Effectiveness of the Accident Management Structure Civaux and Blayais Incidents

EDF are testing the effectiveness of their Accident Management Structures through periodic drills sometimes involving the French Safety Authority and their Technical Support. Based on scenarios unknown to the participants, be they on the Utility or the Regulatory side, these drills are aiming at evaluating the readiness of all involved teams, confirming that interfaces are well defined and work smoothly, and verifying that responsibilities have been adequately clarified, thus comforting the utility in the robustness of the adopted approach. Beyond this very optimistic vision of drill objectives, one has to recognize that, due to the complexity of some scenarios which are developed until the core starts to melt or beyond, some deficiencies having the potential for decreasing the effectiveness of the whole organization, or putting additional burden on operators can be detected. Analyzing these technical or organizational flaws and implementing adequate alternatives is also of utmost importance as continuous improvement and assessment of the effectiveness of emergency response is key to demonstrate utility readiness. However, these drills, whatever their interest of, cannot fully address two major attributes of real-life situations which are operator stress when confronted to abnormal events and how to deal with the unexpected. Two events, which happened recently on EDF plants, have allowed getting some insights on these issues and have provided very valuable input for further improvements. Though not entirely within the scope of this meeting, as core-melt was never contemplated during these events, they have provided very valuable input on how all parts of the organization operate in case of real events. The incidents which happened in Civaux and Blayais respectively gave very valuable information on personnel behavior in case of emergency. In both cases, though the situation was unconventional, operators and crisis teams behave very well. They also allowed to highlight some very important points which cannot be adequately assessed during drills: - need to be prepared for the unanticipated; - capacity of organization of the personnel in case of unanticipated situation; - personnel reaction under psychological stress. The Blayais incident showed that this increased burden can be adequately handled by operators; - need to better define responsibilities of Resource Headquarters and assess their performance in further drills; - need to prevent overburden of the site headquarters due to trivial logistics problems - the need to clarify the decision making process in case of divergent opinions; - need to improve the alert system to anticipate, reinforce technical assistance, prepare appropriate resources (human, specific equipment); - reliability of the information transfer system even under very adverse meteorological conditions; - at last, need for adequate sharing of information, to have a common basis for assessing the situation: otherwise, precious time is lost for finding adequate information, and this degrades the capability for making the right decisions. This could become crucial for very degraded situations. At the time being, it is fortunately difficult to decide whether all conclusions could apply to real Severe Accident situations. They nevertheless represent valuable inputs for analyzing the effectiveness of at least part of the SAM organization. (authors)