At present, piping in all nuclear power plants is being subject to inservice inspection (ISI) based on certaindeterministic criteria set by Section XI of the ASME Boiler and Pressure Vessel Code and Final Safety Analysis Report (FSAR). Risk informed Inservice Inspection (RI-ISI) methodology for piping has been developed as an alternative to examination location selection requirement of ASME Section XI. Ulchin nuclear power plant Unit 4 was a pilot plant for application of this methodology in Korea. Ulchin Unit 4 was a partial scope (ASME Class 1, 2) program; therefore, class 1,2 piping systems of Ulchin Unit 4 which are modelled in the plant PSA model have been evaluated using the WOG risk-informed ISI process. The overall results from Ulchin Unit 4 RI-ISI program are discussed in this paper.
展开▼
