Development of in-service inspection rules for sodium-cooled fast reactors using the system based code concept

Takaya, Shigeru  

Effective and efficient ISI is crucial for safety, stable operation, and economic efficiency of nuclear power plants. ISI rules need to be developed rationally by considering features of the reactor type and design of an individual nuclear power plant. SFRs have several desirable features while traditional ISI methods are not as easily performed as in light water reactors. ASME Boiler and Pressure Vessel Code, Section XI, Division 3 had provided ISI rules for liquid-metal cooled reactors. However, several parts of the Code were left as being in the course of preparation, thus it was practically difficult to apply. To address this situation, a new Code Case, N-875, was developed based on the SBC concept in cooperation between ASME and JSME. One of key features of the Case is the logic flow to determine ISI requirements by using reliability targets for components. Recently, a new Section XI, Division 2, Reliability and Integrity Management (RIM), has been developed for advanced nuclear reactors. RIM shares some key concepts with SBC, and the Case has been partially incorporated. JSME has also developed a new fitness-for-service code for SFRs by referring the Case, and it will be published soon.