced rapidly both nationally and internationally. Nevertheless, these practices are still not comprehensive, in particular, regarding the interface with the plant design basis, its role in the Defence-in-Depth, selection of requirements, impact on operating limits and conditions and/or selection of DEC sequences to be included in the analyses. As for the selection of DEC sequences, most if not all, the current practices/guidances indicate that ”the selection of events to be analysed shall be justified on the basis of deterministic and probabilistic arguments and of engineering judgement” and that “the selection process shall take into account all those events or combinations of events that cannot be considered extremely unlikely with a high degree of confidence and that might give rise to accident conditions more severe than those considered in design basis accidents”. Thus, there is a broad claim for the use of the PSA models as a tool for the DEC identification process. The Spanish Regulatory Body (CSN), in collaboration with the Universidad Politécnica de Madrid (UPM), has been assembling its own generic standardized model (SPAR-CSN) for 3-loop PWR-WEC designs for different purposes and uses. The present paper aims at enlarging the scope of initially foreseen applications to the goal of designing a suitable PSA-based methodology for DEC sequences. The paper will show the first ideas and provisions foreseen with this aim. Key Words: Design Extension Conditions (DEC), PSA, Standardized PSA models, DEC-A selection, mPSA based

PSAM 16 Conference Paper Overview

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