The structural integrity of a reactor pressure vessel (RPV) should be maintained to ensure the safe long-term operation of a nuclear power plant. The assessment methods for RPV integrity are provided for in the codes and standards. Authors have compared the assessment methods for RPV integrity under pressurized thermal shock in domestic and the United States. After reviewing the technical background of the structural integrity assessment method, we clarified the technical issues based on the latest knowledge in this field, and the differences of postulated crack treatments between domestic and the United States based on fracture mechanics analyses.
