Dependence on Operator Action

No safety dependence on Operator power plant safety should not be dependent on operator action, and should be immune to malicious or incompetent operator action. 

The safety concept of the Package-Reactor is based on inherent safety features and passive safety systems, which do not depend on operator actions or external supports such as water and power supplies this enhances the protection against external impacts and sabotage. 

The results of the PRA show that the AP1000 has significantly less dependence on operator action to reduce plant risk to acceptable levels than current plants. This was shown through the sensitivity analyses and the operator action contributions from both the risk decrease and risk increase measures. Almost all operator actions credited in this PRA are performed in the control room there are very few local actions outside the control room. Further, the human actions modelled in the AP 1000 PRA are generally simple. Thus, the tasks for AP 1000 operators are easier and less likely to fail. If it were assumed that the operators never perform any actions credited in the PRA, the plant events CDF would still be lower than the result obtained for many eurrent pressurised water reactors including operator actions.This low dependence on operator aetion is therefore ALARP. 

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