Special Sessions

SS 2. Integrated Deterministic and Probabilistic Computational Safety Assessment (IDPSA)
Date Oct. 3 (Mon)
Time 13:30-17:20
Venue Vista Hall (B2)
Organizers Francesco DI MAIO (Politecnico Di Milano, Italy)
Enrico ZIO (CentraleSupelec And Politecnico Di Milano, Italy)
Curtis SMITH (Idaho National Laboratory, United States)
Traditionally, regulation of design and operation of Nuclear Power Plants (NPPs) have been based on Deterministic Safety Assessment (DSA) methods to verify criteria that assure plant safety in a number of postulated design basis accident scenarios. These criteria also allow identifying which plant Structures, Systems and Components (SSCs) and activities are important to safety. Design, operation and maintenance of these “safety-related” SSCs and activities are controlled through regulatory requirements and supported by extensive Probabilistic Safety Assessment (PSA). A medium-term challenge is to combine the use of deterministic and probabilistic computational approaches in an Integrated Deterministic and Probabilistic Safety Analysis (IDPSA), and tackle the related problems of addressing aleatory (stochastic aspects of accident scenarios) and epistemic (model and parameters) uncertainties in a consistent manner.

Open issues and challenges of IDPSA to be addressed include, among others:
• Reduction of the computational burden of TH models, thanks to larger employment of meta-models for multi-parameter and non-linear modelling, and exploration of the space of combinatorial plant scenarios.
• Consistent treatment of different sources of uncertainties;
• Identification and characterization of a priori unknown vulnerable scenarios, or “sleeping threats”;
• Description of the time-dependent interactions between physical phenomena, equipment failures, safety and non-safety systems interactions, control logic, operator actions;
• Reduction of reliance on expert judgment and simplifying assumptions about interdependencies;
Preliminary Phase of a MCDET Analysis of a High Pressure Scenario with Potential Steam Generator Tube Rupture Martina KLOOS (Gesellschaft Fur Anlagen- und Reaktorsicherheit (GRS) gGmbH, Germany)
Application of Gaussian Process Model to Generate a Success Criteria Map with Estimate of Safety Margin and Uncertainty Analysis Douglas FYNAN (Korea Atomic Energy Research Institute, Korea, Republic of)
An Approach to Merge PSA-based Premises and BEPU Method in order to Develop the EBEPU Methodology Jose Felipe VILLANUEVA (Universitat Politecnica De Valencia, Spain)
Application of Dynamic PSA for Accident Sequence Precursor Analysis: Case Study for Steam Generator Tube Rupture Gyunyoung HEO (Kyung Hee University, Korea, Republic of)
An Approach to Joint Application of Integrated Deterministic-probabilistic Safety Analysis and PSA Level 2 to Severe Accident Issues in Nordic BWRs Sergey GALUSHIN (Royal Institute of Technology (KTH), Sweden)
A Repairable Dynamic Event Tree for the Safety Assessment of a Steam Generator of a Nuclear Power Plant Francesco DI MAIO (Politecnico Di Milano, Italy)
Framework for Assessing Integrated Site Risk of Small Modular Reactors Using Dynamic Probabilistic Risk Assessment Simulation Mohammad MODARRES (University of Maryland, United States)
Current Status and Applications of ISA (Integrated Safety Assessment) and SCAIS (Simulation Code System for ISA) Cesar QUERAL (Technical University of Madrid, Spain)

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