The Spanish nuclear power generation industry proposed the development of an external Emergency Support Center as one of the measures to strengthen the nuclear safety and Emergency Preparedness and Response, as a consequence of the stress test developed after the Fukushima accident. The CAE project was carried out to define and establish a centralized service composed of intervention equipment and specialized personnel in the framework of an Emergency Support Center shared among all the Spanish nuclear power plants (NPPs). The emergency support service aims to strengthen the NPP emergency capabilities, by integrating with the Emergency Response Organization (ERO) of plants. This service successfully developed preoperational tests at each one of the Spanish NPPs in 2014. With these tests, the development of the different aspects that make up the Emergency Support Center service, at every Spanish NPP, was validated in four stages: (1) CAE mobilization in less than 24 hrs, (2) equipment deployment to its final location in the plant, (3) checking the connections with NPP’s interfaces, and (4) functionality of the equipment. The CAE proved in this way its capability to provide support to the Spanish NPPs, to strengthen their already strong characteristics in EP&R, to face these new extended damage/beyond design basis scenarios.