For a comprehensive risk assessment, as originally foreseen by the European Council, a broader approach would have been necessary, an approach that starts from the underlying root cause of the Fukushima accident that unexpected events can happen, namely events which have not been foreseen when determining the design and operational safety provisions for a nuclear power plant. Under the experience of the Fukushima accident specific configurations and failure modes typical for an aeroplane crash, for example, or internal fires, or human failures or any combination of these events that until now not have been under consideration within the defence in depth are not covered by the “Stress test“. The “Stress test“ therefore will not reveal existing “blind areas” within the design of the nuclear power plants that are crucial for their safety.
A necessary broad approach would require looking at all categories of initiating events and possible combinations of events, possible safety systems’ failures in each case, and severe accident management issues against the background of the system of levels of defence-in depth.
In particular aeroplane crashes are to be considered as a relevant safety issue in the light of the Fukushima accident. ENSREG regards this scenario under the terms of security and therefore claims it not relevant to be included it in the Stress test.21 This is an evidently misleading argument. The fact that aeroplanes might crash on a nuclear power plant is completely independent of its cause, and might therefore happen without any terrorist background.
After all there is a clear grounds for ENSREG to address it as a safety issue that might lead to fatal scenarios.
21 See fn.6