Reliability analysis of the high pressure safety injection system of the NPP Angra II

The realibility of the High Pressure Safety Injection System of Angra 2 is evaluated by means of the fault-tree technique, with the use of the computer program FT-DUAL. The results demonstrate that in case of LOCA the unavailability of the high pressure safety injection function required to mitigate the accident is 3.7E-6. A sensitivity analysis of one isolated train of the high pressure safety injection system was performed for the purpose of identifying which modifications in the conceptual design of the system would increase its reliability in case that were required. The modification introduced led the unavailability of the safety function to 1.7 E-6. (author)