Resumen
This paper summarizes some of the major improvements and features of the Emergency Preparedness and Response developed to face scenarios with Extensive Damage, aspect that has taken particular emphasis after the events happened at the Japanese Fukushima-Daiichi Nuclear Power Plant. After the so called ?stress test" and taken as one of the main references the work developed by the United States, important enhancements are being applied in the nuclear industry both in Spain and internationally. The aim is to review both the historical origin and evolution suffered after the accident at the Japanese nuclear power plant, and the fundamental aspects of Emergency Management that, taken into account its extended nature, have to be addressed by specific strategies that can prevent damage to the fuel and / or mitigate their potential consequences, when the plant response, considered normal, is severely affected. Improvements initially proposed as part of the response to hostile acts, both in terms of improving the Emergency Command and Control as well as the generic Mitigation Strategies, are summarized in the paper. After that, the paper briefly describes the evolution based on the improvements already made. In this way, the paper summarizes the proposal from the international reference (USA) stating, among other measures, the definition of new Flexible and Diverse Response Strategies, called FLEX, supported by new mobile equipment to provide an enhancement on the safety of nuclear installations, providing an additional layer of defense in depth. These improvements include the definition of new emergency centers designed to face these ?beyond design basis? scenarios. The application carried out by the Spanish nuclear industry of some of the major improvements related to the Emergency Preparedness and Response, conducted as part of a wider process of enhancing nuclear safety developed in Spain based on the lessons learned from the accident to the nuclear power Fukushima-Daiichi, is summarized in this paper.