ABSTRACT
The US Nuclear Regulatory Commission (NRC) issued order EA-12-049 (U.S.NRC, 2012a) requiring nuclear power plants to develop mitigation strategies for beyond-design-basis external events, shortly known as FLEX. The nuclear industry in US, through the Nuclear Energy Institute (NEI), developed a generic framework for response to this order that is documented in the NEI FLEX Implementation Guide (NEI 12-06) (NEI, 2012). The FLEX represents an approach to develop flexible and diverse strategies for increased defensein-depth by providing multiple, diverse methods to supply power and water to support key safety functions.
