1. INTRODUCTION ................................................. 1
1.1. Background .............................................. 1
1.2. Objective ............................................... 2
1.3. Scope ................................................... 2
1.4. Structure ............................................... 3
2. INITIATING EVENTS ............................................ 4
2.1. Identification and selection of initiating events ....... 4
2.2. Methods for evaluation of external events and special
internal events ......................................... 6
2.2.1. External events .................................. 6
2.2.2. Special internal events .......................... 7
2.3. Events initiated by humans .............................. 7
3. RULES OR CONVENTIONS ......................................... 8
4. ACCEPTANCE CRITERIA ......................................... 10
5. UTILIZATION AND MODIFICATION ................................ 12
5.1. Reactor utilization .................................... 13
5.2. Reactor modifications .................................. 14
5.2.1. Core conversion ................................. 14
5.2.2. Upgrades ........................................ 14
5.2.3. Core configuration modifications ................ 15
6. METHODS FOR TRANSIENT AND ACCIDENT ANALYSIS ................. 15
6.1. Deterministic analysis ................................. 15
6.1.1. Conservative approach ........................... 16
6.1.2. Best estimate approach .......................... 18
6.2. Probabilistic analysis ................................. 18
7. TYPES OF SAFETY ANALYSIS .................................... 19
7.1. Safety analysis in design .............................. 19
7.2. Safety analysis for licensing .......................... 20
7.3. Support for accident management and emergency
planning ............................................... 21
8. COMPUTATIONAL TOOLS ......................................... 21
8.1. Types of computational tool ............................ 22
8.2. Code qualification ..................................... 24
8.2.1. Code verification ............................... 24
8.2.2. Code Validation ................................. 24
8.2.3. Code documentation .............................. 26
8.3. User qualification and user effect on modelling ........ 26
8.4. Preparation of input data .............................. 27
8.4.1. Engineering handbook ............................ 28
8.4.2. Verification of the input deck .................. 28
8.4.3. Validation of the input deck .................... 28
9. PRESENTATION OF RESULTS ..................................... 29
9.1. Introduction ........................................... 29
9.2. Reactor characteristics ................................ 30
9.2.1. Core parameters ................................. 30
9.2.2. Assumed reactor protection system actions ....... 31
9.3. Selection of initiating events ......................... 31
9.4. Evaluation of individual event sequences ............... 31
9.4.1. Identification of causes ........................ 32
9.4.2. Sequence of events and system Operation ......... 32
9.5. Transient and accident analysis ........................ 32
9.5.1. Computational model ............................. 33
9.5.2. Input parameters and initial conditions ......... 34
9.5.3. Results ......................................... 34
9.5.4. Classification of damage states ................. 35
9.6. Summary ................................................ 35
10. QUALITY ASSURANCE IN DETERMINISTIC SAFETY ANALYSIS ......... 36
REFERENCES ..................................................... 37
ANNEX I: GRADED APPROACH TO SAFETY ANALYSIS ................. 39
ANNEX II: SELECTED POSTULATED INITIATING EVENTS FOR
RESEARCH REACTORS .................................. 47
ANNEX III: INITIATING EVENTS FOR OPEN POOL MTR TYPE RESEARCH
REACTORS OF VARIOUS POWER LEVELS ................... 50
ANNEX IV: POSTULATED INITIATING EVENTS CONSIDERED IN
THE SAFETY ANALYSIS OF SLOWPOKE-2 .................. 54
ANNEX V: EXTERNAL EVENTS CONSIDERED FOR A 20 MW MTR ......... 56
ANNEX VI: SPECTAL INTERNAL EVENTS CONSIDERED FOR A 20 MW
MTR ................................................ 57
ANNEX VII: RULES OF SAFETY ANALYSIS FOR THE REACTIVITY
INSERTION TRANSIENTS ANALYSIS OF A 20 MW MTR TYPE
REACTOR ............................................ 58
ANNEX VIII: SAFETY ANALYSIS RULES IN CANADA .................... 60
ANNEX IX: ACCEPTANCE CRITERIA ADOPTED FOR I HE LICENSING OF
THE MAPLE REACTOR .................................. 62
ANNEX X: ACCEPTANCE CRITERIA FOR RESEARCH REACTORS WITH
ALUMINIUM CLADDING IN ARGENTINA .................... 64
ANNEX XI: ACCEPTANCE CRITERIA ADOPTED FOR THE UPGRADE OF
THE IEA-R1 RESEARCH REACTOR IN BRAZIL .............. 66
ANNEX XII: ACCEPTANCE CRITERIA ADOPTED FOR THE LICENSING OF
THE HANARO RESEARCH REACTOR, REPUBLIC OF KOREA ..... 68
ANNEX XIII: NODALIZATION OF THE SAFARI RESEARCH REACTOR,
SOUTH AFRICA ....................................... 71
ANNEX XIV: EXAMPLE OF A CFD APPLICATION ....................... 73
ANNEX XV: EXAMPLE OF A METHODOLOGY FOR THERMO-HYDRAULIC
CODE VALIDATION FOR SAFETY ANALYSIS IN
RESEARCH REACTORS .................................. 75
ABBREVIATIONS .................................................. 79
CONTRIBUTORS TO DRAFTING AND REVIEW ............................ 81
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