ABSTRACT
Formal PRA requires probability of failure of hazard barriers. For example, the analyst needs
probability of occurrence of failure events (failure of hardware, software, and human) and
adverse conditions modeled in the fault trees and event trees of the PRA to estimate the risk
values. For this purpose this chapter presents a quick review of the elements of performance
assessment of hardware, software, and human elements (e.g., hazard barriers) included in the
PRA, followed by techniques used to gather and evaluate performance data.
