Japanese developments in the ultrasonic examination of pressure vessels

Abstract In Japan, nuclear power plant has grown to such an extent that it now provides a fundamental part of total power generation. In consequence, the assurance of structural integrity is increasingly important. The activities of three representative organizations, the Nuclear Power Engineering Test Center (NUPEC), the Japan Pressure Vessel Research Council (JPVRC) and the Japan Power Engineering and Inspection Corporation (JAPEIC) are briefly overviewed in this paper. NUPEC is carrying out the proving test program of in-service inspection. Manual ultrasonic inspection testing was completed in early 1984; factors affecting defect detection and sizing were examined and some of these test results are introduced here. Mechanized automatic inspection testing with devices now in use in recent operating plants is underway. JPVRC is participating in the international round robin test, PISC-II, and in the test between US-PVRC to investigate the reliability of ultrasonic examination, and some test results are introduced. JAPEIC recently expanded its activities into research and development in the area of structural integrity, robotics, mechanized inspection and non-destructive inspection. Some topical items for these programs are overviewed.