[en] This report illustrates the practical synthesis of component and system operating experience into reliabilty parameters which are used in probabilistic risk evaluations of gas cooled reactors (GCRs). Component and system reliability parameters have been extracted from over 65 sources of reliability data, which are classified into four groups: (1) gas cooled reactor data, (2) U.S. nuclear and fossil fired data, (3) summarized data, and (4) special reliability analysis estimates. The data from these sources are synthesized into generic failure rate estimates with variability ranges for GCR components and their failure modes. Repair times are also given. Either this synthesized information or the basic reference documents can be used to quantify the component level data inputs to fault trees for the probabilistic evaluation of hypothesized GCR accident sequences. This collection of data supports the DOE-funded Accident Initiation and Progression Analysis