BS IEC/TR 61838:2001

FOREWORD
INTRODUCTION
Clause
1 Scope
2 Reference documents
3 Definitions and abbreviations
   3.1 Definitions
4 Limitations regarding the use of PSA
5 The use of PSA: methods and results
   5.1 Introduction
   5.2 Use of PSA in the design of future NPPs
       5.2.1 Overall scope
       5.2.2 Methods
       5.2.3 Plant analysis and modelling I&C in PSA
   5.3 Benefits of the use of PSA for existing NPPs
6 The use of PSA for classification
   6.1 General
   6.2 Approach 1: time and reactor states based approach
       6.2.1 Use of PSA in conjunction with a functional
             deterministic method
       6.2.2 Classification of functions, systems and
             equipment
       6.2.3 Associated technical requirements
       6.2.4 Complementary use of PSA alongside the
             iterative design process
   6.3 Approach 2: quantitative importance based approach
       6.3.1 Quantitative assignment criteria
       6.3.2 Quantitative criteria
       6.3.3 Category assignment
       6.3.4 Classification procedure
       6.3.5 Determination of requirements
Annex A (informative) Proposal for modelling I&C in PSA
        A.1 Scope
            A.1.1 Background
            A.1.2 I&C modelling in PSA
        A.2 Modelling description
            A.2.1 Global description
            A.2.2 Sensor part
            A.2.3 Logic part
            A.2.4 Actuator part
        A.3 Quantitative analysis: unavailability values
            A.3.1 Use of less classified systems for
                  safety functions and modelling in PSA
            A.3.2 Sensor part
            A.3.3 Specific logic part
            A.3.4 Non-specific logic part
            A.3.5 Actuator part
        A.4 Use of modelling in the event trees of PSA
            A.4.1 Taking account of different I&C configurations
            A.4.2 Importance of the actuators
            A.4.3 Integration in PSA event trees
Annex B (informative) Bibliography

Gives a survey of some of the methods by which probabilistic risk assessment results can be used to establish "risk based" classification criteria, so as to allow FSEs to be placed within the four categories established within IEC 61226.

Provides a survey of some of the methods by which probabilistic risk assessment results can be used to establish \'risk based\' classification criteria, so as to allow FSEs to be placed within the four categories established within IEC 61226.