RRC-A definition methodology

1. RRC-A definition methodology

2. Summary Operating plant RRC-A methodology EPR RRC-A methodology

3. RRC-A scope of analysis Internal event concerning the reactor or the spent fuel pool leading to core melt + Long term loss of offsite power + Long term loss of the cooling chain

4. Operating plants RRC-A methodology Identification of potential RRC-A features Specific non-F1 systems (CHRS, SBO-diesels, EBS, diversified coooling of LHSI pump…) Specific functions (feed and bleed, manual cooldown,…)

5. Definition of a reference plant state PSA level 1 without feature • Identification of elementary functional sequences • criteria : Pcore melt > Probabilistic target P bypass > Probabilistic target • groupment of sequences : • Common functional characteristics • The same feature can reduce the risk Functional sequences Operating plants RRC-A methodology • Identification of potential RRC-A features • Identification of the sequences not covered by the PCCs

6. P< Probabilistic target P> Probabilistic target RRC-A Feature needed RRC-A Feature not needed Operating plants RRC-A methodology Identification of potential RRC-A features Identification of the sequences not covered by the PCCs • Identification of problematic sequences and definition of potential RRC-A features PSA level without feature

7. Determination of the PSA parameter Equipment Reliability Reliability study of the equipment Operator action Maximum operator delay Thermal-hydraulic study Operating plants RRC-A methodology Identification of potential RRC-A features Identification of the sequences not covered by the PCCs • Identification of problematic sequences and definition of potential RRC-A features • Checking for the efficiency of the features PSA level 1 + RRC-A feature

8. Operating plants RRC-A methodology Identification of potential RRC-A features Identification of the sequences not covered by the PCCs • Identification of problematic sequences and definition of potential RRC-A features • Checking for the efficiency of the features PSA level 1 + RRC-A feature • Determination of the PSA parameter • Thermal-hydraulicanalysisrules : • dominant physicalparameterscoverat 95 % • no Single Failure goal : To define maximum time limit to perform the action to meet PCC4 criteria

9. Operating plants RRC-A methodology Identification of potential RRC-A features Identification of the sequences not covered by the PCCs • Identification of problematic sequences and definition of potential RRC-A features • Checking for the efficiency of the features PSA level 1 + RRC-A feature • Determination of the PSA parameter • Introduction of the PSA parameter in PSA level 1

10. Operating plants RRC-A methodology Identification of potential RRC-A features Identification of the sequences not covered by the PCCs • Identification of problematic sequences and definition of potential RRC-A features • Checking for the efficiency of the features PSA level 1 + RRC-A feature • Determination of the PSA parameter • Introduction of the PSA parameter in PSA level 1 • Evaluation of the probability of functional sequence with RRC-A feature

11. P> Probabilistic target P< Probabilistic target RRC-A feature not efficient RRC-A feature efficient Operating plants RRC-A methodology Identification of potential RRC-A features Identification of the sequences not covered by the PCCs • Identification of problematicsequences and definition of potential RRC-A features • Checking for the efficiency of the features PSA level 1 + RRC-A feature

12. Operating plants RRC-A methodology Risk reduction category for prevention of core melt Identification of the potential RRC-A features • Identification of the sequences not covered by the PCCs • Identification of problematic sequences and definition of potential RRC-A features • Checking for the efficiency of the features • Checking for global probabilistic target meeting

13. EPR RRC-A methodology Identification of the potential RRC-A features • Identification of the sequences not covered by the PCCs

14. P< Probabilistic target RRC-A Feature not needed EPR RRC-A methodology Identification of potential RRC-A features Identification of the sequences not covered by the PCCs • Identification of problematic sequences and definition of potential RRC-A features PSA level without feature P> Probabilistic target RRC-A Feature need examined case by case depending on the risk

15. EPR RRC-A methodology Identification of potential RRC-A features Identification of the sequences not covered by the PCCs • Identification of problematic sequences and definition of potential RRC-A features If needed, RRC-A thermo-hydraulics or neutronics analysis will be performed • Thermal-hydraulic analysis rules : • dominant physical parameters cover at 95 % • no Single Failure • Operator action at 30 minutes (1 hour for local action) goal : To demonstrate RRC-A feature efficiency

16. EPR RRC-A methodology Identification of potential RRC-A features Identification of the sequences not covered by the PCCs • Identification of problematic sequences and definition of potential RRC-A features • Checking by PSA level 1