Operator versus safety system logic

Nuclear power plants are provided with a series of automatic systems, in particular in the field of reactor protection and other safety systems. Many of these systems were designed to mitigate design basis events and may not be optimized for lesser events. Therefore, it may be necessary to override or modify the automatic safety functions as part of the EOPs. If it does become necessary to override or modify safety functions as part of the EOF actions the following administrative rules are recommended  

Plant status Strategy Procedures Accordin gto Ref [6] USA France Germany Rest of Europe and South Africa WWERs  

Normal Prevent Written and Normal Normal Normal Normal Normal Normal 

Anticipated operational Verify Incident Abnorm Abnorm Abnormal Abnormal Abnormal Abnormal 

DBAs (safety functions Verify EOPs EOPs EOPs EOPs EOPs EOPs EOPs  

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