Method used to estimate screening-level total failure probability for human error events

This document briefly describes the method used to estimate a screening value for the Total Failure Probability (FT) of human error events that are identified in the fault trees which describe potential liquid UF6 release accidents at two U.S. Gaseous Diffusion Plants. A discussion is provided of the assumptions, limitations, and overall logic of the FT assignment method, and a description is presented of how the method is employed. The description herein, and more completely in Burns and Turner, presents the screening technique used to quantify human errors in the accident analysis portion of the Gaseous Diffusion Plant Safety Analysis Report Upgrade Program. 2 refs., 3 figs