The report provides guidance on modelling and implementation of man-made hazards (mainly external fires and explosions) and accidental aircraft crash hazards in an Extended PSA Level 1.
1) Hazard assessment methodologies, including issues related to hazard combinations.
5) Multi-unit problems.
Executive SUMMARY 12
ASAMPSA_E Partners 13
CONTENT 14
GLOSSARY 15
DEFINITIONS 16
1INTRODUCTION 21
1.1Background 21
1.2Starting considerations 22
1.3Structure of the report 24
2DATA FOR HAZARD CHARACTERISATION 25
1.1Data related to hazard sources 25
1.2Data related to plant design 26
3HAZARD ASSESSMENT METHODOLOGIES 27
3.1Introduction 27
3.1.1External fire and explosion 27
3.1.2Aircraft crash 29
3.2Hazard Categorization 30
3.2.1External fire and explosion 30
3.2.2Aircraft crash 31
3.3Frequency Assessment Methodology 33
3.3.1External fire and explosion 33
3.3.2Aircraft crash 35
3.4Consequence Analysis 37
3.5Uncertainty Assessment 39
3.6From hazard to initiating event 40
3.6.1External Fires and explosions 40
3.6.2Aircraft crash 41
3.7Limitations and gaps in existing methods 44
3.7.1External Fires and explosions 44
3.7.2Aircraft crash 45
4HAZARDS COMBINATIONS 46
4.1External explosions 46
4.1.1Explosion hazard correlations 46
4.1.2Combinations of explosion and other external hazards 47
4.1.3Screening of explosions and hazards combinations with explosions 48
4.2External fires 51
4.2.1Causally connected fire hazards – correlated fire hazards 52
4.2.2Associated fire hazards 53
4.2.3Screening of fire 54
4.2.4Examples of hazard combinations 57
4.2.5Assessment of coincident hazards based on estimates of duration time of hazard 58
4.2.6Worst case hazard combinations 58
4.3Aircraft crash 59
4.3.1Identification of Hazard Combinations 59
5METHODS FOR THE ASSESSMENT OF HAZARDS COMBINATIONS 64
5.1General description 64
5.2Data needs 66
5.3Initiating events 66
5.4Reference to known methods 67
5.5Best practices 68
6STRUCTURE OF MAN_MADE HAZARDS AND AIRCRAFT CRASH PSA 70
7SOLUTION FOR THE MODELLING OF MAN_MADE HAZARDS AND AIRCRAFT CRASH FOR L1 PSA 78
1.3Use of L1 Internal Events and Hazards PSA 78
1.4State of the Art Methodology for PSA Model Development 79
7.1.1Consequence analysis of PSA Initiating Events 79
7.1.2Accident Sequences 83
7.1.3Development of Accident Sequence Models 84
1.5Limitations and Gaps in Existing Methods 84
8SOLUTION TO MODEL THE EQUIPMENT SSCS FOR MAN-MADE HAZARDS AND AIRCRAFT CRASH PSA 85
8.1Definition of Failure Modes for SSCs 86
8.2Categorization of Failure Modes as Transient Initiating Events and Failures in Mitigation Systems 88
8.3Event tree construction 89
8.3.1Initiating events 89
8.3.2Additional systems modelling 92
8.4Fault Tree Development 94
8.5Analysis of Input Reliability Data 100
9SOLUTION TO MODEL HRA FOR MAN-MADE HAZARDS AND AIRCRAFT CRASH PSA 101
9.1Background 101
9.2Considerations on applicability of current HRA methods 103
9.2.1Definition and modelling of human interaction events 104
9.2.2Quantification of human failure events 105
9.2.3Recovery analysis 106
9.2.4Revision 106
9.3Specific Analysis Tasks 107
9.3.1Selection of HFEs 108
9.3.2Qualitative Analysis 112
9.3.3Quantification 117
9.4Challenges and Open Issues 125
10SOLUTION TO MODEL ADDITIONAL EMERGENCY RESPONSE 126
10.1Mobile equipment and help from outside the plant site 126
10.2Special provisions 133
10.3Preventive measures 134
11SOLUTION TO MODEL MULTI-UNIT FOR MAN-MADE HAZARDS AND AIRCRAFT CRASH PSA 135
11.1Accident sequences 135
11.2CCF 135
11.3Multiple initiatiors 136
11.4CrosS connection between different units 137
11.5Considerations 138
11.6Connections with other facilities outside the plant 139
12L1 PSA QUANTIFICATION 139
13CONCLUSION AND RECOMMENDATIONS 142
13.1Feasibility and pragmatic approach 142
13.2Recommendations 142
14LIST OF OPEN ISSUES 143
15LIST OF REFERENCES 143
16LIST OF TABLES 148
17LIST OF FIGURES 148
Appendix 1 – Example of French approach 149
Appendix 2 – Methodologies for estimating frequencies of aircraft crash rates 155
Appendix 3 – Additional issues for emergency response related to aircraft crash hazards 161