Application of an ultrasonic data recording and processing system to reactor pressure vessel examination

Abstract Pre-service and periodic in-service nondestructive examinations of nuclear reactor pressure vessels in the USA are mandated by law and are performed in accordance with Section XI of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code and Nuclear Regulatory Commission (NRC) requirements. Although acceptable to Code and regulatory requirements, conventional examination procedures and techniques may not meet utility needs, such as providing an adequate technical basis for plant license extension arguments and responding to concerns for nuclear plant safety. A multichannel Ultrasonic Data Recording and Processing System (UDRPS) was developed to address these concerns and was applied to the inspection of reactor pressure vessels in parallel with the Code-required inspection. The inspection requirements and the UDRPS and Code-required conventional NDE data acquisition and analysis are described. Results from the Calvert Cliffs RPV inspections demonstrated that the UDRPS examination was more sensitive than the Code-required examination, and caused only minimal impact on the Code-required examination and overall inspection schedule.