Regional Basic Professional Training Course in Korea

❙ 579 ❙
9. Probabilistic Safety Analysis
Due to these specificities, the treatment of hazards needs particular analysis, including
new event sequences and new system analysis. For example, for the treatment of internal
fires, the number of possible IEs and scenarios could be extremely high. In order to limit
the volume of the study, the usual methodology consists first of identification, by a
simplified method, of the critical zones (the rooms in which a fire could lead to core
damagesequences with a non negligible probability). In a further step, the fire scenarios
are analysed and quantified only for the critical zones.
9.3. PARAMETERS ESTIMATION AND
SEQUENCES QUANTIFICATION
9.3.1. Data used in a PSA
After the construction of the logic models (event trees - fault trees), and in order to
quantify these models, it is necessary to introduce numerical values for the different
parameters.
The data necessary for quantification can be grouped into the following categories:
Frequency of initiating events;
Reliability data of components;
Common Cause Failure (CCF) data;