Practical and Theoretical Training on Level-1 PSA for Internal Initiating Events

                                                         Minimum number of Participants: 7

Lecturers and Code Instructors: A. Lyubarskiy (AEP), S. Pogosyan (IAEA)

 

                                                      Day 1

  • Brief overview of the Training Curriculum
  • Overview of the Main Terms and Concepts of the Probabilistic Safety Assessment
    • Concept of Risk
    • Typical PSA Scope
    • Terms and Definitions used in PSA
    • Introduction to Boolean Algebra
    • Brief overview of Typical Level-1 PSA Tasks
  • Initiating Events (IE) Analysis
    • Definition of an Initiating Event in PSA
    • Initiating Events Selection
    • Initiating Events Grouping
    • Initiating Events Frequency Assessment
    • Typical Lists of IEs for Different Reactor Types
    • IEs Frequencies Assessment
  • Presentation on the Design of the Facility to be Used for the Case Study on PSA Model Development
    • Presentation of the Main Design Features of a Simplified Nuclear Installation to be used during training
      • Main Safety Systems
      • Main Support Systems
    • All needed Material will distributed in paper copies and electronic form
  • Accident Sequence Models Development
    • Safety Functions and Modelling Functions in the Accident Sequence Models
    • Successful and Non-Successful End States
    • Typical definition of End States in Accident Sequence Models
    • Success Criteria Definition
    • Supporting Analyses
    • Mission Time and Cliff-Edge Effects
    • Typical Formats of Accident Sequence Models
    • Approach for Construction of Small Event Tree - Large Fault Tree PSA Models
    • Example of Event Trees Construction Process
  • Introduction to PSA Software and Construction of Event Trees
    • Brief description of the PSA Software Used (SAPHIRE or RISKSPECTRUM)
    • Work in working groups: each group develops one ET (later to be integrated in one PSA model)
    • Each working group construct one ET (Large LOCA, Medium LOCA, Small LOCA, Loss of Off-Site Power)
    • Expert(s) provides advices at request and reviews the work done

 

                                                      Day 2

  • System Models Development
    • Typical Methods for System Models Development
    • Fault Tree (FT) Method
      • Structure of FT
      • Typical Elements of FT
      • Typical Basic Events in FT
      • Types of Components, Components Failure Modes and Related Probabilistic Models
      • Components Boundaries and Link with Existing Reliability Data
    • Methods to Control the Logic of System Models in FTs (house events, boundary condition sets, etc.)
    • Typical Coding Scheme for Naming Basic Events in the PSA Model
    • Failure Modes and Effects Analysis (FMEA)
    • Example of a FT Development Process, Breaking Logic Loops
  • Exercise: Construction of Fault Trees. Work in working groups:
    • Each group constructs one or two systems models - FTs (depending on the system complexity)
    • Development of the Coding Scheme to be used in the PSA Model Development Process
    • Performing and Documenting FMEA
    • Construction of System Models in the Form of FT (using PSA Software)
    • Defining Reliability Models for Basic Events and Introduction of “Dummy” Values
    • System Models Quantification
    • Analyses of Minimal Cutsets (MCSs) obtained

 

                                                      Day 3

  • Discussion on the Intermediate Results Achieved
  • PSA Data Analysis
    • Overview of Data required for PSA
    • Component Reliability Data Collection and Treatment Process
    • Initiating Events Data Collection and Treatment
    • Methods for Reliability Parameters and IEs Frequencies Estimation
      • Classical Statistic Methods
      • Bayesian Updating Process
    • Demonstration of the EXCEL Programme for Reliability Parameters and IEs Frequencies Estimation
    • Introduction to Human Error Probability (HEP) Evaluation
  • Exercises on data assessment. Work in working groups:
    • Each Group Performs Assessment of the Data Needed for their part of the PSA Model
    • Treatment of the Raw Data (data to be provided by experts)
    • Estimation of Reliability Parameters for the Components and Failure Modes to be used in the PSA Model Under Development
    • Entering the Data obtained in the PSA Model
    • Quantification of MCSs with the Data obtained (replacement of “dummy” values)

 

                                                      Day 4

  • Discussion on the Intermediate Result Achieved
  • Modelling Dependencies in PSA (including Common Cause Failures [CCF])
    • Types of Dependencies to be modelled in the PSA
    • Common Cause Failures (CCF)
      • CCF Models
      • CCF Parameters and Sources of Data
      • CCF Groups
    • Inclusion of CCF Events in the PSA Model (depending on the software to be used)
  • Exercise: Modelling of the CCF in the PSA model. Work in working groups:
    • Each Group perform CCF Analyses for the Equipment Modelled in their part of the Model
    • Defining CCF Groups
    • Introduction of CCF Groups in the PSA Model
    • Re-Quantification of the Model with CCF Data
  • Discussion on the Intermediate Result Achieved

 

                                                      Day 5

  • PSA Model Quantification and Analysis of the Results
    • Typical Results from Level-1 PSA
    • Analysis of MCSs and Dominant Accident Sequences
    • Importance Measures Quantification and Analysis:
      • Types of Importance Measure
      • Typical Insights from Importance Measures
    • Uncertainty Analyses and Types of Uncertainties in PSA:
      • Parametric Uncertainty
      • Modelling Uncertainty
      • Incompleteness Uncertainty
    • Sensitivity Studies:
      • Sensitivity Studies to Address Uncertainties
      • Sensitivity Studies to Assess the Impact of Modifications
      • Other Sensitivity Studies
  • Exercise: PSA Model Quantification and Analysis of the Results. All working groups are working with the same model
    • Each group performs Quantification of the Model and Review MCSs obtained
    • Each group reviews the Results of Importance Measures Quantification and Uncertainty of the Results
    • Each group defines one Sensitivity Case and performs:
      • Model Adjustment for the case
      • Model Quantification for the case
  • Discussion on the Final Results achieved
  • High-Level overview of Internal and External Hazards Level-1 PSA, Level-2 PSA and use of PSA Results
    • High-Level overview of Internal and External Hazards Level-1 PSA, Level-2 PSA and use of PSA Results
    • High-Level overview of Level-2 PSA Tasks
    • High-Level overview of Use and Application of PSA
  • Evaluation of the Training Course

 

 

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