[en] This report describes the first phase of an NRC-sponsored project that identified and evaluated system interaction events that have occurred at commercial nuclear power plants in the United States. The project included: (1) an assessment of nuclear power plant operating experience data sources; (2) the development of search methods and event selection criteria for identifying system interaction events; (3) a review of possible events; and (4) a final evaluation and categorization of the events. The report, organized in two volumes, outlines each of these steps and presents the results of the project. Volume 1 contains an introduction to the project, describes the process by which the project identifed and evaluated the system interaction events, and presents the results and recommendations from that evaluation. Volume 1 also contains appendixes that review the data sources used in identifying events and outlines the information collected for each event. Volume 2 provides a description of each adverse system interaction event and lists the references for the events