This paper focuses on the assessment of the hazards and safety critical areas and equipment related to the integral circulation experiments to be conducted on a molten lead-bismuth-eutectic-alloy facility, the CIRCulation Experiment (CIRCE) facility in Brasimone, Italy, for heavy-liquid-metal technology development. A well-structured failure mode and effect analysis procedure, customary in risk assessment studies, has been adopted to address the task, in order to obtain a complete picture of all the failure modes pertaining to the system, to determine its effects on the system and to classify them according to their severity.
The analysis identified a major hazard relative to the facility in the experimental configuration to be the risk related to the water-lead-bismuth reaction, although with a very low probability, with the potential for steam explosion within the main vessel. This conclusion necessitates additional research on the concerned phenomena, both at the experimental and analytical levels, the results of which should help analysts quantify the risk and designers take the necessary provisions to cope with this risk.
The analysis provides a set of accident initiators, that is, events postulated to initiate an accident situation, together with the total frequency and the list of component failures that could induce it. For any of them a deterministic analysis is suggested in order to verify the plant behavior with respect to accident transients, in terms of the parameters that can have an impact on accident analysis and modeling.