Experience on implementing risk-oriented in-service inspection at NPP in USA

Experience of implementing risk-oriented in-service inspection (RIISI) of pipelines at the US NPP analyzed. RIISI processes according to the methodologies developed by Westinghouse and EPRI are described and compared. The information is addressed concerning practical matters of RIISI implementing at NPP Beaver Valley and Arkansas Nuclear One. Regulatory activity of the US NRC while implementing NRC at the US NPP. It is shown that using RIISI at NPP is aimed at improvement of examination efficiency, decreasing costs and occupational dose loads while inspecting pipelines