Risk Plus Some Attributes (R + SA): A New Risk-Informed Method for Prioritizing Inspection Activities During New Fuel Facility Construction

Risk plus Some Attributes (R + SA) is a method that risk informs the prioritization of inspection activities related to new fuel cycle facility construction. The method uses information available in the Integrated Safety Analysis (ISA) summary to compute the risk-informed importance score of each item relied on for safety (IROFS) referenced in the ISA summary. The approach is based on approximating the risk for each accident sequence and then apportioning that risk to IROFSs associated with that sequence. Once the IROFS risk-informed importance score is computed, the importance score can be adjusted to account for other factors besides the risk. These other factors capture attributes of the IROFSs that affect the prioritization they should receive for inspection. An example of an attribute is the complexity of the IROFSs; complex as opposed to simple IROFSs warrant a higher inspection priority. This paper provides a description of the theoretical and mathematical framework of the R + SA methodology.