Comparison of Computed and Observed Probabilities of Failure and Core Damage Frequencies

The Fukushima event has again questioned the safety of nuclear power plants (NPP). Statisticians and parts of the public claim that there is a significant difference of the Core Damage Frequency (CDF) based on Probabilistic Safety Analysis (PSA) and on historical data of accidents including the Fukushima event. This paper compares the results of both approaches including a short discussion of the goal values, the different methodologies, special properties of the different technical systems and the history. Furthermore, the paper extends the comparison approach also to the safety of structures. The safety of structures is often expressed as Probability of Failure (PF). Finally, results of both comparisons are given in the paper.