Equipment qualification (EQ): Risk scoping study

The objective of the EQ--Risk Scoping Study was to use probabilistic risk assessment (PRA) techniques (1) to assess the impact of electrical equipment environmental qualification or lack thereof on reactor risk and its uncertainties, and (2) to identify any analyses or testing that may be necessary to reduce the risk or its uncertainties stemming from lack of qualification of equipment important to safety. To achieve these objectives, PRA techniques and insights were employed to identify equipment that must function in accident-induced harsh environments and whose failure would be risk significant. Several components from the resultant list were then selected for more detailed analyses. Accident scenarios and environments, which PRAs suggest are risk significant, were determined for each selected equipment operation. For these accident conditions, both equipment qualification research and test experiences were examined to determine whether equipment accident reliability might differ substantially from the reliability values based on normal operation conditions employed in past PRA analyses. Note, accident reliability information is generally unavailable. Where significant differences were considered probable, parametric risk achievement analyses were used to assess the potential risk impact of the equipment failures. In addition, those equipment qualification practices and outstanding research issues that potentially could impact the accident equipment reliability were noted. This information, when combined with perspectives regarding potential equipment risk impact, provided a basis for assessing the potential risk importance of various EQ practices and issues. Additional discussion regarding the study's approach, conclusions, and recommendations is provided. 54 refs., 9 figs., 33 tabs