A risk-informed method for safety analyses of nuclear power generating systems is provided. In an exemplary embodiment, the method includes ordering events by an initiating event frequency, defining an initiating event frequency threshold value, defining acceptance criteria having an adjusted amount of conservatism, where the amount of conservatism is a function of the initiating event frequency, and analyzing an event by a deterministic safety analysis methodology when the event has an event initiating frequency at or above the threshold value, or analyzing an event by a probabilistic risk assessment methodology when the event has an event initiating frequency below the threshold value.