Application of probabilistic fracture mechanics to pressure vessels and piping of nuclear power plants. JSME activity

Probabilistic fracture mechanics (PFM) is a key technique in probabilistic safety assessment (PSA) of nuclear power plants. The Japan Society of Mechanical Engineers (JSME) has a research committee on PFM applications to pressure vessels and piping of nuclear power plants (RC111[5]). This paper reviews the activity of the committee. The activity consists of surveys of available data, benchmark calculations and sensitivity calculations. The surveys are on analysis methods, modeling of defects and data on defects, loading and material properties. Surveyed methods and data are used in the succeeding calculations. They are performed on three problems, piping, pressure vessel subject to normal loading and pressure vessel subject to pressurized thermal shock (PTS) loading. The last one is especially important in the safety analysis and will be summarized by another paper of this conference. This paper summarizes the sensitivity calculations of pressure vessels and piping subject to normal loading. Parameters reviewed here are: crack depth distribution, neutron irradiation, uncertainty of fracture toughness, ISI interval, and loading conditions. (author)