Research on PSA Event Tree of Excessive Radioactive Release Risk for Aqueous Homogeneous Reactor

The design characteristics and safety features of aqueous homogeneous prototype medical isotope research reactor (AHR) are significantly different from those of traditional solid fuel pressurized water reactor, thus the purpose and range of probabilistic safety analysis (PSA) of these two kind of reactors, especially the event tree analysis are also different. Taking the AHR as the research object, the differences between its fuel form, safety barrier and mitigation system and that of the traditional PWR are analyzed. The radioactive release path, containment boundary and the main accident types that should be considered in the internal event PSA for the purpose of analysis of excessive radioactive release are determined, and the universal excessive radioactive release event trees of typical accident categories are constructed. The study can provide guidance for the PSA and further risk quantification of radioactive release risk of this type of reactor.